Some additional info about the systemd unit files

content/post/self-hosted-voice-control.md

@@ -73,7 +73,7 @@ One downside is, however, that the ReSpeaker technically supports directional au
 
 The LED portion of the ReSpeaker requires a little more work. The [examples library for the 4-mic hat](https://github.com/respeaker/4mics_hat) provides all the basic tools needed to get the LEDs working, including several samples based on Google and Amazon device patterns. In my case, I went for a very simple LED feedback design: the LEDs turn on blue while listening, then quickly turn either green on a successful command, or red on a failed command, giving some sort of user feedback without having to listen to the unit try and talk!
 
-To do this, I created a simple Python "daemon" running under Systemd to listen for commands on a FIFO pipe and perform the required action, as well as a helper client utility to trigger the pipe. The code for these can be found [on my GitLab](https://dev.bonifacelabs.ca/joshua-automation/respeaker-led) for convenience.
+To do this, I created a simple Python "daemon" running under Systemd to listen for commands on a FIFO pipe and perform the required action, as well as a helper client utility to trigger the pipe. The code for these can be found [on my GitLab](https://dev.bonifacelabs.ca/joshua-automation/respeaker-led) for convenience. One interesting feature of this configuration is the Systemd unit file. It performs a git pull inside the service directory (e.g. the repo directory) to ensure the service is automatically up-to-date when the service is started. I do the same thing in my Kalliope unit file for its configuration.
 
 ### Kalliope configuration
 
@@ -145,6 +145,32 @@ The next step is to actually configure Kalliope. The examples are a good startin
 
 Using this configuration as a jumping-off point, you can add multiple other options, and including the various shell commands you can ensure that the LED ring shows the status of every task.
 
+I use a custom Systemd unit to ensure everything is started correctly, including output buffering, and as mentioned above ensures the configuration repository is always up-to-date with the origin, making configuration updates on-the-fly to multiple devices quick and painless.
+
+```
+# Kalliope service unit file
+[Unit]
+Description = Kalliope voice assistant
+After = network-online.target
+
+[Service]
+Type = simple
+WorkingDirectory = /srv/kalliope-config
+User = kalliope
+ExecStartPre = /usr/bin/pulseaudio --daemon
+ExecStartPre = /usr/bin/ssh-agent bash -c 'ssh-add /srv/git-deploy.key; git pull; exit 0'
+ExecStart = /usr/bin/stdbuf -oL /usr/local/bin/kalliope start
+
+[Install]
+WantedBy = multi-user.target
+```
+
+Install and enable the systemd unit file using a full path; this is a relatively unknown feature of systemctl that comes in handy here:
+
+```
+pi@kalliope:~$ sudo systemctl enable /srv/kalliope-config/kalliope.service
+```
+
 ## The Next Steps
 
 With all of this assembled, you can test out the ring and make sure it's doing what you want. Here's a sample video of my ring in action!