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Simplify! Removed Context and Throw monad classes. Removed embedded pool from replica-set. Not backwards-compatible, starts new major version 1.x

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Tony Hannan 2011-07-05 10:37:01 -04:00
parent f7ae5b7235
commit 9f48c26384
12 changed files with 491 additions and 766 deletions
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27
Control/Monad/Context.hs
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@ -1,27 +0,0 @@
{- | This is just like "Control.Monad.Reader.Class" except you can access the context of any Reader in the monad stack instead of just the top one as long as the context types are different. If two or more readers in the stack have the same context type you get the context of the top one. -}
{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances, OverlappingInstances #-}
module Control.Monad.Context where
import Control.Monad.Reader
import Control.Monad.Error
-- | Same as 'MonadReader' but without functional dependency so the same monad can have multiple contexts with different types
class (Monad m) => Context x m where
context :: m x
-- ^ Get the context in the Reader in the monad stack that has @x@ context type. Analogous to 'ask'.
push :: (x -> x) -> m a -> m a
-- ^ Push new context in the Reader in the monad stack that has @x@ context type. Analogous to 'local'
instance (Monad m) => Context x (ReaderT x m) where
context = ask
push = local
instance (Context x m) => Context x (ReaderT r m) where
context = lift context
push f m = ReaderT (push f . runReaderT m)
instance (Context x m, Error e) => Context x (ErrorT e m) where
context = lift context
push f = ErrorT . push f . runErrorT

50
Control/Monad/Throw.hs
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@ -1,50 +0,0 @@
{- | This is just like "Control.Monad.Error.Class" except you can throw/catch the error of any ErrorT in the monad stack instead of just the top one as long as the error types are different. If two or more ErrorTs in the stack have the same error type you get the error of the top one. -}
{-# LANGUAGE MultiParamTypeClasses, FlexibleInstances, OverlappingInstances, UndecidableInstances #-}
module Control.Monad.Throw where
import Prelude hiding (catch)
import Control.Monad.Reader
import Control.Monad.Error
import Control.Arrow ((+++))
import Control.Applicative ((<$>))
-- | Same as 'MonadError' but without functional dependency so the same monad can have multiple errors with different types
class (Monad m) => Throw e m where
throw :: e -> m a
-- ^ Abort action and throw give exception. Analogous to 'throwError'.
catch :: m a -> (e -> m a) -> m a
-- ^ If first action aborts with exception then execute second action. Analogous to 'catchError'
throwLeft :: (Throw e m) => m (Either e a) -> m a
-- ^ Execute action and throw exception if result is Left, otherwise return the Right result
throwLeft = throwLeft' id
throwLeft' :: (Throw e m) => (x -> e) -> m (Either x a) -> m a
-- ^ Execute action and throw transformed exception if result is Left, otherwise return Right result
throwLeft' f = (either (throw . f) return =<<)
onException :: (Throw e m) => m a -> (e -> m b) -> m a
-- ^ If first action throws an exception then run second action then re-throw
onException action releaser = catch action $ \e -> releaser e >> throw e
instance (Error e) => Throw e (Either e) where
throw = throwError
catch = catchError
instance (Error e, Monad m) => Throw e (ErrorT e m) where
throw = throwError
catch = catchError
instance (Error e, Throw e m, Error x) => Throw e (ErrorT x m) where
throw = lift . throw
catch a h = ErrorT $ catch (runErrorT a) (runErrorT . h)
instance (Throw e m) => Throw e (ReaderT x m) where
throw = lift . throw
catch a h = ReaderT $ \x -> catch (runReaderT a x) (flip runReaderT x . h)
mapError :: (Functor m) => (e -> e') -> ErrorT e m a -> ErrorT e' m a
-- ^ Convert error type
mapError f (ErrorT m) = ErrorT $ (f +++ id) <$> m

39
Control/Monad/Util.hs
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@ -1,39 +0,0 @@
-- | Extra monad functions and instances
{-# LANGUAGE FlexibleInstances, UndecidableInstances #-}
module Control.Monad.Util where
import Control.Applicative (Applicative(..), (<$>))
import Control.Arrow ((+++))
import Control.Monad.Reader
import Control.Monad.Error
-- | MonadIO with extra Applicative and Functor superclasses
class (MonadIO m, Applicative m, Functor m) => MonadIO' m
instance (MonadIO m, Applicative m, Functor m) => MonadIO' m
loop :: (Functor m, Monad m) => m (Maybe a) -> m [a]
-- ^ Repeatedy execute action, collecting results, until it returns Nothing
loop act = act >>= maybe (return []) (\a -> (a :) <$> loop act)
untilJust :: (Monad m) => (a -> m (Maybe b)) -> [a] -> m (Maybe b)
-- ^ Apply action to elements one at a time until one returns Just. Return Nothing if all return Nothing.
untilJust _ [] = return Nothing
untilJust f (a:as) = f a >>= maybe (untilJust f as) (return . Just)
untilSuccess :: (MonadError e m, Error e) => (a -> m b) -> [a] -> m b
-- ^ Apply action to elements one at a time until one succeeds. Throw last error if all fail. Throw 'strMsg' error if list is empty.
untilSuccess = untilSuccess' (strMsg "empty untilSuccess")
untilSuccess' :: (MonadError e m) => e -> (a -> m b) -> [a] -> m b
-- ^ Apply action to elements one at a time until one succeeds. Throw last error if all fail. Throw given error if list is empty
untilSuccess' e _ [] = throwError e
untilSuccess' _ f (x : xs) = catchError (f x) (\e -> untilSuccess' e f xs)
mapError :: (Functor m) => (e' -> e) -> ErrorT e' m a -> ErrorT e m a
-- ^ Convert error type thrown
mapError f (ErrorT m) = ErrorT $ (f +++ id) <$> m
whenJust :: (Monad m) => Maybe a -> (a -> m ()) -> m ()
whenJust mVal act = maybe (return ()) act mVal

8
Database/MongoDB.hs
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@ -6,15 +6,15 @@ Simple example below. Use with language extension /OvererloadedStrings/.
> {-# LANGUAGE OverloadedStrings #-}
>
> import Database.MongoDB
> import Data.CompactString () -- Show and IsString instances of UString
> import Control.Monad.Trans (liftIO)
>
> main = do
> pool <- newConnPool 1 (host "127.0.0.1")
> e <- access safe Master pool run
> pipe <- runIOE $ connect (host "127.0.0.1")
> e <- access pipe safe Master "baseball" run
> close pipe
> print e
>
> run = use (Database "baseball") $ do
> run = do
> clearTeams
> insertTeams
> printDocs "All Teams" =<< allTeams

