Module Tezos_stdlib_unix.Process_manager

Alternative implementation of Lwt_process API which does not rely on Unix.fork.

This module provides functions for creating and managing external processes. It uses Lwt_domain to spawn processes, making it a safer alternative to Lwt_process in multi-threaded applications that use system threads.

The API mirrors Lwt_process, providing functions to open processes with different I/O configurations (open_process_in, open_process_out, etc.) and corresponding "with" functions (with_process_in, etc.) that handle resource cleanup automatically.

Note: This module does not support the Windows platform.

Opening Processes

val open_process_in : (string * string array) -> Lwt_process.process_in Lwt.t

open_process_in (command, args) starts the given command. The standard output of the process is connected to a pipe, which can be read via the stdout method of the returned object.

  • parameter command

    A tuple containing the command name and its arguments.

  • returns

    A promise that resolves to a Lwt_process.process_in object.

val open_process_out : (string * string array) -> Lwt_process.process_out Lwt.t

open_process_out (command, args) starts the given command. The standard input of the process is connected to a pipe, which can be written to via the stdin method of the returned object.

  • parameter command

    A tuple containing the command name and its arguments.

  • returns

    A promise that resolves to a Lwt_process.process_out object.

val open_process : (string * string array) -> Lwt_process.process Lwt.t

open_process (command, args) starts the given command. The standard input and standard output of the process are connected to pipes, which can be accessed via the stdin and stdout methods of the returned object.

  • parameter command

    A tuple containing the command name and its arguments.

  • returns

    A promise that resolves to a Lwt_process.process object.

val open_process_full : (string * string array) -> Lwt_process.process_full Lwt.t

open_process_full (command, args) starts the given command. The standard input, standard output, and standard error of the process are connected to pipes, accessible via the stdin, stdout, and stderr methods of the returned object.

  • parameter command

    A tuple containing the command name and its arguments.

  • returns

    A promise that resolves to a Lwt_process.process_full object.

val open_process_none : (string * string array) -> Lwt_process.process_none Lwt.t

open_process_none (command, args) starts the given command. The standard input, standard output, and standard error are redirected to the ones of the caller.

  • parameter command

    A tuple containing the command name and its arguments.

  • returns

    A promise that resolves to a Lwt_process.process_full object.

Managing Processes

These are helper functions that manage the lifecycle of a process. They start a process, apply a given function, and ensure the process is properly closed afterward, even if the function raises an exception. This is the recommended way to interact with processes.

val with_process_in : (string * string array) -> (Lwt_process.process_in -> 'a Lwt.t) -> 'a Lwt.t

with_process_in cmd f is a safe wrapper for open_process_in. It starts a process, applies f to the process object, and guarantees cleanup.

  • parameter cmd

    The command and arguments to execute.

  • parameter f

    A function to apply to the created process.

  • returns

    The result of f proc.

val with_process_out : (string * string array) -> (Lwt_process.process_out -> 'a Lwt.t) -> 'a Lwt.t

with_process_out cmd f is a safe wrapper for open_process_out. It starts a process, applies f to the process object, and guarantees cleanup.

  • parameter cmd

    The command and arguments to execute.

  • parameter f

    A function to apply to the created process.

  • returns

    The result of f proc.

val with_process : (string * string array) -> (Lwt_process.process -> 'a Lwt.t) -> 'a Lwt.t

with_process cmd f is a safe wrapper for open_process. It starts a process, applies f to the process object, and guarantees cleanup.

  • parameter cmd

    The command and arguments to execute.

  • parameter f

    A function to apply to the created process.

  • returns

    The result of f proc.

val with_process_full : (string * string array) -> (Lwt_process.process_full -> 'a Lwt.t) -> 'a Lwt.t

with_process_full cmd f is a safe wrapper for open_process_full. It starts a process, applies f to the process object, and guarantees cleanup.

  • parameter cmd

    The command and arguments to execute.

  • parameter f

    A function to apply to the created process.

  • returns

    The result of f proc.

val with_process_none : (string * string array) -> (Lwt_process.process_none -> 'a Lwt.t) -> 'a Lwt.t

with_process_none cmd f is a safe wrapper for open_process_none. It starts a process, applies f to the process object, and guarantees cleanup.

  • parameter cmd

    The command and arguments to execute.

  • parameter f

    A function to apply to the created process.

  • returns

    The result of f proc.