Add changed_charts and chart_version outputs (#130)

* Add `changed_charts` and `chart_version` outputs

This should let downstream steps make conditional decisions
based on what we found.

Also: fix a confusing double-negative test in main().

Signed-off-by: Nathan J. Mehl <n@oden.io>

---------

Signed-off-by: Nathan J. Mehl <n@oden.io>

README.md

@@ -21,6 +21,11 @@ A GitHub action to turn a GitHub project into a self-hosted Helm chart repo, usi
 - `skip_packaging`: This option, when populated, will skip the packaging step. This allows you to do more advanced packaging of your charts (for example, with the `helm package` command) before this action runs. This action will only handle the indexing and publishing steps.
 - `mark_as_latest`: When you set this to `false`, it will mark the created GitHub release not as 'latest'.
 
+### Outputs
+
+- `changed_charts`: A comma-separated list of charts that were released on this run. Will be an empty string if no updates were detected, will be unset if `--skip_packaging` is used: in the latter case your custom packaging step is responsible for setting its own outputs if you need them.
+- `chart_version`: The version of the most recently generated charts; will be set even if no charts have been updated since the last run.
+
 ### Environment variables
 
 - `CR_TOKEN` (required): The GitHub token of this repository (`${{ secrets.GITHUB_TOKEN }}`)

action.yml

@@ -32,11 +32,19 @@ inputs:
     description: Mark the created GitHub release as 'latest'
     required: false
     default: true
+outputs:
+  changed_charts:
+    description: "A comma-separated list of charts that were released on this run. Will be an empty string if no updates were detected, will be unset if `--skip_packaging` is used: in the latter case your custom packaging step is responsible for setting its own outputs if you need them."
+    value: ${{ steps.release.outputs.changed_charts }}
+  chart_version:
+    description: "The version of the most recently generated charts; will be set even if no charts have been updated since the last run."
+    value: ${{ steps.release.outputs.chart_version }}
 
 runs:
   using: composite
   steps:
-    - run: |
+    - id: release
+      run: |
         owner=$(cut -d '/' -f 1 <<< "$GITHUB_REPOSITORY")
         repo=$(cut -d '/' -f 2 <<< "$GITHUB_REPOSITORY")
 
@@ -77,4 +85,12 @@ runs:
         fi
 
         "$GITHUB_ACTION_PATH/cr.sh" "${args[@]}"
+
+        if [[ -f changed_charts.txt ]]; then
+            cat changed_charts.txt >> "$GITHUB_OUTPUT"
+        fi
+        if [[ -f chart_version.txt ]]; then
+            cat chart_version.txt >> "$GITHUB_OUTPUT"
+        fi
+        rm -f changed_charts.txt chart_version.txt
       shell: bash

cr.sh

@@ -21,7 +21,7 @@ set -o pipefail
 DEFAULT_CHART_RELEASER_VERSION=v1.6.0
 
 show_help() {
-cat << EOF
+  cat <<EOF
 Usage: $(basename "$0") <options>
 
     -h, --help               Display help
@@ -56,16 +56,16 @@ main() {
 
   local repo_root
   repo_root=$(git rev-parse --show-toplevel)
-    pushd "$repo_root" > /dev/null
+  pushd "$repo_root" >/dev/null
 
-    if ! [[ -n "$skip_packaging" ]]; then
+  if [[ -z "$skip_packaging" ]]; then
     echo 'Looking up latest tag...'
     local latest_tag
     latest_tag=$(lookup_latest_tag)
 
     echo "Discovering changed charts since '$latest_tag'..."
     local changed_charts=()
-        readarray -t changed_charts <<< "$(lookup_changed_charts "$latest_tag")"
+    readarray -t changed_charts <<<"$(lookup_changed_charts "$latest_tag")"
 
