Locust如何测试物联网MQTT

愿君学长松，慎勿作桃李。这篇文章主要讲述Locust如何测试物联网MQTT相关的知识，希望能为你提供帮助。
MQTT是干什么的简单来说，它是物联网的通信协议，是消息通道建立，消息发送和消息订阅的标准。如果大家想了解更多概念上的详细可以网上搜索。
Locust测试MQTT的步骤测试步骤，可以用以下图形表示：

准备环境，安装Locust测试环境
这个比较简单，主要是准备好python的虚拟开发环境，并安装好locust的python软件包。可以在Locust官方网站找到相关步骤，这里不再赘述。
安装MQTT客户端库 paho-mqtt
可以在Python虚拟环境，执行如下安装命令：

pip install paho-mqtt

locustfile中首先实现消息发送
这里为了简单起见，使用公共的MQTT broker： EMQX, 它的地址为："
【Locust如何测试物联网MQTT】broker.emqx.io"
具体实现的代码如下：

broker_add = broker.emqx.io
port = 1883
topic = "/python/mqtt_topic_for_python"

client_id = f"python-mqtt-random.randint(0,100)"

def connect_mqtt():
def on_connect(client,userdata,flags,rc):
if rc == 0:
print("Connected to MQTT Broker!")
else:
print("Failed to connect, return code %d\\n",rc)

client = mqtt_c.Client(client_id)
client.on_connect= on_connect
client.connect(broker_add,port)

return client

def publish(client):
msg_count = 0
while True:
time.sleep(3)
msg = f"message: msg_count"
result = client.publish(topic,msg)
status = result[0]
if status == 0:
print(f"send `msg` to topic `topic` ")
else:
print(f"Failed to send message to topic topic")
msg_count += 1

def run():
client = connect_mqtt()
client.loop_start()
publish(client)

完善locustfile中关于Taskset和User的相关配置
具体如下代码，所以会发现，用Python-Locust去测试非HTTP协议的应用系统还是比较方便的，代码即测试。

class TheTaskSet(TaskSet):
@task
def task_1(self):
run()

class TheUser(User):
tasks = [TheTaskSet]
wait_time = constant_pacing(1)

完整的locustfile如下：

import random,time

from paho.mqtt import client as mqtt_c
from locust import TaskSet,task,User,constant_pacing

broker_add = broker.emqx.io
port = 1883
topic = "/python/mqtt_topic_for_python"

client_id = f"python-mqtt-random.randint(0,100)"

def connect_mqtt():
def on_connect(client,userdata,flags,rc):
if rc == 0:
print("Connected to MQTT Broker!")
else:
print("Failed to connect, return code %d\\n",rc)

client = mqtt_c.Client(client_id)
client.on_connect= on_connect
client.connect(broker_add,port)

return client

def publish(client):
msg_count = 0
while True:
time.sleep(3)
msg = f"message: msg_count"
result = client.publish(topic,msg)
status = result[0]
if status == 0:
print(f"send `msg` to topic `topic` ")
else:
print(f"Failed to send message to topic topic")
msg_count += 1

def run():
client = connect_mqtt()
client.loop_start()
publish(client)

class TheTaskSet(TaskSet):
@task
def task_1(self):
run()

class TheUser(User):
tasks = [TheTaskSet]
wait_time = constant_pacing(1)

具体的执行结果如下：

Connected to MQTT Broker!
send `message: 0` to topic `/python/mqtt_topic_for_python`
send `message: 1` to topic `/python/mqtt_topic_for_python`
send `message: 2` to topic `/python/mqtt_topic_for_python`
send `message: 3` to topic `/python/mqtt_topic_for_python`
send `message: 4` to topic `/python/mqtt_topic_for_python`
send `message: 5` to topic `/python/mqtt_topic_for_python`
...

参考文档：EMQ官方文档，https://www.emqx.com/zh/blog/how-to-use-mqtt-in-python