Data.Conduit.Process.Unix

Process tracking

Ensure that child processes are killed, regardless of how the parent process exits.

The technique used here is:

• Create a pipe.
• Fork a new child process that listens on the pipe.
• In the current process, send updates about processes that should be auto-killed.
• When the parent process dies, listening on the pipe in the child process will get an EOF.
• When the child process receives that EOF, it kills all processes it was told to auto-kill.

This code was originally written for Keter, but was moved to unix-process conduit in the 0.2.1 release.

Types

data ProcessTracker

Represents the child process which handles process cleanup.

Since 0.2.1

Functions

initProcessTracker :: IO ProcessTracker

Fork off the child cleanup process.

This will ideally only be run once for your entire application.

Since 0.2.1

Monitored process

data MonitoredProcess

Abstract type containing information on a process which will be restarted.

monitorProcess

Arguments

:: (ByteString -> IO ())

log

-> ProcessTracker

-> Maybe ByteString

setuid

-> ByteString

executable

-> ByteString

working directory

-> [ByteString]

command line parameter

-> [(ByteString, ByteString)]

environment

-> (ByteString -> IO ())

-> (ExitCode -> IO Bool)

should we restart?

-> IO MonitoredProcess

Run the given command, restarting if the process dies.

terminateMonitoredProcess :: MonitoredProcess -> IO ()

Terminate the process and prevent it from being restarted.

printStatus :: MonitoredProcess -> IO Text