Inject version information into images

.github/workflows/controller-sharding.yaml

@@ -54,15 +54,35 @@ jobs:
       id: meta
       # generate comma-separated tags and labels for image build (similar to docker/metadata-action)
       run: |
+        build_date="$(date -u +%Y-%m-%dT%H:%M:%SZ)"
+        # revision is the commit sha
+        revision=${{ github.sha }}
+        # version is the commit sha, or the semantic version git tag
+        version=$revision
+        # short_ref is the branch name, or the pr-<number> string, or the semantic version git tag
         short_ref=${{ github.ref_name }}
+
         if ${{ github.event_name == 'pull_request' }} ; then
           # for PR events, ref_name is '<pr-number>/merge' but tags may not contain /
           short_ref=pr-${{ github.event.pull_request.number }}
         fi
+  
+        major_version="0"
+        minor_version="0+"
+        if [[ ${{ github.ref }} = refs/tags/* && $short_ref =~ ^v([0-9]+)\.([0-9]+)\.([0-9]+)([-].*)?([+].*)?$ ]] ; then
+          version=$short_ref
+          short_ref=$short_ref
+
+          major_version=${BASH_REMATCH[1]}
+          minor_version=${BASH_REMATCH[2]}
+          if [[ -n "${BASH_REMATCH[4]}" ]]; then
+            minor_version+="+"
+          fi
+        fi
 
         tags=(
           $short_ref
-          sha-$( echo ${{ github.sha }} | head -c7 )
+          sha-$( echo $revision | head -c7 )
         )
 
         if ${{ github.ref_name == 'master' }} ; then
@@ -72,19 +92,48 @@ jobs:
         echo "tags=$(IFS=, ; echo "${tags[*]}")" >> $GITHUB_OUTPUT
 
         labels=(
-          org.opencontainers.image.created=$( date -u +%Y-%m-%dT%H:%M:%SZ )
+          org.opencontainers.image.created=$build_date
           org.opencontainers.image.licenses=Apache-2.0
-          org.opencontainers.image.revision=${{ github.sha }}
+          org.opencontainers.image.revision=$revision
           org.opencontainers.image.source=https://github.com/${{ github.repository }}
           org.opencontainers.image.url=https://github.com/${{ github.repository }}
-          org.opencontainers.image.version=$short_ref
+          org.opencontainers.image.version=$version
         )
 
         echo "labels=$(IFS=, ; echo "${labels[*]}")" >> $GITHUB_OUTPUT
+
+        # calculate ldflags for injecting version information into binaries
+        tree_state="$([ -z git status --porcelain 2>/dev/null ] && echo clean || echo dirty)"
+
+        echo "LDFLAGS<<EOF
+        -X k8s.io/component-base/version.gitMajor=$major_version
+        -X k8s.io/component-base/version.gitMinor=$minor_version
+        -X k8s.io/component-base/version.gitVersion=$version
+        -X k8s.io/component-base/version.gitTreeState=$tree_state
+        -X k8s.io/component-base/version.gitCommit=$revision
+        -X k8s.io/component-base/version.buildDate=$build_date
+        -X k8s.io/component-base/version/verflag.programName=kubernetes-controller-sharding
+        EOF" >> $GITHUB_ENV
     - name: ko build
       run: |
         set -ex
 
-        ko build --push=${{ github.event_name != 'pull_request' }} --sbom none --base-import-paths --platform linux/amd64,linux/arm64 \
-          --tags "${{ steps.meta.outputs.tags }}" --image-label "${{ steps.meta.outputs.labels }}" \
+        # prepare .ko.yaml to inject build settings into all images
+        entrypoints=(
           ./cmd/sharder
+        )
+        
+        echo builds: > .ko.yaml
+        for entrypoint in "${entrypoints[@]}" ; do
+        cat >> .ko.yaml <<EOF
+        - main: $entrypoint
+          ldflags:
+          - |
+            {{.Env.LDFLAGS}}
+        EOF
+        done
+
+        ko build --push=${{ github.event_name != 'pull_request' }} --sbom none --base-import-paths \
+          --tags "${{ steps.meta.outputs.tags }}" --image-label "${{ steps.meta.outputs.labels }}" \
+          --platform linux/amd64,linux/arm64 \
+          "${entrypoints[@]}"