NED File src/inet/common/ExternalProcess.ned

Name	Type	Description
ExternalProcess	simple module	Launches an external OS process in the background, using the command line given in the 'command' parameter. The process is terminated when the module is deleted. This module requires using the ~RealTimeScheduler class as the simulation event scheduler.

Source code

//
// Copyright (C) 2024 OpenSim Ltd.
//
// SPDX-License-Identifier: LGPL-3.0-or-later
//

package inet.common;

import inet.common.SimpleModule;

//
// Launches an external OS process in the background, using the command line
// given in the 'command' parameter. The process is terminated when the module
// is deleted. This module requires using the ~RealTimeScheduler class as the
// simulation event scheduler.
//
// To run a command that requires elevated privileges without sudo, user and
// network namespaces need to be unshared from the host OS (unshare-namespaces = true).
// In this case, the state of the host OS's external processes are not accessible
// from the unshared namespace in the usual way (e.g. displaying routing tables with `ip route`).
// To work around this, use `nsenter`:
//
//    sudo nsenter -t <PID> -n <command>
//
// PID is the ID of the process running in the unshared namespace.
//
// To list process IDs in all network namespaces:
//
//    sudo lsns -t net
//
// @see ~ExternalApp, ~ExternalEnvironment
//
simple ExternalProcess extends SimpleModule
{
    parameters:
        @class(ExternalProcess);
        string namespace = default(""); // Name of the OS network namespace (optional)
        string command; // Executable with arguments (e.g. "ping google.com"); not a shell command as it will be passed to execvp
        string onExit @enum("terminateSimulation","relaunch","ignore") = default("ignore"); // Determines what happens when the process exits
        double startTime @unit(s) = default(0s);
        double relaunchDelay @unit(s) = default(0s);
        bool printStdout = default(false); // Print STDOUT to the simulation's STDOUT
        bool printStderr = default(true); // Print STDERR to the simulation's STDERR
        @display("i=block/app");
}