Locust性能测试工具核心技术@task和@events

Sun, 18 Jan 2026 00:00:00 +0000

Tasks和Events是Locust性能测试工具的核心技术，有了它们，Locust才能称得上是一个性能工具。

locustfile中的User类和HttpUser类

Sat, 17 Jan 2026 00:00:00 +0000

本书作者：测试开发刚哥，文章版权归个人所有，未经授权请勿转载。

locustfile是什么？

locustfile是Locust性能测试工具的用户脚本，描述了单个用户的行为。

locustfile是个普通的Python模块，如果写作locustfile.py，那么路径切换到文件所在目录，直接执行命令就能运行：

$ locust

如果换个名字，那么只能通过-f参数指定文件名运行：

$ locust -f locust_files/my_locust_file.py

与一般Python模块不同的是：locustfile必须至少定义一个类，且继承自User类。

User类

User类表示性能测试的模拟用户，Locust会在运行时创建User类的实例。

wait_time属性

设置等待时间，默认值不等待，立即执行。

Locust支持4种方式设置wait_time属性。

为了便于理解实际意义，我把源码贴在了下面。

constant函数，常量，任务执行完毕等待X秒开始下一任务。

def constant(wait_time):
    """
    Returns a function that just returns the number specified by the wait_time argument

    Example::

        class MyUser(User):
            wait_time = constant(3)
    """
    return lambda instance: wait_time

between函数，区间随机值，任务执行完毕等待X-Y秒（中间随机取值）开始下一任务。

def between(min_wait, max_wait):
    """
    Returns a function that will return a random number between min_wait and max_wait.

    Example::

        class MyUser(User):
            # wait between 3.0 and 10.5 seconds after each task
            wait_time = between(3.0, 10.5)
    """
    return lambda instance: min_wait + random.random() * (max_wait - min_wait)

constant_pacing函数，自适应，若任务耗时超过该时间，则任务结束后立即执行下一任务；若任务耗时不超过该时间，则等待达到该时间后执行下一任务。

def constant_pacing(wait_time):
    """
    Returns a function that will track the run time of the tasks, and for each time it's
    called it will return a wait time that will try to make the total time between task
    execution equal to the time specified by the wait_time argument.

    In the following example the task will always be executed once every second, no matter
    the task execution time::

        class MyUser(User):
            wait_time = constant_pacing(1)
            @task
            def my_task(self):
                time.sleep(random.random())

    If a task execution exceeds the specified wait_time, the wait will be 0 before starting
    the next task.
    """

    def wait_time_func(self):
        if not hasattr(self, "_cp_last_run"):
            self._cp_last_wait_time = wait_time
            self._cp_last_run = time()
            return wait_time
        else:
            run_time = time() - self._cp_last_run - self._cp_last_wait_time
            self._cp_last_wait_time = max(0, wait_time - run_time)
            self._cp_last_run = time()
            return self._cp_last_wait_time

    return wait_time_func

自定义wait_time方法，比如每次等待时间1秒2秒3秒递增：

class MyUser(User):
    last_wait_time = 0

    def wait_time(self):
        self.last_wait_time += 1
        return self.last_wait_time

    ...

Python技术栈性能测试工具Locust入门

Fri, 16 Jan 2026 00:00:00 +0000