Add script to automate the update process more

We recommend creating an update script in the install notes so why not provide one that works for the environment we refer to there (Debian/Ubuntu)? This script automates the git pull and setting of permissions on writable directories. It has a bit of error handling for safety and allows the admin to choose whether to update to the tip of master (current behaviour) or to the latest tag.

update_cloudlog.sh

@@ -0,0 +1,86 @@
+#!/bin/bash
+# Cloudlog update script
+#
+# Pulls changes from Git remote and re-sets appropriate directory ownership.
+# Can be run manually or on a schedule using Cron.
+#
+# Please check the DIR_OWNERSHIP variable carefully to make sure it is
+# appropriately set for your system!
+
+# The user and group that own the CLOUDLOG_SUBDIR directories. Passed to 'chown' as-is.
+DIR_OWNERSHIP="root:www-data"
+# The list of directories that need to have ownership restored after a git pull
+declare -a CLOUDLOG_SUBDIRS=("application/config" "assets/qslcard" "backup" "updates" "uploads")
+# The name of the Git remote to fetch/pull from
+GIT_REMOTE="origin"
+# If true, pull from the HEAD of the configured origin, otherwise the latest tag
+BLEEDING_EDGE="true"
+# If true, restore directory ownership on CLOUDLOG_SUBDIRS after a git pull
+RESTORE_OWNERSHIP="true"
+
+check_working_dir() {
+	# Quick sanity check to make sure that pwd looks like a Cloudlog install
+	if [[ ! -d "$(pwd)/application" ]]
+	then
+		echo "$(pwd) doesn't look like a Cloudlog install directory! Stopping here."
+		exit 1
+	fi
+}
+
+fast_forward_to_tag() {
+	# Find the latest tag on the current branch
+	# See https://git-scm.com/docs/git-describe for details on retrieving tags
+	LATEST_TAG=$(git describe --tags --abbrev=0)
+	echo "Fast-forwarding to latest tag: $LATEST_TAG..."
+	if git pull $GIT_REMOTE $LATEST_TAG ; then
+		echo "Fast-forward finished successfully."
+	else
+		echo "Fast-forward failed; stopping here."
+		exit 2
+	fi
+}
+
+fast_forward_to_head() {
+	echo "Fast-forwarding to HEAD (bleeding-edge)..."
+	if git pull $GIT_REMOTE ; then
+		echo "Fast-forward finished successfully".
+	else
+		echo "Fast-forward failed; stopping here."
+		exit 3
+	fi
+}
+
+restore_ownership() {
+	for dir in "${CLOUDLOG_SUBDIRS[@]}"; do
+		echo "Setting ownership as $DIR_OWNERSHIP on $dir"
+		chown -R $DIR_OWNERSHIP $(pwd)/$dir
+	done
+}
+
+
+echo "Cloudlog update started"
+echo "-----------------------"
+echo "Using $(pwd) as working directory"
+
+check_working_dir
+
+# Fetch the latest changes from the master branch
+echo "Fetching changes from remote..."
+if git fetch $GIT_REMOTE --tags ; then
+	echo "Fetched latest changes successfully"
+else
+	echo "Fetch failed; stopping here."
+	exit 4
+fi
+
+if [ "$BLEEDING_EDGE" = true ]; then
+	fast_forward_to_head
+else
+	fast_forward_to_tag
+fi
+
+if [ "$RESTORE_OWNERSHIP" = true ]; then
+	restore_ownership
+fi
+
+echo "Cloudlog update finished"