Add GitHub Notifications for cherry picks (#8115)

* add github PR notification for backport cherry picks

* count number of backport failures and exit after looping through all of them

.circleci/scripts/cherry-picker.sh

@@ -23,6 +23,10 @@ function cherry_pick_with_slack_notification {
     #   $1 - branch to cherry-pick to
     #   $2 - commit to cherry-pick
     #   $3 - url to PR of commit
+    #
+    # Return:
+    #   0 for success
+    #   1 for error
 
     local branch="$1"
     local commit="$2"
@@ -32,6 +36,8 @@ function cherry_pick_with_slack_notification {
     # If git cherry-pick fails, we send a failure notification
     if ! git cherry-pick --mainline 1 "$commit"; then
         status "🍒❌ Cherry pick of commit ${commit:0:7} from $pr_url onto $branch failed!"
+
+        # send slack notification
         curl -X POST -H 'Content-type: application/json' \
         --data \
         "{ \
@@ -45,11 +51,22 @@ function cherry_pick_with_slack_notification {
             } \
         ] \
         }" "${CONSUL_SLACK_WEBHOOK_URL}"
+
+        # post PR comment to GitHub
+        github_message=":cherries::x: Cherry pick of commit ${commit} onto \`$branch\` failed! [Build Log]($CIRCLE_BUILD_URL)"
+        pr_id=$(basename ${pr_url})
+        curl -f -s -H "Authorization: token ${GITHUB_TOKEN}" \
+             -X POST \
+             -d "{ \"body\": \"${github_message}\"}" \
+             "https://api.github.com/repos/${CIRCLE_PROJECT_USERNAME}/${CIRCLE_PROJECT_REPONAME}/issues/${pr_id}/comments"
+
+        # run git status to leave error in CircleCI log
         git status
-        exit 1
+        return 1
+
     # Else we send a success notification
     else
-        status "🍒✅ Cherry picking of PR commit ${commit:0:7} from $pr_url succeeded!"
+        status "🍒✅ Cherry picking of PR commit ${commit:0:7} from ${pr_url} succeeded!"
         # push changes to the specified branch
         git push origin "$branch"
         curl -X POST -H 'Content-type: application/json' \
@@ -58,18 +75,28 @@ function cherry_pick_with_slack_notification {
         \"attachments\": [ \
             { \
             \"fallback\": \"Cherry pick succeeded!\", \
-            \"text\": \"🍒✅ Cherry picking of <$pr_url|${commit:0:7}> to \`$branch\` succeeded!\n\nBuild Log: ${CIRCLE_BUILD_URL}\", \
+            \"text\": \"🍒✅ Cherry picking of <$pr_url|${commit:0:7}> to \`$branch\` succeeded!\", \
             \"footer\": \"${CIRCLE_PROJECT_USERNAME}/${CIRCLE_PROJECT_REPONAME}\", \
             \"ts\": \"$(date +%s)\", \
             \"color\": \"good\" \
             } \
         ] \
         }" "${CONSUL_SLACK_WEBHOOK_URL}"
+
+        # post PR comment to GitHub
+        github_message=":cherries::white_check_mark: Cherry pick of commit ${commit} onto \`$branch\` succeeded!"
+        pr_id=$(basename ${pr_url})
+        curl -f -s -H "Authorization: token ${GITHUB_TOKEN}" \
+             -X POST \
+             -d "{ \"body\": \"${github_message}\"}" \
+             "https://api.github.com/repos/${CIRCLE_PROJECT_USERNAME}/${CIRCLE_PROJECT_REPONAME}/issues/${pr_id}/comments"
     fi
+
+    return 0
 }
 
 # search for the PR labels applicable to the specified commit
-resp=$(curl -f -s -H "Authorization: token $GITHUB_TOKEN" "https://api.github.com/search/issues?q=repo:$CIRCLE_PROJECT_USERNAME/$CIRCLE_PROJECT_REPONAME+sha:$CIRCLE_SHA1")
+resp=$(curl -f -s -H "Authorization: token ${GITHUB_TOKEN}" "https://api.github.com/search/issues?q=repo:${CIRCLE_PROJECT_USERNAME}/${CIRCLE_PROJECT_REPONAME}+sha:${CIRCLE_SHA1}")
 ret="$?"
 if [[ "$ret" -ne 0 ]]; then
     status "The GitHub API returned $ret which means it was probably rate limited."
@@ -85,7 +112,9 @@ fi
 
 # If the API returned a non-zero count, we have found a PR with that commit so we find
 # the labels from the PR
-labels=$(echo "$resp" | jq --raw-output '.items[].labels[] | .name')
+
+# sorts the labels from a PR via version sort
+labels=$(echo "$resp" | jq --raw-output '.items[].labels[] | .name' | sort -rV)
 ret="$?"
 pr_url=$(echo "$resp" | jq --raw-output '.items[].pull_request.html_url')
 if [[ "$ret" -ne 0 ]]; then
@@ -95,6 +124,7 @@ if [[ "$ret" -ne 0 ]]; then
     exit 0
 fi
 
+backport_failures=0
 # loop through all labels on the PR
 for label in $labels; do
     git config --local user.email "hashicorp-ci@users.noreply.github.com"
@@ -105,10 +135,17 @@ for label in $labels; do
         status "backporting to stable-website"
         branch="stable-website"
         cherry_pick_with_slack_notification "$branch" "$CIRCLE_SHA1" "$pr_url"
+        (( backport_failures += "$?" ))
     # else if the label matches backport/*, it will attempt to cherry-pick to the release branch
     elif [[ $label =~ backport/* ]]; then
         status "backporting to $label"
         branch="${label/backport/release}.x"
         cherry_pick_with_slack_notification "$branch" "$CIRCLE_SHA1" "$pr_url"
+        (( backport_failures += "$?" ))
     fi
 done
+
+if [ "$backport_failures" -ne 0 ]; then
+    echo "$backport_failures backports failed"
+    exit $backport_failures
+fi