Saved Image Missing RepoTags

[cholick]

This seems a bit related to #78, but isn't the same issue.

When I do a docker save, the manifest.json in the tar file includes a populated RepoTags array. For example, after running

 docker save gcr.io/kubernetes-helm/tiller:v2.8.2 -o tiller.2.8.2.tgz

the tarball has:

...
  "RepoTags": ["gcr.io/kubernetes-helm/tiller:v2.8.2"],
...

In contrast, the /image file in concourse has an empty RepoTags:

...
  "RepoTags":null
...

/tag is correctly populated: unlike #78, and I am specifying a concrete version.

The docker load command uses that manifest's metadata, such that using the image saved via docker's cli:

docker load -i tiller-v2.8.2.tgz

results in an image with proper repository and tag:

$ docker images
REPOSITORY                           TAG                 IMAGE ID            CREATED             SIZE
gcr.io/kubernetes-helm/tiller        v2.8.2              1c5314e713c2        2 months ago        71.6MB

but loading an image generated via concourse does not.

Example pipeline used to test:

---

resources:
- name: tiller-image
  type: docker-image
  source:
    repository: gcr.io/kubernetes-helm/tiller
    tag: "v2.8.2"

jobs:
- name: image-test
  plan:
  - aggregate:
    - get: tiller-image
      params:
        save: true
  - task: do-test
    config:
      inputs:
      - name: tiller-image
      platform: linux
      image_resource:
        type: docker-image
        source:
          repository: bash
      run:
        path: bash
        args:
        - -exc
        - |
          echo "Exit 1 to keep around container"
          exit 1

[cholick]

Hesitate to claim this ugly hack, but... if anyone gets to this issue via Google search, probably using this as a stopgap workaround:

---
resource_types:
- name: gcs-resource
  type: docker-image
  source:
    repository: frodenas/gcs-resource

resources:
- name: tiller-image
  type: docker-image
  source:
    repository: gcr.io/kubernetes-helm/tiller
    tag: "v2.8.2"

- name: output-test
  type: gcs-resource
  source:
    bucket: temp-delete
    regexp: image.tar
    json_key: {....}

jobs:
- name: image-test
  plan:
  - aggregate:
    - get: tiller-image
      params:
        save: true
  - task: do-test
    config:
      inputs:
      - name: tiller-image
      outputs:
      - name: out
      platform: linux
      image_resource:
        type: docker-image
        source:
          repository: <some image with python and bash>
      run:
        path: bash
        args:
        - -exc
        - |
          pushd tiller-image
          mkdir -p new-image out
          pushd new-image
          tar -xvf ../image
          popd

          cp new-image/manifest.json manifest.json.bk

          echo '
          import json

          with open("repository") as repo_file:
          	repo = repo_file.read().strip()

          with open("tag") as tag_file:
          	tag = tag_file.read().strip()

          with open("new-image/manifest.json", "r+") as file:
          	manifest = json.load(file)
          	repo_tags = ["{}:{}".format(repo, tag)]
          	manifest[0]["RepoTags"] = repo_tags
          	new_manifest = json.dumps(manifest)

          	file.seek(0)
          	print("\n", new_manifest, "\n")
          	file.write(new_manifest)
          ' > fix_manifest.py

          python fix_manifest.py

          tar -cvf ../out/new-image.tar -C new-image $(ls new-image)

  - put: output-test
    params:
      file: out/new-image.tar

[tchaloupka]

I've been bitten by this too.
It's because of:

docker-image-resource/assets/in

Line 56 in 9e07b92

image_name="${repository}@${digest}"

And the behavior described here: moby/moby#3877

Thx for the workaround.

[xtremerui]

Unfortunately we have to use image_name="${repository}@${digest}" since later the variable is used for docker pull (as mentioned in moby/moby#3877 digest to image could be 1:M mapping) and digest is unique.

Giving that moby/moby#3877 is closed and solution is available if one wants to have the repo & tag saved in output image, i will closing this issue now.