93
Database/MongoDB/Admin.hs
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@ -38,7 +38,8 @@ import Data.IORef
import qualified Data.Set as S
import System.IO.Unsafe (unsafePerformIO)
import Control.Concurrent (forkIO, threadDelay)
import Database.MongoDB.Internal.Util ((<.>), true1)
import Database.MongoDB.Internal.Util (MonadIO', (<.>), true1)
import Control.Monad.MVar (MonadMVar)
-- * Admin
@ -51,17 +52,17 @@ coptElem Capped = "capped" =: True
coptElem (MaxByteSize n) = "size" =: n
coptElem (MaxItems n) = "max" =: n
createCollection :: (DbAccess m) => [CollectionOption] -> Collection -> m Document
createCollection :: (MonadIO' m) => [CollectionOption] -> Collection -> Action m Document
-- ^ Create collection with given options. You only need to call this to set options, otherwise a collection is created automatically on first use with no options.
createCollection opts col = runCommand $ ["create" =: col] ++ map coptElem opts
renameCollection :: (DbAccess m) => Collection -> Collection -> m Document
renameCollection :: (MonadIO' m) => Collection -> Collection -> Action m Document
-- ^ Rename first collection to second collection
renameCollection from to = do
Database db <- thisDatabase
use admin $ runCommand ["renameCollection" =: db <.> from, "to" =: db <.> to, "dropTarget" =: True]
db <- thisDatabase
useDb admin $ runCommand ["renameCollection" =: db <.> from, "to" =: db <.> to, "dropTarget" =: True]
dropCollection :: (DbAccess m) => Collection -> m Bool
dropCollection :: (MonadIO' m) => Collection -> Action m Bool
-- ^ Delete the given collection! Return True if collection existed (and was deleted); return False if collection did not exist (and no action).
dropCollection coll = do
resetIndexCache
@ -70,7 +71,7 @@ dropCollection coll = do
if at "errmsg" r == ("ns not found" :: UString) then return False else
fail $ "dropCollection failed: " ++ show r
validateCollection :: (DbAccess m) => Collection -> m Document
validateCollection :: (MonadIO' m) => Collection -> Action m Document
-- ^ This operation takes a while
validateCollection coll = runCommand ["validate" =: coll]
@ -87,7 +88,7 @@ data Index = Index {
} deriving (Show, Eq)
idxDocument :: Index -> Database -> Document
idxDocument Index{..} (Database db) = [
idxDocument Index{..} db = [
"ns" =: db <.> iColl,
"key" =: iKey,
"name" =: iName,
@ -102,7 +103,7 @@ genName :: Order -> IndexName
genName keys = intercalate "_" (map f keys) where
f (k := v) = k `append` "_" `append` pack (show v)
ensureIndex :: (DbAccess m) => Index -> m ()
ensureIndex :: (MonadIO' m) => Index -> Action m ()
-- ^ Create index if we did not already create one. May be called repeatedly with practically no performance hit, because we remember if we already called this for the same index (although this memory gets wiped out every 15 minutes, in case another client drops the index and we want to create it again).
ensureIndex idx = let k = (iColl idx, iName idx) in do
icache <- fetchIndexCache
@ -111,23 +112,23 @@ ensureIndex idx = let k = (iColl idx, iName idx) in do
writeMode (Safe []) (createIndex idx)
liftIO $ writeIORef icache (S.insert k set)
createIndex :: (DbAccess m) => Index -> m ()
createIndex :: (MonadIO' m) => Index -> Action m ()
-- ^ Create index on the server. This call goes to the server every time.
createIndex idx = insert_ "system.indexes" . idxDocument idx =<< thisDatabase
dropIndex :: (DbAccess m) => Collection -> IndexName -> m Document
dropIndex :: (MonadIO' m) => Collection -> IndexName -> Action m Document
-- ^ Remove the index
dropIndex coll idxName = do
resetIndexCache
runCommand ["deleteIndexes" =: coll, "index" =: idxName]
getIndexes :: (DbAccess m) => Collection -> m [Document]
getIndexes :: (MonadMVar m, Functor m) => Collection -> Action m [Document]
-- ^ Get all indexes on this collection
getIndexes coll = do
Database db <- thisDatabase
db <- thisDatabase
rest =<< find (select ["ns" =: db <.> coll] "system.indexes")
dropIndexes :: (DbAccess m) => Collection -> m Document
dropIndexes :: (MonadIO' m) => Collection -> Action m Document
-- ^ Drop all indexes on this collection
dropIndexes coll = do
resetIndexCache
@ -143,7 +144,7 @@ type IndexCache = IORef (S.Set (Collection, IndexName))
dbIndexCache :: DbIndexCache
-- ^ initialize cache and fork thread that clears it every 15 minutes
dbIndexCache = unsafePerformIO $ do
table <- T.new (==) (T.hashString . unpack . databaseName)
table <- T.new (==) (T.hashString . unpack)
_ <- forkIO . forever $ threadDelay 900000000 >> clearDbIndexCache
return table
{-# NOINLINE dbIndexCache #-}
@ -153,7 +154,7 @@ clearDbIndexCache = do
keys <- map fst <$> T.toList dbIndexCache
mapM_ (T.delete dbIndexCache) keys
fetchIndexCache :: (DbAccess m) => m IndexCache
fetchIndexCache :: (MonadIO m) => Action m IndexCache
-- ^ Get index cache for current database
fetchIndexCache = do
db <- thisDatabase
@ -166,7 +167,7 @@ fetchIndexCache = do
T.insert dbIndexCache db idx
return idx
resetIndexCache :: (DbAccess m) => m ()
resetIndexCache :: (MonadIO m) => Action m ()
-- ^ reset index cache for current database
resetIndexCache = do
icache <- fetchIndexCache
@ -174,74 +175,74 @@ resetIndexCache = do
-- ** User
allUsers :: (DbAccess m) => m [Document]
allUsers :: (MonadMVar m, Functor m) => Action m [Document]
-- ^ Fetch all users of this database
allUsers = map (exclude ["_id"]) <$> (rest =<< find
(select [] "system.users") {sort = ["user" =: (1 :: Int)], project = ["user" =: (1 :: Int), "readOnly" =: (1 :: Int)]})
addUser :: (DbAccess m) => Bool -> Username -> Password -> m ()
addUser :: (MonadIO' m) => Bool -> Username -> Password -> Action m ()
-- ^ Add user with password with read-only access if bool is True or read-write access if bool is False
addUser readOnly user pass = do
mu <- findOne (select ["user" =: user] "system.users")
let usr = merge ["readOnly" =: readOnly, "pwd" =: pwHash user pass] (maybe ["user" =: user] id mu)
save "system.users" usr
removeUser :: (DbAccess m) => Username -> m ()
removeUser :: (MonadIO m) => Username -> Action m ()
removeUser user = delete (select ["user" =: user] "system.users")
-- ** Database
admin :: Database
-- ^ \"admin\" database
admin = Database "admin"
admin = "admin"
cloneDatabase :: (Access m) => Database -> Host -> m Document
cloneDatabase :: (MonadIO' m) => Database -> Host -> Action m Document
-- ^ Copy database from given host to the server I am connected to. Fails and returns @"ok" = 0@ if we don't have permission to read from given server (use copyDatabase in this case).
cloneDatabase db fromHost = use db $ runCommand ["clone" =: showHostPort fromHost]
cloneDatabase db fromHost = useDb db $ runCommand ["clone" =: showHostPort fromHost]
copyDatabase :: (Access m) => Database -> Host -> Maybe (Username, Password) -> Database -> m Document
copyDatabase :: (MonadIO' m) => Database -> Host -> Maybe (Username, Password) -> Database -> Action m Document
-- ^ Copy database from given host to the server I am connected to. If username & password is supplied use them to read from given host.
copyDatabase (Database fromDb) fromHost mup (Database toDb) = do
copyDatabase fromDb fromHost mup toDb = do
let c = ["copydb" =: (1 :: Int), "fromhost" =: showHostPort fromHost, "fromdb" =: fromDb, "todb" =: toDb]
use admin $ case mup of
useDb admin $ case mup of
Nothing -> runCommand c
Just (usr, pss) -> do
n <- at "nonce" <$> runCommand ["copydbgetnonce" =: (1 :: Int), "fromhost" =: showHostPort fromHost]
runCommand $ c ++ ["username" =: usr, "nonce" =: n, "key" =: pwKey n usr pss]
dropDatabase :: (Access m) => Database -> m Document
dropDatabase :: (MonadIO' m) => Database -> Action m Document
-- ^ Delete the given database!
dropDatabase db = use db $ runCommand ["dropDatabase" =: (1 :: Int)]
dropDatabase db = useDb db $ runCommand ["dropDatabase" =: (1 :: Int)]
repairDatabase :: (Access m) => Database -> m Document
repairDatabase :: (MonadIO' m) => Database -> Action m Document
-- ^ Attempt to fix any corrupt records. This operation takes a while.
repairDatabase db = use db $ runCommand ["repairDatabase" =: (1 :: Int)]
repairDatabase db = useDb db $ runCommand ["repairDatabase" =: (1 :: Int)]
-- ** Server
serverBuildInfo :: (Access m) => m Document
serverBuildInfo = use admin $ runCommand ["buildinfo" =: (1 :: Int)]
serverBuildInfo :: (MonadIO' m) => Action m Document
serverBuildInfo = useDb admin $ runCommand ["buildinfo" =: (1 :: Int)]
serverVersion :: (Access m) => m UString
serverVersion :: (MonadIO' m) => Action m UString
serverVersion = at "version" <$> serverBuildInfo
-- * Diagnostics
-- ** Collection
collectionStats :: (DbAccess m) => Collection -> m Document
collectionStats :: (MonadIO' m) => Collection -> Action m Document
collectionStats coll = runCommand ["collstats" =: coll]
dataSize :: (DbAccess m) => Collection -> m Int
dataSize :: (MonadIO' m) => Collection -> Action m Int
dataSize c = at "size" <$> collectionStats c
storageSize :: (DbAccess m) => Collection -> m Int
storageSize :: (MonadIO' m) => Collection -> Action m Int
storageSize c = at "storageSize" <$> collectionStats c
totalIndexSize :: (DbAccess m) => Collection -> m Int
totalIndexSize :: (MonadIO' m) => Collection -> Action m Int
totalIndexSize c = at "totalIndexSize" <$> collectionStats c
totalSize :: (DbAccess m) => Collection -> m Int
totalSize :: (MonadMVar m, MonadIO' m) => Collection -> Action m Int
totalSize coll = do
x <- storageSize coll
xs <- mapM isize =<< getIndexes coll
@ -253,35 +254,35 @@ totalSize coll = do
data ProfilingLevel = Off | Slow | All deriving (Show, Enum, Eq)
getProfilingLevel :: (DbAccess m) => m ProfilingLevel
getProfilingLevel :: (MonadIO' m) => Action m ProfilingLevel
getProfilingLevel = toEnum . at "was" <$> runCommand ["profile" =: (-1 :: Int)]
type MilliSec = Int
setProfilingLevel :: (DbAccess m) => ProfilingLevel -> Maybe MilliSec -> m ()
setProfilingLevel :: (MonadIO' m) => ProfilingLevel -> Maybe MilliSec -> Action m ()
setProfilingLevel p mSlowMs =
runCommand (["profile" =: fromEnum p] ++ ("slowms" =? mSlowMs)) >> return ()
-- ** Database
dbStats :: (DbAccess m) => m Document
dbStats :: (MonadIO' m) => Action m Document
dbStats = runCommand ["dbstats" =: (1 :: Int)]
currentOp :: (DbAccess m) => m (Maybe Document)
currentOp :: (MonadIO m) => Action m (Maybe Document)
-- ^ See currently running operation on the database, if any
currentOp = findOne (select [] "$cmd.sys.inprog")
type OpNum = Int
killOp :: (DbAccess m) => OpNum -> m (Maybe Document)
killOp :: (MonadIO m) => OpNum -> Action m (Maybe Document)
killOp op = findOne (select ["op" =: op] "$cmd.sys.killop")
-- ** Server
serverStatus :: (Access m) => m Document
serverStatus = use admin $ runCommand ["serverStatus" =: (1 :: Int)]
serverStatus :: (MonadIO' m) => Action m Document
serverStatus = useDb admin $ runCommand ["serverStatus" =: (1 :: Int)]
{- Authors: Tony Hannan <tony@10gen.com>
Copyright 2010 10gen Inc.
Copyright 2011 10gen Inc.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0. Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -}

