replace cronjob with systemd timer

.github/workflows/ci.yaml

@@ -0,0 +1,20 @@
+name: CI
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+
+jobs:
+  python:
+    name: Lint Python
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install black
+        run: pip install ruff
+      - name: Check style
+        run: ruff format --quiet --line-length 120 --diff */*.py
+      - name: Lint
+        run: ruff check */*.py

pyinfra_borgbackup/__init__.py

@@ -2,7 +2,7 @@
 import random
 from io import StringIO
 
-from pyinfra.operations import apt, files, server
+from pyinfra.operations import apt, files, server, systemd
 
 
 def deploy_borgbackup(
@@ -56,9 +56,7 @@ def deploy_borgbackup(
     if borg_repo.startswith("hetzner-backup:"):
         files.put(
             name="create SSH config",
-            src=importlib.resources.files(__package__)
-            .joinpath("dot_ssh", "config")
-            .open("rb"),
+            src=importlib.resources.files(__package__).joinpath("dot_ssh", "config").open("rb"),
             dest="/root/.ssh/config",
             user="root",
             group="root",
@@ -90,13 +88,36 @@ def deploy_borgbackup(
             ],
         )
 
-    files.template(
-        name="Create cron job for backup script",
-        src=importlib.resources.files(__package__).joinpath("borgbackup.cron"),
-        dest="/etc/cron.d/borgbackup",
-        user="root",
-        group="root",
+    files.file(
+        name="Remove old backup cronjob, replaced by systemd timer",
+        path="/etc/cron.d/borgbackup",
+        present=False,
+    )
+
+    backup_service_file = files.put(
+        src=importlib.resources.files(__package__).joinpath("borgbackup.service"),
+        dest="/etc/systemd/system/borgbackup.service",
+        mode="644",
+    )
+    systemd.service(
+        name="Setup borgbackup service",
+        service="borgbackup.service",
+        running=False,
+        enabled=False,
+        daemon_reload=backup_service_file.changed,
+    )
+
+    backup_timer_file = files.template(
+        src=importlib.resources.files(__package__).joinpath("borgbackup.timer.j2"),
+        dest="/etc/systemd/system/borgbackup.timer",
         mode="644",
         minute=str(random.randint(0, 59)),
         hour=str(random.randint(0, 4)),
     )
+    systemd.service(
+        name="Setup borgbackup timer",
+        service="borgbackup.timer",
+        running=True,
+        enabled=True,
+        daemon_reload=backup_timer_file.changed,
+    )

pyinfra_borgbackup/backup-pre.py

@@ -3,6 +3,12 @@
 import argparse
 import os
 
+
+def cmd(command: str) -> int:
+    """Run a command and return its exit code."""
+    return os.waitstatus_to_exitcode(os.system(command))
+
+
 services = {
     "isolationbot": "isolationbot.service",
     "root": "docker.service",
@@ -19,10 +25,8 @@
 
 for user in services:
     if user == "root":
-        returncode = os.system(f"systemctl {args.command} {services[user]}")
+        returncode = cmd(f"systemctl {args.command} {services[user]}")
     else:
-        returncode = os.system(
-            f"su -l {user} -c 'systemctl --user {args.command} {services[user]}'"
-        )
+        returncode = cmd(f"su -l {user} -c 'systemctl --user {args.command} {services[user]}'")
     if returncode != 0:
         print(f"WARNING: Failed to {args.command} {services[user]} as {user} user")

pyinfra_borgbackup/backup.sh.j2

@@ -2,7 +2,9 @@
 
 function start_services {
   # start the services/containers which write data again
+  rv=$?
   if [ -f /root/backup-pre.py ]; then python3 /root/backup-pre.py start; fi
+  exit $(( $rv + $? ))
 }
 
 trap "start_services" EXIT
@@ -21,65 +23,45 @@ echo "$DEST1" > /dev/null
 
 export BORG_RSH='ssh -F /root/.ssh/config -o "StrictHostKeyChecking=no"'
 
-# don't fail just because the pod is not running
-set +e
+function run_borg () {
+  set +e  # don't fail if borg quits with exit code 1 (warning)
+  borg $@
+  borg_rc=$?
+  if [[ $borg_rc -gt 1 ]]; then
+    exit $borg_rc
+  fi
+  set -e
+}
 
 # check if variable exists: https://stackoverflow.com/a/11369388
 if [ "$SKIP_CHECK" = "true" ]; then
   echo "skipping borg check."
 else
-  borg check ${DEST1} &
-  if [ -n "${DEST2-}" ]; then
-    borg check ${DEST2} &
-  fi
+  run_borg check ${DEST1}
 fi
-wait
 
 # stop services/containers which write data
 if [ -f /root/backup-pre.py ]; then python3 /root/backup-pre.py stop; fi
 
-borg create --stats --compression lzma ${DEST1}::'backup{now:%Y-%m-%d-%H}' {{ borg_args }} \
-        --exclude *.cache/           \
-        --exclude /dev               \
-        --exclude /proc              \
-        --exclude /sys               \
-        --exclude /var/run           \
-        --exclude /run               \
-        --exclude /lost+found        \
-        --exclude /mnt               \
-        --exclude /tmp               \
-        --exclude /media             \
-        --exclude /var/lib/lxcfs && FINISHED=true &
-if [ -n "${DEST2-}" ]; then
-  # If there is a second backup destination, create a backup there.
-  # Note: not yet supported by pyinfra deploy.
-  borg create --stats --compression lzma ${DEST2}::'backup{now:%Y-%m-%d-%H}' {{ borg_args }} \
+run_borg create --stats --compression lzma ${DEST1}::'backup{now:%Y-%m-%d-%H}' {{ borg_args }} \
         --exclude *.cache/           \
         --exclude /dev               \
         --exclude /proc              \
         --exclude /sys               \
         --exclude /var/run           \
+        --exclude /var/log           \
         --exclude /run               \
         --exclude /lost+found        \
         --exclude /mnt               \
         --exclude /tmp               \
         --exclude /media             \
-        --exclude /var/lib/lxcfs && FINISHED=true &
-fi
-wait
+        --exclude /var/lib/lxcfs
 
 {% if prometheus_file is defined %}
-if [ "$FINISHED" = "true" ]; then
-  echo "borgbackup_last_completed $(date +%s)" > {{ prometheus_file }}
-fi
+echo "borgbackup_last_completed $(date +%s)" > {{ prometheus_file }}
 {%- endif %}
 start_services
 
-set -e
-borg prune --keep-daily=7 --keep-weekly=4 ${DEST1}
-borg compact ${DEST1}
-if [ -n "${DEST2-}" ]; then
-  borg prune --keep-daily=7 --keep-weekly=4 ${DEST2}
-  borg compact ${DEST2}
-fi
+run_borg prune --keep-daily=7 --keep-weekly=4 ${DEST1}
+run_borg compact ${DEST1}
 

pyinfra_borgbackup/borgbackup.service

@@ -0,0 +1,9 @@
+[Unit]
+Description=Run nightly backups
+After=network.target
+
+[Service]
+Type=oneshot
+ExecStart=/root/backup.sh
+
+

pyinfra_borgbackup/borgbackup.timer.j2

@@ -0,0 +1,8 @@
+[Unit]
+Description=Run nightly backups
+
+[Timer]
+OnCalendar=*-*-* {{ hour }}:{{ minute }}:00
+
+[Install]
+WantedBy=timers.target