procmgr

procmgr is a simple process manager for managing running processes. It is loosely based on process management of services like upstart and systemd.

procmgr was designed to provide a simple way to manage services in a system without sufficient /sbin/init process management (e.g. lxc or docker containers)

Config

procmgr reads a yaml config file with a description of various processes to run.

Example:

processes:
-
  name: hello
  command: echo 'Hello, World'
  streams: [stdout]

Given the above config file, procmgr will start the process echo 'Hello, World' when run. The process will have it's stdout piped to the current stdout. Stdin and stderr are discarded.

Dependencies

Processes can be chained by providing the after: field. All processes are run in parallel, and will wait for processes which have been marked in their after section to finish before starting.

processes:
-
  name: database
  command: pg_ctl -D /var/lib/postgres/data/ start
-
  name: webapp
  command: unicorn
  streams: [stdin, stdout, stderr]
  after: [database.finished]

Given the above config, the database process would be started, and only after the process has completed will the webapp process be started.

Restarting

Processes can be restarted when they exit cleanly (0 exit code) by providing a restart: true field:

processes:
-
  # This process prints 'Hello' to stdout once every 2 seconds.
  # It is restarted by the service manager when it stops cleanly (0 exit code).
  # If it exists with non-zero exit code, it will not be restarted.
  name: greeter
  command: echo 'Hello' ; sleep 2
  streams: [stdout]
  restart: true 

Example

processes:
-
  # Simple task.
  # Attaches stdout so that the echo will be printed to screen.
  name: hello
  command: echo 'Hello World'
  streams: [stdout]
-
  # Sleep for 2 seconds to demonstrate the dependencies
  name: sleep
  command: sleep 2
  streams: []
  after: [hello.finished]
-
  # Wait until the sleep finishes and say hello again
  name: helloagain
  command: echo 'Hello Again'
  streams: [stdout]
  after: [sleep.finished]
-
  # Run at the same time as 'helloagain' and print goodbye to stderr
  # Attaches stderr so that the echo will be printed to the screen.
  name: goodbye
  command: echo 'Goodbye World' 1>&2
  streams: [stderr]
  after: [helloagain.started]

Planned Features

• Changing the cwd of a process.
• Changing the user/group of a process.