This project shows a web application built using a microservices architecture.

There are two microservices:

• rest-count implemented in Python (Flask microframework) using a Redis database
• rest-ip implemented in Node.js (Express framework) using a MongoDB database

Using consul-template you can generate a dynamic Nginx configuration so that you can deploy new microservices version with no downtime.

You can find additional information on my Slideshare presentation "Always be shipping"

Docker 1.11

docker-compose 1.7

Run the following commands in terminal (the first time you have to wait for a few minutes to download the Docker base images):

docker-compose -f application/docker-compose.yml up -d

open your browser to https://localhost:8080/

you can check the Consul state on https://localhost:8500/ui/

now edit rest-count/main.py (for example, you can increase the version to 1.1)

docker build -t francescou/rest-count:legacy rest-count/
docker-compose -f application/docker-compose.yml up -d restcountprimary
sleep 15
docker-compose -f application/docker-compose.yml up -d restcountbackup

the updated microservice will be deployed with no downtime.

You can also modify the rest-ip microservice in the same way (see rest-ip/app.js).

this section will explain how to can scale up and down docker-compose services.

open your browser to https://localhost:8500/ui/. There you will find a rest-count service, running on two nodes (one primary and one backup). Note that each node is a Docker container. Execute

docker-compose -f application/docker-compose.yml scale restcountprimary=3

check again https://localhost:8500/ui to ensure that there are now four rest-count instance (three primary and one backup).

Make a few requests to https://localhost:8080/api/v1/count and then run docker-compose -f application/docker-compose.yml logs to see how requests are processed by different rest-count instances.

You can now scale down the rest-count service without having any down time, e.g.:

docker-compose -f application/docker-compose.yml scale restcountprimary=2

Again, you can check https://localhost:8500/ui to see that there are now only two primary instances.