Paladin

A simple process supervisor written in Go.

Description

Paladin is a simple way to launch and maintain services. It provides the following features:

• Simple TOML configuration.
• Automatically restart failed processes.
• Log each process to a different file, even separating stdout and stderr.
• Specify process dependencies, so things start in the right order.
• Launch processes under different users and groups.

Installation

• Clone this repo in your $GOPATH.
• Copy etc/paladin.conf.sample to /etc/paladin.conf and set your values.
• Run go build.
• Put paldin in your path.

Compile with something like -ldflags="-X main.localbase=/usr/local" on systems where the config file will not live under /etc, such as FreeBSD.

License

This code is under the BSD-2-Clause license. See the LICENSE file for the full text.

Configuration

The config file uses TOML format. It consists of general options, and several [[process]] blocks that define each process that paladin is responsible for.

General Options

The following general options do not go inside a TOML block:

Name	Required	Description
log_file	N	File path for main output. An empty string means stderr.

Process-specific Options

The following options are per-process, and go in a [[process]] block:

Name	Required	Description
name	Y	Used to identify the process. Must be unique.
path	Y	The full path to the program to be run.
args	N	An array of string arguments for the process.
cwd	N	The current working directory for the process.
stdout	N	The file path for logging stdout.
stderr	N	The file path for logging stderr. Follows stdout if unset.
user	N	Run the process as this user.
group	N	Run the process as this group.
restart_delay	N	Milliseconds to wait before restarting.
ignore_failure	N	Boolean. Set to true to disable restarting on failure.
min_runtime	N	Don't restart if it fails in fewer than this many milliseconds.
soft_depends	N	List of processes that must be started before this one.

Example Configuration

log_file = "/var/log/paladin.log"

[[process]]
name = "my-program"
path = "/path/to/my-program"
args = []
cwd = "/path/to"
restart_delay = 1000
min_runtime = 100
stdout = "/tmp/my-program-stdout"
user = "myuser"
group = "mygroup"

[[process]]
name = "my-other-program"
path = "/path/to/my-other-program"
args = ["-a", "-d"]
min_runtime = 100
soft_depends = [ "my-program" ]
restart_delay = 1000

Command-line Options

Name	Required	Description
-f	N	The config file to use. Defaults to /etc/paladin.conf (unless localbase is set).