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: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Locust支持4种方式设置wait_time属性。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
...
weight属性设置创建类实例的权重,默认每个类创建相同数量的实例。locustfile中可以有多个继承了User类的类。$ locust -f locust_file.py WebUser MobileUser
通过weight属性可以让类更大概率创建实例,比如:class WebUser(User): weight = 3 ...
class MobileUser(User): weight = 1 ...
WebUser类比MobileUser类多三倍概率创建实例。host属性一般是在Locust的Web UI或者命令行,通过--host 指定URL前缀。如果没有通过--host 指定,并且类中设置了host属性,那么类的host属性才会生效。environment属性比如在task方法中通过environment属性终止运行:self.environment.runner.quit()
注意,单机会终止所有运行,分布式只会终止单个worker节点。 on_start和on_stop方法HttpUser类开篇文章的示例脚本,没有继承User类,而是继承了它的子类HttpUser:它比User类更常用,因为它添加了一个client 属性,用来发送HTTP请求。client属性/HttpSessionHttpUser类的client属性是HttpSession类的一个实例:HttpSession是requests.Session 的子类,requests就是常用来做接口测试的那个requests库:HttpSession没有对requests.Session 做什么改动,主要是传递请求结果给Locust,比如success/fail,response time,response length,name。response = self.client.post("/login", {"username":"testuser", "password":"secret"}) print("Response status code:", response.status_code) print("Response text:", response.text) response = self.client.get("/my-profile")
由于requests.Session 会暂存cookie,所以示例中登录/login 请求后可以继续请求/my-profile 。断言响应结果可以使用with语句和catch_response参数对响应结果进行断言:with self.client.get("/", catch_response=True) as response: if response.text == "Success": response.success() elif response.text != "Success": response.failure("Got wrong response") elif response.elapsed.total_seconds() > 0.5: response.failure("Request took too long")
from locust.exception import RescheduleTask ... with self.client.get("/does_not_exist/", catch_response=True) as response: if response.status_code == 404: raise RescheduleTask()
name参数name参数用于把不同api按同一分组进行统计,比如:for i in range(10): self.client.get("/blog?id=%i" % i, name="/blog?id=[id]")
会按/blog/?id=[id] 统计1条数据,而不是分成10条数据。HTTP代理Locust默认设置了requests.Session的trust_env为False,不查找代理,以提高运行性能。如果需要可以设置locust_instance.client.trust_env 为True。示例代码from json import JSONDecodeError ... with self.client.post("/", json={"foo": 42, "bar": None}, catch_response=True) as response: try: if response.json()["greeting"] != "hello": response.failure("Did not get expected value in greeting") except JSONDecodeError: response.failure("Response could not be decoded as JSON") except KeyError: response.failure("Response did not contain expected key 'greeting'")
小结locustfile是个普通Python模块,必须继承User类或其子类HttpUser等。本文对User类和HttpUser类的属性和方法进行了介绍,使用它们可以编写性能测试的用户脚本。locustfile还有另外一个重要组成元素,@task 。https://docs./en/stable/writing-a-locustfile.htmlhttps://blog.csdn.net/Orangesir/article/details/114914969 更文进度https://dongfanger./blog/Python进阶系列 teprunner测试平台 Locust官方文档学习
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