aws_signv4_mqtt

Functions to generate aws signature v4 to use with AWS IOT MQTT

I created this because I couldn't find a library to easily generate signed urls that you can use with amazon's MQTT for IOT in python. All the libraries I could find would be to generate headers for HTTP requests and it wouldn't work with wss for MQTT.

Inspired by:

• https://gist.github.com/prestomation/24b959e51250a8723b9a5a4f70dcae08
• https://gist.github.com/kn9ts/4b5a9942b6afbfc2534f2f14c87b9b54

Installing

pip install aws-signv4-mqtt

How to use use

There are two interfaces:

aws_signv4_mqtt.generate_signv4_mqtt( iot_host, iot_region, access_key, secret_key, session_token = None)

Basic interface to created the signed url.

aws_signv4_mqtt.generate_signv4_mqtt_boto( iot_host, iot_region)

Gets the credentials from your environment or iam role internally using boto3.

Examples

import aws_signv4_mqtt
print(aws_signv4_mqtt.generate_signv4_mqtt('<your_iot>.iot.us-east-1.amazonaws.com', 'us-east-1', '<aws_access_key>', '<aws_secret>'))

Prints something like:

wss://<your_iot>.iot.us-east-1.amazonaws.com/mqtt?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=%3Caws_access_key%3E%2F20190216%2Fus-east-1%2Fiotdevicegateway%2Faws4_request&X-Amz-Date=20190216T115653Z&X-Amz-SignedHeaders=host&X-Amz-Signature=92bfc2b5a77489c5786a820044bf6c8ccb3c2f9b40c1d6a5f016b4d9c8662a5e

Testing your url

After you generate your url using AWS credentials with sufficient AWS IOT permissions, you can test it with any MQTT library.

For instance, you could execute the javascript code below:

var mqtt = require('mqtt')
url = '<your_signed_url>'
port = 443
topic = '<your_topic>'
i = 0

var client  = mqtt.connect(url,
    {
        connectTimeout:5*1000,
        port: port,
    })
 
client.on('connect', function () {
  client.subscribe(topic, function (err) {
    if (!err) {
      client.publish(topic, 'Hello mqtt')
    }
  })
})
 
client.on('message', function (topic, message) {
  console.log(message.toString())
  i = i+1
  client.publish(topic, 'Hello mqtt '+String(i))
})