Docker-compose to speed up setup dev environment

Sometimes a developer should spent too much time setting up a development environment due to requirement. Docker an docker compose can comes to the resque

Even if you do not plan to use Docker to distribute your application you can use it to speedup setup of development environment, for new developers and for new machines. I have a project where we use MongoDb and ElasticSearch, mongodb should be authenticated and ElasticSearch needs to have some special plugin installed.

Time to setup a new machine sometimes is high due to dependencies.

I’m aware that for experienced user setting up mongodb and ElasticSearch is not a complex task, but nevertheless you usually can have some problem.

  • Which is the correct version of ElasticSearch/Mongodb that our software is using?
  • Are there some Es plugin to install? Which version?
  • Which version of JAVA should I install?
  • How can I configure a user in Mongodb?

Clearly I wish for a developer not to be worried about these things, thus you can simply use docker-compose to setup most of the requirements. Here is an example.

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# Use root/example as user/password credentials
version: '3.1'

services:

  mongo:
    image: mongo:latest
    restart: on-failure
    volumes:
      - ${MONGODB_DATA_LOCATION}:/data/db
    ports:
      - 27017:27017
    environment:
      MONGO_INITDB_ROOT_USERNAME: admin
      MONGO_INITDB_ROOT_PASSWORD: ${MONGODB_ADMIN_PASSWORD}

  es:
    image: elasticsearch:2.4.6
    restart: on-failure
    volumes:
      - ${ES_DATA_LOCATION}:/usr/share/elasticsearch/data
    ports: 
      - 9200:9200

This is a really simple file, it runs a mongodb image and a specific elasticsearch image. It uses environment variables to let each developer to specify location of data files and password for mongodb. These environment variables: ES_DATA_LOCATION, MONGODB_DATA_LOCATION, MONGODB_ADMIN_PASSWORD could be simple environment variables or you can specify in a .env file contained in the very same directory of docker-compose file.

MONGODB_DATA_LOCATION=g:\Nosql\dockermongo
ES_DATA_LOCATION=g:\Nosql\dockeres
MONGODB_ADMIN_PASSWORD=123456##

Thanks to these few lines of code I can now start up a mongodb and an elasticsearch instance in mere seconds thanks to the command

docker-compose -f filename.yml up -d

Now the only thing I need to do is installing plugins inside ElasticSearch container, with simple docker-compose exec commands.

docker-compose -f .\filename.yml exec es /usr/share/elasticsearch/bin/plugin install royrusso/elasticsearch-HQ/v2.0.3
docker-compose -f .\filename.yml exec es /usr/share/elasticsearch/bin/plugin install delete-by-query

To simplify everything I create a simple Windows batch file called FirstExecution.bat that call docker-compose up, wait for 20 seconds to give elasticsearch cluster time to start and the install plugin with docker-compose.

You could obtain the very same result modifying the startup script of the container, but in my opinion: using standard elasticsearch container without modification, then installing plugin with standard command line is more stable and simple to understand for people not used to docker and docker-compose.

Now a simple click and the developer can start developing not worrying about database engines.

Gian Maria.

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