log4js-node/lib/appenders/file.js

68 lines
2.2 KiB
JavaScript

var layouts = require('../layouts')
, path = require('path')
, fs = require('fs')
, streams = require('../streams');
/**
* 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 streams.BufferedWriteStream(
new streams.RollingFileStream(
file,
fileSize,
numFiles
)
);
} else {
stream = new streams.BufferedWriteStream(fs.createWriteStream(file, { encoding: "utf8", mode: 0644, flags: 'a' }));
}
stream.on("error", function (err) {
console.error("log4js.fileAppender - Writing to file %s, error happened ", file, err);
});
return stream;
}
var logFile = openTheStream(file, logSize, numBackups);
//close the file on process exit.
process.on('exit', function() {
logFile.end();
});
return function(loggingEvent) {
logFile.write(layout(loggingEvent)+'\n', "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;