281
Database/MongoDB/Connection.hs
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@ -1,61 +1,42 @@
{- | A pool of TCP connections to a single server or a replica set of servers. -}
-- | Connect to a single server or a replica set of servers
{-# LANGUAGE CPP, OverloadedStrings, ScopedTypeVariables, RecordWildCards, NamedFieldPuns, MultiParamTypeClasses, FlexibleContexts, TypeFamilies, DoRec, RankNTypes, FlexibleInstances #-}
{-# LANGUAGE CPP, OverloadedStrings, ScopedTypeVariables, TupleSections #-}
module Database.MongoDB.Connection (
-- * Pipe
Pipe,
IOE, runIOE,
-- * Connection
Pipe, close, isClosed,
-- * Host
Host(..), PortID(..), host, showHostPort, readHostPort, readHostPortM,
-- * ReplicaSet
ReplicaSet(..), Name,
-- * MasterOrSlaveOk
MasterOrSlaveOk(..),
-- * Connection Pool
Service(..),
connHost, replicaSet
Host(..), PortID(..), host, showHostPort, readHostPort, readHostPortM, connect,
-- * Replica Set
ReplicaSetName, openReplicaSet, ReplicaSet, primary, secondaryOk
) where
import Prelude hiding (lookup)
import Database.MongoDB.Internal.Protocol as X
import qualified Network.Abstract as C
import Network.Abstract (IOE, NetworkIO, ANetwork)
import Data.Bson ((=:), at, lookup, UString)
import Control.Pipeline as P
import Control.Applicative ((<$>))
import Control.Exception (assert)
import Control.Monad.Error
import Control.Monad.MVar
import Network (HostName, PortID(..))
import Data.Bson (Document, look)
import Database.MongoDB.Internal.Protocol (Pipe, writeMessage, readMessage)
import System.IO.Pipeline (IOE, IOStream(..), newPipeline, close, isClosed)
import System.IO.Error as E (try)
import System.IO (hClose)
import Network (HostName, PortID(..), connectTo)
import Text.ParserCombinators.Parsec as T (parse, many1, letter, digit, char, eof, spaces, try, (<|>))
import Control.Monad.Identity
import Control.Monad.Util (MonadIO', untilSuccess)
import Database.MongoDB.Internal.Util () -- PortID instances
import Var.Pool
import System.Random (newStdGen, randomRs)
import Data.List (delete, find, nub)
import System.IO.Unsafe (unsafePerformIO)
import Control.Monad.Identity (runIdentity)
import Control.Monad.Error (ErrorT(..), lift, throwError)
import Control.Monad.MVar
import Control.Monad (forM_)
import Control.Applicative ((<$>))
import Data.UString (UString, unpack)
import Data.Bson as D (Document, lookup, at, (=:))
import Database.MongoDB.Query (access, safe, MasterOrSlaveOk(SlaveOk), Failure(ConnectionFailure), Command, runCommand)
import Database.MongoDB.Internal.Util (untilSuccess, liftIOE, runIOE, updateAssocs, shuffle)
import Data.List as L (lookup, intersect, partition, (\\))
type Name = UString
adminCommand :: Document -> Request
-- ^ Convert command to request
adminCommand cmd = Query{..} where
qOptions = [SlaveOK]
qFullCollection = "admin.$cmd"
qSkip = 0
qBatchSize = -1
qSelector = cmd
qProjector = []
commandReply :: String -> Reply -> Document
-- ^ Extract first document from reply. Error if query error, using given string as prefix error message.
commandReply title Reply{..} = if elem QueryError rResponseFlags
then error $ title ++ ": " ++ at "$err" (head rDocuments)
else if null rDocuments
then error ("empty reply to: " ++ title)
else head rDocuments
adminCommand :: Command -> Pipe -> IOE Document
-- ^ Run command against admin database on server connected to pipe. Fail if connection fails.
adminCommand cmd pipe =
liftIOE failureToIOError . ErrorT $ access pipe safe SlaveOk "admin" $ runCommand cmd
where
failureToIOError (ConnectionFailure e) = e
failureToIOError e = userError $ show e
-- * Host
@ -97,152 +78,86 @@ readHostPort :: String -> Host
-- ^ Read string \"hostname:port\" as @Host hostname port@ or \"hostname\" as @host hostname@ (default port). Error if string does not match either syntax.
readHostPort = runIdentity . readHostPortM
connect :: Host -> IOE Pipe
-- ^ Connect to Host returning pipelined TCP connection. Throw IOError if problem connecting.
connect (Host hostname port) = do
handle <- ErrorT . E.try $ connectTo hostname port
lift $ newPipeline $ IOStream (writeMessage handle) (readMessage handle) (hClose handle)
-- * Replica Set
data ReplicaSet = ReplicaSet {setName :: Name, seedHosts :: [Host]} deriving (Show)
-- ^ Replica set of hosts identified by set name. At least one of the seed hosts must be an active member of the set. However, this list is not used to identify the set, just the set name.
type ReplicaSetName = UString
instance Eq ReplicaSet where ReplicaSet x _ == ReplicaSet y _ = x == y
-- | Maintains a connection (created on demand) to each server in the named replica set
data ReplicaSet = ReplicaSet ReplicaSetName (MVar [(Host, Maybe Pipe)])
-- ** Replica Info
openReplicaSet :: (ReplicaSetName, [Host]) -> IOE ReplicaSet
-- ^ Open connections (on demand) to servers in replica set. Supplied hosts is seed list. At least one of them must be a live member of the named replica set, otherwise fail.
openReplicaSet (rsName, seedList) = do
rs <- ReplicaSet rsName <$> newMVar (map (, Nothing) seedList)
_ <- updateMembers rs
return rs
getReplicaInfo :: ConnPool Host -> IOE ReplicaInfo
-- ^ Get replica info of the connected host. Throw IOError if connection fails or host is not part of a replica set (no /hosts/ and /primary/ field).
getReplicaInfo conn = do
pipe <- getHostPipe conn
promise <- X.call pipe [] (adminCommand ["ismaster" =: (1 :: Int)])
info <- commandReply "ismaster" <$> promise
_ <- look "hosts" info
_ <- look "ismaster" info
return $ ReplicaInfo (connHost conn) info
primary :: ReplicaSet -> IOE Pipe
-- ^ Return connection to current primary of replica set
primary rs@(ReplicaSet rsName _) = do
mHost <- statedPrimary <$> updateMembers rs
case mHost of
Just host' -> connection rs Nothing host'
Nothing -> throwError $ userError $ "replica set " ++ unpack rsName ++ " has no primary"
data ReplicaInfo = ReplicaInfo {_infoHost :: Host, infoDoc :: Document} deriving (Show)
-- ^ Configuration info of a host in a replica set (result of /ismaster/ command). Contains all the hosts in the replica set plus its role in that set (master, slave, or arbiter)
secondaryOk :: ReplicaSet -> IOE Pipe
-- ^ Return connection to a random member (secondary or primary)
secondaryOk rs = do
info <- updateMembers rs
hosts <- lift $ shuffle (possibleHosts info)
untilSuccess (connection rs Nothing) hosts
{- isPrimary :: ReplicaInfo -> Bool
-- ^ Is the replica described by this info a master/primary (not slave or arbiter)?
isPrimary = true1 "ismaster"
type ReplicaInfo = (Host, Document)
-- ^ Result of isMaster command on host in replica set. Returned fields are: setName, ismaster, secondary, hosts, [primary]. primary only present when ismaster = false
isSecondary :: ReplicaInfo -> Bool
-- ^ Is the replica described by this info a slave/secondary (not master or arbiter)
isSecondary = true1 "secondary" -}
statedPrimary :: ReplicaInfo -> Maybe Host
-- ^ Primary of replica set or Nothing if there isn't one
statedPrimary (host', info) = if (at "ismaster" info) then Just host' else readHostPort <$> D.lookup "primary" info
primary :: ReplicaInfo -> Maybe Host
-- ^ Read primary from configuration info. During failover or minor network partition there is no primary (Nothing).
primary (ReplicaInfo host' info) = if at "ismaster" info then Just host' else readHostPort <$> lookup "primary" info
possibleHosts :: ReplicaInfo -> [Host]
-- ^ Non-arbiter, non-hidden members of replica set
possibleHosts (_, info) = map readHostPort $ at "hosts" info
replicas :: ReplicaInfo -> [Host]
-- ^ All replicas in set according to this replica configuration info with primary at head, if there is one.
replicas info = maybe members (\m -> m : delete m members) master where
members = map readHostPort $ at "hosts" (infoDoc info)
master = primary info
-- * MasterOrSlaveOk
data MasterOrSlaveOk =
Master -- ^ connect to master only
| SlaveOk -- ^ connect to a slave, or master if no slave available
deriving (Show, Eq)
{- isMS :: MasterOrSlaveOk -> ReplicaInfo -> Bool
-- ^ Does the host (as described by its replica-info) match the master/slave type
isMS Master i = isPrimary i
isMS SlaveOk i = isSecondary i || isPrimary i -}
-- * Connection Pool
type Pool' = Pool IOError
-- | A Service is a single server ('Host') or a replica set of servers ('ReplicaSet')
class Service t where
data ConnPool t
-- ^ A pool of TCP connections ('Pipe's) to a host or a replica set of hosts
newConnPool :: (NetworkIO m) => Int -> t -> m (ConnPool t)
-- ^ Create a ConnectionPool to a host or a replica set of hosts. Actual TCP connection is not attempted until 'getPipe' request, so no IOError can be raised here. Up to N TCP connections will be established to each host.
getPipe :: MasterOrSlaveOk -> ConnPool t -> IOE Pipe
-- ^ Return a TCP connection (Pipe) to the master or a slave in the server. Master must connect to the master, SlaveOk may connect to a slave or master. To spread the load, SlaveOk requests are distributed amongst all hosts in the server. Throw IOError if failed to connect to right type of host (Master/SlaveOk).
killPipes :: ConnPool t -> IO ()
-- ^ Kill all open pipes (TCP Connections). Will cause any users of them to fail. Alternatively you can let them die on their own when they get garbage collected.
-- ** ConnectionPool Host
instance Service Host where
data ConnPool Host = HostConnPool {connHost :: Host, connPool :: Pool' Pipe}
-- ^ A pool of TCP connections ('Pipe's) to a server, handed out in round-robin style.
newConnPool poolSize' host' = liftIO . newHostConnPool poolSize' host' =<< C.network
-- ^ Create a connection pool to server (host or replica set)
getPipe _ = getHostPipe
-- ^ Return a TCP connection (Pipe). If SlaveOk, connect to a slave if available. Round-robin if multiple slaves are available. Throw IOError if failed to connect.
killPipes (HostConnPool _ pool) = killAll pool
instance Show (ConnPool Host) where
show HostConnPool{connHost} = "ConnPool " ++ show connHost
newHostConnPool :: Int -> Host -> ANetwork -> IO (ConnPool Host)
-- ^ Create a pool of N 'Pipe's (TCP connections) to server. 'getHostPipe' will return one of those pipes, round-robin style.
newHostConnPool poolSize' host' net = HostConnPool host' <$> newPool Factory{..} poolSize' where
newResource = tcpConnect net host'
killResource = P.close
isExpired = P.isClosed
getHostPipe :: ConnPool Host -> IOE Pipe
-- ^ Return next pipe (TCP connection) in connection pool, round-robin style. Throw IOError if can't connect to host.
getHostPipe (HostConnPool _ pool) = aResource pool
tcpConnect :: ANetwork -> Host -> IOE Pipe
-- ^ Create a TCP connection (Pipe) to the given host. Throw IOError if can't connect.
tcpConnect net (Host hostname port) = newPipeline =<< C.connect net (C.Server hostname port)
-- ** Connection ReplicaSet
instance Service ReplicaSet where
data ConnPool ReplicaSet = ReplicaSetConnPool {
network :: ANetwork,
repsetName :: Name,
currentMembers :: MVar [ConnPool Host] } -- master at head after a refresh
newConnPool poolSize' repset = liftIO . newSetConnPool poolSize' repset =<< C.network
getPipe = getSetPipe
killPipes ReplicaSetConnPool{..} = withMVar currentMembers (mapM_ killPipes)
instance Show (ConnPool ReplicaSet) where
show r = "ConnPool " ++ show (unsafePerformIO $ replicaSet r)
replicaSet :: (MonadIO' m) => ConnPool ReplicaSet -> m ReplicaSet
-- ^ Return replicas set name with current members as seed list
replicaSet ReplicaSetConnPool{..} = ReplicaSet repsetName . map connHost <$> readMVar currentMembers
newSetConnPool :: Int -> ReplicaSet -> ANetwork -> IO (ConnPool ReplicaSet)
-- ^ Create a connection pool to each member of the replica set.
newSetConnPool poolSize' repset net = assert (not . null $ seedHosts repset) $ do
currentMembers <- newMVar =<< mapM (\h -> newHostConnPool poolSize' h net) (seedHosts repset)
return $ ReplicaSetConnPool net (setName repset) currentMembers
getMembers :: Name -> [ConnPool Host] -> IOE [Host]
-- ^ Get members of replica set, master first. Query supplied connections until config found.
-- TODO: Verify config for request replica set name and not some other replica set. "ismaster" reply includes "setName" in result.
getMembers _repsetName connections = replicas <$> untilSuccess getReplicaInfo connections
refreshMembers :: ANetwork -> Name -> [ConnPool Host] -> IOE [ConnPool Host]
-- ^ Update current members with master at head. Reuse unchanged members. Throw IOError if can't connect to any and fetch config. Dropped connections are not closed in case they still have users; they will be closed when garbage collected.
refreshMembers net repsetName connections = do
n <- liftIO . poolSize . connPool $ head connections
mapM (liftIO . connection n) =<< getMembers repsetName connections
updateMembers :: ReplicaSet -> IOE ReplicaInfo
-- ^ Fetch replica info from any server and update members accordingly
updateMembers rs@(ReplicaSet _ vMembers) = do
(host', info) <- untilSuccess (fetchReplicaInfo rs) =<< readMVar vMembers
modifyMVar vMembers $ \members -> do
let ((members', old), new) = intersection (map readHostPort $ at "hosts" info) members
lift $ forM_ old $ \(_, mPipe) -> maybe (return ()) close mPipe
return (members' ++ map (, Nothing) new, (host', info))
where
connection n host' = maybe (newHostConnPool n host' net) return mc where
mc = find ((host' ==) . connHost) connections
intersection :: (Eq k) => [k] -> [(k, v)] -> (([(k, v)], [(k, v)]), [k])
intersection keys assocs = (partition (flip elem inKeys . fst) assocs, keys \\ inKeys) where
assocKeys = map fst assocs
inKeys = intersect keys assocKeys
getSetPipe :: MasterOrSlaveOk -> ConnPool ReplicaSet -> IOE Pipe
-- ^ Return a pipe to primary or a random secondary in replica set. Use primary for SlaveOk if and only if no secondaries. Note, refreshes members each time (makes ismaster call to primary).
getSetPipe mos ReplicaSetConnPool{..} = modifyMVar currentMembers $ \conns -> do
connections <- refreshMembers network repsetName conns -- master at head after refresh
pipe <- case mos of
Master -> getHostPipe (head connections)
SlaveOk -> do
let n = length connections - 1
is <- take (max 1 n) . nub . randomRs (min 1 n, n) <$> liftIO newStdGen
untilSuccess (getHostPipe . (connections !!)) is
return (connections, pipe)
fetchReplicaInfo :: ReplicaSet -> (Host, Maybe Pipe) -> IOE ReplicaInfo
-- Connect to host and fetch replica info from host creating new connection if missing or closed (previously failed). Fail if not member of named replica set.
fetchReplicaInfo rs@(ReplicaSet rsName _) (host', mPipe) = do
pipe <- connection rs mPipe host'
info <- adminCommand ["isMaster" =: (1 :: Int)] pipe
case D.lookup "setName" info of
Nothing -> throwError $ userError $ show host' ++ " not a member of any replica set, including " ++ unpack rsName ++ ": " ++ show info
Just setName | setName /= rsName -> throwError $ userError $ show host' ++ " not a member of replica set " ++ unpack rsName ++ ": " ++ show info
Just _ -> return (host', info)
connection :: ReplicaSet -> Maybe Pipe -> Host -> IOE Pipe
-- ^ Return new or existing connection to member of replica set. If pipe is already known for host it is given, but we still test if it is open.
connection (ReplicaSet _ vMembers) mPipe host' =
maybe conn (\p -> lift (isClosed p) >>= \bad -> if bad then conn else return p) mPipe
where
conn = modifyMVar vMembers $ \members -> do
let new = connect host' >>= \pipe -> return (updateAssocs host' (Just pipe) members, pipe)
case L.lookup host' members of
Just (Just pipe) -> lift (isClosed pipe) >>= \bad -> if bad then new else return (members, pipe)
_ -> new
{- Authors: Tony Hannan <tony@10gen.com>

