Polysemy.Process.SystemProcess

The effect SystemProcess is a low-level abstraction of a native system process.

Documentation

data SystemProcess :: Effect

Low-level interface for a process, operating on raw chunks of bytes. Interface is modeled after System.Process.

wait :: forall r. Member SystemProcess r => Sem r ExitCode

Wait for the process to terminate, returning its exit code.

signal :: forall r. Member SystemProcess r => Signal -> Sem r ()

Send a Signal to the process.

withSystemProcess :: forall param err r. Member (Scoped param (SystemProcess !! err)) r => param -> InterpreterFor (SystemProcess !! err) r

Create a scoped resource for SystemProcess. The process configuration may depend on the provided value of type param.

interrupt :: Member SystemProcess r => Sem r ()

Send signal INT(2) to the process.

pid :: forall r. Member SystemProcess r => Sem r Pid

Obtain the process ID.

readStderr :: forall r. Member SystemProcess r => Sem r ByteString

Read a chunk from stderr.

readStdout :: forall r. Member SystemProcess r => Sem r ByteString

Read a chunk from stdout.

writeStdin :: forall r. Member SystemProcess r => ByteString -> Sem r ()

Write a ByteString to stdin.

type SysProcConf = ProcessConfig () () ()

Convenience alias for a vanilla ProcessConfig, which will usually be transformed by interpreters to use Handles.

interpretSystemProcessNative :: forall param r. Members [Resource, Embed IO] r => (param -> Sem r (Either Text SysProcConf)) -> InterpreterFor (Scoped param (SystemProcess !! SystemProcessError) !! SystemProcessScopeError) r

Interpret SystemProcess as a scoped Process that's started wherever withSystemProcess is called and terminated when the wrapped action finishes. This variant is for parameterized scopes, allowing the consumer to supply a value of type param to create the process config.

interpretSystemProcessWithProcess :: forall r. Member (Embed IO) r => Process Handle Handle Handle -> InterpreterFor (SystemProcess !! SystemProcessError) r

Interpret SystemProcess with a concrete Process with connected pipes.

interpretSystemProcessNativeSingle :: forall r. Members [Stop SystemProcessScopeError, Resource, Embed IO] r => SysProcConf -> InterpreterFor (SystemProcess !! SystemProcessError) r

Interpret SystemProcess as a single global Process that's started immediately.

module Polysemy.Process.SysProcConf

currentPid :: Member (Embed IO) r => Sem r Pid

Obtain the current process's Pid.