Fix undefined issue while logging from node-loggly-bulk library

[Shwetajain148]

I debugged code with node-loggly-bulk library and found that type of msg is a string which should be an object(winston-loggly-bulk library is sending log data to node-loggly-bulk in object form). That's why the value of msg.message object was undefined.

From node version 7.0.0, node will throw an error when we will pass invalid input to Buffer.byteLength.

Ref: https://github.com/nodejs/node/blob/master/doc/changelogs/CHANGELOG_V7.md#7.0.0
Merged PR: nodejs/node#8946

In this PR I have put a condition to check if the msg is a string (If we are logging using node-loggly-bulk) and then converting to an object. So both library will work correctly.

It will fix the issue #10.

[Shwetajain148]

I have tested below scenarios with both node-loggly-bulk and winston-loggly-bulk libraries.

log type	node-loggly-bulk	winston-loggly-bulk
Sending string	Working fine	Working fine
Sending JSON	Working fine	Working fine
Event Truncation	Working fine	Working fine

[mostlyjason]

When you test sending JSON, does Loggly parse the JSON automatically?

[Shwetajain148]

@mostlyjason Yes, Loggly parsed the JSON with both node-loggly-bulk and winston-loggly-bulk libraries. See the below examples with parsed JSON screenshots.

winston-loggly-bulk library:

I am sending JSON data:

var source = {
    foo: 1,
    bar: 2,
    buzz: {
      sheep: 'jumped',
      times: 10
    }
  };

winston.log('info', source);

JSON parsed result on Loggly:

node-loggly-bulk library:

I am sending JSON data:

var source = {
    foo: 1,
    bar: 2,
    buzz: {
      sheep: 'jumped',
      times: 10
    }
  };

input.log(source);

JSON parsed result on Loggly: