Hi everyone,

This is a tutorial I am going to walk through how to run docker containers in GitHub Action workflows.
This task is often useful in testing workflows where we need a temporary database to run test cases. we will run a PostgreSQL database in this tutorial.

name: Running Tests

on: [push]

jobs:
  Test:
    runs-on: ubuntu-latest

    services:
      postgres:
        image: postgres

        env:
          POSTGRES_PASSWORD: postgres
          POSTGRES_USER: postgres
          POSTGRES_DB: postgres

        options: >-
          --health-cmd pg_isready
          --health-interval 10s
          --health-timeout 5s
          --health-retries 5
        ports:

          - 5432:5432

in the above workflow snippet, we do several things.

1.

on: [push]

will set when to run this workflow. here we have specified push, so on every push event, this workflow will run. keep in mind that this is an array so we can use multiple options like pull_request etc.

2.

jobs:
  service-container-demo:

this code snippet will specify our job . service-container-demo is the name of our job.

3.

runs-on: ubuntu-latest

specifies, on what operating system we need to run this job. here we have specified to run it on ubuntu's latest operating system.

4.

 services:
      postgres:

here we specify the services we need to run, and the name of the service container. name of the service container is used to access it.

5.

image: postgres

this line will specify what image we need to run. these docker images are fetched from Docker Hub . so we need to specify the respective image name from Docker Hub.

6.

    env:
      POSTGRES_PASSWORD: postgres
      POSTGRES_USER: postgres
      POSTGRES_DB: postgres

here we have specified the environment variables we need to provide to the service container. we have provided the password, username, and the default database here, so we can later access the database via those credentials.

7.

  options: >-
    --health-cmd pg_isready
    --health-interval 10s
    --health-timeout 5s
    --health-retries 5

we have to wait some time till the container is up and running .so to check that we have specified options to periodically check and after it is started proceed to the next steps.

8.

 ports:
   - 5432:5432

here we have specified the port mapping. 5432 host port
is mapped to 5432 container port.

next, we can define the steps of the workflow. here we can migrate to the service container database, and run the required tests.

# define steps of workflow
    steps:
      # run steps required in the workflow
      - name: Checkout repository
        uses: actions/checkout@v2

      - name: Set up Node.js 14.x
        uses: actions/setup-node@v1
        with:
          node-version: 14.x

      - name: Install dependencies
        run: npm install

      - name: migrate database
        run: node migrate.js
        env:
          DBURL: "postgres://postgres:postgres@localhost:5432/postgres"

      - name: Run the mock tests function
        run: node getuser.js
        env:
          DBURL: postgres://postgres:postgres@localhost:5432/postgres

in above snippet DBURL is set to postgres://postgres:postgres@localhost:5432/postgres . it is derived through the configurations we set in the service container earlier. the host is provided as localhost because the docker and host machine both runs on localhost. and here, we are passing it to the step, through an environment variable.

database migration

database query

complete workflow file .

example GitHub repo

Thanks for reading till the end 🙌

I value your opinions, and appreciate you taking the time to share your thoughts.