When I create a GitHub Actions workflow file, the example YAML file contains runs-on: ubuntu-latest. According to the docs, I only have the options between a couple versions of Ubuntu, Windows Server and macOS X.
I thought GitHub Actions runs inside Docker. How do I choose my Docker image?
GitHub actions provision a virtual machine - as you noted, either Ubuntu, Windows or macOS - and run your workflow inside of that. You can then use that virtual machine to run a workflow inside a container.
Use the container specifier to run a step inside a container. Be sure to specify runs-on as the appropriate host environment for your container (ubuntu-latest for Linux containers, windows-latest for Windows containers). For example:
jobs:
vm:
runs-on: ubuntu-latest
steps:
- run: |
echo This job does not specify a container.
echo It runs directly on the virtual machine.
name: Run on VM
container:
runs-on: ubuntu-latest
container: node:10.16-jessie
steps:
- run: |
echo This job does specify a container.
echo It runs in the container instead of the VM.
name: Run in container
container is a private image in the GH registry? Will this still work?
A job (as part of a workflow) runs inside a virtual machine. You choose one of the environments provided by them (e.g. ubuntu-latest or windows-2019).
A job consists of one or more steps. A step may be a simple shell command, using run. But it may also be an action, using uses
name: CI
on: [push]
jobs:
myjob:
runs-on: ubuntu-18.04 # linux required if you want to use docker
steps:
# Those steps are executed directly on the VM
- run: ls /
- run: echo $HOME
- name: Add a file
run: touch $HOME/stuff.txt
# Those steps are actions, which may run inside a container
- uses: actions/checkout@v1
- uses: ./.github/actions/my-action
- uses: docker://continuumio/anaconda3:2019.07
run: <COMMAND> executes the command with the shell of the OSuses: actions/checkout@v1 runs the action from the user / organization actions in the repository checkout (https://github.com/actions/checkout), major release 1uses: ./.github/actions/my-action runs the action which is defined in your own repository under this pathuses: docker://continuumio/anaconda3:2019.07 runs the anaconda3 image from user / organization continuumio, version 2019.07, from the Docker Hub (https://hub.docker.com/r/continuumio/anaconda3)Keep in mind that you need to select a linux distribution as the environment if you want to use Docker.
Take a look at the documentation for uses and run for further details.
It should also be noted that there is a container option, allowing you to run any steps that would usually run on the host to be runned inside a container: https://help.github.com/en/articles/workflow-syntax-for-github-actions#jobsjob_idcontainer
run commands to execute properly in the container, not even echo "hello world". It just dies right after it was started, and then the job fails with Error response from daemon: Container 60e7cf...0b17 is not running. Do you know why that happens / how to fix it? The image I used was python:3.7-alpine.
docker:// scheme with uses, how can I specify run configurations?
with: entripoint: yaml subtree allows specifying a script to run (relative to repository root), like (minified yaml one-liner to put it in a comment) [{uses: 'docker://ghcr.io/user/image:tag', with: {entrypoint: ./build-artifacts.sh}}] 