owl

OWL is the process status notifier

Overview

The tool wraps command in child process and sends it's state periodically over UDP.

The usage is owl [OPTS] command [ARGS] where [OPTS] are tool options and [ARGS] are command arguments passed without any modification.

E.g. owl +Host:127.0.0.1 +Port:9090 rsync -avz /home/user root@192.168.56.102:/home

Shell scripts can be wrapped as well with modification of shebang, e.g.

#!/usr/bin/env owl +Name:Awesome_Job bash
...commands...

The tool accepts options which have form of +Name:value where Name is the name of the option, case is sensitive, and value is the value.

Installing

The tool requires rustc of version 1.39 or above to successful compilcation.

Options

The format of options starting with plus and delimited with colon had been choosen to have OWL options visually and physically separated from other command line arguments.

Name	Default	Description	Example
Conf		The location of the configuration file.	+Conf:/usr/local/owl.conf
Host	0.0.0.0	The host address to delivert state to.	+Host:192.168.0.90
Port	39576	The port to deliver state to.	+Port:20304
Heartbeat	1000	The delay between deliveries in milliseconds.	+Heartbeat:10000

Configuration File

Options can be organized in a configuration file which is the text file in toml format.

The file should contain one section [watch] where all process watch related options are. Option names here are the same as command line options.

Example configuration file.

[watch]
Host = "192.168.20.19"
Port = 9090
Heartbeat = 5000

The location of the configuration file to load on tool start can be set explicitly with the Conf option. In the case the Conf option omitted the configuration file is searched through the default locations in the order as shown below.

1. owl.toml in the current work directory of the process.
2. /etc/owl/owl.toml
3. /etc/owl.toml

Delivery Protocol

The protocol used for UDP packet encoding is SSDPD (Simply Stupid Double Pipe Delimited).

The data in the packed is a number of text fields delimited with double pipe || . The field order and meaning is below.

1. ID of the owl watcher process.
2. ID of the command process.
3. The name of the command running, or the name from the Name option.
4. The state of the command process.

E.g. 1280||1281||rsync||Sleeping

Security

Some sort of Please do not sniff my UDP packets.

Known issues

• The tool cannot watch after daemon processes because they detach from the parent process and it dies so the tool thinks the command finished and finishes too.

Licensing

Licensed under Apache License 2.0