Close #4 Log file limits

README.md

@@ -73,6 +73,10 @@ log.transports.console.format = (msg) => msg.text;
 log.transports.file.level = 'warning';
 log.transports.file.format = '{h}:{i}:{s}:{ms} {text}';
 
+// Set maximum log size in bytes. When it exceeds, old log will be saved
+// as log.old.log file
+log.maxSize = 5 * 1024 * 1024;
+
 // Write to this file, must be set before first logging
 log.transports.file.file = __dirname + '/log.txt';
 
@@ -94,4 +98,4 @@ log.appName = 'test';
 
 ## License
 
-Licensed under MIT.
+Licensed under MIT.

index.js

@@ -57,6 +57,8 @@ module.exports.transports.console.level = 'silly';
 module.exports.transports.file = transportFile;
 module.exports.transports.file.format = formatFile;
 module.exports.transports.file.level = 'warning';
+module.exports.transports.file.maxSize = 1024 * 1024;
+module.exports.transports.file.streamConfig = undefined;
 
 module.exports.findLogPath = findLogPath;
 
@@ -119,7 +121,11 @@ function transportFile(msg) {
       log('warning', 'electron-log.transports.file: Could not set a log file');
       return;
     }
-
+
+    if (transportFile.maxSize > 0) {
+      logRotate(transportFile.file, transportFile.maxSize);
+    }
+
     transportFile.stream = fs.createWriteStream(
       transportFile.file,
       transportFile.streamConfig || { flags: 'a' }
@@ -132,6 +138,15 @@ function transportFile(msg) {
 
   transportFile.stream.write(text + EOL);
 }
+
+function logRotate(file, maxSize) {
+  try {
+    const stat = fs.statSync(file);
+    if (stat.size > maxSize) {
+      fs.renameSync(file, file.replace(/log$/, 'old.log'));
+    }
+  } catch (e) {}
+}
 // endregion transport
 
 // region get log path
@@ -308,4 +323,4 @@ function pad(number, zeros) {
   zeros = zeros || 2;
   return (new Array(zeros + 1).join('0') + number).substr(-zeros, zeros);
 }
-// endregion formatter
+// endregion formatter

index.spec.js

@@ -3,13 +3,16 @@
 
 const expect = require('chai').expect;
 const index  = require('rewire')('.');
+const os     = require('os');
+const fs     = require('fs');
 
 const format         = index.__get__('format');
 const formatConsole  = index.__get__('formatConsole');
 const formatFile     = index.__get__('formatFile');
 const pad            = index.__get__('pad');
 const compareLevels  = index.__get__('compareLevels');
 const loadAppPackage = index.__get__('loadAppPackage');
+const logRotate      = index.__get__('logRotate');
 
 
 describe('module', () => {
@@ -95,6 +98,41 @@ describe('loadAppPackage', () => {
   });
 });
 
+describe('logRotate', () => {
+  const log    = os.tmpdir() + '/temp.log';
+  const oldLog = os.tmpdir() + '/temp.old.log';
+
+  beforeEach(done => {
+    fs.unlink(oldLog, () => done());
+  });
+
+  it('should move log to a new path if its size exceeds maxSize', done => {
+    fs.writeFile(log, '7 bytes', err => {
+      if (err) {
+        return done(err);
+      }
+      logRotate(log, 5);
+      fs.stat(oldLog, e => done(e));
+    });
+  });
+
+  it('should not move log to a new path if its size not exceeds maxSize', done => {
+    fs.writeFile(log, '7 bytes', err => {
+      if (err) {
+        return done(err);
+      }
+      logRotate(log, 10);
+      fs.stat(oldLog, e => {
+        if (e) {
+          done();
+        } else {
+          done('Log is rotated when its size is not exceeds maxSize');
+        }
+      });
+    });
+  });
+});
+
 function requireLog() {
   delete require.cache[require.resolve('./index')];
   return require('./index');

package.json

@@ -1,6 +1,6 @@
 {
   "name": "electron-log",
-  "version": "1.0.12",
+  "version": "1.0.13",
   "description": "Just a very simple logging module for your Electron application",
   "main": "index.js",
   "scripts": {