feat(multiFile): added multiFile appender (#437)

lib/appenders/multiFile.js

@@ -0,0 +1,47 @@
+'use strict';
+
+const debug = require('debug')('log4js:multiFile');
+const path = require('path');
+const fileAppender = require('./file');
+
+const findFileKey = (property, event) => event[property] || event.context[property];
+
+module.exports.configure = (config, layouts) => {
+  debug('Creating a multi-file appender');
+  const files = new Map();
+
+  const appender = (logEvent) => {
+    const fileKey = findFileKey(config.property, logEvent);
+    debug('fileKey for property ', config.property, ' is ', fileKey);
+    if (fileKey) {
+      let file = files.get(fileKey);
+      debug('existing file appender is ', file);
+      if (!file) {
+        debug('creating new file appender');
+        config.filename = path.join(config.base, fileKey + config.extension);
+        file = fileAppender.configure(config, layouts);
+        files.set(fileKey, file);
+      }
+
+      file(logEvent);
+    }
+    debug('No fileKey for logEvent, quietly ignoring this log event');
+  };
+
+  appender.shutdown = (cb) => {
+    let shutdownFunctions = files.size;
+    let error;
+    files.forEach((app, fileKey) => {
+      debug('calling shutdown for ', fileKey);
+      app.shutdown((err) => {
+        error = error || err;
+        shutdownFunctions -= 1;
+        if (shutdownFunctions <= 0) {
+          cb(error);
+        }
+      });
+    });
+  };
+
+  return appender;
+};

test/tap/multi-file-appender-test.js

@@ -0,0 +1,115 @@
+'use strict';
+
+const test = require('tap').test;
+const log4js = require('../../lib/log4js');
+const fs = require('fs');
+
+test('multiFile appender', (batch) => {
+  batch.test('should write to multiple files based on the loggingEvent property', (t) => {
+    log4js.configure({
+      appenders: { multi: { type: 'multiFile', base: 'logs/', property: 'categoryName', extension: '.log' } },
+      categories: { default: { appenders: ['multi'], level: 'info' } }
+    });
+    const loggerA = log4js.getLogger('A');
+    const loggerB = log4js.getLogger('B');
+    loggerA.info('I am in logger A');
+    loggerB.info('I am in logger B');
+    log4js.shutdown(() => {
+      t.contains(fs.readFileSync('logs/A.log', 'utf-8'), 'I am in logger A');
+      t.contains(fs.readFileSync('logs/B.log', 'utf-8'), 'I am in logger B');
+      t.end();
+    });
+  });
+
+  batch.test('should write to multiple files based on loggingEvent.context properties', (t) => {
+    log4js.configure({
+      appenders: { multi: { type: 'multiFile', base: 'logs/', property: 'label', extension: '.log' } },
+      categories: { default: { appenders: ['multi'], level: 'info' } }
+    });
+    const loggerC = log4js.getLogger('cheese');
+    const loggerD = log4js.getLogger('biscuits');
+    loggerC.addContext('label', 'C');
+    loggerD.addContext('label', 'D');
+    loggerC.info('I am in logger C');
+    loggerD.info('I am in logger D');
+    log4js.shutdown(() => {
+      t.contains(fs.readFileSync('logs/C.log', 'utf-8'), 'I am in logger C');
+      t.contains(fs.readFileSync('logs/D.log', 'utf-8'), 'I am in logger D');
+      t.end();
+    });
+  });
+
+  batch.test('should fail silently if loggingEvent property has no value', (t) => {
+    log4js.configure({
+      appenders: { multi: { type: 'multiFile', base: 'logs/', property: 'label', extension: '.log' } },
+      categories: { default: { appenders: ['multi'], level: 'info' } }
+    });
+    const loggerE = log4js.getLogger();
+    loggerE.addContext('label', 'E');
+    loggerE.info('I am in logger E');
+    loggerE.removeContext('label');
+    loggerE.info('I am not in logger E');
+    loggerE.addContext('label', null);
+    loggerE.info('I am also not in logger E');
+    log4js.shutdown(() => {
+      const contents = fs.readFileSync('logs/E.log', 'utf-8');
+      t.contains(contents, 'I am in logger E');
+      t.notMatch(contents, 'I am not in logger E');
+      t.notMatch(contents, 'I am also not in logger E');
+      t.end();
+    });
+  });
+
+  batch.test('should pass options to rolling file stream', (t) => {
+    log4js.configure({
+      appenders: { multi: {
+        type: 'multiFile',
+        base: 'logs/',
+        property: 'label',
+        extension: '.log',
+        maxLogSize: 61,
+        backups: 2
+      } },
+      categories: { default: { appenders: ['multi'], level: 'info' } }
+    });
+    const loggerF = log4js.getLogger();
+    loggerF.addContext('label', 'F');
+    loggerF.info('Being in logger F is the best');
+    loggerF.info('I am also in logger F');
+    loggerF.info('I am in logger F');
+    log4js.shutdown(() => {
+      let contents = fs.readFileSync('logs/F.log', 'utf-8');
+      t.contains(contents, 'I am in logger F');
+      contents = fs.readFileSync('logs/F.log.1', 'utf-8');
+      t.contains(contents, 'I am also in logger F');
+      contents = fs.readFileSync('logs/F.log.2', 'utf-8');
+      t.contains(contents, 'Being in logger F is the best');
+      t.end();
+    });
+  });
+
+  batch.test('should inherit config from category hierarchy', (t) => {
+    log4js.configure({
+      appenders: {
+        out: { type: 'stdout' },
+        test: {
+          type: 'multiFile', base: 'logs/', property: 'categoryName', extension: '.log'
+        }
+      },
+      categories: {
+        default: { appenders: ['out'], level: 'info' },
+        test: { appenders: ['test'], level: 'debug' }
+      }
+    });
+
+    const testLogger = log4js.getLogger('test.someTest');
+    testLogger.debug('This should go to the file');
+    log4js.shutdown(() => {
+      const contents = fs.readFileSync('logs/test.someTest.log', 'utf-8');
+      t.contains(contents, 'This should go to the file');
+      t.end();
+    });
+  });
+
+  batch.end();
+});