Merge pull request #1386 from gabriel-cloud/gabriel-cloud/issue1385

add maxLength to recording - closes #1385

docs/recording.md

@@ -5,6 +5,7 @@ This appender stores the log events in memory. It is mainly useful for testing (
 ## Configuration
 
 - `type` - `recording`
+- `maxLength` - `integer` (optional, defaults to undefined) - the maximum array length for the recording. If not specified, the array will grow until cleared
 
 There is no other configuration for this appender.
 

lib/appenders/recording.js

@@ -2,12 +2,15 @@ const debug = require('debug')('log4js:recording');
 
 const recordedEvents = [];
 
-function configure() {
+function configure(config) {
   return function (logEvent) {
     debug(
       `received logEvent, number of events now ${recordedEvents.length + 1}`
     );
     debug('log event was ', logEvent);
+    if (config.maxLength && recordedEvents.length >= config.maxLength) {
+      recordedEvents.shift();
+    }
     recordedEvents.push(logEvent);
   };
 }

test/tap/recordingAppender-test.js

@@ -1,32 +1,79 @@
 const { test } = require('tap');
 const log4js = require('../../lib/log4js');
 
-test('recording appender', (t) => {
-  log4js.configure({
-    appenders: { rec: { type: 'recording' } },
-    categories: { default: { appenders: ['rec'], level: 'debug' } },
+test('recording appender', (batch) => {
+  batch.test('should store logs in memory until cleared', (t) => {
+    log4js.configure({
+      appenders: { rec: { type: 'recording' } },
+      categories: { default: { appenders: ['rec'], level: 'debug' } },
+    });
+
+    const logger = log4js.getLogger();
+    logger.level = 'debug';
+    logger.debug('This will go to the recording!');
+    logger.debug('Another one');
+
+    const recording = log4js.recording();
+    const loggingEvents = recording.playback();
+
+    t.equal(loggingEvents.length, 2, 'There should be 2 recorded events');
+    t.equal(loggingEvents[0].data[0], 'This will go to the recording!');
+    t.equal(loggingEvents[1].data[0], 'Another one');
+
+    recording.reset();
+    const loggingEventsPostReset = recording.playback();
+
+    t.equal(
+      loggingEventsPostReset.length,
+      0,
+      'There should be 0 recorded events'
+    );
+
+    t.end();
   });
 
-  const logger = log4js.getLogger();
-  logger.level = 'debug';
-  logger.debug('This will go to the recording!');
-  logger.debug('Another one');
+  batch.test('should store 2 rolling logs in memory until cleared', (t) => {
+    log4js.configure({
+      appenders: { rec2: { type: 'recording', maxLength: 2 } },
+      categories: { default: { appenders: ['rec2'], level: 'debug' } },
+    });
 
-  const recording = log4js.recording();
-  const loggingEvents = recording.playback();
+    const logger = log4js.getLogger();
+    logger.level = 'debug';
+    logger.debug('First log entry');
+    logger.debug('Second log entry');
 
-  t.equal(loggingEvents.length, 2, 'There should be 2 recorded events');
-  t.equal(loggingEvents[0].data[0], 'This will go to the recording!');
-  t.equal(loggingEvents[1].data[0], 'Another one');
+    const recording = log4js.recording();
 
-  recording.reset();
-  const loggingEventsPostReset = recording.playback();
+    t.equal(
+      recording.playback().length,
+      2,
+      'There should be 2 recorded events'
+    );
+    t.equal(recording.playback()[0].data[0], 'First log entry');
+    t.equal(recording.playback()[1].data[0], 'Second log entry');
 
-  t.equal(
-    loggingEventsPostReset.length,
-    0,
-    'There should be 0 recorded events'
-  );
+    logger.debug('Third log entry');
 
-  t.end();
+    t.equal(
+      recording.playback().length,
+      2,
+      'There should still be 2 recording events'
+    );
+    t.equal(recording.playback()[0].data[0], 'Second log entry');
+    t.equal(recording.playback()[1].data[0], 'Third log entry');
+
+    recording.reset();
+    const loggingEventsPostReset = recording.playback();
+
+    t.equal(
+      loggingEventsPostReset.length,
+      0,
+      'There should be 0 recorded events'
+    );
+
+    t.end();
+  });
+
+  batch.end();
 });