[server/logging] Allow opting out of UTC (#14705)

* [server/logging] make use of UTC configurable

* [server/logging/tests] try removing TZ from moment

* [server/log/formatJson] use strict equality checks

* [server/log/format] note in method name that time is extracted

(cherry picked from commit b79ba98)

src/server/config/schema.js

@@ -108,7 +108,9 @@ export default () => Joi.object({
       is: 'stdout',
       then: Joi.default(!process.stdout.isTTY),
       otherwise: Joi.default(true)
-    })
+    }),
+
+    useUTC: Joi.boolean().default(true),
   })
   .default(),
 

src/server/logging/__tests__/log_format_json.js

@@ -0,0 +1,49 @@
+import moment from 'moment';
+import expect from 'expect.js';
+
+import {
+  createListStream,
+  createPromiseFromStreams,
+} from '../../../utils';
+
+import KbnLoggerJsonFormat from '../log_format_json';
+
+const time = +moment('2010-01-01T05:15:59Z', moment.ISO_8601);
+
+const makeEvent = () => ({
+  event: 'log',
+  timestamp: time,
+  tags: ['tag'],
+  pid: 1,
+  data: 'my log message'
+});
+
+describe('KbnLoggerJsonFormat', () => {
+  it('logs in UTC when useUTC is true', async () => {
+    const format = new KbnLoggerJsonFormat({
+      useUTC: true
+    });
+
+    const result = await createPromiseFromStreams([
+      createListStream([makeEvent()]),
+      format
+    ]);
+
+    const { '@timestamp': timestamp } = JSON.parse(result);
+    expect(timestamp).to.be(moment.utc(time).format());
+  });
+
+  it('logs in local timezone when useUTC is false', async () => {
+    const format = new KbnLoggerJsonFormat({
+      useUTC: false
+    });
+
+    const result = await createPromiseFromStreams([
+      createListStream([makeEvent()]),
+      format
+    ]);
+
+    const { '@timestamp': timestamp } = JSON.parse(result);
+    expect(timestamp).to.be(moment(time).format());
+  });
+});

src/server/logging/__tests__/log_format_string.js

@@ -0,0 +1,49 @@
+import moment from 'moment';
+import expect from 'expect.js';
+
+import {
+  createListStream,
+  createPromiseFromStreams,
+} from '../../../utils';
+
+import KbnLoggerStringFormat from '../log_format_string';
+
+const time = +moment('2010-01-01T05:15:59Z', moment.ISO_8601);
+
+const makeEvent = () => ({
+  event: 'log',
+  timestamp: time,
+  tags: ['tag'],
+  pid: 1,
+  data: 'my log message'
+});
+
+describe('KbnLoggerStringFormat', () => {
+  it('logs in UTC when useUTC is true', async () => {
+    const format = new KbnLoggerStringFormat({
+      useUTC: true
+    });
+
+    const result = await createPromiseFromStreams([
+      createListStream([makeEvent()]),
+      format
+    ]);
+
+    expect(String(result))
+      .to.contain(moment.utc(time).format('HH:mm:ss.SSS'));
+  });
+
+  it('logs in local timezone when useUTC is false', async () => {
+    const format = new KbnLoggerStringFormat({
+      useUTC: false
+    });
+
+    const result = await createPromiseFromStreams([
+      createListStream([makeEvent()]),
+      format
+    ]);
+
+    expect(String(result)).to
+      .contain(moment(time).format('HH:mm:ss.SSS'));
+  });
+});

src/server/logging/configuration.js

@@ -42,6 +42,8 @@ export default function loggingConfiguration(config) {
         config: {
           json: config.get('logging.json'),
           dest: config.get('logging.dest'),
+          useUTC: config.get('logging.useUTC'),
+
           // I'm adding the default here because if you add another filter
           // using the commandline it will remove authorization. I want users
           // to have to explicitly set --logging.filter.authorization=none or

src/server/logging/log_format.js

@@ -46,10 +46,19 @@ export default class TransformObjStream extends Stream.Transform {
     next();
   }
 
+  extractAndFormatTimestamp(data, format) {
+    const { useUTC } = this.config;
+    const date = moment(data['@timestamp']);
+    if (useUTC) {
+      date.utc();
+    }
+    return date.format(format);
+  }
+
   readEvent(event) {
     const data = {
       type: event.event,
-      '@timestamp': moment.utc(event.timestamp).format(),
+      '@timestamp': event.timestamp,
       tags: [].concat(event.tags || []),
       pid: event.pid
     };

src/server/logging/log_format_json.js

@@ -8,6 +8,7 @@ const stripColors = function (string) {
 export default class KbnLoggerJsonFormat extends LogFormat {
   format(data) {
     data.message = stripColors(data.message);
+    data['@timestamp'] = this.extractAndFormatTimestamp(data);
     return stringify(data);
   }
 }

src/server/logging/log_format_string.js

@@ -1,6 +1,5 @@
 import _ from 'lodash';
 import ansicolors from 'ansicolors';
-import moment from 'moment';
 
 import LogFormat from './log_format';
 
@@ -44,9 +43,9 @@ const type = _.memoize(function (t) {
 
 const workerType = process.env.kbnWorkerType ? `${type(process.env.kbnWorkerType)} ` : '';
 
-export default class KbnLoggerJsonFormat extends LogFormat {
+export default class KbnLoggerStringFormat extends LogFormat {
   format(data) {
-    const time = color('time')(moment(data.timestamp).utc().format('HH:mm:ss.SSS'));
+    const time = color('time')(this.extractAndFormatTimestamp(data, 'HH:mm:ss.SSS'));
     const msg = data.error ? color('error')(data.error.stack) : color('message')(data.message);
 
     const tags = _(data.tags)