74
Database/MongoDB/Internal/Protocol.hs
View file

@ -5,10 +5,12 @@ This module is not intended for direct use. Use the high-level interface at "Dat
{-# LANGUAGE RecordWildCards, StandaloneDeriving, OverloadedStrings, FlexibleContexts, TupleSections, TypeSynonymInstances, MultiParamTypeClasses, FlexibleInstances, UndecidableInstances #-}
module Database.MongoDB.Internal.Protocol (
MasterOrSlaveOk(..),
FullCollection,
-- * Pipe
Pipe, send, call,
-- * Message
FullCollection,
writeMessage, readMessage,
-- ** Notice
Notice(..), UpdateOption(..), DeleteOption(..), CursorId,
-- ** Request
@ -23,7 +25,9 @@ import Prelude as X
import Control.Applicative ((<$>))
import Control.Arrow ((***))
import Data.ByteString.Lazy as B (length, hPut)
import qualified Control.Pipeline as P
import System.IO.Pipeline (IOE, Pipeline)
import qualified System.IO.Pipeline as P (send, call)
import System.IO (Handle)
import Data.Bson (Document, UString)
import Data.Bson.Binary
import Data.Binary.Put
@ -34,22 +38,21 @@ import Data.IORef
import System.IO.Unsafe (unsafePerformIO)
import qualified Crypto.Hash.MD5 as MD5 (hash)
import Data.UString as U (pack, append, toByteString)
import qualified Data.ByteString as BS (ByteString, unpack)
import Data.Word (Word8)
import System.IO.Error as E (try)
import Control.Monad.Error
import Control.Monad.Util (whenJust)
import Network.Abstract hiding (send)
import System.IO (hFlush)
import Database.MongoDB.Internal.Util (hGetN, bitOr)
import Numeric (showHex)
import Database.MongoDB.Internal.Util (whenJust, hGetN, bitOr, byteStringHex)
-- Network -> Server -> (Sink, Source)
-- (Sink, Source) -> Pipeline
-- * MasterOrSlaveOk
data MasterOrSlaveOk =
Master -- ^ connect to master only
| SlaveOk -- ^ connect to a slave, or master if no slave available
deriving (Show, Eq)
-- * Pipe
type Pipe = P.Pipeline Message Response
type Pipe = Pipeline Response Message
-- ^ Thread-safe TCP connection with pipelined requests
send :: Pipe -> [Notice] -> IOE ()
@ -69,32 +72,34 @@ call pipe notices request = do
-- * Message
type Message = ([Notice], Maybe (Request, RequestId))
-- ^ A write notice(s), write notice(s) with getLastError request, or just query request.
-- ^ A write notice(s) with getLastError request, or just query request.
-- Note, that requestId will be out of order because request ids will be generated for notices after the request id supplied was generated. This is ok because the mongo server does not care about order just uniqueness.
instance WriteMessage Message where
writeMessage handle (notices, mRequest) = ErrorT . E.try $ do
forM_ notices $ \n -> writeReq . (Left n,) =<< genRequestId
whenJust mRequest $ writeReq . (Right *** id)
hFlush handle
writeMessage :: Handle -> Message -> IOE ()
-- ^ Write message to socket
writeMessage handle (notices, mRequest) = ErrorT . E.try $ do
forM_ notices $ \n -> writeReq . (Left n,) =<< genRequestId
whenJust mRequest $ writeReq . (Right *** id)
hFlush handle
where
writeReq (e, requestId) = do
hPut handle lenBytes
hPut handle bytes
where
writeReq (e, requestId) = do
hPut handle lenBytes
hPut handle bytes
where
bytes = runPut $ (either putNotice putRequest e) requestId
lenBytes = encodeSize . toEnum . fromEnum $ B.length bytes
encodeSize = runPut . putInt32 . (+ 4)
bytes = runPut $ (either putNotice putRequest e) requestId
lenBytes = encodeSize . toEnum . fromEnum $ B.length bytes
encodeSize = runPut . putInt32 . (+ 4)
type Response = (ResponseTo, Reply)
-- ^ Message received from a Mongo server in response to a Request
instance ReadMessage Response where
readMessage handle = ErrorT . E.try $ readResp where
readResp = do
len <- fromEnum . decodeSize <$> hGetN handle 4
runGet getReply <$> hGetN handle len
decodeSize = subtract 4 . runGet getInt32
readMessage :: Handle -> IOE Response
-- ^ read response from socket
readMessage handle = ErrorT $ E.try readResp where
readResp = do
len <- fromEnum . decodeSize <$> hGetN handle 4
runGet getReply <$> hGetN handle len
decodeSize = subtract 4 . runGet getInt32
type FullCollection = UString
-- ^ Database name and collection name with period (.) in between. Eg. \"myDb.myCollection\"
@ -314,10 +319,7 @@ pwHash u p = pack . byteStringHex . MD5.hash . toByteString $ u `U.append` ":mon
pwKey :: Nonce -> Username -> Password -> UString
pwKey n u p = pack . byteStringHex . MD5.hash . toByteString . U.append n . U.append u $ pwHash u p
byteStringHex :: BS.ByteString -> String
-- ^ Hexadecimal string representation of a byte string. Each byte yields two hexadecimal characters.
byteStringHex = concatMap byteHex . BS.unpack
byteHex :: Word8 -> String
-- ^ Two char hexadecimal representation of byte
byteHex b = (if b < 16 then ('0' :) else id) (showHex b "")
{- Authors: Tony Hannan <tony@10gen.com>
Copyright 2011 10gen Inc.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0. Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -}

60
Database/MongoDB/Internal/Util.hs
View file

@ -1,11 +1,10 @@
-- | Miscellaneous general functions and Show, Eq, and Ord instances for PortID
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE FlexibleInstances, UndecidableInstances, StandaloneDeriving #-}
module Database.MongoDB.Internal.Util where
import Prelude hiding (length)
import Control.Applicative ((<$>))
import Control.Applicative (Applicative(..), (<$>))
import Network (PortID(..))
import Data.UString as U (cons, append)
import Data.Bits (Bits, (.|.))
@ -14,11 +13,56 @@ import Data.ByteString.Lazy as S (ByteString, length, append, hGet)
import System.IO (Handle)
import System.IO.Error (mkIOError, eofErrorType)
import Control.Exception (assert)
import Control.Monad.Error
import Control.Arrow (left)
import qualified Data.ByteString as BS (ByteString, unpack)
import Data.Word (Word8)
import Numeric (showHex)
import System.Random.Shuffle (shuffle')
import System.Random (newStdGen)
import Data.List as L (length)
deriving instance Show PortID
deriving instance Eq PortID
deriving instance Ord PortID
-- | MonadIO with extra Applicative and Functor superclasses
class (MonadIO m, Applicative m, Functor m) => MonadIO' m
instance (MonadIO m, Applicative m, Functor m) => MonadIO' m
shuffle :: [a] -> IO [a]
-- ^ Randomly shuffle items in list
shuffle list = shuffle' list (L.length list) <$> newStdGen
loop :: (Functor m, Monad m) => m (Maybe a) -> m [a]
-- ^ Repeatedy execute action, collecting results, until it returns Nothing
loop act = act >>= maybe (return []) (\a -> (a :) <$> loop act)
untilSuccess :: (MonadError e m, Error e) => (a -> m b) -> [a] -> m b
-- ^ Apply action to elements one at a time until one succeeds. Throw last error if all fail. Throw 'strMsg' error if list is empty.
untilSuccess = untilSuccess' (strMsg "empty untilSuccess")
untilSuccess' :: (MonadError e m) => e -> (a -> m b) -> [a] -> m b
-- ^ Apply action to elements one at a time until one succeeds. Throw last error if all fail. Throw given error if list is empty
untilSuccess' e _ [] = throwError e
untilSuccess' _ f (x : xs) = catchError (f x) (\e -> untilSuccess' e f xs)
whenJust :: (Monad m) => Maybe a -> (a -> m ()) -> m ()
whenJust mVal act = maybe (return ()) act mVal
liftIOE :: (MonadIO m) => (e -> e') -> ErrorT e IO a -> ErrorT e' m a
-- ^ lift IOE monad to ErrorT monad over some MonadIO m
liftIOE f = ErrorT . liftIO . fmap (left f) . runErrorT
runIOE :: ErrorT IOError IO a -> IO a
-- ^ Run action while catching explicit error and rethrowing in IO monad
runIOE (ErrorT action) = action >>= either ioError return
updateAssocs :: (Eq k) => k -> v -> [(k, v)] -> [(k, v)]
-- ^ Change or insert value of key in association list
updateAssocs key valu assocs = case back of [] -> (key, valu) : front; _ : back' -> front ++ (key, valu) : back'
where (front, back) = break ((key ==) . fst) assocs
bitOr :: (Bits a) => [a] -> a
-- ^ bit-or all numbers together
bitOr = foldl (.|.) 0
@ -40,7 +84,15 @@ hGetN :: Handle -> Int -> IO ByteString
-- ^ Read N bytes from hande, blocking until all N bytes are read. If EOF is reached before N bytes then raise EOF exception.
hGetN h n = assert (n >= 0) $ do
bytes <- hGet h n
let x = fromEnum $ length bytes
let x = fromEnum $ S.length bytes
if x >= n then return bytes
else if x == 0 then ioError (mkIOError eofErrorType "hGetN" (Just h) Nothing)
else S.append bytes <$> hGetN h (n - x)
byteStringHex :: BS.ByteString -> String
-- ^ Hexadecimal string representation of a byte string. Each byte yields two hexadecimal characters.
byteStringHex = concatMap byteHex . BS.unpack
byteHex :: Word8 -> String
-- ^ Two char hexadecimal representation of byte
byteHex b = (if b < 16 then ('0' :) else id) (showHex b "")

