If you are running a custom implementation of Airmessage and you have a domain in Route 53 with an Alias record that is pointing to your IP address. Update a few Values to reflect your aws account, local credentials, and local Mac configuration to create a service that will use launchd to ensure the Alias record is updated when your public up is changed.

Setting up a job with launchctl on mac

Assuming you have copied all of these files over to ~/scripts folder. You will want to ensure you update the com.airmessage.dns file to your liking. Replace youruser with your actual user. Then ensure you have the ~/.aws/Credentials file loaded with the user you will want to the aws cli as. You will need to update the dnsupdate.sh script to have the proper values denoted with angle brackets. You can run the start command below, or you can log out and log back in. If the service file is in the ~/Library/LaunchAgents directory it will start up

Setup the service

First you put the plist file into your user library launch agent directory and make sure the directory has the right privs for any scripts you use or logs your write.

cp ~/scripts/com.airmessage.dns.plist ~/Library/LaunchAgents/
chmod +rx ~/scripts/*.sh
chmod +rw ~/scripts/*.log
chmod +rw ~/scripts/*.json
launchctl start com.airmessage.dns

Depending on the interval used, you will see the log files appear in your scripts directory. You can also see the logs in the mac Console. That is is under system utilites, not the terminal.

tail -10 ~/scripts/stdout.log

Updating the service

If for some reason you need to make a change to the service itself you will need to stop the service, and update the file, and start the service. After you have ran the start launchctl start command, you should see logs

launchctl stop com.airmessage.dns
nano com.airmessage.dns.plist
cp com.airmessage.dns.plist ~/Library/LaunchAgents/ && launchtl start com.airmessage.dns

# to restart
launchctl start com.airmessage.dns

# to remove the service completely
launchctl boutout user/com.airmessage.dns 
# you could also rm ~/Library/LaunchAgents/com.airmessage.dns.plist

Then boom, you should have your service running. Now these logs are being put into the file called out in the service for output and error directories.

Logging and Cleanup

So I actually threw in another service that cleans up the logs every day.

cp com.airmessage.logs ~/Library/LaunchAgents/
launchctl bootstrap user/com.airmessage.logs

Then it is a matter of repeating the same process as above but for the other service