Add release steps to serve Helm Charts Repository on Github Pages

build.sbt

@@ -75,13 +75,15 @@ lazy val kafkaLagExporter =
         updateHelmChartRelease,                 // Update the Helm Chart
         publishDockerImage,                     // Publish the Docker images used by the chart
         packageChart,                           // Package the Helm Chart
+        buildChartsIndex,                       // Build Helm Charts index
         packageJavaApp,                         // Package the standalone Java App
         commitReleaseVersion,
         updateReadmeRelease,                    // Update the README.md with this version
         commitReadmeVersion,                    // Commit the README.md
         commitChartThisVersion,                 // Commit the Helm Chart
         tagRelease,
         githubReleaseDraft,                     // Create a GitHub release draft
+        publishChartsIndex,                     // Publish Helm Charts index
         setNextVersion,
         updateHelmChartNextVersion,             // Update the Helm Chart with the next snapshot version
         commitChartNextVersion,                 // Commit the Helm Chart
@@ -191,10 +193,23 @@ lazy val packageChart = ReleaseStep(action = st => {
   st
 })
 
+lazy val buildChartsIndex = ReleaseStep(action = st => {
+  val (releaseVersion, _) = st.get(versions).getOrElse(sys.error("No versions are set! Was this release part executed before inquireVersions?"))
+  exec(
+    s"./scripts/build_charts_index.sh https://github.com/lightbend/kafka-lag-exporter/releases/download/v$releaseVersion/ https://lightbend.github.io/kafka-lag-exporter/index.yaml",
+    "Error while building Helm Charts index")
+  st
+})
+
+lazy val publishChartsIndex = ReleaseStep(action = st => {
+  exec("./scripts/publish_charts_index.sh", "Error while publishing Helm Charts index")
+  st
+})
+
 lazy val githubReleaseDraft = ReleaseStep(action = st => {
   val (releaseVersion, _) = st.get(versions).getOrElse(sys.error("No versions are set! Was this release part executed before inquireVersions?"))
   exec(
-    s"./scripts/github_release.sh lightbend/kafka-lag-exporter v$releaseVersion -- kafka-lag-exporter-$releaseVersion.tgz ./target/universal/kafka-lag-exporter-$releaseVersion.zip",
+    s"./scripts/github_release.sh lightbend/kafka-lag-exporter v$releaseVersion -- .helm-release-packages/kafka-lag-exporter-$releaseVersion.tgz ./target/universal/kafka-lag-exporter-$releaseVersion.zip",
     "Error while publishing GitHub release draft")
   st
 })

scripts/build_charts_index.sh

@@ -0,0 +1,24 @@
+#!/usr/bin/env bash
+
+set -e
+
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
+
+cd $DIR/..
+
+REMOTE_URL_BASE=$1
+REMOTE_INDEX_URL=$2
+CHARTS_DIR=".helm-release-packages"
+
+EXISTING_INDEX=$(mktemp /tmp/index.yaml.XXXXXX)
+
+REMOTE_CODE=$(curl -s -L -w "%{http_code}" $REMOTE_INDEX_URL -o $EXISTING_INDEX)
+if [ $REMOTE_CODE -eq 200 ]; then
+  echo Adding new packages to existing index
+  helm repo index --merge $EXISTING_INDEX --url $REMOTE_URL_BASE CHARTS_DIR
+else
+  echo Creating new index
+  helm repo index --url $REMOTE_URL_BASE $CHARTS_DIR
+fi
+
+rm "${EXISTING_INDEX}"

scripts/package_chart.sh

@@ -6,8 +6,11 @@ DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
 
 cd $DIR/..
 
+CHARTS_DIR=".helm-release-packages"
+
 # Bundle Kafka Lag Exporter Helm Chart into a tarball artifact.  The `helm package` command will output the artifact
-# in the CWD it is executed from.
+# in the CHARTS_DIR.
 echo Package helm chart
-rm -f ./kafka-lag-exporter-*.tgz
-helm package ./charts/kafka-lag-exporter
+mkdir -p $CHARTS_DIR
+rm -f $CHARTS_DIR/kafka-lag-exporter-*.tgz
+helm package ./charts/kafka-lag-exporter -d $CHARTS_DIR

scripts/publish_charts_index.sh

@@ -0,0 +1,67 @@
+#!/usr/bin/env bash
+
+set -e
+
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null && pwd )"
+
+cd $DIR/..
+
+CHARTS_DIR=".helm-release-packages"
+GITHUB_PAGES_BRANCH="gh-pages"
+
+function pages_branch_missing() {
+    local existed_in_remote=$(git ls-remote --heads origin $GITHUB_PAGES_BRANCH)
+
+    [ -z "${existed_in_remote}" ]
+}
+
+function create_pages_branch() {
+  echo "Creating pages branch ${GITHUB_PAGES_BRANCH}"
+  git checkout --quiet --orphan $GITHUB_PAGES_BRANCH
+  git rm --quiet -rf .
+  git commit --quiet --allow-empty -m "Pages initial commit"
+  git push --quiet origin HEAD:refs/heads/$GITHUB_PAGES_BRANCH
+  git checkout --detach --quiet
+  git branch --quiet -d $GITHUB_PAGES_BRANCH
+}
+
+function add_pages_worktree() {
+  local worktree_dir=${1}
+
+  if pages_branch_missing; then
+    git worktree add --quiet --detach ${worktree_dir}
+    pushd ${worktree_dir} > /dev/null
+    create_pages_branch
+    popd > /dev/null
+  else
+    git worktree add --quiet ${worktree_dir} "origin/${GITHUB_PAGES_BRANCH}"
+  fi
+}
+
+function remove_pages_worktree() {
+  local worktree_dir=${1}
+  git worktree remove --force ${worktree_dir}
+  rm -rf ${worktree_dir}
+}
+
+function push_index() {
+  if [[ ! -f "${CHARTS_DIR}/index.yaml" ]]; then
+    return -1
+  fi
+
+  local worktree=$(mktemp -d /tmp/worktree.XXXXXX)
+  add_pages_worktree ${worktree}
+
+  cp ${CHARTS_DIR}/index.yaml ${worktree}/
+  pushd ${worktree} > /dev/null
+  git add index.yaml
+  git commit --quiet --message "Update index.yaml"
+  git push --quiet origin HEAD:refs/heads/$GITHUB_PAGES_BRANCH
+  popd > /dev/null
+
+  remove_pages_worktree ${worktree}
+}
+
+push_index
+
+