471
Database/MongoDB/Query.hs
View file

@ -3,19 +3,18 @@
{-# LANGUAGE OverloadedStrings, RecordWildCards, NamedFieldPuns, TupleSections, FlexibleContexts, FlexibleInstances, UndecidableInstances, MultiParamTypeClasses, GeneralizedNewtypeDeriving, StandaloneDeriving, TypeSynonymInstances, RankNTypes #-}
module Database.MongoDB.Query (
-- * Access
access, Access, Action, runAction, Failure(..),
-- * Monad
Action, Failure(..), access,
-- * Database
Database(..), allDatabases, DbAccess, use, thisDatabase,
Database, allDatabases, useDb, thisDatabase,
-- ** Authentication
P.Username, P.Password, auth,
Username, Password, auth,
-- * Collection
Collection, allCollections,
-- ** Selection
Selection(..), Selector, whereJS,
Select(select),
-- * Write
-- ** WriteMode
WriteMode(..), safe, GetLastError, writeMode,
-- ** Insert
insert, insert_, insertMany, insertMany_,
@ -24,7 +23,7 @@ module Database.MongoDB.Query (
-- ** Delete
delete, deleteOne,
-- * Read
readMode,
MasterOrSlaveOk(..), readMode,
-- ** Query
Query(..), QueryOption(..), Projector, Limit, Order, BatchSize,
explain, find, findOne, count, distinct,
@ -40,109 +39,83 @@ module Database.MongoDB.Query (
) where
import Prelude as X hiding (lookup)
import Control.Applicative ((<$>), Applicative(..))
import Control.Arrow (first)
import Control.Monad.Context
import Control.Monad.Reader
import Control.Monad.Error
import Control.Monad.Throw
import Data.UString as U (UString, dropWhile, any, tail)
import Data.Bson (Document, at, lookup, look, Field(..), (=:), (=?), Label, Value(String,Doc), Javascript, genObjectId)
import Database.MongoDB.Internal.Protocol (MasterOrSlaveOk(..), Pipe, Notice(..), Request(GetMore), Reply(..), QueryOption(..), ResponseFlag(..), UpdateOption(..), DeleteOption(..), CursorId, FullCollection, Username, Password, pwKey)
import qualified Database.MongoDB.Internal.Protocol as P (send, call, Request(Query))
import Database.MongoDB.Internal.Util (MonadIO', loop, liftIOE, true1, (<.>))
import Control.Monad.MVar
import qualified Database.MongoDB.Internal.Protocol as P
import Database.MongoDB.Internal.Protocol hiding (Query, QueryOption(..), send, call)
import Database.MongoDB.Connection (MasterOrSlaveOk(..), Service(..))
import Data.Bson
import Data.Word
import Data.Int
import Control.Monad.Error
import Control.Monad.Reader
import Control.Applicative (Applicative, (<$>))
import Data.Maybe (listToMaybe, catMaybes)
import Data.UString as U (dropWhile, any, tail)
import Control.Monad.Util (MonadIO', loop)
import Database.MongoDB.Internal.Util ((<.>), true1)
import Data.Int (Int32)
import Data.Word (Word32)
mapErrorIO :: (Throw e m, MonadIO m) => (e' -> e) -> ErrorT e' IO a -> m a
mapErrorIO f = throwLeft' f . liftIO . runErrorT
-- * Monad
-- * Mongo Monad
access :: (Service s, MonadIO m) => WriteMode -> MasterOrSlaveOk -> ConnPool s -> Action m a -> m (Either Failure a)
-- ^ Run action under given write and read mode against the server or replicaSet behind given connection pool. Return Left Failure if there is a connection failure or read/write error.
access w mos pool act = do
ePipe <- liftIO . runErrorT $ getPipe mos pool
either (return . Left . ConnectionFailure) (runAction act w mos) ePipe
-- | A monad with access to a 'Pipe', 'MasterOrSlaveOk', and 'WriteMode', and throws 'Failure' on read, write, or pipe failure
class (Context Pipe m, Context MasterOrSlaveOk m, Context WriteMode m, Throw Failure m, MonadIO' m) => Access m
instance (Context Pipe m, Context MasterOrSlaveOk m, Context WriteMode m, Throw Failure m, MonadIO' m) => Access m
wrapIO :: (Access m) => (WriteMode -> MasterOrSlaveOk -> Pipe -> IO (Either Failure a)) -> m a
-- ^ Lift IO with Access context and failure into Access monad
wrapIO act = do
writeMod <- context
mos <- context
pipe <- context
e <- liftIO (act writeMod mos pipe)
either throw return e
modifyMVar' :: (Access m) => MVar a -> (a -> Action IO (a, b)) -> m b
modifyMVar' var act = wrapIO $ \w m p -> modifyMVar var $ \a -> do
e <- runAction (act a) w m p
return $ either ((a,) . Left) (Right <$>) e
addMVarFinalizer' :: (Access m) => MVar a -> Action IO () -> m ()
addMVarFinalizer' var act = wrapIO $ \w m p -> do
addMVarFinalizer var $ runAction act w m p >> return () -- ignore any failure
return (Right ())
newtype Action m a = Action (ErrorT Failure (ReaderT WriteMode (ReaderT MasterOrSlaveOk (ReaderT Pipe m))) a)
deriving (Context Pipe, Context MasterOrSlaveOk, Context WriteMode, Throw Failure, MonadIO, Monad, Applicative, Functor)
-- ^ Monad with access to a 'Pipe', 'MasterOrSlaveOk', and 'WriteMode', and throws a 'Failure' on read, write or pipe failure
instance MonadTrans Action where
lift = Action . lift . lift . lift . lift
runAction :: Action m a -> WriteMode -> MasterOrSlaveOk -> Pipe -> m (Either Failure a)
-- ^ Run action with given write mode and read mode (master or slave-ok) against given pipe (TCP connection). Return Left Failure if read/write error or connection failure.
-- 'access' calls runAction. Use this directly if you want to use the same connection and not take from the pool again. However, the connection may still be used by other threads at the same time. For instance, the pool will still hand this connection out.
runAction (Action action) w mos = runReaderT (runReaderT (runReaderT (runErrorT action) w) mos)
type Action m = ErrorT Failure (ReaderT Context m)
-- ^ A monad on top of m (which must be a MonadIO) with access to a 'Context' and may throw a 'Failure'
-- | A connection failure, or a read or write exception like cursor expired or inserting a duplicate key.
-- Note, unexpected data from the server is not a Failure, rather it is a programming error (you should call 'error' in this case) because the client and server are incompatible and requires a programming change.
data Failure =
ConnectionFailure IOError -- ^ TCP connection ('Pipe') failed. Make work if you try again on the same Mongo 'Connection' which will create a new Pipe.
ConnectionFailure IOError -- ^ TCP connection ('Pipeline') failed. May work if you try again on the same Mongo 'Connection' which will create a new Pipe.
| CursorNotFoundFailure CursorId -- ^ Cursor expired because it wasn't accessed for over 10 minutes, or this cursor came from a different server that the one you are currently connected to (perhaps a fail over happen between servers in a replica set)
| QueryFailure String -- ^ Query failed for some reason as described in the string
| WriteFailure ErrorCode String -- ^ Error observed by getLastError after a write, error description is in string
deriving (Show, Eq)
type ErrorCode = Int
-- ^ Error code from getLastError
instance Error Failure where strMsg = error
-- ^ 'fail' is treated the same as 'error'. In other words, don't use it.
-- | Values needed when executing a db operation
data Context = Context {
myPipe :: Pipe, -- | operations read/write to this pipelined TCP connection to a MongoDB server
myReadMode :: MasterOrSlaveOk, -- | queries set slaveOk according to this mode
myWriteMode :: WriteMode, -- | writes will automatically issue a getlasterror when this writeMode is `Safe`
myDatabase :: Database } -- | operations query/update this database
access :: (MonadIO m) => Pipe -> WriteMode -> MasterOrSlaveOk -> Database -> Action m a -> m (Either Failure a)
-- ^ Run action under given context. Return Left on Failure.
access myPipe myWriteMode myReadMode myDatabase action = runReaderT (runErrorT action) Context{..}
send :: (MonadIO m) => [Notice] -> Action m ()
-- ^ Send notices as a contiguous batch to server with no reply. Throw 'ConnectionFailure' if pipe fails.
send ns = do
pipe <- asks myPipe
liftIOE ConnectionFailure $ P.send pipe ns
call :: (MonadIO m) => [Notice] -> Request -> Action m (ErrorT Failure IO Reply)
-- ^ Send notices and request as a contiguous batch to server and return reply promise, which will block when invoked until reply arrives. This call will throw 'ConnectionFailure' if pipe fails on send, and promise will throw 'ConnectionFailure' if pipe fails on receive.
call ns r = do
pipe <- asks myPipe
promise <- liftIOE ConnectionFailure $ P.call pipe ns r
return (liftIOE ConnectionFailure promise)
-- * Database
newtype Database = Database {databaseName :: UString} deriving (Eq, Ord)
-- ^ Database name
type Database = UString
instance Show Database where show (Database x) = unpack x
-- | 'Access' monad with a particular 'Database' in context
class (Context Database m, Access m) => DbAccess m
instance (Context Database m, Access m) => DbAccess m
allDatabases :: (Access m) => m [Database]
allDatabases :: (MonadIO' m) => Action m [Database]
-- ^ List all databases residing on server
allDatabases = map (Database . at "name") . at "databases" <$> use (Database "admin") (runCommand1 "listDatabases")
allDatabases = map (at "name") . at "databases" <$> useDb "admin" (runCommand1 "listDatabases")
use :: Database -> ReaderT Database m a -> m a
-- ^ Run action against given database
use = flip runReaderT
thisDatabase :: (DbAccess m) => m Database
thisDatabase :: (Monad m) => Action m Database
-- ^ Current database in use
thisDatabase = context
thisDatabase = asks myDatabase
useDb :: (Monad m) => Database -> Action m a -> Action m a
-- ^ Run action against given database
useDb = local . \db ctx -> ctx {myDatabase = db}
-- * Authentication
auth :: (DbAccess m) => Username -> Password -> m Bool
-- ^ Authenticate with the database (if server is running in secure mode). Return whether authentication was successful or not. Reauthentication is required for every new pipe.
auth :: (MonadIO' m) => Username -> Password -> Action m Bool
-- ^ Authenticate with the current database (if server is running in secure mode). Return whether authentication was successful or not. Reauthentication is required for every new pipe.
auth usr pss = do
n <- at "nonce" <$> runCommand ["getnonce" =: (1 :: Int)]
true1 "ok" <$> runCommand ["authenticate" =: (1 :: Int), "user" =: usr, "nonce" =: n, "key" =: pwKey n usr pss]
@ -152,7 +125,7 @@ auth usr pss = do
type Collection = UString
-- ^ Collection name (not prefixed with database)
allCollections :: (DbAccess m) => m [Collection]
allCollections :: (MonadMVar m, Functor m) => Action m [Collection]
-- ^ List all collections in this database
allCollections = do
db <- thisDatabase
@ -160,7 +133,7 @@ allCollections = do
return . filter (not . isSpecial db) . map dropDbPrefix $ map (at "name") docs
where
dropDbPrefix = U.tail . U.dropWhile (/= '.')
isSpecial (Database db) col = U.any (== '$') col && db <.> col /= "local.oplog.$main"
isSpecial db col = U.any (== '$') col && db <.> col /= "local.oplog.$main"
-- * Selection
@ -186,8 +159,6 @@ instance Select Query where
-- * Write
-- ** WriteMode
-- | Default write-mode is 'Unsafe'
data WriteMode =
Unsafe -- ^ Submit writes without receiving acknowledgments. Fast. Assumes writes succeed even though they may not.
@ -201,52 +172,40 @@ safe :: WriteMode
-- ^ Safe []
safe = Safe []
writeMode :: (Access m) => WriteMode -> m a -> m a
writeMode :: (Monad m) => WriteMode -> Action m a -> Action m a
-- ^ Run action with given 'WriteMode'
writeMode = push . const
writeMode = local . \w ctx -> ctx {myWriteMode = w}
write :: (DbAccess m) => Notice -> m ()
write :: (MonadIO m) => Notice -> Action m ()
-- ^ Send write to server, and if write-mode is 'Safe' then include getLastError request and raise 'WriteFailure' if it reports an error.
write notice = do
mode <- context
