This program is for simple server monitoring and notifications with signal-cli, matrix-commander or through LXMF (Reticulum mesh network).
It's goal is to be able to run on supersimple servers, like NAS, raspberry pi, home routers, etc.
First, if you want to use signal-cli, install and configure signal-cli (or uncomment the right part in notify function for different kind of notification - matrix-commander or LXMF-notify, see below).
Then modify script and configure your sending number, recipient number and optionally path to java. I add PATH to signal-cli and java commands as well.
Then at the bottom of the script, configure ping checks, URL string match checks and successful ssh (key) authentication.
check_ping takes one argument, which is the name of the server
check_url takes three arguments: "check identificator" (can be anything recognizable that can be a part of filename, such as hostname), URL and string to look for on the web page.
check_ssh takes three arguments: username, hostname a optional port (otherwise it's 22). Make sure that ssh key authentication is working, because it does not simply check for open port, but if the authentication succeeds. It only needs to be able to run echo command, or you can configure the shell to just print "ssh_connection_ok" on stdout. It does not need to be able to execute any other commands.
check_script takes a check identificator as the first parameter and the rest are executed (warning, no sanity checking, we expect no user input coming to this). If the script returns an error status, it failed (exit status >0)
attempts tries a check more times before notifying. Good for checks that sometimes fail, but it is not a big deal, if it works in a few seconds/minutes. attempts tries number_of_attempts times, with sleep_between_attempts seconds between intervals (these are the first two arguments) and the rest is just a normal check call.
The last signal-cli command just downloads all messages for this instance and drops them. Use this if this script is the only user using this server to ease up storage requirements for signal servers and make sure that it does not store too much (encrypted) messages for you.
Run it from cron or task scheduler of your OS. Please refer to the documentation of your OS.
I added Matrix protocol support, because Signal now sometimes asks for CAPTCHAs and I would really like to get notifications even if Signal descides it wants to ask for CAPTCHA.
Install matrix-commander using python. Login with
matrix-commander --login password # password is a string, not your password
It will ask you for the device name, I use server name, so I know where the notification came from.
It will also ask you for the room name, it is best if it already created and has both this user and the user that needs to access the messages in the room already.
Then verify your device keys with other device (such element):
matrix-commander --verify emoji
After you are done, move config and store to correct directories:
mkdir -p ~/.local/share/matrix-commander/ ~/.config/matrix-commander/
mv store ~/.local/share/matrix-commander/
mv credentials.json ~/.config/matrix-commander/
Try sending a message:
matrix-commander -m "Hello from Matrix commander"
The message will go to the default room you configured in the first place.
If you are done, make sure matrix-commander is in the path for the script and uncomment the matrix-commander line in notify function (alternatively comment the two signal-cli lines in the script - the one above matrix-commander and the receive at the end of the script).
Reticulum is immensly cool. It is a mesh network that is medium agnostic, encrypted by default. The reason I am using it is that I want to be able to receive a notification even if my internet connection is down. The network will find a way, for example through LoRA. If my phone is online and I have more than one interface, it will find a way to deliver the message to my phone by itself. So this is the most resilient way to deliver the message that should work regardless on how the infrastructure works. If you are on home wifi, it will even deliver it locally if autointerface is configured in reticulum.
It works by using my command-line LXMF notify bot.
You need to install and configure Sideband on your phone, get the address. You can also use a propagation node, where the message is stored if you are not online.
I wanted to be able to perform a simple monitoring for my hosted server from my home NAS. Signal is what I read, so e-mail notifications won't do it, I don't read e-mail that often.
The script sends one notification per hour, if the service is consistently down. When it goes up again, it sends up notification.
If you like this script, support me by sending a small donation