improve Backport Pull Request Title & Description Quality (#2373)

Signed-off-by: kpango <kpango@vdaas.org>
Co-authored-by: Kosuke Morimoto <ksk@vdaas.org>

.github/workflows/backport.yml

@@ -44,25 +44,20 @@ jobs:
           gpg_private_key: ${{ secrets.GPG_PRIVATE_KEY }}
           git_user_signingkey: true
           git_commit_gpgsign: true
-      - name: Set context
-        id: set_context
+      - name: Get PR title and body
+        id: pr_info
         run: |
-          LABEL_NAMES=`cat ${GITHUB_EVENT_PATH} | jq -r --arg PREFIX $TARGET_LABEL_NAME_PREFIX '[.pull_request.labels[]? | select(.name | startswith($PREFIX)) | .name] | join(" ")'`
-          echo "LABEL_NAMES=${LABEL_NAMES}" >> $GITHUB_OUTPUT # e.g.) actions/backport/v1.7 actions/backport/v1.8
-          echo "${LABEL_NAMES}"
+          echo "PR_TITLE=$(jq --raw-output .pull_request.title $GITHUB_EVENT_PATH)" >> $GITHUB_ENV
+          echo "PR_BODY=$(jq --raw-output .pull_request.body $GITHUB_EVENT_PATH)" >> $GITHUB_ENV
       - name: Create PR
-        if: ${{ steps.set_context.outputs.LABEL_NAMES != '' }}
+        if: ${{ github.event.pull_request.labels.*.name == '${TARGET_LABEL_NAME_PREFIX}*' }}
         env:
-          LABEL_NAMES: ${{ steps.set_context.outputs.LABEL_NAMES }}
+          PR_TITLE: ${{ steps.pr_info.outputs.PR_TITEL }}
+          PR_BODY: ${{ steps.pr_info.outputs.PR_BODY }}
           GITHUB_USER: ${{ secrets.DISPATCH_USER }}
           GITHUB_TOKEN: ${{ secrets.DISPATCH_TOKEN }}
         run: |
-          PR_TITLE=`cat $GITHUB_EVENT_PATH | jq -r ".pull_request.title"`
-          PR_BODY=`cat $GITHUB_EVENT_PATH | jq -r ".pull_request.body"`
-          PR_NUM=`cat $GITHUB_EVENT_PATH | jq -r ".pull_request.number"`
-
-          echo "${PR_NUM} ${PR_TITLE}: ${PR_BODY}"
-
+          LABEL_NAMES=`echo "${{ github.event.pull_request.labels.*.name }}" | jq -r '[.[] | select(startswith("actions/backport/"))] | join(" ")'`
           for LABEL_NAME in ${LABEL_NAMES}; do
               BRANCH_NAME=`echo "${LABEL_NAME}" | sed -e "s:^${TARGET_LABEL_NAME_PREFIX}::"`           # e.g) release/vx.x, main
               BACKPORT_BRANCH_NAME="${BACKPORT_BRANCH_NAME_PREFIX}/${BRANCH_NAME}/${GITHUB_HEAD_REF}"  # e.g) backport/release/vx.x/{current branch name}
@@ -79,6 +74,6 @@ jobs:
               git push origin ${BACKPORT_BRANCH_NAME}
 
               gh pr create --base ${BRANCH_NAME} \
-                           --title "Backport PR #${PR_NUM} to ${BRANCH_NAME} for ${PR_TITLE}" \
+                           --title "Backport to ${BRANCH_NAME} for ${PR_TITLE}" \
                            --body "${PR_BODY}"
           done