format data sent to splunk HEC (#61)

* format data sent to splunk HEC
 🐿 v2.7.0

* adding more format hec tests
 🐿 v2.7.0

src/lib/formatHEC.js

@@ -0,0 +1,5 @@
+const formatHEC = ({ level, message, meta = {} } = {}) => {
+	return message ? Object.assign({}, { level, message }, meta) : Object.assign({}, { level }, meta);
+};
+
+export default formatHEC;

src/lib/transports/splunkHEC.js

@@ -1,18 +1,20 @@
 import winston from 'winston';
+import formatHEC from '../formatHEC';
 const https = require('https');
 
 class SplunkHEC extends winston.Transport {
 
 	log (level, message, meta) {
 		const httpsAgent = new https.Agent({ keepAlive: true });
+		const formattedMessage = formatHEC({ level, message, meta });
 
 		const data = {
 			'time': Date.now(),
 			'host': 'localhost',
 			'source': `/var/log/apps/heroku/ft-${process.env.SYSTEM_CODE}.log`,
 			'sourcetype': '_json',
 			'index': 'heroku',
-			'event': { level, message, meta }
+			'event': formattedMessage
 		};
 
 		return fetch('https://http-inputs-financialtimes.splunkcloud.com/services/collector/event', {

test/lib/formatHEC.test.js

@@ -0,0 +1,66 @@
+const chai = require('chai');
+chai.should();
+const expect = chai.expect;
+
+import formatHEC from '../../dist/lib/formatHEC';
+
+describe('FormatHEC', () => {
+
+	it('should exist', () => {
+		formatHEC.should.exist;
+	});
+
+	it('should format all data options', () => {
+		const options = {
+			level: 'info',
+			message: 'Hello world',
+			meta: { event: 'TEST' }
+		}
+
+		expect(formatHEC(options)).to.deep.equal({
+			level: 'info',
+			message: 'Hello world',
+			event: 'TEST'
+			});
+	});
+
+	it('should handle data containing an error', () => {
+		const err = new Error('This is an error');
+		const options = {
+			level: 'error',
+			meta: { event: 'TEST_ERROR', err }
+		}
+
+		expect(formatHEC(options)).to.deep.equal({
+			level: 'error',
+			event: 'TEST_ERROR', err
+			});
+	});
+
+	it('should handle no meta data ', () => {
+		const options = {
+			level: 'info',
+			message: 'a message'
+		}
+
+		expect(formatHEC(options)).to.deep.equal({
+			level: 'info',
+			message: 'a message'
+		});
+	});
+
+	it('should handle no message', () => {
+		const count = 10;
+		const options = {
+			level: 'info',
+			meta: { event: 'TEST', count }
+		}
+
+		expect(formatHEC(options)).to.deep.equal({
+			level: 'info',
+			event: 'TEST',
+			count: 10
+			});
+	});
+
+});