Locust：深入使用 参数 类 方法

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前面的文章，对locust进行了简单介绍和使用，

现在深入一下，

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Locust no-web模式

熟悉 Apache ab 工具的同学都知道，它是没有界面的，通过命令行执行。 Locust 同样也提供的命令行运行，好处就是更节省客户端资源。

locust -f ./locustfile.py --host=http://127.0.0.1:5000 --headless -u 1 -r 1 -t 1m

--headless 表示不使用Web界面运行测试。

-u 设置虚拟用户数。

-r 设置每秒启动虚拟用户数。

-t 设置设置运行时间。

如果不知道怎么使用，就使用locust --help 查看一下帮助文档，

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Locust 参数说明

是时候该讲一下 locust 工具的参数了，虽然前面几节我们已经使用了不少参数，例如 “-f” 、“–host” 等。

打开命令提示符（或Linux终端），输入 locust --help 。

Usage: locust [OPTIONS] [UserClass ...]

Common options:
  -h, --help            show this help message and exit  # 这是查看帮助文档
  -f LOCUSTFILE, --locustfile LOCUSTFILE     # 这是指定运行脚本
                        Python module file to import, e.g. '../other.py'. Default: locustfile
  --config CONFIG       Config file path
  -H HOST, --host HOST  Host to load test in the following format: http://10.21.32.33  # 这是指定host
  -u NUM_USERS, --users NUM_USERS  # 这是指定用户数
                        Peak number of concurrent Locust users. Primarily used together with --headless or --autostart. Can be changed during a test by keyboard inputs w, W (spawn 1, 10 users) and s, S (stop 1, 10 users)
  -r SPAWN_RATE, --spawn-rate SPAWN_RATE  # 这是指定每秒增加的用户数 可以和 --headless一起使用 
                        Rate to spawn users at (users per second). Primarily used together with --headless or --autostart
  -t RUN_TIME, --run-time RUN_TIME  # 这是运行时间
                        Stop after the specified amount of time, e.g. (300s, 20m, 3h, 1h30m, etc.). Only used together with --headless or --autostart. Defaults to run forever.
  -l, --list            Show list of possible User classes and exit

Web UI options:
  --web-host WEB_HOST   Host to bind the web interface to. Defaults to '*' (all interfaces)
  --web-port WEB_PORT, -P WEB_PORT
                        Port on which to run web host
  --headless            Disable the web interface, and start the test immediately. Use -u and -t to control user count and run time  # 无页面启动
  --autostart           Starts the test immediately (without disabling the web UI). Use -u and -t to control user count and run time
  --autoquit AUTOQUIT   Quits Locust entirely, X seconds after the run is finished. Only used together with --autostart. The default is to keep Locust running until you shut it down using CTRL+C
  --web-auth WEB_AUTH   Turn on Basic Auth for the web interface. Should be supplied in the following format: username:password
  --tls-cert TLS_CERT   Optional path to TLS certificate to use to serve over HTTPS
  --tls-key TLS_KEY     Optional path to TLS private key to use to serve over HTTPS

Master options:
  Options for running a Locust Master node when running Locust distributed. A Master node need Worker nodes that connect to it before it can run load tests.

  --master              Set locust to run in distributed mode with this process as master  # Locust 分布式模式使用，当前节点为 master 节点。
  --master-bind-host MASTER_BIND_HOST
                        Interfaces (hostname, ip) that locust master should bind to. Only used when running with --master. Defaults to * (all available interfaces).
  --master-bind-port MASTER_BIND_PORT
                        Port that locust master should bind to. Only used when running with --master. Defaults to 5557.
  --expect-workers EXPECT_WORKERS
                        How many workers master should expect to connect before starting the test (only when --headless/autostart is used).
  --expect-workers-max-wait EXPECT_WORKERS_MAX_WAIT
                        How long should the master wait for workers to connect before giving up. Defaults to wait forever

Worker options:
  Options for running a Locust Worker node when running Locust distributed.    # 这是分布式的一个节点，
  Only the LOCUSTFILE (-f option) needs to be specified when starting a Worker, since other options such as -u, -r, -t are specified on the Master node.

  --worker              Set locust to run in distributed mode with this process as worker
  --master-host MASTER_NODE_HOST
                        Host or IP address of locust master for distributed load testing. Only used when running with --worker. Defaults to 127.0.0.1.
  --master-port MASTER_NODE_PORT
                        The port to connect to that is used by the locust master for distributed load testing. Only used when running with --worker. Defaults to 5557.

Tag options:
  Locust tasks can be tagged using the @tag decorator. These options let specify which tasks to include or exclude during a test.