case mode of
Unsafe -> send [notice]
Safe params -> do
me <- getLastError [notice] params
maybe (return ()) (throw . uncurry WriteFailure) me
type ErrorCode = Int
-- ^ Error code from getLastError
getLastError :: (DbAccess m) => [Notice] -> GetLastError -> m (Maybe (ErrorCode, String))
-- ^ Send notices (writes) then fetch what the last error was, Nothing means no error
getLastError writes params = do
r <- runCommand' writes $ ("getlasterror" =: (1 :: Int)) : params
return $ (at "code" r,) <$> lookup "err" r
{-resetLastError :: (DbConn m) => m ()
-- ^ Clear last error
resetLastError = runCommand1 "reseterror" >> return ()-}
write notice = asks myWriteMode >>= \mode -> case mode of
Unsafe -> send [notice]
Safe params -> do
let q = query (("getlasterror" =: (1 :: Int)) : params) "$cmd"
Batch _ _ [doc] <- fulfill =<< request [notice] =<< queryRequest False q {limit = 1}
case lookup "err" doc of
Nothing -> return ()
Just err -> throwError $ WriteFailure (maybe 0 id $ lookup "code" doc) err
-- ** Insert
insert :: (DbAccess m) => Collection -> Document -> m Value
insert :: (MonadIO' m) => Collection -> Document -> Action m Value
-- ^ Insert document into collection and return its \"_id\" value, which is created automatically if not supplied
insert col doc = head <$> insertMany col [doc]
insert_ :: (DbAccess m) => Collection -> Document -> m ()
insert_ :: (MonadIO' m) => Collection -> Document -> Action m ()
-- ^ Same as 'insert' except don't return _id
insert_ col doc = insert col doc >> return ()
insertMany :: (DbAccess m) => Collection -> [Document] -> m [Value]
insertMany :: (MonadIO m) => Collection -> [Document] -> Action m [Value]
-- ^ Insert documents into collection and return their \"_id\" values, which are created automatically if not supplied
insertMany col docs = do
Database db <- thisDatabase
db <- thisDatabase
docs' <- liftIO $ mapM assignId docs
write (Insert (db <.> col) docs')
mapM (look "_id") docs'
insertMany_ :: (DbAccess m) => Collection -> [Document] -> m ()
insertMany_ :: (MonadIO m) => Collection -> [Document] -> Action m ()
-- ^ Same as 'insertMany' except don't return _ids
insertMany_ col docs = insertMany col docs >> return ()
@ -258,60 +217,58 @@ assignId doc = if X.any (("_id" ==) . label) doc
-- ** Update
save :: (DbAccess m) => Collection -> Document -> m ()
save :: (MonadIO' m) => Collection -> Document -> Action m ()
-- ^ Save document to collection, meaning insert it if its new (has no \"_id\" field) or update it if its not new (has \"_id\" field)
save col doc = case look "_id" doc of
Nothing -> insert_ col doc
Just i -> repsert (Select ["_id" := i] col) doc
replace :: (DbAccess m) => Selection -> Document -> m ()
replace :: (MonadIO m) => Selection -> Document -> Action m ()
-- ^ Replace first document in selection with given document
replace = update []
repsert :: (DbAccess m) => Selection -> Document -> m ()
repsert :: (MonadIO m) => Selection -> Document -> Action m ()
-- ^ Replace first document in selection with given document, or insert document if selection is empty
repsert = update [Upsert]
type Modifier = Document
-- ^ Update operations on fields in a document. See <http://www.mongodb.org/display/DOCS/Updating#Updating-ModifierOperations>
modify :: (DbAccess m) => Selection -> Modifier -> m ()
modify :: (MonadIO m) => Selection -> Modifier -> Action m ()
-- ^ Update all documents in selection using given modifier
modify = update [MultiUpdate]
update :: (DbAccess m) => [UpdateOption] -> Selection -> Document -> m ()
update :: (MonadIO m) => [UpdateOption] -> Selection -> Document -> Action m ()
-- ^ Update first document in selection using updater document, unless 'MultiUpdate' option is supplied then update all documents in selection. If 'Upsert' option is supplied then treat updater as document and insert it if selection is empty.
update opts (Select sel col) up = do
Database db <- thisDatabase
db <- thisDatabase
write (Update (db <.> col) opts sel up)
-- ** Delete
delete :: (DbAccess m) => Selection -> m ()
delete :: (MonadIO m) => Selection -> Action m ()
-- ^ Delete all documents in selection
delete = delete' []
deleteOne :: (DbAccess m) => Selection -> m ()
deleteOne :: (MonadIO m) => Selection -> Action m ()
-- ^ Delete first document in selection
deleteOne = delete' [SingleRemove]
delete' :: (DbAccess m) => [DeleteOption] -> Selection -> m ()
delete' :: (MonadIO m) => [DeleteOption] -> Selection -> Action m ()
-- ^ Delete all documents in selection unless 'SingleRemove' option is given then only delete first document in selection
delete' opts (Select sel col) = do
Database db <- thisDatabase
db <- thisDatabase
write (Delete (db <.> col) opts sel)
-- * Read
-- ** MasterOrSlaveOk
readMode :: (Access m) => MasterOrSlaveOk -> m a -> m a
readMode :: (Monad m) => MasterOrSlaveOk -> Action m a -> Action m a
-- ^ Execute action using given read mode. Master = consistent reads, SlaveOk = eventually consistent reads.
readMode = push . const
readMode = local . \r ctx -> ctx {myReadMode = r}
msOption :: MasterOrSlaveOk -> [P.QueryOption]
msOption :: MasterOrSlaveOk -> [QueryOption]
msOption Master = []
msOption SlaveOk = [P.SlaveOK]
msOption SlaveOk = [SlaveOK]
-- ** Query
@ -328,18 +285,6 @@ data Query = Query {
hint :: Order -- ^ Force MongoDB to use this index, [] = no hint. Default = []
} deriving (Show, Eq)
data QueryOption =
TailableCursor -- ^ Tailable means cursor is not closed when the last data is retrieved. Rather, the cursor marks the final object's position. You can resume using the cursor later, from where it was located, if more data were received. Like any "latent cursor", the cursor may become invalid at some point – for example if the final object it references were deleted. Thus, you should be prepared to requery on CursorNotFound exception.
| NoCursorTimeout -- The server normally times out idle cursors after an inactivity period (10 minutes) to prevent excess memory use. Set this option to prevent that.
| AwaitData -- ^ Use with TailableCursor. If we are at the end of the data, block for a while rather than returning no data. After a timeout period, we do return as normal.
deriving (Show, Eq)
pOption :: QueryOption -> P.QueryOption
-- ^ Convert to protocol query option
pOption TailableCursor = P.TailableCursor
pOption NoCursorTimeout = P.NoCursorTimeout
pOption AwaitData = P.AwaitData
type Projector = Document
-- ^ Fields to return, analogous to the select clause in SQL. @[]@ means return whole document (analogous to * in SQL). @[x =: 1, y =: 1]@ means return only @x@ and @y@ fields of each document. @[x =: 0]@ means return all fields except @x@.
@ -356,6 +301,54 @@ query :: Selector -> Collection -> Query
-- ^ Selects documents in collection that match selector. It uses no query options, projects all fields, does not skip any documents, does not limit result size, uses default batch size, does not sort, does not hint, and does not snapshot.
query sel col = Query [] (Select sel col) [] 0 0 [] False 0 []
find :: (MonadMVar m) => Query -> Action m Cursor
-- ^ Fetch documents satisfying query
find q@Query{selection, batchSize} = do
db <- thisDatabase
dBatch <- request [] =<< queryRequest False q
newCursor db (coll selection) batchSize dBatch
findOne :: (MonadIO m) => Query -> Action m (Maybe Document)
-- ^ Fetch first document satisfying query or Nothing if none satisfy it
findOne q = do
Batch _ _ docs <- fulfill =<< request [] =<< queryRequest False q {limit = 1}
return (listToMaybe docs)
explain :: (MonadIO m) => Query -> Action m Document
-- ^ Return performance stats of query execution
explain q = do -- same as findOne but with explain set to true
Batch _ _ docs <- fulfill =<< request [] =<< queryRequest True q {limit = 1}
return $ if null docs then error ("no explain: " ++ show q) else head docs
count :: (MonadIO' m) => Query -> Action m Int
-- ^ Fetch number of documents satisfying query (including effect of skip and/or limit if present)
count Query{selection = Select sel col, skip, limit} = at "n" <$> runCommand
(["count" =: col, "query" =: sel, "skip" =: (fromIntegral skip :: Int32)]
++ ("limit" =? if limit == 0 then Nothing else Just (fromIntegral limit :: Int32)))
distinct :: (MonadIO' m) => Label -> Selection -> Action m [Value]
-- ^ Fetch distinct values of field in selected documents
distinct k (Select sel col) = at "values" <$> runCommand ["distinct" =: col, "key" =: k, "query" =: sel]
queryRequest :: (Monad m) => Bool -> Query -> Action m (Request, Limit)
-- ^ Translate Query to Protocol.Query. If first arg is true then add special $explain attribute.
queryRequest isExplain Query{..} = do
ctx <- ask
return $ queryRequest' (myReadMode ctx) (myDatabase ctx)
where
queryRequest' mos db = (P.Query{..}, remainingLimit) where
qOptions = msOption mos ++ options
qFullCollection = db <.> coll selection
qSkip = fromIntegral skip
(qBatchSize, remainingLimit) = batchSizeRemainingLimit batchSize limit
qProjector = project
mOrder = if null sort then Nothing else Just ("$orderby" =: sort)
mSnapshot = if snapshot then Just ("$snapshot" =: True) else Nothing
mHint = if null hint then Nothing else Just ("$hint" =: hint)
mExplain = if isExplain then Just ("$explain" =: True) else Nothing
special = catMaybes [mOrder, mSnapshot, mHint, mExplain]
qSelector = if null special then s else ("$query" =: s) : special where s = selector selection
batchSizeRemainingLimit :: BatchSize -> Limit -> (Int32, Limit)
-- ^ Given batchSize and limit return P.qBatchSize and remaining limit
batchSizeRemainingLimit batchSize limit = if limit == 0
@ -366,137 +359,83 @@ batchSizeRemainingLimit batchSize limit = if limit == 0
where batchSize' = if batchSize == 1 then 2 else batchSize
-- batchSize 1 is broken because server converts 1 to -1 meaning limit 1
queryRequest :: Bool -> MasterOrSlaveOk -> Query -> Database -> (Request, Limit)
-- ^ Translate Query to Protocol.Query. If first arg is true then add special $explain attribute.
queryRequest isExplain mos Query{..} (Database db) = (P.Query{..}, remainingLimit) where
qOptions = msOption mos ++ map pOption options
qFullCollection = db <.> coll selection
qSkip = fromIntegral skip
(qBatchSize, remainingLimit) = batchSizeRemainingLimit batchSize limit
qProjector = project
mOrder = if null sort then Nothing else Just ("$orderby" =: sort)
mSnapshot = if snapshot then Just ("$snapshot" =: True) else Nothing
mHint = if null hint then Nothing else Just ("$hint" =: hint)
mExplain = if isExplain then Just ("$explain" =: True) else Nothing
special = catMaybes [mOrder, mSnapshot, mHint, mExplain]
qSelector = if null special then s else ("$query" =: s) : special where s = selector selection
type DelayedBatch = ErrorT Failure IO Batch
-- ^ A promised batch which may fail
runQuery :: (DbAccess m) => Bool -> [Notice] -> Query -> m DelayedCursorState
-- ^ Send query request and return cursor state
runQuery isExplain ns q = do
db <- thisDatabase
slaveOK <- context
request ns (queryRequest isExplain slaveOK q db)
data Batch = Batch Limit CursorId [Document]
-- ^ CursorId = 0 means cursor is finished. Documents is remaining documents to serve in current batch. Limit is remaining limit for next fetch.
find :: (DbAccess m) => Query -> m Cursor
-- ^ Fetch documents satisfying query
find q@Query{selection, batchSize} = do
db <- thisDatabase
dcs <- runQuery False [] q
newCursor db (coll selection) batchSize dcs
findOne' :: (DbAccess m) => [Notice] -> Query -> m (Maybe Document)
