Add docker-compose file for dev environment

README.md

@@ -11,3 +11,68 @@ This is the Haskell MongoDB driver (client). [MongoDB](http://www.mongodb.org) i
 * [MapReduce example](http://github.com/mongodb-haskell/mongodb/blob/master/doc/map-reduce-example.md)
 * [Driver design](https://github.com/mongodb-haskell/mongodb/blob/master/doc/Article1.md)
 * [MongoDB DBMS](http://www.mongodb.org)
+
+### Dev Environment
+
+It's important for this library to be tested with various versions of mongodb
+server and with different ghc versions. In order to achieve this we use docker
+containers and docker-compose. This repository contains two files: docker-compose.yml
+and reattach.sh.
+
+Docker compose file describes two containers.
+
+One container is for running mongodb server. If you want a different version of
+mongodb server you need to change the tag of mongo image in the
+docker-compose.yml. In order to start your mongodb server you need to run:
+
+```
+docker-compose up -d mongodb
+```
+
+In order to stop your containers without loosing the data inside of it:
+
+```
+docker-compose stop mongodb
+```
+
+Restart:
+
+```
+docker-compose start mongodb
+```
+
+If you want to remove the mongodb container and start from scratch then:
+
+```
+docker-compose stop mongodb
+docker-compose rm mongodb
+docker-compose up -d mongodb
+```
+
+The other container is for compiling your code. By specifying the tag of the image
+you can change the version of ghc you will be using. If you never started this
+container then you need:
+
+```
+docker-compose run mongodb-haskell
+```
+
+It will start the container and mount your working directory to
+`/opt/mongodb-haskell` If you exit the bash cli then the conainer will stop.
+In order to reattach to an old stopped container you need to run script
+`reattach.sh`.  If you run `docker-compose run` again it will create another
+container and all work made by cabal will be lost. `reattach.sh` is a
+workaround for docker-compose's inability to pick up containers that exited.
+
+When you are done with testing you need to run:
+```
+docker-compose stop mongodb
+```
+
+Next time you will need to do:
+```
+docker-compose start mongodb
+reattach.sh
+```
+It will start your stopped container with mongodb server and pick up the stopped
+container with haskell.

docker-compose.yml

@@ -0,0 +1,14 @@
+version: '3'
+services:
+  mongodb:
+    image: mongo:3.4.3
+  mongodb-haskell:
+    image: phadej/ghc:8.0.2
+    environment:
+      - HASKELL_MONGODB_TEST_HOST=mongodb
+    entrypoint:
+      - /bin/bash
+    volumes:
+      - ./:/opt/mongodb-haskell
+
+# vim: ts=2 et sw=2 ai

reattach.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+docker start -ai mongodb_mongodb-haskell_run_1