Formatting feature

lib/winston/formatter/defaultTransform.js

@@ -0,0 +1,6 @@
+const formatDefaultTransform = (info) => {
+  return info;
+};
+
+module.exports = { formatDefaultTransform };
+

lib/winston/formatter/ecsTransform.js

@@ -0,0 +1,9 @@
+const formatEcsTransform = (info) => {
+  if (typeof info.service === 'string') {
+    info.service = { name: info.service };
+  }
+  return info;
+};
+
+module.exports = { formatEcsTransform };
+

lib/winston/formatter/formatInput.js

@@ -0,0 +1,12 @@
+const { formatDefaultTransform } = require('./defaultTransform');
+const { formatEcsTransform } = require('./ecsTransform');
+
+function formatInput(info, formatTransformName) {
+  const func = {
+    ecsTransform: formatEcsTransform
+  }[formatTransformName] || formatDefaultTransform;
+
+  return func(info);
+}
+
+module.exports = { formatInput };

lib/winston/logger.js

@@ -11,6 +11,7 @@ const { Stream, Transform } = require('readable-stream');
 const asyncForEach = require('async/forEach');
 const { LEVEL, SPLAT } = require('triple-beam');
 const isStream = require('is-stream');
+const { formatInput } = require('./formatter/formatInput');
 const ExceptionHandler = require('./exception-handler');
 const RejectionHandler = require('./rejection-handler');
 const LegacyTransportStream = require('winston-transport/legacy');
@@ -310,6 +311,7 @@ class Logger extends Transform {
     // (and re-throw) any errors generated by the user-provided format, but also
     // guarantee that the streams callback is invoked so that we can continue flowing.
     try {
+      info = formatInput(info, this.format.transform.name);
       this.push(this.format.transform(info, this.format.options));
     } finally {
       this._writableState.sync = false;

test/helpers/index.js

@@ -25,9 +25,10 @@ var helpers = exports;
  * @param {function} write Write function for the specified stream
  * @returns {Logger} A winston.Logger instance
  */
-helpers.createLogger = function (write, format) {
+helpers.createLogger = function (write, format, defaultMeta) {
   return winston.createLogger({
     format,
+    defaultMeta,
     transports: [
       mockTransport.createMockTransport(write)
     ]

test/helpers/mocks/mock-ecsFormat.js

@@ -0,0 +1,57 @@
+const winston = require('../../../lib/winston');
+const { MESSAGE } = require('triple-beam');
+
+/**
+ * Create a mock Winston format for ecs-logging output.
+ *
+ * @param {object} info object to be transformed
+ * @returns {object} object with ecs format
+ */
+function ecsTransform(info) {
+  const reservedFields = {
+    level: true,
+    'log.level': true,
+    ecs: true,
+    '@timestamp': true,
+    err: true,
+    req: true,
+    res: true
+  };
+
+  const ecsFields = {
+    '@timestamp': new Date().toISOString(),
+    'log.level': info.level,
+    message: info.message,
+    ecs: { "version":"1.6.0" }
+  };
+
+  const keys = Object.keys(info);
+  for (let i = 0, len = keys.length; i < len; i++) {
+    const key = keys[i];
+    if (!reservedFields[key]) {
+      ecsFields[key] = info[key];
+    }
+  }
+
+  const mockStringify = function(ecsFields) {
+    let serviceObject; 
+
+    if (typeof ecsFields.service === 'string'){
+      for (let i=0; i <= ecsFields.service.length; i++){
+        serviceObject[`${i}`] = ecsFields.service[i];
+      }
+    } else {
+      serviceObject = ecsFields.service;
+    }
+
+    const serviceString = JSON.stringify(serviceObject);
+    const ecsVersionString = JSON.stringify(ecsFields.ecs);
+
+    return `{"@timestamp":"${ecsFields['@timestamp']}","log.level":${ecsFields['log.level']}","ecs":${ecsVersionString},"service":${serviceString}}`;
+  }
+
+  info[MESSAGE] = mockStringify(ecsFields);
+  return info;
+}
+
+module.exports = winston.format(ecsTransform);

test/unit/winston/formatter/transform.test.js

@@ -0,0 +1,38 @@
+const assume = require("assume");
+const { formatInput } = require('../../../../lib/winston/formatter/formatInput');
+
+describe('Format Info', function () {
+	describe('formatEcsTransform', function () {
+		it('should turn info.service from a string to an object', function() {
+			const info = {
+				level: 'info', 
+				service: 'account'
+			};
+
+			const formattedInfo = formatInput(info, "ecsTransform");
+			const expectedInfo = {
+				level: 'info', 
+				service: {name: 'account'}
+			};
+
+			assume(formattedInfo).deep.equals(expectedInfo);
+		});
+	});
+
+	describe('defaultTransform', function () {
+		it('should do nothing to the info', function() {
+			const info = {
+				level: 'info', 
+				service: 'account'
+			};
+
+			const formattedInfo = formatInput(info, null);
+			const expectedInfo = {
+				level: 'info', 
+				service: 'account'
+			};
+
+			assume(formattedInfo).deep.equals(expectedInfo);
+		});
+	});
+});

test/unit/winston/logger.test.js

@@ -21,6 +21,7 @@ const TransportStream = require('winston-transport');
 const format = require('../../../lib/winston').format;
 const helpers = require('../../helpers');
 const mockTransport = require('../../helpers/mocks/mock-transport');
+const mockEcsFormat = require('../../helpers/mocks/mock-ecsFormat');
 const testLogFixturesPath = path.join(__dirname, '..', '..', 'fixtures', 'logs');
 
 describe('Logger Instance', function () {
@@ -920,6 +921,15 @@ describe('Logger Instance', function () {
         const log = logger.info;
         log('test');
       });
+
+      it('adjust defaultMeta correctly to given format', (done) => {
+        let logger = helpers.createLogger(function (info){
+          assume(info.service).is.a('object');
+          done();
+        }, mockEcsFormat(), {service: 'user-account'});
+        logger.log({level: 'info'});
+      });
+
     });
   });