-- ^ Send notices and fetch first document satisfying query or Nothing if none satisfy it
findOne' ns q = do
CS _ _ docs <- mapErrorIO id =<< runQuery False ns q {limit = 1}
return (listToMaybe docs)
findOne :: (DbAccess m) => Query -> m (Maybe Document)
-- ^ Fetch first document satisfying query or Nothing if none satisfy it
findOne = findOne' []
explain :: (DbAccess m) => Query -> m Document
-- ^ Return performance stats of query execution
explain q = do -- same as findOne but with explain set to true
CS _ _ docs <- mapErrorIO id =<< runQuery True [] q {limit = 1}
return $ if null docs then error ("no explain: " ++ show q) else head docs
count :: (DbAccess m) => Query -> m Int
-- ^ Fetch number of documents satisfying query (including effect of skip and/or limit if present)
count Query{selection = Select sel col, skip, limit} = at "n" <$> runCommand
(["count" =: col, "query" =: sel, "skip" =: (fromIntegral skip :: Int32)]
++ ("limit" =? if limit == 0 then Nothing else Just (fromIntegral limit :: Int32)))
distinct :: (DbAccess m) => Label -> Selection -> m [Value]
-- ^ Fetch distinct values of field in selected documents
distinct k (Select sel col) = at "values" <$> runCommand ["distinct" =: col, "key" =: k, "query" =: sel]
-- *** Cursor
data Cursor = Cursor FullCollection BatchSize (MVar DelayedCursorState)
-- ^ Iterator over results of a query. Use 'next' to iterate or 'rest' to get all results. A cursor is closed when it is explicitly closed, all results have been read from it, garbage collected, or not used for over 10 minutes (unless 'NoCursorTimeout' option was specified in 'Query'). Reading from a closed cursor raises a 'CursorNotFoundFailure'. Note, a cursor is not closed when the pipe is closed, so you can open another pipe to the same server and continue using the cursor.
getCursorState :: (Access m) => Cursor -> m CursorState
-- ^ Extract current cursor status
getCursorState (Cursor _ _ var) = mapErrorIO id =<< readMVar var
type DelayedCursorState = ErrorT Failure IO CursorState
-- ^ A promised cursor state which may fail
request :: (Access m) => [Notice] -> (Request, Limit) -> m DelayedCursorState
-- ^ Send notices and request and return promised cursor state
request :: (MonadIO m) => [Notice] -> (Request, Limit) -> Action m DelayedBatch
-- ^ Send notices and request and return promised batch
request ns (req, remainingLimit) = do
promise <- call ns req
return $ fromReply remainingLimit =<< promise
data CursorState = CS Limit CursorId [Document]
-- ^ CursorId = 0 means cursor is finished. Documents is remaining documents to serve in current batch. Limit is remaining limit for next fetch.
fromReply :: (Throw Failure m) => Limit -> Reply -> m CursorState
-- ^ Convert Reply to CursorState or Failure
fromReply :: Limit -> Reply -> DelayedBatch
-- ^ Convert Reply to Batch or Failure
fromReply limit Reply{..} = do
mapM_ checkResponseFlag rResponseFlags
return (CS limit rCursorId rDocuments)
return (Batch limit rCursorId rDocuments)
where
-- If response flag indicates failure then throw it, otherwise do nothing
checkResponseFlag flag = case flag of
AwaitCapable -> return ()
CursorNotFound -> throw (CursorNotFoundFailure rCursorId)
QueryError -> throw (QueryFailure $ at "$err" $ head rDocuments)
CursorNotFound -> throwError (CursorNotFoundFailure rCursorId)
QueryError -> throwError (QueryFailure $ at "$err" $ head rDocuments)
newCursor :: (Access m) => Database -> Collection -> BatchSize -> DelayedCursorState -> m Cursor
fulfill :: (MonadIO m) => DelayedBatch -> ErrorT Failure m Batch
-- ^ Demand and wait for result, raise failure if exception
fulfill = liftIOE id
-- *** Cursor
data Cursor = Cursor FullCollection BatchSize (MVar DelayedBatch)
-- ^ Iterator over results of a query. Use 'next' to iterate or 'rest' to get all results. A cursor is closed when it is explicitly closed, all results have been read from it, garbage collected, or not used for over 10 minutes (unless 'NoCursorTimeout' option was specified in 'Query'). Reading from a closed cursor raises a 'CursorNotFoundFailure'. Note, a cursor is not closed when the pipe is closed, so you can open another pipe to the same server and continue using the cursor.
newCursor :: (MonadMVar m) => Database -> Collection -> BatchSize -> DelayedBatch -> Action m Cursor
-- ^ Create new cursor. If you don't read all results then close it. Cursor will be closed automatically when all results are read from it or when eventually garbage collected.
newCursor (Database db) col batch cs = do
var <- newMVar cs
let cursor = Cursor (db <.> col) batch var
addMVarFinalizer' var (closeCursor cursor)
newCursor db col batchSize dBatch = do
var <- newMVar dBatch
let cursor = Cursor (db <.> col) batchSize var
addMVarFinalizer var (closeCursor cursor)
return cursor
next :: (Access m) => Cursor -> m (Maybe Document)
next :: (MonadMVar m) => Cursor -> Action m (Maybe Document)
-- ^ Return next document in query result, or Nothing if finished.
next (Cursor fcol batch var) = modifyMVar' var nextState where
next (Cursor fcol batchSize var) = modifyMVar var nextState where
-- Pre-fetch next batch promise from server when last one in current batch is returned.
nextState:: DelayedCursorState -> Action IO (DelayedCursorState, Maybe Document)
nextState dcs = do
CS limit cid docs <- mapErrorIO id dcs
-- nextState:: DelayedBatch -> Action m (DelayedBatch, Maybe Document)
nextState dBatch = do
Batch limit cid docs <- fulfill dBatch
case docs of
doc : docs' -> do
dcs' <- if null docs' && cid /= 0
dBatch' <- if null docs' && cid /= 0
then nextBatch limit cid
else return $ return (CS limit cid docs')
return (dcs', Just doc)
else return $ return (Batch limit cid docs')
return (dBatch', Just doc)
[] -> if cid == 0
then return (return $ CS 0 0 [], Nothing) -- finished
then return (return $ Batch 0 0 [], Nothing) -- finished
else error $ "server returned empty batch but says more results on server"
nextBatch limit cid = request [] (GetMore fcol batchSize cid, remLimit)
where (batchSize, remLimit) = batchSizeRemainingLimit batch limit
nextBatch limit cid = request [] (GetMore fcol batchSize' cid, remLimit)
where (batchSize', remLimit) = batchSizeRemainingLimit batchSize limit
nextN :: (Access m) => Int -> Cursor -> m [Document]
nextN :: (MonadMVar m, Functor m) => Int -> Cursor -> Action m [Document]
-- ^ Return next N documents or less if end is reached
nextN n c = catMaybes <$> replicateM n (next c)
rest :: (Access m) => Cursor -> m [Document]
rest :: (MonadMVar m, Functor m) => Cursor -> Action m [Document]
-- ^ Return remaining documents in query result
rest c = loop (next c)
closeCursor :: (Access m) => Cursor -> m ()
closeCursor (Cursor _ _ var) = modifyMVar' var kill' where
kill' dcs = first return <$> (kill =<< mapErrorIO id dcs)
kill (CS _ cid _) = (CS 0 0 [],) <$> if cid == 0 then return () else send [KillCursors [cid]]
closeCursor :: (MonadMVar m) => Cursor -> Action m ()
closeCursor (Cursor _ _ var) = modifyMVar var $ \dBatch -> do
Batch _ cid _ <- fulfill dBatch
unless (cid == 0) $ send [KillCursors [cid]]
return $ (return $ Batch 0 0 [], ())
isCursorClosed :: (Access m) => Cursor -> m Bool
isCursorClosed cursor = do
CS _ cid docs <- getCursorState cursor
isCursorClosed :: (MonadIO m) => Cursor -> Action m Bool
isCursorClosed (Cursor _ _ var) = do
Batch _ cid docs <- fulfill =<< readMVar var
return (cid == 0 && null docs)
-- ** Group
@ -524,7 +463,7 @@ groupDocument Group{..} =
"initial" =: gInitial,
"cond" =: gCond ]
group :: (DbAccess m) => Group -> m [Document]
group :: (MonadIO' m) => Group -> Action m [Document]
-- ^ Execute group query and return resulting aggregate value for each distinct key
group g = at "retval" <$> runCommand ["group" =: groupDocument g]
@ -590,23 +529,23 @@ mrOutDoc (Output mrMerge coll mDB) = (mergeName mrMerge =: coll) : mdb mDB where
mergeName Merge = "merge"
mergeName Reduce = "reduce"
mdb Nothing = []
mdb (Just (Database db)) = ["db" =: db]
mdb (Just db) = ["db" =: db]
mapReduce :: Collection -> MapFun -> ReduceFun -> MapReduce
-- ^ MapReduce on collection with given map and reduce functions. Remaining attributes are set to their defaults, which are stated in their comments.
mapReduce col map' red = MapReduce col map' red [] [] 0 Inline Nothing [] False
runMR :: (DbAccess m) => MapReduce -> m Cursor
runMR :: (MonadMVar m, Applicative m) => MapReduce -> Action m Cursor
-- ^ Run MapReduce and return cursor of results. Error if map/reduce fails (because of bad Javascript)
runMR mr = do
res <- runMR' mr
case look "result" res of
Just (String coll) -> find $ query [] coll
Just (Doc doc) -> use (Database $ at "db" doc) $ find $ query [] (at "collection" doc)
Just (Doc doc) -> useDb (at "db" doc) $ find $ query [] (at "collection" doc)
Just x -> error $ "unexpected map-reduce result field: " ++ show x
Nothing -> newCursor (Database "") "" 0 $ return $ CS 0 0 (at "results" res)
Nothing -> newCursor "" "" 0 $ return $ Batch 0 0 (at "results" res)
runMR' :: (DbAccess m) => MapReduce -> m MRResult
runMR' :: (MonadIO' m) => MapReduce -> Action m MRResult
-- ^ Run MapReduce and return a MR result document containing stats and the results if Inlined. Error if the map/reduce failed (because of bad Javascript).
runMR' mr = do
doc <- runCommand (mrDocument mr)
@ -617,40 +556,20 @@ runMR' mr = do
type Command = Document
-- ^ A command is a special query or action against the database. See <http://www.mongodb.org/display/DOCS/Commands> for details.
runCommand' :: (DbAccess m) => [Notice] -> Command -> m Document
-- ^ Send notices then run command and return its result
runCommand' ns c = maybe err id <$> findOne' ns (query c "$cmd") where
runCommand :: (MonadIO' m) => Command -> Action m Document
-- ^ Run command against the database and return its result
runCommand c = maybe err id <$> findOne (query c "$cmd") where
err = error $ "Nothing returned for command: " ++ show c
runCommand :: (DbAccess m) => Command -> m Document
-- ^ Run command against the database and return its result
runCommand = runCommand' []
runCommand1 :: (DbAccess m) => UString -> m Document
runCommand1 :: (MonadIO' m) => UString -> Action m Document
-- ^ @runCommand1 foo = runCommand [foo =: 1]@
runCommand1 c = runCommand [c =: (1 :: Int)]
eval :: (DbAccess m) => Javascript -> m Document
eval :: (MonadIO' m) => Javascript -> Action m Document
-- ^ Run code on server
eval code = at "retval" <$> runCommand ["$eval" =: code]
-- * Primitives
send :: (Context Pipe m, Throw Failure m, MonadIO m) => [Notice] -> m ()
-- ^ Send notices as a contiguous batch to server with no reply. Throw 'ConnectionFailure' if pipe fails.
send ns = do
pipe <- context
mapErrorIO ConnectionFailure (P.send pipe ns)
call :: (Context Pipe m, Throw Failure m, MonadIO m, Throw Failure n, MonadIO n) =>
[Notice] -> Request -> m (n Reply)
-- ^ Send notices and request as a contiguous batch to server and return reply promise, which will block when invoked until reply arrives. This call will throw 'ConnectionFailure' if pipe fails on send, and promise will throw 'ConnectionFailure' if pipe fails on receive.
call ns r = do
pipe <- context
promise <- mapErrorIO ConnectionFailure (P.call pipe ns r)
return (mapErrorIO ConnectionFailure promise)
{- Authors: Tony Hannan <tony@10gen.com>
Copyright 2010 10gen Inc.
Copyright 2011 10gen Inc.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0. Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -}

