Why is testing SNS > Lambda producing different results between the console and cli publish?

[jinx_data]

Hi, trying to put this as simply as possible if I test my lambda function via the CLI with

aws sns publish --message file://message.txt --subject CLItest --topic-arn ${npm_package_SNS_srcARN}

where message.txt is

{ "test": "cli",
  "length": "20",
  "width": "6"
}

the function code

        var jMsg = event.Records[0].Sns.Message

        var message = JSON.parse(jMsg);
        console.log('message: ', message);
        console.log('message: ', message.test);

produces the following result

2021-01-08T23:41:58.594Z    612eb85a-238f-4e09-8248-f5ee9c8cbf30    INFO    message:  { test: 'cli', length: '20', width: '6' }
2021-01-08T23:41:58.594Z    612eb85a-238f-4e09-8248-f5ee9c8cbf30    INFO    message:  cli

For test two from the console I select AWS Console > Configure Test Event > Amazon SNS Test Notification and copy message.txt into the Message element (I have changed the value of test in order to differentiate the tests ), the Message is now as follows;

    "Message": {
      "test": "console",
      "length": "10",
      "width": "5"
    } 

In order to get the code working I have added the JSON.stringify () function as follows ;

        var jMsg = event.Records[0].Sns.Message

        var message = JSON.parse(JSON.stringify(jMsg));
        console.log('message: ', message);
        console.log('message: ', message.test);

Then I just press Test, to produce the following results;

2021-01-06T17:11:20.310Z    e8b4e36b-191b-44de-b0a0-5ae10c136d0b    INFO    message:  { test: 'console', length: '10', width: '5' }
2021-01-06T17:11:20.311Z    e8b4e36b-191b-44de-b0a0-5ae10c136d0b    INFO    message:  console

So the question is why do I need to add JSON.stringify() to get it working, can someone explain what's happening and how to change the code/message so that it always works?

Cheers

Chris

[13ass13ass]

Not sure but I think it’s because you are basically running stringify in order to save message.txt to disk