Support for Pre-tag hook

[JJRdec]

This probably a feature request - unless there is support already available

I am trying to use pre-build hooks to run a command which parses and stores my app's version as an environment variable ($APP_VERSION) from a properties file. Then I use envTemplate to reference variable for the tagPolicy.

As you can see in the output snippet the image is tagged before the pre-build hook runs. I would like to parse and export the version with hooks before the tags are generated.

Also, my command works great on the command line however not when used with hooks - any tips?

Skaffold Snippet:

apiVersion: skaffold/v2beta28
kind: Config
profiles:
  - name: local
    build:
      tagPolicy:
        envTemplate:
          template: "{{.APP_VERSION}}"
      artifacts:
        - image: my-app
          hooks:
            before:
              - command: [ "sh", "-c", "export APP_VERSION=$(grep \"applicationVersion\" gradle.properties | awk -F '='  '{ print $2 }')" ]
                os: [ darwin, linux ]
          custom:
            buildCommand: ./build.sh

Output Snippet:
Command: skaffold dev -p local

Listing files to watch...
 - my-app
Generating tags...
 - my-app -> my-app:latest
Some taggers failed. Rerun with -vdebug for errors.
Starting build...
Found [docker-desktop] context, using local docker daemon.
Building [my-app]...
Target platforms: [linux/amd64]
Starting pre-build hooks...
Completed pre-build hooks
.
.

Any thoughts?

Many thanks in advance :)

[tejal29]

This is a great request and wondering if we should run the pre-build hooks before tagging. /cc @gsquared94 for more input on was this considered during design.

[gsquared94]

we unfortunately don't support any mechanism to propagate or persist environment variables set in any of the hooks command. As such running the hooks before or after generating the tag doesn't make a difference to the output.

We have a section on propagating environment variables in the design doc here that we can look to implement:
https://github.com/GoogleContainerTools/skaffold/blob/main/docs/design_proposals/lifecycle-hooks.md#env-propagation

[tomer-ds]

Any idea if this is going to see the light of day any time soon?
The concept of a single hook that runs during the initial phase before tagging seems like a slam-dunk feature! Seriously useful and clearly lacking! Anything that could be done towards this should as it would help streamline many arbitrary code requirements during the dev phase! Especially in a mono-repo setup with multiple services.

Big +1 👍🏼

[ericzzzzzzz]

hi @JJRdec , the skaffold v2.1.0 support running a shell command in template filed..
Could you try it to see if this fits your use case.

apiVersion: skaffold/v2beta28
kind: Config
profiles:
  - name: local
    build:
      tagPolicy:
        envTemplate:
          template: '{{"cmd" "bash" "-c" "grep \"applicationVersion\" gradle.properties | awk -F '='  '{ print $2 }'"}}'