Using .tags as a build_arg in the docker plugin

Drone Support
1

I want to stamp my docker images with the tag which I write to .tags in a previous step.

Basically I’d like to accomplish

build_args:
  - BUILD_ID: $(cat .tags)
2

Is this possible in the latest release of drone?

3

You cannot use bash commands inside of yaml properties like this. bash commands can only be executed in the commands section.

4

I didn’t mean to actually execute the bash command, I meant if there’s even a way to pass the content of .tags to the build_args

5

the .tags file is tied to the tags attribute in the yaml. it is not possible to use this file to populate other attributes.

6

Can you think of any workaround to stamp a custom build arg to an image?

Basically I want build-${DRONE_BUILD_NUMBER} for regular builds and ${DRONE_TAG} when it’s a tag push. I have logic to write that to .tags but I need to stamp it onto the image as well.

7

you can do this:

- name: build
  image: plugins/docker
  settings:
    tags: build-${DRONE_BUILD_NUMBER}
    repo: ...
  when:
    event: [ push, pull_request ]

- name: build_tag
  image: plugins/docker
  settings:
    tags: ${DRONE_TAG}
    repo: ...
  when:
    event: [ tag ]

and if you need to keep things DRY you can use anchors.

8

This works like a charm and is so much neater than writing to .tags. Thank you very much!

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