mqtt5_x509

MQTT5 X509 PubSub

Return to main sample list

Jump To:

• Introduction
• Requirements
• How To Build
• How To Run
• Additional Information

Introduction

This sample uses the Message Broker for AWS IoT to send and receive messages through an MQTT connection using MQTT5.

You can read more about MQTT5 for the CPP IoT Device SDK V2 in the MQTT5 user guide.

Requirements

This sample assumes you have the required AWS IoT resources available. Information about AWS IoT can be found HERE and instructions on creating AWS IoT resources (AWS IoT Policy, Device Certificate, Private Key) can be found HERE.

Your IoT Core Thing's Policy must provide privileges for this sample to connect, subscribe, publish, and receive. Below is a sample policy that can be used on your IoT Core Thing that will allow this sample to run as intended.

(see sample policy)

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "iot:Publish",
        "iot:Receive"
      ],
      "Resource": [
        "arn:aws:iot:region:account:topic/test/topic"
      ]
    },
    {
      "Effect": "Allow",
      "Action": [
        "iot:Subscribe"
      ],
      "Resource": [
        "arn:aws:iot:region:account:topicfilter/test/topic"
      ]
    },
    {
      "Effect": "Allow",
      "Action": [
        "iot:Connect"
      ],
      "Resource": [
        "arn:aws:iot:region:account:client/mqtt5-sample-*"
      ]
    }
  ]
}

Replace with the following with the data from your AWS account:

• <region>: The AWS IoT Core region where you created your AWS IoT Core thing you wish to use with this sample. For example us-east-1.
• <account>: Your AWS IoT Core account ID. This is the set of numbers in the top right next to your AWS account name when using the AWS IoT Core website.

Note that in a real application, you may want to avoid the use of wildcards in your ClientID or use them selectively. Please follow best practices when working with AWS on production applications using the SDK. Also, for the purposes of this sample, please make sure your policy allows a client ID of mqtt5-sample-* to connect or use --client_id <client ID here> to send the client ID your policy supports.

How to build

To build the sample, change directory into the sample's folder and run the cmake commands. The sample executable will be built into the samples/mqtt/mqtt5_x509/build folder.

cd samples/mqtt/mqtt5_x509/
# If you followed the SDK build instruction, you would use the path to `sdk-workspace` folder for `CMAKE_PREFIX_PATH` here
cmake -B build -S . -DCMAKE_PREFIX_PATH="<absolute path sdk-workspace dir>" -DCMAKE_BUILD_TYPE="Debug" .
cmake --build build --config "Debug"

How to run

To run this sample, navigate to the build directory where the executable was created:

# From samples/mqtt/mqtt5_x509/, go to the build directory
cd build
./mqtt5_x509 --endpoint <endpoint> --cert <path to the certificate> --key <path to the private key>

If you would like to see what optional arguments are available, use the --help argument:

./mqtt5_x509 --help

will result in the following output

>./mqtt5_x509 --help
MQTT5 X509 Sample (mTLS)
options:
  --help        show this help message and exit
required arguments:
  --endpoint    IoT endpoint hostname
  --cert        Path to the certificate file to use during mTLS connection establishment
  --key         Path to the private key file to use during mTLS connection establishment
optional arguments:
  --client_id   Client ID (default: mqtt5-sample-<uuid>)
  --topic       Topic (default: test/topic)
  --message     Message payload (default: Hello from mqtt5 sample)
  --count       Messages to publish (0 = infinite) (default: 5)

The sample will not run without the required arguments and will notify you of missing arguments.

Additional Information

Additional help with the MQTT5 Client can be found in the MQTT5 Userguide. This guide will provide more details on MQTT5 operations, lifecycle events, connection methods, and other useful information.