added a synchronous file appender

lib/appenders/fileSync.js

@@ -0,0 +1,180 @@
+"use strict";
+var debug = require('../debug')('fileSync')
+, layouts = require('../layouts')
+, path = require('path')
+, fs = require('fs')
+, streams = require('../streams')
+, os = require('os')
+, eol = os.EOL || '\n'
+;
+
+function RollingFileSync (filename, size, backups, options) {
+  debug("In RollingFileStream");
+
+  function throwErrorIfArgumentsAreNotValid() {
+    if (!filename || !size || size <= 0) {
+      throw new Error("You must specify a filename and file size");
+    }
+  }
+  
+  throwErrorIfArgumentsAreNotValid();
+  
+  this.filename = filename;
+  this.size = size;
+  this.backups = backups || 1;
+  this.options = options || { encoding: 'utf8', mode: parseInt('0644', 8), flags: 'a' };
+  this.currentSize = 0;
+  
+  function currentFileSize(file) {
+    var fileSize = 0;
+    try {
+      fileSize = fs.statSync(file).size;
+    } catch (e) {
+      // file does not exist
+    }
+    return fileSize;
+  }
+
+  this.currentSize = currentFileSize(this.filename);
+}
+
+RollingFileSync.prototype.shouldRoll = function() {
+  debug("should roll with current size %d, and max size %d", this.currentSize, this.size);
+  return this.currentSize >= this.size;
+};
+
+RollingFileSync.prototype.roll = function(filename) {
+  var that = this,
+  nameMatcher = new RegExp('^' + path.basename(filename));
+  
+  function justTheseFiles (item) {
+    return nameMatcher.test(item);
+  }
+  
+  function index(filename_) {
+    return parseInt(filename_.substring((path.basename(filename) + '.').length), 10) || 0;
+  }
+  
+  function byIndex(a, b) {
+    if (index(a) > index(b)) {
+      return 1;
+    } else if (index(a) < index(b) ) {
+      return -1;
+    } else {
+      return 0;
+    }
+  }
+
+  function increaseFileIndex (fileToRename) {
+    var idx = index(fileToRename);
+    debug('Index of ' + fileToRename + ' is ' + idx);
+    if (idx < that.backups) {
+      //on windows, you can get a EEXIST error if you rename a file to an existing file
+      //so, we'll try to delete the file we're renaming to first
+      try {
+        fs.unlinkSync(filename + '.' + (idx+1));
+      } catch(e) {
+        //ignore err: if we could not delete, it's most likely that it doesn't exist
+      }
+      
+      debug('Renaming ' + fileToRename + ' -> ' + filename + '.' + (idx+1));
+      fs.renameSync(path.join(path.dirname(filename), fileToRename), filename + '.' + (idx + 1));
+    }
+  }
+
+  function renameTheFiles() {
+    //roll the backups (rename file.n to file.n+1, where n <= numBackups)
+    debug("Renaming the old files");
+    
+    var files = fs.readdirSync(path.dirname(filename));
+    files.filter(justTheseFiles).sort(byIndex).reverse().forEach(increaseFileIndex);
+  }
+
+  debug("Rolling, rolling, rolling");
+  renameTheFiles();
+};
+
+RollingFileSync.prototype.write = function(chunk, encoding) {
+  var that = this;
+  
+  
+  function writeTheChunk() {
+    debug("writing the chunk to the file");
+    that.currentSize += chunk.length;
+    fs.appendFileSync(that.filename, chunk, {encoding: encoding});
+  }
+
+  debug("in write");
+  
+
+  if (this.shouldRoll()) {
+    this.currentSize = 0;
+    this.roll(this.filename);
+  }
+  
+  writeTheChunk();
+};
+
+
+/**
+ * File Appender writing the logs to a text file. Supports rolling of logs by size.
+ *
+ * @param file file log messages will be written to
+ * @param layout a function that takes a logevent and returns a string 
+ *   (defaults to basicLayout).
+ * @param logSize - the maximum size (in bytes) for a log file, 
+ *   if not provided then logs won't be rotated.
+ * @param numBackups - the number of log files to keep after logSize 
+ *   has been reached (default 5)
+ */
+function fileAppender (file, layout, logSize, numBackups) {
+  var bytesWritten = 0;
+  file = path.normalize(file);
+  layout = layout || layouts.basicLayout;
+  numBackups = numBackups === undefined ? 5 : numBackups;
+  //there has to be at least one backup if logSize has been specified
+  numBackups = numBackups === 0 ? 1 : numBackups;
+
+  function openTheStream(file, fileSize, numFiles) {
+    var stream;
+    
+    if (fileSize) {
+      stream = new RollingFileSync(
+        file,
+        fileSize,
+        numFiles
+      );
+    } else {
+      stream = (function(f){
+        return {write: function(data, encoding) {
+            encoding = encoding || 'utf8';
+            fs.appendFileSync(f, data, {encoding: encoding});
+        }};
+      })(file);
+    }
+
+    return stream;
+  }
+
+  var logFile = openTheStream(file, logSize, numBackups);
+  
+  return function(loggingEvent) {
+    logFile.write(layout(loggingEvent) + eol, "utf8");
+  };
+}
+
+function configure(config, options) {
+  var layout;
+  if (config.layout) {
+    layout = layouts.layout(config.layout.type, config.layout);
+  }
+
+  if (options && options.cwd && !config.absolute) {
+    config.filename = path.join(options.cwd, config.filename);
+  }
+
+  return fileAppender(config.filename, layout, config.maxLogSize, config.backups);
+}
+
+exports.appender = fileAppender;
+exports.configure = configure;