Refactor makefile script

* Fix shellcheck issues
* Fix some shell style inconsistencies.
* Split out some functions.

Signed-off-by: Ben Kochie <superq@gmail.com>

scripts/sync_makefiles.sh

@@ -1,5 +1,5 @@
-#!/bin/bash
+#!/usr/bin/env bash
-
+# vim: ts=2 et
 # Setting -x is absolutely forbidden as it could leak the GitHub token.
 set -uo pipefail
 
@@ -20,38 +20,56 @@ if [ -z "${GITHUB_TOKEN}" ]; then
 fi
 
 # Go to the root of the repo
-cd "$(git rev-parse --show-cdup)"
+cd "$(git rev-parse --show-cdup)" || exit 1
 
 source_makefile="$(pwd)/Makefile.common"
 source_checksum="$(sha256sum Makefile.common | cut -d' ' -f1)"
 
-tmp_dir=$(mktemp -d)
+tmp_dir="$(mktemp -d)"
-trap "rm -rf ${tmp_dir}" EXIT
+trap 'rm -rf "${tmp_dir}"' EXIT
 
-for org in $orgs
+fetch_repos() {
-do
+  local url="https://api.github.com/users/${1}/repos?per_page=100"
-	# Iterate over all repositories in ${org}. The GitHub API can return 100 items
+  curl --retry 5 --silent -u "${git_user}:${GITHUB_TOKEN}" "${url}" 2>/dev/null |
-	# at most but it should be enough for us as there are less than 40 repositories
+    jq -r '.[] | select( .name != "prometheus" ) | .name'
-	# currently.
+}
-	curl --retry 5 --silent -u "${git_user}:${GITHUB_TOKEN}" https://api.github.com/users/${org}/repos?per_page=100 2>/dev/null | jq -r '.[] | select( .name != "prometheus" ) | .name' | while read -r; do
-		repo="${REPLY}"
-		echo -e "\e[32mAnalyzing '${repo}'\e[0m"
 
-		target_makefile="$(curl -s --fail "https://raw.githubusercontent.com/${org}/${repo}/master/Makefile.common")"
+push_branch() {
+  # stdout and stderr are redirected to /dev/null otherwise git-push could leak
+  # the token in the logs.
+  git push --quiet \
+    "https://${GITHUB_TOKEN}:@github.com/${1}" \
+    --set-upstream "${branch}" 1>/dev/null 2>&1
+}
+
+post_template='{"title":"%s","base":"master","head":"%s","body":"%s"}'
+post_json="$(printf "${post_template}" "${pr_title}" "${branch}" "${pr_msg}")"
+post_pull_request() {
+  curl --show-error --silent --fail \
+    -u "${git_user}:${GITHUB_TOKEN}" \
+    -d "${post_json}" \
+    "https://api.github.com/repos/${1}/pulls"
+}
+
+process_repo() {
+  local org_repo="$1"
+  echo -e "\e[32mAnalyzing '${org_repo}'\e[0m"
+
+  target_makefile="$(curl -s --fail "https://raw.githubusercontent.com/${org_repo}/master/Makefile.common")"
   if [ -z "${target_makefile}" ]; then
-			echo "Makefile.common doesn't exist in ${repo}"
+    echo "Makefile.common doesn't exist in ${org_repo}"
-			continue
+    return
   fi
-		target_checksum="$(echo ${target_makefile} | sha256sum | cut -d' ' -f1)"
+  target_checksum="$(echo "${target_makefile}" | sha256sum | cut -d' ' -f1)"
   if [ "${source_checksum}" == "${target_checksum}" ]; then
     echo "Makefile.common is already in sync."
-			continue
+    return
   fi
 
   # Clone target repo to temporary directory and checkout to new branch
-		git clone --quiet "https://github.com/${org}/${repo}.git" "${tmp_dir}/${repo}"
+  git clone --quiet "https://github.com/${org_repo}.git" "${tmp_dir}/${org_repo}"
-		cd "${tmp_dir}/${repo}"
+  cd "${tmp_dir}/${org_repo}" || return 1
-		git checkout -b "${branch}"
+  git checkout -b "${branch}" || return 1
 
   # Replace Makefile.common in target repo by one from prometheus/prometheus
   cp -f "${source_makefile}" ./
@@ -60,14 +78,21 @@ do
     git config user.name "${git_user}"
     git add .
     git commit -s -m "${commit_msg}"
-			# stdout and stderr are redirected to /dev/null otherwise git-push could leak the token in the logs.
+    if push_branch "${org_repo}"; then
-			if git push --quiet "https://${GITHUB_TOKEN}:@github.com/${org}/${repo}" --set-upstream "${branch}" 1>/dev/null 2>&1; then
+      post_pull_request "${org_repo}"
-				curl --show-error --silent \
-					-u "${git_user}:${GITHUB_TOKEN}" \
-					-X POST \
-					-d "{\"title\":\"${pr_title}\",\"base\":\"master\",\"head\":\"${branch}\",\"body\":\"${pr_msg}\"}" \
-					"https://api.github.com/repos/${org}/${repo}/pulls"
     fi
   fi
+}
+
+for org in ${orgs}; do
+  mkdir -p "${tmp_dir}/${org}"
+  # Iterate over all repositories in ${org}. The GitHub API can return 100 items
+  # at most but it should be enough for us as there are less than 40 repositories
+  # currently.
+  fetch_repos "${org}" | while read -r repo; do
+    if ! process_repo "${org}/${repo}"; then
+      echo "Failed to process '${org}/${repo}'"
+      exit 1
+    fi
   done
 done