  -T [TAG ...], --tags [TAG ...]
                        List of tags to include in the test, so only tasks with any matching tags will be executed
  -E [TAG ...], --exclude-tags [TAG ...]
                        List of tags to exclude from the test, so only tasks with no matching tags will be executed

Request statistics options:
  --csv CSV_PREFIX      Store current request stats to files in CSV format. Setting this option will generate three files: [CSV_PREFIX]_stats.csv, [CSV_PREFIX]_stats_history.csv and [CSV_PREFIX]_failures.csv
  --csv-full-history    Store each stats entry in CSV format to _stats_history.csv file. You must also specify the '--csv' argument to enable this.
  --print-stats         Print stats in the console
  --only-summary        Only print the summary stats   # 只打印摘要统计
  --reset-stats         Reset statistics once spawning has been completed. Should be set on both master and workers when running in distributed mode
  --html HTML_FILE      Store HTML report file  # 这是输出html报告

Logging options:
  --skip-log-setup      Disable Locust's logging setup. Instead, the configuration is provided by the Locust test or Python defaults.
  --loglevel LOGLEVEL, -L LOGLEVEL
                        Choose between DEBUG/INFO/WARNING/ERROR/CRITICAL. Default is INFO.
  --logfile LOGFILE     Path to log file. If not set, log will go to stderr

Other options:
  --show-task-ratio     Print table of the User classes' task execution ratio
  --show-task-ratio-json
                        Print json data of the User classes' task execution ratio
  --version, -V         Show program's version number and exit  # 查看版本
  --exit-code-on-error EXIT_CODE_ON_ERROR
                        Sets the process exit code to use when a test result contain any failure or error
  -s STOP_TIMEOUT, --stop-timeout STOP_TIMEOUT
                        Number of seconds to wait for a simulated user to complete any executing task before exiting. Default is to terminate immediately. This parameter only needs to be specified 
　　　　　　　　　　　　　　 for the master process when
                        running Locust distributed.
  --equal-weights       Use equally distributed task weights, overriding the weights specified in the locustfile.
  --enable-rebalancing  Allow to automatically rebalance users if new workers are added or removed during a test run.

User classes:
  UserClass             Optionally specify which User classes that should be used (available User classes can be listed with -l or --list)

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分布式运行Locust

一旦单台机器不够模拟足够多的用户时，Locust支持运行在多台机器中进行压力测试。

为了实现这个，你应该在 master 模式中使用--master标记来启用一个 Locust 实例。这个实例将会运行你启动测试的 Locust 交互网站并查看实时统计数据。master 节点的机器自身不会模拟任何用户。

相反，你必须使用 --worker 标记启动一台到多台 Locust worker 机器节点，与标记 --master-host 一起使用(指出master机器的IP/hostname)。

常用的做法是在一台独立的机器中运行master，在worker机器中每个处理器内核运行一个worker实例。

注意：master 和每一台 worker 机器，在运行分布式测试时都必须要有 locust 的测试文件。

示例

在 master 模式下启动 Locust:

locust -f my_loucstfile.py --master

在每个 worker 中执行(192.168.0.14 替换为你 msater 的IP):

locust -f my_locustfile.py --worker --master-host=192.168.0.14

参数说明

参数

–master   设置 Locust 为 master 模式。网页交互会在这台节点机器中运行。

–worker   设置 Locust 为 slave 模式。

–master-host=X.X.X.X  可选项，与 --slave 一起结合使用，用于设置 master 模式下的 master 机器的IP/hostname(默认设置为127.0.0.1)

–master-port=5557  可选项，与 --slave 一起结合使用，用于设置 master 模式下的 master 机器中 Locust 的端口(默认为5557)。注意，locust 将会使用这个指定的端口号，同时指定端口+1的号也会被占用。因此，5557 会被使用，Locust将会使用 5557 和 5558。

–master-bind-host=X.X.X.X`   可选项，与 --master 一起结合使用。决定在 master 模式下将会绑定什么网络接口。默认设置为*(所有可用的接口)。

–master-bind-port=5557   可选项，与 --master 一起结合使用。决定哪个网络端口 master 模式将会监听。默认设置为 5557。注意 Locust 会使用指定的端口号，同时指定端口+1的号也会被占用。因此，5557 会被使用，Locust 将会使用 5557 和 5558。

–expect-worker=X   在 no-web 模式下启动 master 时使用。master 将等待X连接节点在测试开始之前连接。

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locust的类和方法

针对你的业务，你如何进行测试测试，需要通过编写性能测试脚本实现。所以，我们要熟悉 Locust 提供了哪些类和方法，它们分别实现什么操作。

还是要看官网的例子：https://docs.locust.io/en/stable/writing-a-locustfile.html

Now, lets look at a more complete/realistic example of what your tests might look like:

一个更复杂，更真实的例子

import time
from locust import HttpUser, task, between

class QuickstartUser(HttpUser):
    wait_time = between(1, 5)

    @task
    def hello_world(self):
        self.client.get("/hello")
        self.client.get("/world")

    @task(3)
    def view_items(self):
        for item_id in range(10):
            self.client.get(f"/item?id={item_id}", name="/item")
            time.sleep(1)

    def on_start(self):
        self.client.post("/login", json={"username":"foo", "password":"bar"})

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1，继承HttpUser，然后就会有一个client方法

2，wait_time = between(1, 5)，Our class defines a wait_time that will make the simulated users wait between 1 and 5 seconds after each task (see below) is executed.

3，view_items(self): In the view_items task we load 10 different URLs by using a variable query parameter. 

4，还有很多，后面要细细研究一下，

 https://docs.locust.io/en/stable/api.html

这是完整的官网的locust的类和方法的文档，

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