doc: add systemd timer and service example

- add self-update option

🤖

.renovaterc.json

@@ -1,6 +0,0 @@
-{
-  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
-  "extends": [
-    "local>infrastructure/renovate-config"
-  ]
-}

README.md

@@ -18,6 +18,50 @@ See `requirements.txt`
 2. Adapt `config.yml.example` to your needs and save it as `config.yml`
 3. Run `dc-ops` from the shell or from a cron job
 
+### Cron
+
+Recommended crontab usage:
+
+`*/15 * * * * python3 /opt/dc-ops/dc-ops 2>&1 | ts "\%FT\%H:\%M:\%S" >>/var/log/dc-ops.log`
+
+(do not forget logrotate)
+
+### Systemd
+
+Recommended systemd usage:
+
+```toml
+# /etc/systemd/system/dc-ops.service
+[Unit]
+Description=Run dc-ops once
+After=docker.target
+
+[Service]
+Type=simple
+WorkingDirectory=/opt/dc-ops/
+ExecStart=python3 dc-ops
+```
+
+```toml
+# /etc/systemd/system/dc-ops.timer
+[Unit]
+Description=Start dc-ops service periodically
+
+[Timer]
+Persistent=true
+OnCalendar=*:0/15
+Unit=dc-ops.service
+
+[Install]
+WantedBy=timers.target
+```
+
+Enable and start the timer:
+```
+systemctl enable dc-ops.timer
+systemctl start dc-ops.timer
+```
+
 ## Parameters
 
 See `dc-ops --help`

config.yml.example

@@ -1,3 +1,4 @@
+self-update: true # optional
 loglevdel: "INFO" # optional
 compose-opts: "--dry-run"
 stacks:

dc-ops

@@ -5,6 +5,8 @@
 # CC-BY-SA (https://creativecommons.org/licenses/by-sa/4.0/deed.de)
 # for civil use only
 
+# pylint: disable=missing-module-docstring,invalid-name
+
 import argparse
 import logging as log
 from pathlib import Path
@@ -15,12 +17,12 @@ from lib.helper import run_subprocess, update_git_repo, do_selfupdate
 
 # read config file
 configfile = Path(__file__).with_name("config.yml")
-with configfile.open("r") as f:
+with configfile.open("r", encoding="utf-8") as f:
     cfg = yaml.safe_load(f.read())
 
 # fmt: off
 parser = argparse.ArgumentParser()
-parser.add_argument("--ignore-git-status", action="store_true", help="continue even if there are no new commits")  # noqa
+parser.add_argument("--ignore-git-status", action="store_true", help="continue even if there are no new commits")
 parser.add_argument("--loglevel", help="set loglevel (overrides config file)")
 args = parser.parse_args()
 # fmt: on
@@ -47,7 +49,7 @@ for stack in cfg["stacks"]:
 
     # header
     stackdir = stack["dir"]
-    log.info(f"* processing {stackdir}")
+    log.info("processing: %s", stackdir)
 
     # update repo and check for new commits
     if not update_git_repo(stackdir, args.ignore_git_status):
@@ -55,6 +57,7 @@ for stack in cfg["stacks"]:
 
     # run pre-command
     if "pre" in stack:
+        log.info("-> executing pre-command")
         if not run_subprocess(stack["pre"], stackdir):
             continue
 
@@ -62,6 +65,7 @@ for stack in cfg["stacks"]:
     # (or just for the directory if no compose-file defined)
     composefiles = stack.get("compose-files", ["docker-compose.yml"])
     for composefile in composefiles:
+        log.info("-> bringing up %s", composefile)
         if not run_subprocess(
             f"docker compose --file {composefile} up --detach {composeopts}",
             stackdir,
@@ -70,5 +74,6 @@ for stack in cfg["stacks"]:
 
     # run post-command
     if "post" in stack:
+        log.info("-> executing post-command")
         if not run_subprocess(stack["post"], stackdir):
             continue

lib/helper.py

@@ -1,3 +1,5 @@
+# pylint: disable=missing-module-docstring
+
 import logging as log
 import subprocess
 import sys
@@ -16,9 +18,9 @@ def do_selfupdate():
         log.error(str(e))
         return
     if pull_res.old_commit:
-        log.info("selfupdate: successfully updated myself - exiting")
+        log.info("SelfUpdate: successfully updated myself - exiting")
         sys.exit(0)
-    log.info("selfupdate: no updates found for myself")
+    log.info("SelfUpdate: no updates found for myself")
 
 
 def run_subprocess(command: str, workdir: str) -> bool:
@@ -32,7 +34,9 @@ def run_subprocess(command: str, workdir: str) -> bool:
         bool: False if subprocess fails
     """
     try:
-        log.debug(subprocess.run(command.split(" "), cwd=workdir, text=True))
+        log.debug(
+            subprocess.run(command.split(" "), cwd=workdir, text=True, check=False)
+        )
     except subprocess.CalledProcessError:
         return False
 
@@ -49,11 +53,12 @@ def update_git_repo(repo_path: str, ignore_git_status: bool) -> bool:
     Returns:
         bool: False if any step fails
     """
+
     # create repo instance if it exists
     try:
         repo = git.Repo(repo_path)
     except git.exc.NoSuchPathError:
-        log.error("directory not found")
+        log.error("-> directory not found")
         return False
 
     if not ignore_git_status:
@@ -61,19 +66,19 @@ def update_git_repo(repo_path: str, ignore_git_status: bool) -> bool:
         try:
             fetch_res = repo.remotes.origin.fetch()[0]
         except git.exc.GitCommandError as e:
-            log.error(str(e))
+            log.error("-> %s ", str(e))
             return False
 
         # check for new commits
         if not fetch_res.old_commit:
-            log.info("no changes - skipping")
+            log.info("-> no changes - skipping")
             return False
 
     # pull remote changes to local branch
     try:
-        log.info(repo.git.pull())
+        log.info("-> %s", repo.git.pull())
     except git.exc.GitCommandError as e:
-        log.error(str(e))
+        log.error("-> %s", str(e))
         return False
 
     return True