[enh] New helpers for logrotate

Add and remove logrotate config

data/helpers.d/backend

@@ -0,0 +1,53 @@
+# Use logrotate to manage the logfile
+#
+# usage: ynh_use_logrotate [logfile]
+# | arg: logfile - absolute path of logfile
+#
+# If no argument provided, a standard directory will be use. /var/log/${app}
+# You can provide a path with the directory only or with the logfile.
+# /parentdir/logdir/
+# /parentdir/logdir/logfile.log
+#
+# It's possible to use this helper several times, each config will added to same logrotate config file.
+ynh_use_logrotate () {
+	if [ -n "$1" ]; then
+		if [ "$(echo ${1##*.})" == "log" ]; then	# Keep only the extension to check if it's a logfile
+			logfile=$1	# In this case, focus logrotate on the logfile
+		else
+			logfile=$1/.log	# Else, uses the directory and all logfile into it.
+		fi
+	else
+		logfile="/var/log/${app}/.log" # Without argument, use a defaut directory in /var/log
+	fi
+	cat > ./${app}-logrotate << EOF	# Build a config file for logrotate
+$logfile {
+		# Rotate if the logfile exceeds 100Mo
+	size 100M
+		# Keep 12 old log maximum
+	rotate 12
+		# Compress the logs with gzip
+	compress
+		# Compress the log at the next cycle. So keep always 2 non compressed logs
+	delaycompress
+		# Copy and truncate the log to allow to continue write on it. Instead of move the log.
+	copytruncate
+		# Do not do an error if the log is missing
+	missingok
+		# Not rotate if the log is empty
+	notifempty
+		# Keep old logs in the same dir
+	noolddir
+}
+EOF
+	sudo mkdir -p $(dirname "$logfile")	# Create the log directory, if not exist
+	cat ${app}-logrotate | sudo tee -a /etc/logrotate.d/$app > /dev/null	# Append this config to the others for this app. If a config file already exist
+}
+
+# Remove the app's logrotate config.
+#
+# usage: ynh_remove_logrotate
+ynh_remove_logrotate () {
+	if [ -e "/etc/logrotate.d/$app" ]; then
+		sudo rm "/etc/logrotate.d/$app"
+	fi
+}