Merge pull request #1497 from edx/jarv/get-rc-branches

adds a utility script to get rc branches

util/jenkins/get-rc-branches.sh

+#!/bin/bash
+
+usage() {
+
+  prog=$(basename "$0")
+  cat<<EOF
+
+  This will clone a repo and look for release
+  candidate branches that will be returned as
+  a sorted list in json to be 
+  parsed by the dynamic choice jenkins plugin
+
+  Usage: $prog
+            -v    add verbosity (set -x)
+            -n    echo what will be done
+            -h    this
+            -r    repo to look in
+            -f    filter string for branch list
+
+  Example: $prog -r https://github.com/edx/edx-platform -f "rc/"
+EOF
+}
+
+while getopts "vnhr:f:" opt; do
+  case $opt in
+    v)
+      set -x
+      shift
+      ;;
+    h)
+      usage
+      exit 0
+      ;;
+    n)
+      noop="echo Would have run: "
+      shift
+      ;;
+    r)
+      repo=$OPTARG
+      ;;
+    f)
+      filter=$OPTARG
+      ;;
+  esac
+done
+
+if [[ -z $repo || -z $filter ]]; then
+    echo  'Need to specify a filter and a repo'
+    usage
+    exit 1
+fi
+
+repo_basename=$(basename "$repo")
+cd /var/tmp
+
+if [[ ! -d $repo_basename ]]; then
+    $noop git clone "$repo" "$repo_basename" --mirror
+else
+    $noop cd "/var/tmp/$repo_basename"
+    $noop git fetch
+fi
+
+$noop cd "/var/tmp/$repo_basename"
+if [[ -z $noop ]]; then
+    git branch -a | grep "$filter" | sort -r | head | python -c 'import sys, json; print json.dumps([line.strip() for line in sys.stdin])'
+else
+    echo "Would have checked for branches using filter $filter"
+fi