Test client device communications

Download and install the AWS IoT Device SDK v2 for Python to the AWS IoT thing to connect as a client device.

On the client device, do the following:

1. Clone the AWS IoT Device SDK v2 for Python repository to download it.

   git clone https://github.com/aws/aws-iot-device-sdk-python-v2.git

2. Install the AWS IoT Device SDK v2 for Python.

   python3 -m pip install --user ./aws-iot-device-sdk-python-v2

Change to the samples folder in the AWS IoT Device SDK v2 for Python.

cd aws-iot-device-sdk-python-v2/samples

Run the sample Greengrass discovery application. This application expects arguments that specify the client device thing name, the MQTT topic and message to use, and the certificates that authenticate and secure the connection. The following example sends a Hello World message to the clients/MyClientDevice1/hello/world topic.

python3 basic_discovery.py \\
  --thing_name MyClientDevice1 \\
  --topic 'clients/MyClientDevice1/hello/world' \\
  --message 'Hello World!' \\
  --ca_file ~/certs/AmazonRootCA1.pem \\
  --cert ~/certs/device.pem.crt \\
  --key ~/certs/private.pem.key \\
  --region us-east-1 \\
  --verbosity Warn

The discovery sample application sends the message 10 times and disconnects. It also subscribes to the same topic where it publishes messages. If the output indicates that the application received MQTT messages on the topic, the client device can successfully communicate with the core device.

Performing greengrass discovery...
awsiot.greengrass_discovery.DiscoverResponse(gg_groups=[awsiot.greengrass_discovery.GGGroup(gg_group_id='greengrassV2-coreDevice-MyGreengrassCore', cores=[awsiot.greengrass_discovery.GGCore(thing_arn='arn:aws:iot:us-east-1:123456789012:thing/MyGreengrassCore', connectivity=[awsiot.greengrass_discovery.ConnectivityInfo(id='203.0.113.0', host_address='203.0.113.0', metadata='', port=8883)])], certificate_authorities=['-----BEGIN CERTIFICATE-----\
MIICiT...EXAMPLE=\
-----END CERTIFICATE-----\
'])])
Trying core arn:aws:iot:us-east-1:123456789012:thing/MyGreengrassCore at host 203.0.113.0 port 8883
Connected!
Published topic clients/MyClientDevice1/hello/world: {"message": "Hello World!", "sequence": 0}

Publish received on topic clients/MyClientDevice1/hello/world
b'{"message": "Hello World!", "sequence": 0}'
Published topic clients/MyClientDevice1/hello/world: {"message": "Hello World!", "sequence": 1}

Publish received on topic clients/MyClientDevice1/hello/world
b'{"message": "Hello World!", "sequence": 1}'

...

Published topic clients/MyClientDevice1/hello/world: {"message": "Hello World!", "sequence": 9}

Publish received on topic clients/MyClientDevice1/hello/world
b'{"message": "Hello World!", "sequence": 9}'

If the application outputs an error instead, see Troubleshooting Greengrass discovery issues.

You can also view the Greengrass logs on the core device to verify if the client device successfully connects and sends messages. For more information, see Monitor AWS IoT Greengrass logs.

Download and build the AWS IoT Device SDK v2 for C++ to the AWS IoT thing to connect as a client device.

On the client device, do the following:

1. Create a folder for the AWS IoT Device SDK v2 for C++ workspace, and change to it.

   cd
   mkdir iot-device-sdk-cpp
   cd iot-device-sdk-cpp

2. Clone the AWS IoT Device SDK v2 for C++ repository to download it. The --recursive flag specifies to download submodules.

   git clone --recursive https://github.com/aws/aws-iot-device-sdk-cpp-v2.git

3. Create a folder for the AWS IoT Device SDK v2 for C++ build output, and change to it.

   mkdir aws-iot-device-sdk-cpp-v2-build
   cd aws-iot-device-sdk-cpp-v2-build

4. Build the AWS IoT Device SDK v2 for C++.

   cmake -DCMAKE_INSTALL_PREFIX="~/iot-device-sdk-cpp" -DCMAKE_BUILD_TYPE="Release" ../aws-iot-device-sdk-cpp-v2
   cmake --build . --target install

