Function build_tracer

celery/app/trace.py:344–686

Return a function that traces task execution. Catches all exceptions and updates result backend with the state and result. If the call was successful, it saves the result to the task result backend, and sets the task status to `"SUCCESS"`. If the call raises :exc:`~@Retry`, it

(name, task, loader=None, hostname=None, store_errors=True,
                 Info=TraceInfo, eager=False, propagate=False, app=None,
                 monotonic=time.monotonic, trace_ok_t=trace_ok_t,
                 IGNORE_STATES=IGNORE_STATES)

def build_tracer(name, task, loader=None, hostname=None, store_errors=True,
                 Info=TraceInfo, eager=False, propagate=False, app=None,
                 monotonic=time.monotonic, trace_ok_t=trace_ok_t,
                 IGNORE_STATES=IGNORE_STATES):
    """Return a function that traces task execution.

    Catches all exceptions and updates result backend with the
    state and result.

    If the call was successful, it saves the result to the task result
    backend, and sets the task status to `"SUCCESS"`.

    If the call raises :exc:`~@Retry`, it extracts
    the original exception, uses that as the result and sets the task state
    to `"RETRY"`.

    If the call results in an exception, it saves the exception as the task
    result, and sets the task state to `"FAILURE"`.

    Return a function that takes the following arguments:

        :param uuid: The id of the task.
        :param args: List of positional args to pass on to the function.
        :param kwargs: Keyword arguments mapping to pass on to the function.
        :keyword request: Request dict.

    """

    # pylint: disable=too-many-statements

    # If the task doesn't define a custom __call__ method
    # we optimize it away by simply calling the run method directly,
    # saving the extra method call and a line less in the stack trace.
    fun = task if task_has_custom(task, '__call__') else task.run

    loader = loader or app.loader
    deduplicate_successful_tasks = ((app.conf.task_acks_late or task.acks_late)
                                    and app.conf.worker_deduplicate_successful_tasks
                                    and app.backend.persistent)

    hostname = hostname or gethostname()
    inherit_parent_priority = app.conf.task_inherit_parent_priority

    loader_task_init = loader.on_task_init
    loader_cleanup = loader.on_process_cleanup

    task_before_start = None
    task_on_success = None
    task_after_return = None
    if task_has_custom(task, 'before_start'):
        task_before_start = task.before_start
    if task_has_custom(task, 'on_success'):
        task_on_success = task.on_success
    if task_has_custom(task, 'after_return'):
        task_after_return = task.after_return

    pid = os.getpid()