Overview

This repo serves as an example of how to replicate data from MongoDB to PostgreSQL. For more information, see the webinar: http://landing.chartio.com/slides-compose-switched-from-mongodb-to-postgres.

Usage

• Spin up an AWS VPC isolated from the rest of your infrastructure:

  aws --region us-west-2 cloudformation create-stack \
  --stack-name mosql-example \
  --template-body file://./cf.json \
  --parameters \
  ParameterKey=LocalIP,ParameterValue=<YOUR_LOCAL_IP_ADDRESS> \
  ParameterKey=KeyName,ParameterValue=<YOUR_AWS_SSH_KEY_NAME>
  

• Spin up and configure an EC2 instance in the above VPC using Vagrant and Salt:

  AWS_REGION=us-west-2 vagrant up mosql-example
  

• SSH into the EC2 instance:

  AWS_REGION=us-west-2 vagrant ssh mosql-example
  

• Use a terminal multiplexer such as tmux to start 3 sessions or SSH into the instance 2 more times.

• Start mosql in one session:

  mosql
  

• Start the mongo shell in a second session and view the documents in collection 1:

  mongo demo
  db.collection1.find()
  

• Start the psql shell in a third session and check that the data has been replicated:

  psql
  \x auto
  select * from collection1;
  

• Modify a specific document in the mongo shell:

  db.collection1.find({"_id":ObjectId("<INSERT_DOCUMENT_ID>")})
  db.collection1.update({"_id":ObjectId("<INSERT_DOCUMENT_ID>")},{$set:{"productID":"foo"}})
  

• Check that the modification has been replicated in the psql shell:

  select * from collection1 where id = '<INSERT_DOCUMENT_ID>';