Horust is a supervisor / init system written in rust and designed to be run inside containers.
init system.At this point, this should be considered Alpha software. As in, you can (and should) use it, but under your own discretion.
Assume you'd like to create a website health monitoring system. You can create one using Horust and a small python script.
That will contain our services:
shell
mkdir -p /etc/horust/services
Pro Tip: You can also bootstrap the creation of a new service, by using
horust --sample-service > new_service.toml.
Create a new configuration file for Horust under /etc/horust/services/healthchecker.toml:
toml
command = "/tmp/healthcheck.py"
start-delay = "10s"
[restart]
strategy = "never"
A couple of notes are due here:
* This library uses TOML for configuration, to go along nicely with Rust's chosen configuration language.
* There are many supported properties for your service file, but only command is required.
On startup, Horust will read this service file, and run the command. According to the restart strategy "never", as soon as the service has carried out its task it will not restart, and Horust will exit.
As you can see, it will run the /tmp/healthcheck.py Python script, which doesn't exist yet. Let's create it!
Create a new Python script under /tmp/healthcheck.py:
```python
import urllib.request import sys req = urllib.request.Request("https://www.google.com", method="HEAD") resp = urllib.request.urlopen(req) if resp.status == 200: sys.exit(0) else: sys.exit(1) ```
Don't forget to make it executable:
shell
chmod +x /tmp/healthcheck.py
This step is only required because we don't have a release yet, or if you like to live on the edge.
For building Horust, you will need Rust. As soon as it's installed, you can build Horust with Rust's cargo:
shell
cargo build --release
Now you can just:
shell
./horust
By default Horust searches for services inside the /etc/horust/services folder (which we have created in step 1).
Every 10 seconds from now on, Horust will send an HTTP HEAD request to https://google.it. If the response is different than 200, then there is an issue!
In this case, we're just exiting with a different exit code (i.e. a 1 instead of a 0). But in real life, you could trigger other actions - maybe storing this information in a database for long-term analysis, or sending an e-mail to the website's owner.
Use Ctrl+C to stop Horust. Horust will send a SIGTERM signal to all the running services, and if it doesn't hear back for a while - it will terminate them by sending an additional SIGKILL signal.
Check out the documentation for a complete reference of the options available on the service config file. A general overview is available below as well:
```toml command = "/bin/bash -c 'echo hello world'" start-delay = "2s" start-after = ["database", "backend.toml"] stdout = "STDOUT" stderr = "/var/logs/helloworldsvc/stderr.log" user = "root" working-directory = "/tmp/"
[restart] strategy = "never" backoff = "0s" attempts = 0
[healthiness] http-endpoint = "http://localhost:8080/healthcheck" file-path = "/var/myservice/up"
[failure] successful-exit-code = [ 0, 1, 255] strategy = "ignore"
[termination] signal = "TERM" wait = "10s" die-if-failed = ["db.toml"]
[environment] keep-env = false re-export = [ "PATH", "DB_PASS"] additional = { key = "value"} ```
Thanks for considering contributing to horust! To get started have a look on CONTRIBUTING.md.
Horust is provided under the MIT license. Please read the attached license file.