Send an MQTT Message to another IoT Topic using a triggered Lambda function?

Question

I have created an AWS IoT rule. It triggers a Lambda function when client sends a message to the terminal1/ topic (Client is sending messages to the terminal1/ using certificate files generated from AWS IoT.). I need a Lambda function to generate a new message using the client message and send to another topic (terminal2/test).

I have tried triggering "Republish messages to an AWS IoT topic". However, it sends data to a particular topic. It just forwards the same message (I need to send a different message).

I have created a Lambda function to send a message to another topic. But I could not authenticate the endpoint.

Here is the Lambda Function I have created (According to this),

'use strict';

 // Load the AWS SDK
 var AWS = require("aws-sdk");

exports.handler = (event, context, callback) => {

     var iotdata = new AWS.IotData({
     endpoint: 'akugdx70brb.iot.us-west-2.amazonaws.com:8883',
     apiVersion: '2015-05-28'
   });

         var params = {
      topic: 'terminal2/test/',
      payload: new Buffer('...') || 'STRING_VALUE',
      qos:1
    };
    iotdata.publish(params, function(err, data) {
      if (err) console.log(err, err.stack); // an error occurred
      else     console.log(data);           // successful response
    });

};

It generates this error,

2018-05-01T06:22:02.394Z f5a570ef-4d07-11e8-b8a2-6bad8f2982f7 { Error: write EPROTO 139935652661056:error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate:../deps/openssl/openssl/ssl/s3_pkt.c:1493:SSL alert number 42
139935652661056:error:1409E0E5:SSL routines:ssl3_write_bytes:ssl handshake failure:../deps/openssl/openssl/ssl/s3_pkt.c:659:

at exports._errnoException (util.js:1018:11)
at WriteWrap.afterWrite (net.js:800:14)
message: 'write EPROTO 139935652661056:error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate:../deps/openssl/openssl/ssl/s3_pkt.c:1493:SSL alert number 42\n139935652661056:error:1409E0E5:SSL routines:ssl3_write_bytes:ssl handshake failure:../deps/openssl/openssl/ssl/s3_pkt.c:659:\n',
code: 'NetworkingError',
errno: 'EPROTO',
syscall: 'write',
region: 'us-west-2',
hostname: 'akugdx70brb.iot.us-west-2.amazonaws.com',
retryable: true,
time: 2018-05-01T06:22:02.394Z } 'Error: write EPROTO 139935652661056:error:14094412:SSL routines:ssl3_read_bytes:sslv3 alert bad certificate:../deps/openssl/openssl/ssl/s3_pkt.c:1493:SSL alert number 42\n139935652661056:error:1409E0E5:SSL routines:ssl3_write_bytes:ssl handshake failure:../deps/openssl/openssl/ssl/s3_pkt.c:659:\n\n at exports._errnoException (util.js:1018:11)\n at WriteWrap.afterWrite (net.js:800:14)'

I guess that it means I could not authenticate the host, I have not used any certificates when creating the Lambda Function. How can I send an MQTT message to the same host, but to a different topic using AWS Lambda? (The above Lambda Function triggers when a client sends a message, Do I have to re-authenticate the server to send a message to a different topic?)

Yohan Yohan · Accepted Answer · 2018-05-01T11:53:09

try using

AWS.config.update({
    accessKeyId: <accessKeyId>,
    secretAccessKey: <secretAccessKey>,
    region: <region>
  });

Send an MQTT Message to another IoT Topic using a triggered Lambda function?

3 Answers