from __future__ import annotations
import logging
import time
import traceback
from collections.abc import Generator
from contextlib import contextmanager
from typing import Any
from . import log
from .exception import InterruptTaskSet, RescheduleTask, RescheduleTaskImmediately, StopUser
[docs]class EventHook:
"""
Simple event class used to provide hooks for different types of events in Locust.
Here's how to use the EventHook class::
my_event = EventHook()
def on_my_event(a, b, **kw):
print("Event was fired with arguments: %s, %s" % (a, b))
my_event.add_listener(on_my_event)
my_event.fire(a="foo", b="bar")
If reverse is True, then the handlers will run in the reverse order
that they were inserted
"""
def __init__(self):
self._handlers = []
def add_listener(self, handler):
self._handlers.append(handler)
return handler
def remove_listener(self, handler):
self._handlers.remove(handler)
def fire(self, *, reverse=False, **kwargs):
if reverse:
handlers = reversed(self._handlers)
else:
handlers = self._handlers
for handler in handlers:
try:
handler(**kwargs)
except (StopUser, RescheduleTask, RescheduleTaskImmediately, InterruptTaskSet):
# These exceptions could be thrown by, for example, a request handler,
# in which case they are entirely appropriate and should not be caught
raise
except Exception:
logging.error("Uncaught exception in event handler: \n%s", traceback.format_exc())
log.unhandled_greenlet_exception = True
[docs] @contextmanager
def measure(
self, request_type: str, name: str, response_length: int = 0, context=None
) -> Generator[dict[str, Any], None, None]:
"""Convenience method for firing the event with automatically calculated response time and automatically marking the request as failed if an exception is raised (this is really only useful for the *request* event)
Example usage (in a task):
with self.environment.events.request.measure("myrequestType", "myRequestName") as request_meta:
# do the stuff you want to measure
You can optionally add/overwrite entries in the request_meta dict and they will be passed to the request event.
Experimental.
"""
start_time = time.time()
start_perf_counter = time.perf_counter()
request_meta = {
"request_type": request_type,
"name": name,
"response_length": response_length,
"context": context or {},
"exception": None,
"start_time": start_time,
}
try:
yield request_meta
except Exception as e:
request_meta["exception"] = e
finally:
request_meta["response_time"] = (time.perf_counter() - start_perf_counter) * 1000
self.fire(**request_meta)
class DeprecatedEventHook(EventHook):
def __init__(self, message):
self.message = message
super().__init__()
def add_listener(self, handler):
logging.warning(self.message)
return super().add_listener(handler)
[docs]class Events:
request: EventHook
"""
Fired when a request in completed.
Event arguments:
:param request_type: Request type method used
:param name: Path to the URL that was called (or override name if it was used in the call to the client)
:param response_time: Time in milliseconds until exception was thrown
:param response_length: Content-length of the response
:param response: Response object (e.g. a :py:class:`requests.Response`)
:param context: :ref:`User/request context <request_context>`
:param exception: Exception instance that was thrown. None if request was successful.
If you want to simplify a custom client, you can have Locust measure the time for you by using :meth:`measure() <locust.event.EventHook.measure>`
"""
user_error: EventHook
"""
Fired when an exception occurs inside the execution of a User class.
Event arguments:
:param user_instance: User class instance where the exception occurred
:param exception: Exception that was thrown
:param tb: Traceback object (from e.__traceback__)
"""
report_to_master: EventHook
"""
Used when Locust is running in --worker mode. It can be used to attach
data to the dicts that are regularly sent to the master. It's fired regularly when a report
is to be sent to the master server.
Note that the keys "stats" and "errors" are used by Locust and shouldn't be overridden.
Event arguments:
:param client_id: The client id of the running locust process.
:param data: Data dict that can be modified in order to attach data that should be sent to the master.
"""
worker_report: EventHook
"""
Used when Locust is running in --master mode and is fired when the master
server receives a report from a Locust worker server.
This event can be used to aggregate data from the locust worker servers.
Event arguments:
:param client_id: Client id of the reporting worker
:param data: Data dict with the data from the worker node
"""
worker_connect: EventHook
"""
Fired on master when a new worker connects. Note that is fired immediately after the connection is established, so init event may not yet have finished on worker.
:param client_id: Client id of the connected worker
"""
spawning_complete: EventHook
"""
Fired when all simulated users has been spawned.
Event arguments:
:param user_count: Number of users that were spawned
"""
quitting: EventHook
"""
Fired when the locust process is exiting.
Event arguments:
:param environment: Environment instance
"""
quit: EventHook
"""
Fired after quitting events, just before process is exited.
Event arguments:
:param exit_code: Exit code for process
"""
init: EventHook
"""
Fired when Locust is started, once the Environment instance and locust runner instance
have been created. This hook can be used by end-users' code to run code that requires access to
the Environment. For example to register listeners to other events.
Event arguments:
:param environment: Environment instance
"""
init_command_line_parser: EventHook
"""
Event that can be used to add command line options to Locust
Event arguments:
:param parser: ArgumentParser instance
"""
test_start: EventHook
"""
Fired on each node when a new load test is started. It's not fired again if the number of
users change during a test.
"""
test_stopping: EventHook
"""
Fired on each node when a load test is about to stop - before stopping users.
"""
test_stop: EventHook
"""
Fired on each node when a load test is stopped.
"""
reset_stats: EventHook
"""
Fired when the Reset Stats button is clicked in the web UI.
"""
cpu_warning: EventHook
"""
Fired when the CPU usage exceeds runners.CPU_WARNING_THRESHOLD (90% by default)
"""
def __init__(self):
# For backward compatibility use also values of class attributes
for name, value in vars(type(self)).items():
if value == "EventHook":
setattr(self, name, EventHook())
for name, value in self.__annotations__.items():
if value == "EventHook":
setattr(self, name, EventHook())