lambda-mqtt-test

AWS Lambda which function as a brdge between custom events and MQTT Broker.

Dependencies

• AWS account
  • http://aws.amazon.com/
• AWS Lambda service is currently in preview, so you need to be whitelisted to use it:
  • http://aws.amazon.com/lambda/
• AWS CLI tools
  • http://docs.aws.amazon.com/cli/latest/userguide/installing.html
  • on Linux or OSX this probably will do the job:

  sudo easy_install pip
  sudo pip install awscli

We use this public MQTT broker for testing:

• http://test.mosquitto.org/

We use following npm module which implements MQTT client for Node.js:

• https://www.npmjs.org/package/mqtt

We'll need an MQTT CLI client. We can use one that comes with Mosquitto MQTT broker:

• http://mosquitto.org/download/

Or we can use the MQTT CLI client that comes with mqtt npm module (which is much easier to install):

npm install -g mqtt

Test that it works:

mqtt_sub 1883 test.mosquitto.org '#'
...
<topic> <value>
...
CTRL-C

or same thing with mosquitto CLI client:

mosquitto_sub -h test.mosquitto.org -t '#' -v
...
<topic> <value>
...
CTRL-C

You should receive a bunch of messages. Press CTRL-C to kill the client.

Replace lambda execution role for the script upload.sh:

export lambda_execution_role_arn="arn:aws:iam::************:role/lambda_exec_role"

Prepare and upload function to the AWS Lambda service with:

./upload.sh

Now in one terminal window run:

mqtt_sub 1883 test.mosquitto.org my-topic

or alternatively using mosquitto CLI client:

mosquitto_sub -h test.mosquitto.org -t my-topic -v

We subscribed and listening to all messages published to MQTT topic my-topic.

The lambda function expects custom events like this (see event-mqtt.json file):

{
    "topic": "my-topic",
    "value": "hello, lambda!",
    "retain": false
}

In another terminal window let's invoke lambda function with:

aws lambda invoke-async --function-name "lambda-mqtt-test" --invoke-args event-mqtt.json

You should receive the message in the first terminal.

Testing lambda function locally (using CoffeeScript):

coffee index_test.coffee

or using Javascript:

node index_test.js