Introduce new generate-labels task

task/generate-labels/0.1/README.md

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+# generate-labels task
+
+Generate labels based on templates.
+
+Usage may look like the following.
+
+> - name: generate-labels
+>   params:
+>   - name: LABEL_TEMPLATES
+>     value:
+>       - "release=$SOURCE_DATE_EPOCH"
+>       - "build-date=$SOURCE_DATE"
+
+The following environment variables are defined for use in LABEL_TEMPLATES
+
+* ACTUAL_DATE - a date time string containing the time this task runs, formatted +'%Y-%m-%dT%H:%M:%S'
+* ACTUAL_DATE_EPOCH - the timestamp at the time this task runs
+* SOURCE_DATE - a date time string containing the provided source timestamp, formatted +'%Y-%m-%dT%H:%M:%S'
+* SOURCE_DATE_EPOCH - the timestamp provided as a param meant to represent the timestamp at which the source was last modified
+
+
+## Parameters
+|name|description|default value|required|
+|---|---|---|---|
+|LABEL_TEMPLATES|A list of templates that should be rendered and exposed as a list of labels|[]|false|
+|SOURCE_DATE_EPOCH|A standardised environment variable for build tools to consume in order to produce reproducible output.|""|false|
+
+## Results
+|name|description|
+|---|---|
+|LABELS|The rendered labels, rendered from the provided templates|
+

task/generate-labels/0.1/generate-labels.yaml

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+apiVersion: tekton.dev/v1beta1
+kind: Task
+metadata:
+  labels:
+    app.kubernetes.io/version: "0.1"
+  annotations:
+    tekton.dev/pipelines.minVersion: "0.12.1"
+    tekton.dev/tags: "konflux"
+  name: generate-labels
+spec:
+  description: |
+    Generate labels based on templates.
+
+    Usage may look like the following.
+
+    > - name: generate-labels
+    >   params:
+    >   - name: LABEL_TEMPLATES
+    >     value: '["release=$SOURCE_DATE_EPOCH", "build-date=$SOURCE_DATE"]'
+
+    The following environment variables are defined for use in LABEL_TEMPLATES
+
+    * ACTUAL_DATE - a date time string containing the time this task runs, formatted +'%Y-%m-%dT%H:%M:%S'
+    * ACTUAL_DATE_EPOCH - the timestamp at the time this task runs
+    * SOURCE_DATE - a date time string containing the provided source timestamp, formatted +'%Y-%m-%dT%H:%M:%S'
+    * SOURCE_DATE_EPOCH - the timestamp provided as a param meant to represent the timestamp at which the source was last modified
+
+  params:
+  - name: label-templates
+    description: A json array of templates that should be rendered and exposed as a list of labels
+    type: string
+  - name: source-date-epoch
+    description: A standardised environment variable for build tools to consume in order to produce reproducible output.
+    default: ""
+  results:
+    - name: labels
+      description: The rendered labels, rendered from the provided templates
+  steps:
+    - name: render
+      image: quay.io/konflux-ci/yq:latest@sha256:91a7fe73fd28bbfd93ebdcc68cdfd7087d4f2612c627ccd0d5f984190eb7dba6
+      env:
+      - name: LABEL_TEMPLATES
+        value: "$(params.label-templates)"
+      - name: SOURCE_DATE_EPOCH
+        value: "$(params.source-date-epoch)"
+      script: |
+          #!/bin/bash
+
+          ACTUAL_DATE_EPOCH=$(date -u +'%s')
+          # shellcheck disable=SC2034  # Unused variable used implicitly in envsubst
+          ACTUAL_DATE=$(date -u --date=@"$ACTUAL_DATE_EPOCH" +'%Y-%m-%dT%H:%M:%S') 
+
+          if [ "$SOURCE_DATE_EPOCH" == "" ]; then
+            SOURCE_DATE_EPOCH="$ACTUAL_DATE_EPOCH"
+          fi
+          # shellcheck disable=SC2034  # Unused variable used implicitly in envsubst
+          SOURCE_DATE=$(date -u --date=@"$SOURCE_DATE_EPOCH" +'%Y-%m-%dT%H:%M:%S') 
+
+          export ACTUAL_DATE
+          export ACTUAL_DATE_EPOCH
+          export SOURCE_DATE
+          export SOURCE_DATE_EPOCH
+
+          printf "[]" > result.json
+
+          for template in $(echo "${LABEL_TEMPLATES}" | yq -r '.[]'); do
+            echo "Processing template $template"
+            label=$(echo "$template" | envsubst)
+            yq -oj -i '. += ["'"$label"'"]' result.json
+          done
+
+          echo "Created the following labels:"
+          tee "$(results.labels.path)" < result.json

task/generate-labels/OWNERS

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+# See the OWNERS docs: https://go.k8s.io/owners
+approvers:
+  - build-team
+  - ralphbean
+reviewers:
+  - build-team
+  - ralphbean