Source Code: https://github.com/amard33p/ansible-docker
We have a simple docker compose file which defines 2 components - ui and api.
# docker-compose.yml
version: "3.5"
services:
ui:
build: ./ui
ports:
- "8080:8000"
depends_on:
- api
api:
build: ./api
ports:
- "8081:5000"
A common need during development is to mount the source code inside containers for faster iterations.
To solve this we generally create a compose override file.
# docker-compose.override.yml
version: "3.5"
services:
ui:
volumes:
- ./ui/index.html:/app/index.html
The override file should be present in Dev environment but must be absent in Production as we would already have a tested pre-built image by then.
There are pre-processors like jsonnet that allows the ability to add “logic” to dumb YAML files. However, in my opinion, a simpler solution can be achieved using Ansible Playbooks.
Using the Ansible modules docker_network, docker_image and docker_container, the equivalent standalone ansible playbook for the above compose files would be:
---
- hosts: localhost
gather_facts: no
vars:
# Compose creates entities based on the directory name
curdir: "{{ playbook_dir.split('/')[-1] }}"
tasks:
# Get value of devenv from extra args
- set_fact:
devenv: "{{ devenv | default(false) }}"
- debug:
msg: Dev Environment = {{ devenv }}
- name: Creating bridge network {{ curdir }}_default
docker_network:
name: "{{ curdir }}_default"
- name: Building image {{ curdir }}_api
docker_image:
build:
path: ./api
source: build
name: "{{ curdir }}_api"
when: devenv|bool
- name: Starting container {{ curdir }}_api_1
docker_container:
name: "{{ curdir }}_api_1"
image: "{{ curdir }}_api"
networks_cli_compatible: yes
network_mode: "{{ curdir }}_default"
networks:
- name: "{{ curdir }}_default"
ports:
- '8081:5000'
- name: Building image {{ curdir }}_ui
docker_image:
build:
path: ./ui
source: build
name: "{{ curdir }}_ui"
when: devenv|bool
- name: Starting container {{ curdir }}_ui_1
docker_container:
name: "{{ curdir }}_ui_1"
image: "{{ curdir }}_ui"
networks_cli_compatible: yes
network_mode: "{{ curdir }}_default"
networks:
- name: "{{ curdir }}_default"
ports:
- '8080:8000'
volumes:
- "{{ './ui/index.html:/app/index.html' if devenv else omit }}"
We pass in a flag through extra-args to specify the environment and use the volume mount based on that:
volumes:
- "{{ './ui/index.html:/app/index.html' if devenv else omit }}"
Run the playbook as follows:
- In Dev:
ansible-playbook -e "devenv=true" compose_playbook.yml - In Test/Prod:
ansible-playbook compose_playbook.yml
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