supervisor.sh

Description

supervisor.sh is a lightweight Bash script for managing processes based on a YAML configuration file. It runs in foreground or as a daemon, handling the starting, stopping, and monitoring of multiple programs or scripts. This makes it useful for systems where a simple, standalone process manager is needed, or for containerized environments where minimal overhead is desired.

Dependencies

• Bash >= 5.1
• yq - a lightweight and portable command-line YAML processor

The yq dependency can be removed. See below.

Usage

Usage:
  supervisor.sh [OPTION] [COMMAND]

Configuration file:
  By default, the configuration is read from '/etc/supervisor.yaml'.
  If 'yq' is not available, '/etc/supervisor.yaml.sh' will be used instead.
  Provide '--config' to specify a custom configuration file.

Options:
  -c, --config  Specify config file, e.g. 'supervisor.sh -c /path/config.yaml'.
  -h, --help    Show this help.

Commands:
  start           Start supervisor.sh as daemon.
  start <job>     Start job.
  stop            Stop supervisor.sh.
  stop  <job>     Stop job.
  restart         Restart daemon.
  restart <job>   Restart job.
  status          Show process status.
  fix             Fix unclean shutdown.
  log             Show continuously the supervisor.sh log.
  logs            Show continuously the supervisor.sh log + job logs.
  convert         Convert the YAML config file to Bash. This allows the usage
                  without the 'yq' dependency.

If no command is provided, supervisor.sh will start in foreground.

Configuration file (supervisor.yaml)

By default, the configuration is read from /etc/supervisor.yaml. You can specify another location with the --config option.

supervisor

Key	Required	Default	Possible Values	Description
logfile	No	/dev/stdout	Valid file path	Log file for output (only for daemon mode)
sigterm_grace_period	No	2	Any number	Grace period in seconds until SIGKILL is send to processes that keeps running after SIGTERM
keep_running	No	off	on, off	Exit supervisor when all jobs are stopped (off) or keep running (on)
color	No		e.g. \e[0;34m	Sets the text color using an escape sequence for terminal colors. This only applies if running in the foreground.

jobs

Key	Required	Default	Possible Values	Description
name	Yes		Any string	Job name
command	Yes		Any string	Job command
autostart	No	on	on, off	Start job automatically (on) or not (off)
restart	No	error	error, on, off	Restart a job if it exits, only on failure (error) or always (on) or never (off)
logfile	No	/dev/stdout	Valid file path	Log file for output

Example

supervisor:
  logfile: "/var/log/supervisor.log"
  sigterm_grace_period: 2
  keep_running: "off"
  color: "\e[0;34m" # blue text color

jobs:
  - name: "job1"
    command: "echo 'I will fail soon. But supervisor will restart me'; sleep 10; exit 1"
    autostart: "on"
    restart: "error"
    logfile: "/var/log/job1.log"

  - name: "job2"
    command: "echo 'No restart for me on failure'; sleep 3; exit 1"
    restart: "off"
    logfile: /var/log/job2.log

  - name: "job3"
    command: "echo 'This output goes to the supervisor log file'"

  - name: "job4"
    command: "echo 'I was started manually'"
    autostart: "off"
    logfile: "/var/log/job4.log"

Run without the 'yq' dependency

If you want to remove the yq dependency, you can convert the YAML configuration to Bash. However, this conversion must be done in an environment where yq is available.

supervisor.sh -c /etc/supervisor.yaml convert

# Now you can use supervisor.sh without the 'yq' dependency
supervisor.sh -c /etc/supervisor.yaml.sh <command>