p4utils.utils.task_scheduler module

class p4utils.utils.task_scheduler.ProcessType

Bases: enum.IntEnum

Enum class that defines task types.

CHAIN_SUBPROC = 2

MULTIPROC = 0

SUBPROC = 1

class p4utils.utils.task_scheduler.Task(exe, start=0, duration=0, args=(), kwargs={})

Bases: object

Abstraction of a Task executed by the TaskServer.

Parameters:

• exe (str or types.FunctionType) – executable to run (either a shell string command or a python function)
• start (int or float) – task absolute starting time (Unix time).
• duration (int or float) – task duration time in seconds (if duration is lower than or equal to 0, then the task has no time limitation)
• args (tuple or list) – positional arguments for the passed function
• kwargs (dict) – key-word arguments for the passed function

exitcode

Returns the exit code of the task.

Returns:exit code of the task. Return type:int

Note

Returns None if the process has not yet terminated.

is_alive()

Returns whether the process is alive.

Returns:True if the process is alive, False otherwise. Return type:bool

join(timeout=None)

Joins the subprocess.

pid

Returns the PID of the task.

Returns:PID of the running task. Return type:int

Note

Returns None if the task has not been started yet.

schedule(cond=None)

Starts a new thread that orchestrate the execution of the task and stops it if duration expires.

Parameters:cond (threading.Condition) – condition to notify when self.thread is completed

setComm(q)

Set communication queue for the Task. The task will communicate its state putting items in the queue.

Parameters:

• id (int) – task id used to communicate
• q (queue.Queue) – communication queue

start()

Starts the executable in a separate process.

stop()

Stops the task using SIGTERM and, if it fails, SIGKILL.

class p4utils.utils.task_scheduler.TaskClient(unix_socket_file)

Bases: object

Task scheduler client which communicates with servers.

Parameters:unix_socket_file (str) – path to the file used by the Unix socket

send(tasks, retry=False)

Send an object to the server and close connection.

Parameters:

• tasks (list or tuple) – list or tuple of py:class:Task objects to execute
• retry (bool) – whether to attempt a reconnection upon failure

class p4utils.utils.task_scheduler.TaskServer(unix_socket_file)

Bases: object

Task scheduler server which runs on the Mininet nodes.

Parameters:unix_socket_file (string) – path to the file used by the Unix socket