docker run image from (gha or local) cache-CodePudding

How can I execute a command (i.e. run) an image which is only part of the (local) build cache in docker (in GHA) and was not pushed to a registry?

The full example here: https://github.com/geoHeil/containerfun

Dockerfile:

FROM ubuntu:latest as builder
RUN echo hello >> asdf.txt

FROM builder as app
RUN cat asdf.txt

ci.yaml GHA workflow:

name: ci
on:
  push:
    branches:
    - main

jobs:
  testing:
    runs-on: ubuntu-latest
    steps:
    - name: Checkout
      uses: actions/checkout@v3

    - name: Set up Docker Buildx
      id: buildx
      uses: docker/setup-buildx-action@v2
      
    - name: Login to GitHub Container Registry
      uses: docker/login-action@v1
      with:
        registry: ghcr.io
        username: ${{ github.actor }}
        password: ${{ secrets.GITHUB_TOKEN }}

    - name: cache base builder
      uses: docker/build-push-action@v3
      with:
        push: True
        tags: ghcr.io/geoheil/containerfun-cache:latest
        target: builder
        cache-from: type=gha
        cache-to: type=gha,mode=max
        
    - name: build app image (not pushed)
      run: docker buildx build --cache-from type=gha --target app --tag ghcr.io/geoheil/containerfun-app:latest .
    

      
    - name: run some command in image
      run: docker run ghcr.io/geoheil/containerfun-app:latest ls /

    - name: one some other command in image
      run: docker run ghcr.io/geoheil/containerfun-app:latest cat /asdf.txt

When using the pushed image:

docker run ghcr.io/geoheil/containerfun-cache:latest cat /asdf.txt

it works just fine. When using the non-pushed (cached only one) docker fails with:

docker run ghcr.io/geoheil/containerfun-app:latest cat /asdf.txt

fails with

Unable to find image 'ghcr.io/geoheil/containerfun-app:latest' locally

why does it fail? Shouldn`t the image at least reside in the local build cache?

edit

obviously:

- name: fooasdf
      #run: docker buildx build --cache-from type=gha --target app --tag ghcr.io/geoheil/containerfun-app:latest --build-arg BUILDKIT_INLINE_CACHE=1 .
      uses: docker/build-push-action@v3
      with:
        push: True
        tags: ghcr.io/geoheil/containerfun-app:latest
        target: app
        cache-from: ghcr.io/geoheil/containerfun-cache:latest

Is a potential workaround, and docker run ghcr.io/geoheil/containerfun-app:latest cat /asdf.txt now works fine. However:

this is using the registry and not type=gha as the cache
requires to push the internal builder image to the registry (what I not want)
requires to use the image (pull in the run step) from the registry. I would expect to be able to simply run the already existing local image (which was built in the step before

CodePudding user response：

It's failing because now you built the image with buildx and it's available only inside the buildx context. If you have to use the image in docker context, you have to load that image into the docker side by using the parameter --load when you build the image using buildx. See https://docs.docker.com/engine/reference/commandline/buildx_build/#load

So change the step to something like this

- name: build app image (not pushed)
  run: docker buildx build --cache-from type=gha --target app --load --tag ghcr.io/geoheil/containerfun-app:latest .

NOTE: The --load parameter doesn't support multi-arch builds atm