Build the Greengrass discovery sample application in the AWS IoT Device SDK v2 for C++. Do the following:

1. Change to the Greengrass discovery sample folder in the AWS IoT Device SDK v2 for C++.

   cd ../aws-iot-device-sdk-cpp-v2/samples/greengrass/basic_discovery

2. Create a folder for the Greengrass discovery sample build output, and change to it.

   mkdir build
   cd build

3. Build the Greengrass discovery sample application.

   cmake -DCMAKE_PREFIX_PATH="~/iot-device-sdk-cpp" -DCMAKE_BUILD_TYPE="Release" ..
   cmake --build . --config "Release"

Run the sample Greengrass discovery application. This application expects arguments that specify the client device thing name, the MQTT topic to use, and the certificates that authenticate and secure the connection. The following example subscribes to the clients/MyClientDevice1/hello/world topic and publishes a message that you enter on the command line to the same topic.

./basic-discovery \
  --thing_name MyClientDevice1 \
  --topic 'clients/MyClientDevice1/hello/world' \
  --ca_file ~/certs/AmazonRootCA1.pem \
  --cert ~/certs/device.pem.crt \
  --key ~/certs/private.pem.key \
  --region us-east-1

The discovery sample application subscribes to the topic and prompts you to enter a message to publish.

Connecting to group greengrassV2-coreDevice-MyGreengrassCore with thing arn arn:aws:iot:us-east-1:123456789012:thing/MyGreengrassCore, using endpoint 203.0.113.0:8883
Connected to group greengrassV2-coreDevice-MyGreengrassCore, using connection to 203.0.113.0:8883
Successfully subscribed to clients/MyClientDevice1/hello/world
Enter the message you want to publish to topic clients/MyClientDevice1/hello/world and press enter. Enter 'exit' to exit this program.

If the application outputs an error instead, see Troubleshooting Greengrass discovery issues.

Enter a message, such as Hello World!.

Enter the message you want to publish to topic clients/MyClientDevice1/hello/world and press enter. Enter 'exit' to exit this program.
Hello World!

If the output indicates that the application received the MQTT message on the topic, the client device can successfully communicate with the core device.

Operation on packetId 2 Succeeded
Publish received on topic clients/MyClientDevice1/hello/world
Message:
Hello World!

You can also view the Greengrass logs on the core device to verify if the client device successfully connects and sends messages. For more information, see Monitor AWS IoT Greengrass logs.

Download and install the AWS IoT Device SDK v2 for JavaScript to the AWS IoT thing to connect as a client device.

On the client device, do the following:

1. Clone the AWS IoT Device SDK v2 for JavaScript repository to download it.

   git clone https://github.com/aws/aws-iot-device-sdk-js-v2.git

2. Install the AWS IoT Device SDK v2 for JavaScript.

   cd aws-iot-device-sdk-js-v2
   npm install

Change to the Greengrass discovery sample folder in the AWS IoT Device SDK v2 for JavaScript.

cd samples/node/basic_discovery

Install the Greengrass discovery sample application.

npm install

Run the sample Greengrass discovery application. This application expects arguments that specify the client device thing name, the MQTT topic and message to use, and the certificates that authenticate and secure the connection. The following example sends a Hello World message to the clients/MyClientDevice1/hello/world topic.

node dist/index.js \
  --thing_name MyClientDevice1 \
  --topic 'clients/MyClientDevice1/hello/world' \
  --message 'Hello World!' \
  --ca_file ~/certs/AmazonRootCA1.pem \
  --cert ~/certs/device.pem.crt \
  --key ~/certs/private.pem.key \
  --region us-east-1 \
  --verbose warn

The discovery sample application sends the message 10 times and disconnects. It also subscribes to the same topic where it publishes messages. If the output indicates that the application received MQTT messages on the topic, the client device can successfully communicate with the core device.

