Document use case of running backups conditionally based on laptop power level (#419).

NEWS

@@ -1,3 +1,7 @@
+1.5.15.dev0
+ * #419: Document use case of running backups conditionally based on laptop power level:
+   https://torsion.org/borgmatic/docs/how-to/backup-to-a-removable-drive-or-an-intermittent-server/
+
 1.5.14
  * #390: Add link to Hetzner storage offering from the documentation.
  * #398: Clarify canonical home of borgmatic in documentation.

docs/how-to/backup-to-a-removable-drive-or-an-intermittent-server.md

@@ -16,9 +16,14 @@ But if you run borgmatic and your hard drive isn't plugged in, or your buddy's
 server is offline, then you'll get an annoying error message and the overall
 borgmatic run will fail (even if individual repositories still complete).
 
+Another variant is when the source machine is only sometimes available for
+backups, e.g. a laptop where you want to skip backups when the battery falls
+below a certain level.
+
 So what if you want borgmatic to swallow the error of a missing drive
-or an offline server, and continue trucking along? That's where the concept of
-"soft failure" come in.
+or an offline server or a low battery—and exit gracefully? That's where the
+concept of "soft failure" come in.
+
 
 ## Soft failure command hooks
 
@@ -78,6 +83,17 @@ hooks:
       - ping -q -c 1 buddys-server.org > /dev/null || exit 75
 ```
 
+Or to only run backups if the battery level is high enough:
+
+```yaml
+hooks:
+    before_backup:
+      - is_battery_percent_at_least.sh 25
+```
+
+(Writing the battery script is left as an exercise to the reader.)
+
+
 ## Caveats and details
 
 There are some caveats you should be aware of with this feature.

sample/systemd/borgmatic.service

@@ -2,6 +2,8 @@
 Description=borgmatic backup
 Wants=network-online.target
 After=network-online.target
+# Prevent borgmatic from running unless the machine is plugged into power. Remove this line if you
+# want to allow borgmatic to run anytime.
 ConditionACPower=true
 
 [Service]

setup.py

@@ -1,6 +1,6 @@
 from setuptools import find_packages, setup
 
-VERSION = '1.5.14'
+VERSION = '1.5.15.dev0'
 
 
 setup(