sup/README.md

Sup is a small and simple process supervisor. It is originally to monitor some
applications in my X session but it can be used for other things.

## Installing

```shell
$ cargo install https://gitlab.com/rascul/sup
```

## Running

Sup must find the config file sup.toml in the current directory.

## Features

### Restart

Sup can be configured to restart an application when it stops. There are three
conditions sup can watch for:

* Success: In this case, the application has done a normal shutdown and the
exit status is 0.
* Failure: If the application exits with a non zero exit status it is
considered to have failed.
* Terminated: The application was killed by some other mechanism.

### Holds

A hold may be placed on any number of application. If there are any holds, sup
will keep track and while any held applications are running, sup will not exit.
When all held applications are no longer running, and are not configured to
restart anymore, sup will close the other applications and shutdown. If no holds
are specified, sup will just keep running until it's killed.

## Configuration File

The configuration file is sup.toml and will be found in the current directory
when starting sup. This will change in the future. Sup uses the
[toml](https://github.com/toml-lang/toml) format to describe each application
to supervise.

### `[[app]]`

Each application instance to monitor will have an `[[app]]` section. The apps
will be started in the order as read from the file.

#### Required Entries

* name: The name of the application.
* command: The command to run, including path if necessary.
* args: An array of arguments to pass with the command. May be an empty array.

#### Optional Entries

* restart_on_success: Restart the app if it exits successfully. (Default: false)
* restart_on_failure: Restart the app if it fails. (Default: false)
* restart_on_terminate: Restart the app if it is terminated. (Default: false)
* wait: Don't run the next app until this one is finished. (Default: false)
* hold: Don't exit sup until this app has finished. (Default: false)

### Example

```toml
[[app]]
name = "x resource"
command = "xrdb"
args = ["~/.Xresources"]
wait = true

[[app]]
name = "terminal"
command = "alacritty"
args = []
restart_on_success = false
restart_on_failure = true
restart_on_terminate = true
hold = true

[[app]]
name = "environment"
command = "alacritty"
args = ["-e", "env"]

[[app]]
name = "window manager"
command = "twm"
args = []
hold = true
```