get_step: add metadata to build vars

[PentaHelix]

Changes proposed by this PR

get steps provide their metadata to the job as build variables

[linux-foundation-easycla]

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• ✅ login: PentaHelix / name: Jakob Kuen (1d1224e)

[PentaHelix]

There is probably a better place for this function

[taylorsilva]

I'd add it onto a new type of []MetadataField here:

concourse/atc/resource_types.go

Lines 10 to 13 in e81401c

	type MetadataField struct {
	Name string `json:"name"`
	Value string `json:"value"`
	}

Something like:

type Metadata []MetadataField

func (m Metadata) AsMap() map[string]any {
	result := make(map[string]any, len(m))
	for _, v := range m {
		result[v.Name] = v.Value
	}
	return result
}

Then VersionResult can also use that type:

concourse/atc/resource/resource.go

Lines 19 to 22 in e81401c

	type VersionResult struct {
	Version atc.Version `json:"version"`
	Metadata []atc.MetadataField `json:"metadata,omitempty"`
	}

Then AsMap(versionResult.Metadata) would become versionResult.Metadata.AsMap()!

[taylorsilva]

@PentaHelix Thanks for the PR! I have added you the all team in the concourse github org, which will allow you to see the build logs for the PR checks. You'll probably get an email to accept the invite.

[taylorsilva]

Thanks for the PR! Will review after I get 8.0 out.

[taylorsilva]

LGTM! I suggested how you can refactor AsMap() if you want to. As-is though, this works as expected.

Given this pipeline:

resources:
  - name: metadata
    type: mock
    source:
      metadata:
        - name: hello
          value: from metadata
        - name: hope
          value: it works!

jobs:
  - name: job
    plan:
      - get: metadata
      - task: echo
        config:
          platform: linux
          image_resource:
            type: mock
            source:
              mirror_self: true
          run:
            path: bash
            args:
              - -c
              - |
                echo ((.:metadata.hello))
                echo ((.:metadata.hope))

It worked!

If you don't have time to refactor I'll merge it as-is and refactor it later. Let me know. Thanks again for the PR!

[taylorsilva]

I'd add it onto a new type of []MetadataField here:

concourse/atc/resource_types.go

Lines 10 to 13 in e81401c

	type MetadataField struct {
	Name string `json:"name"`
	Value string `json:"value"`
	}

Something like:

type Metadata []MetadataField

func (m Metadata) AsMap() map[string]any {
	result := make(map[string]any, len(m))
	for _, v := range m {
		result[v.Name] = v.Value
	}
	return result
}

Then VersionResult can also use that type:

concourse/atc/resource/resource.go

Lines 19 to 22 in e81401c

	type VersionResult struct {
	Version atc.Version `json:"version"`
	Metadata []atc.MetadataField `json:"metadata,omitempty"`
	}

Then AsMap(versionResult.Metadata) would become versionResult.Metadata.AsMap()!