63
Network/Abstract.hs
View file

@ -1,63 +0,0 @@
-- | Generalize a network connection to a sink and source
{-# LANGUAGE MultiParamTypeClasses, ExistentialQuantification, FlexibleContexts, FlexibleInstances, OverlappingInstances, UndecidableInstances #-}
module Network.Abstract where
import System.IO (Handle, hClose)
import Network (HostName, PortID, connectTo)
import Control.Monad.Error
import System.IO.Error (try)
import Control.Monad.Context
import Control.Monad.Util (MonadIO')
type IOE = ErrorT IOError IO
-- ^ Be explicit about exception that may be raised.
data Server i o = Server HostName PortID
-- ^ A server receives messages of type i and returns messages of type o.
-- | Serialize message over handle
class WriteMessage i where
writeMessage :: Handle -> i -> IOE ()
-- | Deserialize message from handle
class ReadMessage o where
readMessage :: Handle -> IOE o
-- | A network controls connections to other hosts. It may want to overide to log messages or play them back.
class Network n where
connect :: (WriteMessage i, ReadMessage o) => n -> Server i o -> IOE (Connection i o)
-- ^ Connect to Server returning the send sink and receive source, throw IOError if can't connect.
data Connection i o = Connection {
send :: i -> IOE (),
receive :: IOE o,
close :: IO () }
data ANetwork = forall n. (Network n) => ANetwork n
instance Network (ANetwork) where
connect (ANetwork n) = connect n
data Internet = Internet
-- ^ Normal Network instance, i.e. no logging or replay
-- | Connect to server. Write messages and receive replies. Not thread-safe, must be wrapped in Pipeline or something.
instance Network Internet where
connect _ (Server hostname portid) = ErrorT . try $ do
handle <- connectTo hostname portid
return $ Connection (writeMessage handle) (readMessage handle) (hClose handle)
class (MonadIO' m) => NetworkIO m where
network :: m ANetwork
instance (Context ANetwork m, MonadIO' m) => NetworkIO m where
network = context
instance NetworkIO IO where
network = return (ANetwork Internet)
{- Authors: Tony Hannan <tony@10gen.com>
Copyright 2010 10gen Inc.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0. Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -}

80
Control/Pipeline.hs → System/IO/Pipeline.hs
View file

@ -1,53 +1,71 @@
{- | Pipelining is sending multiple requests over a socket and receiving the responses later, in the same order. This is faster than sending one request, waiting for the response, then sending the next request, and so on. This implementation returns a /promise (future)/ response for each request that when invoked waits for the response if not already arrived. Multiple threads can send on the same pipeline (and get promises back); it will pipeline each thread's request right away without waiting.
{- | Pipelining is sending multiple requests over a socket and receiving the responses later, in the same order. This is faster than sending one request, waiting for the response, then sending the next request, and so on. This implementation returns a /promise (future)/ response for each request that when invoked waits for the response if not already arrived. Multiple threads can send on the same pipeline (and get promises back); it will send each thread's request right away without waiting.
A pipeline closes itself when a read or write causes an error, so you can detect a broken pipeline by checking isClosed. It also closes itself when garbage collected, or you can close it explicitly. -}
{-# LANGUAGE DoRec, RecordWildCards, NamedFieldPuns, ScopedTypeVariables #-}
module Control.Pipeline (
module System.IO.Pipeline (
IOE,
-- * IOStream
IOStream(..),
-- * Pipeline
Pipeline, newPipeline, send, call, close, isClosed
) where
import Control.Monad.Throw (onException)
import Control.Monad.Error
import Control.Concurrent (ThreadId, forkIO, killThread)
import Prelude hiding (length)
import GHC.Conc (ThreadStatus(..), threadStatus)
import Control.Monad.MVar
import Control.Concurrent (ThreadId, forkIO, killThread)
import Control.Concurrent.Chan
import Network.Abstract (IOE)
import qualified Network.Abstract as C
import Control.Monad.MVar
import Control.Monad.Error
onException :: (Monad m) => ErrorT e m a -> m () -> ErrorT e m a
-- ^ If first action throws an exception then run second action then re-throw
onException (ErrorT action) releaser = ErrorT $ do
e <- action
either (const releaser) (const $ return ()) e
return e
type IOE = ErrorT IOError IO
-- * IOStream
-- | An IO sink and source where value of type @o@ are sent and values of type @i@ are received.
data IOStream i o = IOStream {
writeStream :: o -> IOE (),
readStream :: IOE i,
closeStream :: IO () }
-- * Pipeline
-- | Thread-safe and pipelined connection
data Pipeline i o = Pipeline {
vConn :: MVar (C.Connection i o), -- ^ Mutex on handle, so only one thread at a time can write to it
responseQueue :: Chan (MVar (Either IOError o)), -- ^ Queue of threads waiting for responses. Every time a response arrive we pop the next thread and give it the response.
vStream :: MVar (IOStream i o), -- ^ Mutex on handle, so only one thread at a time can write to it
responseQueue :: Chan (MVar (Either IOError i)), -- ^ Queue of threads waiting for responses. Every time a response arrive we pop the next thread and give it the response.
listenThread :: ThreadId
}
-- | Create new Pipeline on given connection. You should 'close' pipeline when finished, which will also close connection. If pipeline is not closed but eventually garbage collected, it will be closed along with connection.
newPipeline :: (MonadIO m) => C.Connection i o -> m (Pipeline i o)
newPipeline conn = liftIO $ do
vConn <- newMVar conn
-- | Create new Pipeline over given handle. You should 'close' pipeline when finished, which will also close handle. If pipeline is not closed but eventually garbage collected, it will be closed along with handle.
newPipeline :: IOStream i o -> IO (Pipeline i o)
newPipeline stream = do
vStream <- newMVar stream
responseQueue <- newChan
rec
let pipe = Pipeline{..}
listenThread <- forkIO (listen pipe)
addMVarFinalizer vConn $ do
addMVarFinalizer vStream $ do
killThread listenThread
C.close conn
closeStream stream
return pipe
close :: (MonadIO m) => Pipeline i o -> m ()
close :: Pipeline i o -> IO ()
-- | Close pipe and underlying connection
close Pipeline{..} = liftIO $ do
close Pipeline{..} = do
killThread listenThread
C.close =<< readMVar vConn
closeStream =<< readMVar vStream
isClosed :: (MonadIO m) => Pipeline i o -> m Bool
isClosed Pipeline{listenThread} = liftIO $ do
isClosed :: Pipeline i o -> IO Bool
isClosed Pipeline{listenThread} = do
status <- threadStatus listenThread
return $ case status of
ThreadRunning -> False
@ -59,31 +77,31 @@ isClosed Pipeline{listenThread} = liftIO $ do
listen :: Pipeline i o -> IO ()
-- ^ Listen for responses and supply them to waiting threads in order
listen Pipeline{..} = do
conn <- readMVar vConn
stream <- readMVar vStream
forever $ do
e <- runErrorT $ C.receive conn
e <- runErrorT $ readStream stream
var <- readChan responseQueue
putMVar var e
case e of
Left err -> C.close conn >> ioError err -- close and stop looping
Left err -> closeStream stream >> ioError err -- close and stop looping
Right _ -> return ()
send :: Pipeline i o -> i -> IOE ()
send :: Pipeline i o -> o -> IOE ()
-- ^ Send message to destination; the destination must not response (otherwise future 'call's will get these responses instead of their own).
-- Throw IOError and close pipeline if send fails
send p@Pipeline{..} message = withMVar vConn (flip C.send message) `onException` \(_ :: IOError) -> close p
send p@Pipeline{..} message = withMVar vStream (flip writeStream message) `onException` close p
call :: Pipeline i o -> i -> IOE (IOE o)
call :: Pipeline i o -> o -> IOE (IOE i)
-- ^ Send message to destination and return /promise/ of response from one message only. The destination must reply to the message (otherwise promises will have the wrong responses in them).
-- Throw IOError and closes pipeline if send fails, likewise for promised response.
call p@Pipeline{..} message = withMVar vConn doCall `onException` \(_ :: IOError) -> close p where
doCall conn = do
C.send conn message
call p@Pipeline{..} message = withMVar vStream doCall `onException` close p where
doCall stream = do
writeStream stream message
var <- newEmptyMVar
liftIO $ writeChan responseQueue var
return $ ErrorT (readMVar var) -- return promise
{- Authors: Tony Hannan <tony@10gen.com>
Copyright 2010 10gen Inc.
Copyright 2011 10gen Inc.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at: http://www.apache.org/licenses/LICENSE-2.0. Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. -}

11
mongoDB.cabal
View file

@ -1,5 +1,5 @@
name: mongoDB
version: 0.10.0
version: 1.0.0
build-type: Simple
license: OtherLicense
license-file: LICENSE
@ -16,7 +16,8 @@ build-depends:
cryptohash -any,
network -any,
parsec -any,
random -any
random -any,
random-shuffle -any
stability: alpha
homepage: http://github.com/TonyGen/mongoDB-haskell
package-url:
@ -31,18 +32,14 @@ data-dir: ""
extra-source-files:
extra-tmp-files:
exposed-modules:
Control.Monad.Context
Control.Monad.MVar
Control.Monad.Throw
Control.Monad.Util
Control.Pipeline
Database.MongoDB
Database.MongoDB.Admin
Database.MongoDB.Connection
Database.MongoDB.Internal.Protocol
Database.MongoDB.Internal.Util
Database.MongoDB.Query
Network.Abstract
System.IO.Pipeline
Var.Pool
exposed: True
buildable: True