add delete ref script

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>

github-dev/cleanup-pr-branch

@@ -0,0 +1,52 @@
+#!/bin/bash
+set -e
+set -o pipefail
+
+if [[ ! -z "$TOKEN" ]]; then
+	GITHUB_TOKEN=$TOKEN
+fi
+
+if [[ -z "$GITHUB_TOKEN" ]]; then
+	echo "Set the GITHUB_TOKEN env variable."
+	exit 1
+fi
+
+if [[ -z "$GITHUB_REPOSITORY" ]]; then
+	echo "Set the GITHUB_REPOSITORY env variable."
+	exit 1
+fi
+
+URI=https://api.github.com
+API_VERSION=v3
+API_HEADER="Accept: application/vnd.github.${API_VERSION}+json"
+AUTH_HEADER="Authorization: token ${GITHUB_TOKEN}"
+
+main(){
+	action=$(cat "$GITHUB_EVENT_PATH" | jq --raw-output .action)
+	merged=$(cat "$GITHUB_EVENT_PATH" | jq --raw-output .pull_request.merged)
+
+	echo "action: $action merged: $merged"
+
+	if [[ "$action" == "closed" ]] && [[ "$merged" == "true" ]]; then
+		# delete the branch.
+		ref=$(cat "$GITHUB_EVENT_PATH" | jq --raw-output .pull_request.head.ref)
+		owner=$(cat "$GITHUB_EVENT_PATH" | jq --raw-output .pull_request.head.repo.owner.login)
+		repo=$(cat "$GITHUB_EVENT_PATH" | jq --raw-output .pull_request.head.repo.name)
+
+		if [[ "$ref" == "master" ]]; then
+			# Never delete the master branch.
+			echo "Will not delete master branch for ${owner}/${repo}, exiting."
+			exit 0
+		fi
+
+		echo "Deleting branch ref $ref for owner ${owner}/${repo}..."
+		curl -XDELETE -sSL \
+			-H "${AUTH_HEADER}" \
+			-H "${API_HEADER}" \
+			"/repos/${owner}/${repo}/git/refs/heads/${ref}"
+
+		echo "Branch delete success!"
+	fi
+}
+
+main "$@"