     if [[ -n "${changed_charts[*]}" ]]; then
       install_chart_releaser
@@ -80,14 +80,19 @@ main() {
         if [[ -d "$chart" ]]; then
           package_chart "$chart"
         else
-                    echo "Chart '$chart' no longer exists in repo. Skipping it..."
+          echo "Nothing to do. No chart changes detected."
         fi
       done
 
       release_charts
       update_index
+      echo "changed_charts=$(
+        IFS=,
+        echo "${changed_charts[*]}"
+      )" >changed_charts.txt
     else
       echo "Nothing to do. No chart changes detected."
+      echo "changed_charts=" >changed_charts.txt
     fi
   else
     install_chart_releaser
@@ -97,13 +102,15 @@ main() {
     update_index
   fi
 
-    popd > /dev/null
+  echo "chart_version=${latest_tag}" >chart_version.txt
+
+  popd >/dev/null
 }
 
 parse_command_line() {
   while :; do
     case "${1:-}" in
-            -h|--help)
+    -h | --help)
       show_help
       exit
       ;;
@@ -117,7 +124,7 @@ parse_command_line() {
         exit 1
       fi
       ;;
-            -v|--version)
+    -v | --version)
       if [[ -n "${2:-}" ]]; then
         version="$2"
         shift
@@ -127,7 +134,7 @@ parse_command_line() {
         exit 1
       fi
       ;;
-            -d|--charts-dir)
+    -d | --charts-dir)
       if [[ -n "${2:-}" ]]; then
         charts_dir="$2"
         shift
@@ -137,7 +144,7 @@ parse_command_line() {
         exit 1
       fi
       ;;
-            -o|--owner)
+    -o | --owner)
       if [[ -n "${2:-}" ]]; then
         owner="$2"
         shift
@@ -147,7 +154,7 @@ parse_command_line() {
         exit 1
       fi
       ;;
-            -r|--repo)
+    -r | --repo)
       if [[ -n "${2:-}" ]]; then
         repo="$2"
         shift
@@ -157,19 +164,19 @@ parse_command_line() {
         exit 1
       fi
       ;;
-            -n|--install-dir)
+    -n | --install-dir)
       if [[ -n "${2:-}" ]]; then
         install_dir="$2"
         shift
       fi
       ;;
-            -i|--install-only)
+    -i | --install-only)
       if [[ -n "${2:-}" ]]; then
         install_only="$2"
         shift
       fi
       ;;
-            -s|--skip-packaging)
+    -s | --skip-packaging)
       if [[ -n "${2:-}" ]]; then
         skip_packaging="$2"
         shift
@@ -181,7 +188,7 @@ parse_command_line() {
         shift
       fi
       ;;
-            -l|--mark-as-latest)
+    -l | --mark-as-latest)
       if [[ -n "${2:-}" ]]; then
         mark_as_latest="$2"
         shift
@@ -240,9 +247,9 @@ install_chart_releaser() {
 }
 
 lookup_latest_tag() {
-    git fetch --tags > /dev/null 2>&1
+  git fetch --tags >/dev/null 2>&1
 
-    if ! git describe --tags --abbrev=0 HEAD~ 2> /dev/null; then
+  if ! git describe --tags --abbrev=0 HEAD~ 2>/dev/null; then
     git rev-list --max-parents=0 --first-parent HEAD
   fi
 }
@@ -265,10 +272,10 @@ lookup_changed_charts() {
   local changed_files
   changed_files=$(git diff --find-renames --name-only "$commit" -- "$charts_dir")
 
-    local depth=$(( $(tr "/" "\n" <<< "$charts_dir" | sed '/^\(\.\)*$/d' | wc -l) + 1 ))
+  local depth=$(($(tr "/" "\n" <<<"$charts_dir" | sed '/^\(\.\)*$/d' | wc -l) + 1))
   local fields="1-${depth}"
 
-    cut -d '/' -f "$fields" <<< "$changed_files" | uniq | filter_charts
+  cut -d '/' -f "$fields" <<<"$changed_files" | uniq | filter_charts
 }
 
 package_chart() {