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Readme.md

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# Desktop notifications from borgmatic when it is run from systemd
How to set up desktop notifications to an arbitrary user, while borgmatic is automatically run from a systemd timer. That implies a Linux machine, of course.
This HowTo shows the way to set up *notifications from `borgmatic` to an arbitrary user*, when borgmatic runs as `root` because it was automatically started from a `system` timer. That implies a Linux machine, of course.
This includes workarounds for current (borgmatic 1.5.13, borg 1.1.16) limitations of borg/borgmatic. They may or may not be necessary in the future. This HowTo was written on 2021-05-17, some downloaded files may have changed since then.
It includes workarounds for current (borgmatic 1.5.13, borg 1.1.16) limitations of `borgmatic` and/or `borg`. Also some downloaded files may have changed since the HowTo was written (2021-05-17).
The following needs to be set up for the notifications:
@ -14,13 +13,12 @@ The template from the borgmatic site (the`borgmatic.timer`) is fine, insert a st
---
### systemd service
Again, the template from the borgmatic site (the `borgmatic.service`) is good, but needs an essential change:
The line `CapabilityBoundingSet=…` must grant the additional capabilities `AP_SETUID `and `CAP_SETGID`. This will allow borgmatic (and whatever is called from it!!) to act as a different user (other than root).
*__This means a softening of security settings.__ Make sure all permissions on borgmatic and scripts are set correctly!*
*__This weakens security settings.__ Make sure all permissions on borgmatic and scripts are set correctly!*
---
@ -37,9 +35,8 @@ The `notify-send` command sets the urgency of the notifications, and sends a hea
hooks:
before_backup:
- sudo -u NAME DISPLAY=:0 DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/UID/bus notify-send --urgency=normal 'Headline' 'Body text goes <i>here</i>.'
```
(Note: The config file is YAML, so no shell line continuation (` \`). And spaces, not tabs.)
(Note: All after `sudo …` is one line. The config file is YAML, so there's no shell line continuation (` \`). And spaces, not tabs.)
---
@ -50,7 +47,6 @@ Borgmatic calls an executable script that can do more magic and send the notific
hooks:
on_error:
- /etc/borgmatic/notify-error.sh "{configuration_filename}" "{repository}" "{error}" "{output}"
```
(Note: The placeholders (`{configuration_filename}`, `{repository}`, `{error}`, and `{output}`) are not all supported under all hooks.)
@ -71,21 +67,19 @@ sudo -u NAME DISPLAY=:0 \
---
---
### Example for Overdue Backups Alerts
#### In the borgmatic config
To know when the last complete backup was made, even if there is no connection to the repository, the date and time needs to be stored locally (here in a `last-successful-backup` file), after every successful backup (hook `after_backup:`).
This example uses date and time of the last *complete* backup. Borgmatic does not supply this in a placeholder, so it is identified with `borgmatic list --successful --last 1`, returning only date and time (`--format {time}`) and without control characters (`--no-color `), then the header line is skipped (`sed -n 2p`), and the timezone (that the borgmatic return lacks) is appended (`date +'%:z'`).
It's a good idea to store this value together with the other files for that repository, so `/root/{repository}` would be nice. Unfortunately, `{repository}` is not resolved within borgmatic; the path must be manually copied from the top of the config file and append to `/root/`.
It's a good idea to store this value together with the other files for that repository, so `/root/{repository}` would be nice. Unfortunately, `{repository}` is not resolved within borgmatic; the path must be manually copied from the top of the config file and append to `/root/`, *but __without the `:`__ after the URL!*
If an error occurs during backup, a script (here, `notify-error.sh`) will read that date and time and do the subsequent processing.
Example for a remote repository:
```
location:
repositories:
- BackupUser@BackupServer:/path/to/repository
@ -94,12 +88,12 @@ hooks:
after_backup:
- echo "$(borgmatic list --successful --last 1 --format {time} --no-color \
| sed -n 2p) $(date +'%:z')" \
> "/root/BackupUser@BackupServer:/path/to/repository/last-successful-backup"
> "/root/BackupUser@BackupServer/path/to/repository/last-successful-backup"
...
on_error:
- /etc/borgmatic/notify-error.sh "{configuration_filename}" "{repository}" "{error}" "{output}"
```
(Note: Inside the quotes of `echo …` line continuation (` \`) can be used to improve readability.)
(Note: Line continuation (` \`) can be used inside the quotes of `echo …` to improve readability.)
---
@ -163,7 +157,6 @@ else # backup age is 24 hours or less
sudo -u "$NOTIFYUSER" DISPLAY=:0 "DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/$NOTIFYUSERID/bus" \
notify-send --urgency=critical "Borgmatic Backup Failed" "$NOTIFYTEXT"
fi
```
![picture](https://projects.torsion.org/lasimik/borgmatic_notifications/raw/branch/master/borgmatic-notification.png)
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