Discovery Response:
{"gg_groups":[{"gg_group_id":"greengrassV2-coreDevice-MyGreengrassCore","cores":[{"thing_arn":"arn:aws:iot:us-east-1:123456789012:thing/MyGreengrassCore","connectivity":[{"id":"203.0.113.0","host_address":"203.0.113.0","port":8883,"metadata":""}]}],"certificate_authorities":["-----BEGIN CERTIFICATE-----\nMIICiT...EXAMPLE=\n-----END CERTIFICATE-----\n"]}]}
Trying endpoint={"id":"203.0.113.0","host_address":"203.0.113.0","port":8883,"metadata":""}
[WARN] [2021-06-12T00:46:45Z] [00007f90c0e8d700] [socket] - id=0x7f90b8018710 fd=26: setsockopt() for NO_SIGNAL failed with errno 92. If you are having SIGPIPE signals thrown, you may want to install a signal trap in your application layer.
Connected to endpoint={"id":"203.0.113.0","host_address":"203.0.113.0","port":8883,"metadata":""}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":1}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":2}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":3}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":4}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":5}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":6}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":7}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":8}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":9}
Publish received. topic:"clients/MyClientDevice1/hello/world" dup:false qos:0 retain:false
{"message":"Hello World!","sequence":10}
Complete!

If the application outputs an error instead, see Troubleshooting Greengrass discovery issues.

You can also view the Greengrass logs on the core device to verify if the client device successfully connects and sends messages. For more information, see Monitor AWS IoT Greengrass logs.

Download and build the AWS IoT Device SDK v2 for Java to the AWS IoT thing to connect as a client device.

On the client device, do the following:

1. Clone the AWS IoT Device SDK v2 for Java repository to download it.

   git clone https://github.com/aws/aws-iot-device-sdk-java-v2.git

2. Change to the AWS IoT Device SDK v2 for Java folder.

3. Build the AWS IoT Device SDK v2 for Java.

   cd aws-iot-device-sdk-java-v2
   mvn versions:use-latest-versions -Dincludes="software.amazon.awssdk.crt*"
   mvn clean install

Run the sample Greengrass discovery application. This application expects arguments that specify the client device thing name, the MQTT topic to use, and the certificates that authenticate and secure the connection. The following example subscribes to the clients/MyClientDevice1/hello/world topic and publishes a message that you enter on the command line to the same topic.

DISCOVERY_SAMPLE_ARGS="--thing_name MyClientDevice1 \
  --topic 'clients/MyClientDevice1/hello/world' \
  --ca_file $HOME/certs/AmazonRootCA1.pem \
  --cert $HOME/certs/device.pem.crt \
  --key $HOME/certs/private.pem.key \
  --region us-east-1"

mvn exec:java -pl samples/Greengrass \
  -Dexec.mainClass=greengrass.BasicDiscovery \
  -Dexec.args="$DISCOVERY_SAMPLE_ARGS"

The discovery sample application subscribes to the topic and prompts you to enter a message to publish.

Connecting to group ID greengrassV2-coreDevice-MyGreengrassCore, with thing arn arn:aws:iot:us-east-1:123456789012:thing/MyGreengrassCore, using endpoint 203.0.113.0:8883
Started a clean session
Enter the message you want to publish to topic clients/MyClientDevice1/hello/world and press Enter. Type 'exit' or 'quit' to exit this program:

If the application outputs an error instead, see Troubleshooting Greengrass discovery issues.

Enter a message, such as Hello World!.

Enter the message you want to publish to topic clients/MyClientDevice1/hello/world and press Enter. Type 'exit' or 'quit' to exit this program:
Hello World!

If the output indicates that the application received the MQTT message on the topic, the client device can successfully communicate with the core device.

Message received on topic clients/MyClientDevice1/hello/world: Hello World!

You can also view the Greengrass logs on the core device to verify if the client device successfully connects and sends messages. For more information, see Monitor AWS IoT Greengrass logs.