[nx-docker] How to use extracted metadata in cache-from configurations

[roderik]

I'm trying to recreate my build flow using bare buildx on github actions using this plugin but I've got some issues setting up the buildx caching.

Given the following config:

        "docker": {
          "executor": "@nx-tools/nx-docker:build",
          "options": {
            "file": "apps/api/Dockerfile",
            "tags": ["ghcr.io/settlemint/bpaas-console-api:dev"],
            "meta": {
              "enabled": true,
              "images": ["ghcr.io/settlemint/bpaas-console-api"],
              "tags": [
                "type=schedule",
                "type=ref,event=branch",
                "type=ref,event=tag",
                "type=ref,event=pr",
                "type=sha,format=long,prefix="
              ]
            }
          }
        },

The container gets build and tagged with the long SHA and a slug of my branch name

Good so far.

But some of these build steps do not change, and are very heavy, so I'm used to using cache-from with the branch name slug so these expensive layers only get build once per branch.

      - name: Inject slug/short variables
        uses: rlespinasse/github-slug-action@v3.x

      - name: Build and push Launchpad Cluster Manager (Not Production)
        uses: docker/build-push-action@v2
        with:
          context: ./packages/launchpad-nest/
          file: ./packages/launchpad-nest/cluster-manager.Dockerfile
          pull: true
          push: true
          cache-from: type=registry,ref=ghcr.io/settlemint/launchpad-nest-cluster-manager:${{ env.GITHUB_REF_SLUG }}
          cache-to: type=inline
          tags: |
            ghcr.io/settlemint/launchpad-nest-cluster-manager:${{ env.GITHUB_REF_SLUG }}
            ghcr.io/settlemint/launchpad-nest-cluster-manager:${{ env.GITHUB_REF_SLUG }}-build${{ github.run_number }}

The challenge now with nx-docker is, how do i use the auto extracted metadata, in the cache-from config.

[roderik]

Foud an issue somewhere that mentions the config is pushed to the shell so bash/sh variables work

        "docker": {
          "executor": "@nx-tools/nx-docker:build",
          "options": {
            "file": "apps/cluster-manager/Dockerfile",
            "tags": [
              "ghcr.io/settlemint/bpaas-cluster-manager:${GITHUB_REF_SLUG}",
              "ghcr.io/settlemint/bpaas-cluster-manager:${GITHUB_REF_SLUG}-${GITHUB_SHA_SHORT}"
            ],
            "cache-from": [
              "ghcr.io/settlemint/bpaas-cluster-manager:${GITHUB_REF_SLUG}",
              "ghcr.io/settlemint/bpaas-cluster-manager:alpha"
            ],
            "cache-to": ["type=inline"],
            "pull": true
          }
        },