fix: compatibility with log aggregators

README.md

@@ -22,8 +22,7 @@ To select your desired log levels add the corresponding numbers and set the valu
 
 For example `STAPPS_LOG_LEVEL=17` is 16 + 1 and would log everything that is `OK` or `INFO`.
 
-If you want to use logger in production (`NODE_ENV=production`) and allow all transports to fail set
+If you want to use logger in production (`NODE_ENV=production`) and allow all transports to fail set `ALLOW_NO_TRANSPORT` to `true`.
-`ALLOW_NO_TRANSPORT` to `true`.
 
 Additionally setting the environment variable `STAPPS_EXIT_LEVEL` which works in the same manner as `STAPPS_LOG_LEVEL` will terminate your process after logging at the selected level(s) (usefull for integration tests). It will be ignored in afore mentioned productive environments.
 
@@ -52,7 +51,7 @@ Environment variables are:
 
 ## Transformations
 
-By default the logger will only add the log level to the message.
+By default the logger will only add the log level to the message. It will replace newlines with spaces and might skip some of your choosen Transformers when in production (`NODE_ENV=production`) for compatibility reasons with existing log aggregators and analyzers.
 
 You can change this behavior by setting other Transformers via `Logger.setTransformations`. If you do so, mind the order of the transformers.
 

src/logger.ts

@@ -13,7 +13,7 @@
  * this program. If not, see <https://www.gnu.org/licenses/>.
  */
 import {stringify} from 'flatted';
-import {isNodeEnvironment, isProductiveNodeEnvironment} from './common';
+import {isNodeEnvironment, isProductiveEnvironment, isProductiveNodeEnvironment} from './common';
 import {Transformation} from './transformation';
 import {AddLogLevel} from './transformations/add-log-level';
 import {Transport} from './transport';
@@ -91,17 +91,24 @@ export class Logger {
 
   /**
    * Apply transformations to an output
+   * Will strip newlines in production environment
    *
    * @param logLevel Log level of the output
    * @param output Output to apply transformations to
    */
   private static applyTransformers(logLevel: LogLevel, output: string): string {
+    if (isProductiveEnvironment()) {
+      output = output.replace(/[\n\r]/g, ' ');
+    }
+
     if (!Array.isArray(Logger.transformations) || Logger.transformations.length === 0) {
       return output;
     }
 
     let transformedOutput = output;
-    for (const transformation of Logger.transformations) {
+    for (const transformation of Logger.transformations.filter(transform =>
+      !isProductiveEnvironment() ? true : transform.useInProduction === isProductiveEnvironment(),
+    )) {
       transformedOutput = transformation.transform(logLevel, transformedOutput);
     }
 

src/transformation.ts

@@ -18,6 +18,11 @@ import {LogLevel} from './logger';
  * A transformer for log output
  */
 export interface Transformation {
+  /**
+   * Indicates if this transformation is stripped in production environments
+   */
+  useInProduction: boolean;
+
   /**
    * Transform an output
    *

src/transformations/add-log-level.ts

@@ -19,6 +19,11 @@ import {Transformation} from '../transformation';
  * Transformation that adds the log level to output
  */
 export class AddLogLevel implements Transformation {
+  /**
+   * Keep this transformation in production environments
+   */
+  useInProduction = true;
+
   /**
    * Add log level to output
    *

src/transformations/colorize.ts

@@ -20,6 +20,11 @@ import {Transformation} from '../transformation';
  * Transformation that colorizes log output
  */
 export class Colorize implements Transformation {
+  /**
+   * Skip this transformation in production environments
+   */
+  useInProduction = false;
+
   /**
    * Instantiate a new colorize transformation
    *

src/transformations/timestamp.ts

@@ -14,21 +14,15 @@
  */
 import {LogLevel} from '../logger';
 import {Transformation} from '../transformation';
-import moment from 'moment';
 
 /**
  * Transformation that adds a timestamp to output
  */
 export class Timestamp implements Transformation {
   /**
-   * Instantiate a new timestamp transformation
+   * Keep this transformation in production environments
-   *
-   * @see https://momentjs.com/docs/#/displaying/format/
-   * @param format Format for timestamps
    */
-  constructor(private readonly format = 'LLLL') {
+  useInProduction = true;
-    // noop
-  }
 
   /**
    * Add timestamp to output
@@ -37,8 +31,6 @@ export class Timestamp implements Transformation {
    * @param output Output to add timestamp to
    */
   transform(_logLevel: LogLevel, output: string): string {
-    const now = moment();
+    return `[${new Date().toISOString()}] ${output}`;
-
-    return `[${now.format(this.format)}] ${output}`;
   }
 }

test/logger.spec.ts

@@ -19,6 +19,7 @@ import chaiSpies from 'chai-spies';
 import {suite, test} from '@testdeck/mocha';
 import {Logger} from '../src/logger';
 import {AddLogLevel} from '../src/transformations/add-log-level';
+import {Colorize} from '../src/transformations/colorize';
 import {DummyTransport} from './dummyTransport';
 
 chai.should();
@@ -236,6 +237,27 @@ export class LoggerSpec {
     process.env.NODE_ENV = nodeEnv;
   }
 
+  @test
+  'is compatible with log aggregation in productive environment'() {
+    const nodeEnv = process.env.NODE_ENV;
+    process.env.NODE_ENV = 'production';
+    process.env.ALLOW_NO_TRANSPORT = 'true';
+
+    Logger.setTransformations([new AddLogLevel(), new Colorize()]);
+
+    const spy = LoggerSpec.sandbox.on(console, 'log', () => {
+      // noop
+    });
+
+    Logger.log('Foo\nbar');
+
+    expect(spy).to.have.been.called.once;
+    expect(spy.__spy.calls[0][0]).to.equal('[LOG] Foo bar');
+
+    process.env.NODE_ENV = nodeEnv;
+    delete process.env.ALLOW_NO_TRANSPORT;
+  }
+
   @test
   log() {
     const spy = LoggerSpec.sandbox.on(console, 'log', () => {

test/transformations/timestamp.spec.ts

@@ -15,21 +15,14 @@
 import {expect} from 'chai';
 import {suite, test} from '@testdeck/mocha';
 import {Timestamp} from '../../src/transformations/timestamp';
-import moment = require('moment');
 
 @suite()
-export class ColorizeSpec {
+export class TimeStampSpec {
   @test
   'default'() {
+
     const transformation = new Timestamp();
 
-    expect(transformation.transform('ERROR', 'Foobar')).to.be.equal(`[${moment().format('LLLL')}] Foobar`);
+    expect(transformation.transform('ERROR', 'Foobar')).to.be.contain(`Z`);
-  }
-
-  @test
-  'different format'() {
-    const transformation = new Timestamp('DD.MM.YYYY');
-
-    expect(transformation.transform('ERROR', 'Foobar')).to.be.equal(`[${moment().format('DD.MM.YYYY')}] Foobar`);
   }
 }