Multiple profile configuration (#45)

Adds possibility to have multiple profiles with different backup paths, retention etc.

Co-authored-by: Matt Feifarek <matt.feifarek@gmail.com>
Co-authored-by: Erik Westrup <erik.westrup@gmail.com>

etc/systemd/system/restic-backup.service

@@ -1,11 +0,0 @@
-[Unit]
-Description=Backup with restic to Backblaze B2
-OnFailure=status-email-user@%n.service
-Requires=nm-unmetered-connection.service
-
-[Service]
-Type=simple
-Nice=10
-ExecStart=/usr/local/sbin/restic_backup.sh
-# $HOME or $XDG_CACHE_HOME must be set for restic to find /root/.cache/restic/
-Environment="HOME=/root"

etc/systemd/system/restic-backup@.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=Backup with restic to Backblaze B2
+OnFailure=status-email-user@%n.service
+Requires=nm-unmetered-connection.service
+
+[Service]
+Type=simple
+Nice=10
+# $HOME or $XDG_CACHE_HOME must be set for restic to find /root/.cache/restic/
+Environment="HOME=/root"
+# The random sleep (in seconds) is in the case of multiple backup profiles. Many restic instances started at the same time could case high load or network bandwith usage.
+# `systemd-cat` allows showing the restic output to the systemd journal
+ExecStart=bash -c 'sleep $(shuf -i 0-300 -n 1) && source /etc/restic/%I.env && /usr/local/sbin/restic_backup.sh | systemd-cat'

etc/systemd/system/restic-check@.service

@@ -7,4 +7,5 @@ Requires=nm-unmetered-connection.service
 [Service]
 Type=simple
 Nice=10
-ExecStart=/usr/local/sbin/restic_check.sh
+# `systemd-cat` allows showing the restic output to the systemd journal
+ExecStart=bash -c 'source /etc/restic/%I.env && /usr/local/sbin/restic_check.sh | systemd-cat'