Process Launcher Schema

ProcessLauncher is in responsible for spawning and managing external processes in NRPCore simulations. Typically it is used to bring up Engine server processes, but it can be used to execute arbitrary commands. The schema listed below allows user to specify which commands should be executed in a given NRPCore experiment.

The Simulation Schema contains a parameter ExternalProcesses of type array which elements are of type json://nrp-core/process_launcher.json#ProcessLauncher, i.e, the type defined in the schema listed below. This parameter can be use to specify which commands should be launched alongside with the experiment.

Below is a list of all the parameters needed to configure a ProcessLauncher.

Parameters

Name	Description	Type	Default	Required	Array
ProcCmd	Process Launch command	string		X
ProcStartParams	Process Start Parameters	string			X
ProcEnvParams	Process Environment Parameters	string object	{“LaunchType”:”BasicFork”}		X

Example

Below is listed an example experiment configuration using ProcessLauncher to launch a “custom” command in a forked process.

{
    "SimulationName": "test_sim",
    "SimulationDescription": "Just writting a greetings message from a forked process using an environment variable",
    "SimulationTimeout": 1,
    "ExternalProcesses" : [
        {
            "ProcCmd": "export MSG=$GREETINGS_MSG && echo $MSG",
            "ProcEnvParams": ["GREETINGS_MSG=\"Hello World!\""]
        }
    ]
}

Schema

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Process Launcher",
  "description": "Process Launcher configuration schema",
  "$id": "#ProcessLauncher",
  "type": "object",
  "properties" : {
    "ProcCmd" : {
      "type" : "string",
      "description": "Process Launch command"
    },
    "ProcStartParams" : {
      "type" : "array",
      "items": {"type" : "string"},
      "description": "Process Start Parameters"
    },
    "ProcEnvParams" : {
      "type" : "array",
      "items": {"type" : "string"},
      "description": "Process Environment Parameters"
    },
    "LaunchCommand" : {
      "$schema": "http://json-schema.org/draft-07/schema#",
      "title": "Launch Command",
      "description": "LaunchCommand that will be used to launch the process",
      "$id": "#LaunchCommand",
      "type":"object",
      "oneOf":[
        { "$ref": "json://nrp-core/launch_commands/empty_launch_cmd.json#/empty_launch_cmd" },
        { "$ref": "json://nrp-core/launch_commands/basicfork_cmd.json#/basicfork_cmd" },
        { "$ref": "json://nrp-core/launch_commands/docker_launcher_cmd.json#/docker_launcher_cmd" }
      ],
      "default":{"LaunchType":"BasicFork"}
    }
  },
  "required": ["ProcCmd"]
}