github actions mount file as volume in container

Question

I have following repo structure.

├── .cosmos
│   └── .config
├── .github
│   └── workflows
│       ├── plan.yml
│       └── update.yml
├── .gitignore
├── README.md
├── assets
│   ├── 1.png
│   ├── 2.png
│   └── 3.png
└── us-west-2
    ├── applications
    │   └── test.json
    └── cluster-config.json

And following GH Action yaml file.

plan.yml

name: Cosmos Plan

on:
  pull_request:
    paths:
      - "**/applications/*.json"
      - "**/cluster-config.json"

jobs:
  find:
    name: Find edited clusters
    runs-on: ubuntu-latest
    outputs:
      new: ${{ steps.find.outputs.new }}
      modified: ${{ steps.find.outputs.modified }}
      anyNew: ${{ steps.find.outputs.anyNew }}
      anyModified: ${{ steps.find.outputs.anyModified }}
    steps:
      - name: Checkout
        uses: actions/checkout@v2

      - name: Checkout cosmos-find action
        uses: actions/checkout@v2
        with:
          repository: this/cosmos-find
          ref: refs/tags/v3
          path: ./.github/actions/cosmos-find
          token: ${{ secrets.COSMOS_PAT }}

      - name: Cosmos find
        id: find
        uses: ./.github/actions/cosmos-find

  create:
    needs: find
    if: ${{ needs.find.outputs.anyNew == 'true' }}
    name: Create ${{ matrix.cluster }} cluster (plan)
    runs-on: ubuntu-latest
    container:
      image: ghcr.io/this/cosmos:v2.3.0-prerelease
      credentials:
        username: ${{ github.actor }}
        password: ${{ secrets.COSMOS_PAT }}
      volumes:
        - ${{ github.workspace }}/.cosmos/.config:/github/home/.cosmos/.config
    strategy:
      fail-fast: false
      matrix: ${{fromJson(needs.find.outputs.new)}}
    steps:
      - name: Check cosmos config file
        run: |
          ls -al /github/home/.cosmos/.config 
          cat  /github/home/.cosmos/.config

I want to mount .cosmos/.config file from my current repository to the container that I am running the action on.

According to this Github Workflow Syntax https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#jobsjob_idcontainervolumes , I should be able to do that.

I have specified volumes with following code block in my github action yml file.

container:
  image: ghcr.io/this/cosmos:v2.3.0-prerelease
  credentials:
    username: ${{ github.actor }}
    password: ${{ secrets.COSMOS_PAT }}
  volumes:
    - ${{ github.workspace }}/.cosmos/.config:/github/home/.cosmos/.config

I can see that during the Initialize Containers phase, GH Action is able to mount the file successfully. ( below logs )

    /usr/bin/docker create --name
 ee297063e4994cb488db28bfeadb1b8e_ghcriothiscosmosv230prerelease_487bad
 --label 8a33c1 --workdir /__w/virtualization-ci/virtualization-ci --network github_network_492eeddeb3ec4aca8594cb85567cea02  -e "HOME=/github/home" -e GITHUB_ACTIONS=true -e CI=true -v
 "/var/run/docker.sock":"/var/run/docker.sock" **-v
 "/home/runner/work/virtualization-ci/virtualization-ci/.cosmos/.config":"/github/home/.cosmos/.config"**
 -v "/home/runner/work":"/__w" -v "/home/runner/runners/2.278.0/externals":"/__e":ro -v
 "/home/runner/work/_temp":"/__w/_temp" -v
 "/home/runner/work/_actions":"/__w/_actions" -v
 "/opt/hostedtoolcache":"/__t" -v
 "/home/runner/work/_temp/_github_home":"/github/home" -v
 "/home/runner/work/_temp/_github_workflow":"/github/workflow"
 --entrypoint "tail" ghcr.io/this/cosmos:v2.3.0-prerelease "-f" "/dev/null"

But when I try to list and cat that file through GH Step Check cosmos config file, its telling me that its a directory. ( Error and Failure )

Run ls -al /github/home/.cosmos/.config 
  ls -al /github/home/.cosmos/.config 
  cat  /github/home/.cosmos/.config
  shell: sh -e {0}
cat: /github/home/.cosmos/.config: Is a directory
total 8
drwxr-xr-x 2 root root 4096 May 21 16:50 .
drwxr-xr-x 3 root root 4096 May 21 16:50 ..
Error: Process completed with exit code 1.

I have tried to mount the file on my local docker container by giving the full path and it does so without any issues.

Thanks.

Answer 1

You should be able to do this pretty easily with the cache action. Just cache that file in one job and load that cache in the following job as in the example here

name: Caching Primes

on: push

jobs: build: runs-on: ubuntu-latest

steps:
- uses: actions/checkout@v3

- name: Cache Primes
  id: cache-primes
  uses: actions/cache@v3
  with:
    path: prime-numbers
    key: ${{ runner.os }}-primes

- name: Generate Prime Numbers
  if: steps.cache-primes.outputs.cache-hit != 'true'
  run: /generate-primes.sh -d prime-numbers

- name: Use Prime Numbers
  run: /primes.sh -d prime-numbers