erlexec

Execute and control OS processes from Erlang/OTP.

This project implements an Erlang application with a C++ port program that gives light-weight Erlang processes fine-grain control over execution of OS processes.

The following features are supported:

• Start/stop OS commands and get their OS process IDs, and termination reason (exit code, signal number, core dump status).
• Manage/monitor externally started OS processes.
• Execute OS processes synchronously and asynchronously.
• Set OS command's working directory, environment, process group, effective user, process priority.
• Provide custom termination command for killing a process or relying on default SIGTERM/SIGKILL behavior.
• Specify custom timeout for SIGKILL after the termination command or SIGTERM was executed and the running OS child process is still alive.
• Link an Erlang processes to OS processes (via intermediate Erlang Pids that are linked to an associated OS process).
• Monitor termination of OS processes.
• Terminate all processes beloging to an OS process group.
• Kill processes belonging to an OS process group at process exit.
• Communicate with an OS process via its STDIN.
• Redirect STDOUT and STDERR of an OS process to a file, erlang process, or a custom function. When redirected to a file, the file can be open in append/truncate mode, and given creation access mask.
• Run interactive processes with psudo-terminal pty support.
• Execute OS processes under different user credentials (using Linux capabilities).
• Perform proper cleanup of OS child processes at port program termination time.

This application provides significantly better control over OS processes than built-in erlang:open_port/2 command with a {spawn, Command} option, and performs proper OS child process cleanup when the emulator exits.

The erlexec application has been in production use by Erlang and Elixir systems, and is stable.

See http://saleyn.github.com/erlexec for more information.

Donations

If you find this project useful, please donate to:

• Bitcoin: 12pt8TcoMWMkF6iY66VJQk95ntdN4pFihg
• Ethereum: 0x268295486F258037CF53E504fcC1E67eba014218

SUPPORTED OS's

Linux, Solaris, FreeBSD, OpenBSD, MacOS X

DOCUMENTATION

See http://saleyn.github.io/erlexec

BUILDING

Make sure you have rebar (http://github.com/basho/rebar or http://github.com/basho/rebar3) installed locally and the rebar script is in the path.

If you are deploying the application on Linux and would like to take advantage of exec-port running tasks using effective user IDs different from the real user ID that started exec-port, then either make sure that libcap-dev[el] library is installed or make sure that the user running the port program has sudo rights.

OS-specific libcap-dev installation instructions:

• Fedora, CentOS: "yum install libcap-devel"
• Ubuntu: "apt-get install libcap-dev"

$ git clone [email protected]:saleyn/erlexec.git
$ make

# NOTE: for disabling optimized build of exec-port, do the following instead:
$ OPTIMIZE=0 make

By default port program's implementation uses poll(2) call for event demultiplexing. If you prefer to use select(2), set the following environment variable:

$ USE_POLL=0 make

LICENSE

The program is distributed under BSD license. Copyright (c) 2003 Serge Aleynikov