log4js-node/lib/appenders/gelf.js

142 lines
4.4 KiB
JavaScript

"use strict";
var zlib = require('zlib');
var layouts = require('../layouts');
var levels = require('../levels');
var dgram = require('dgram');
var util = require('util');
var debug = require('../debug')('GELF Appender');
var LOG_EMERG=0; // system is unusable
var LOG_ALERT=1; // action must be taken immediately
var LOG_CRIT=2; // critical conditions
var LOG_ERR=3; // error conditions
var LOG_ERROR=3; // because people WILL typo
var LOG_WARNING=4; // warning conditions
var LOG_NOTICE=5; // normal, but significant, condition
var LOG_INFO=6; // informational message
var LOG_DEBUG=7; // debug-level message
var levelMapping = {};
levelMapping[levels.ALL] = LOG_DEBUG;
levelMapping[levels.TRACE] = LOG_DEBUG;
levelMapping[levels.DEBUG] = LOG_DEBUG;
levelMapping[levels.INFO] = LOG_INFO;
levelMapping[levels.WARN] = LOG_WARNING;
levelMapping[levels.ERROR] = LOG_ERR;
levelMapping[levels.FATAL] = LOG_CRIT;
/**
* GELF appender that supports sending UDP packets to a GELF compatible server such as Graylog
*
* @param layout a function that takes a logevent and returns a string (defaults to none).
* @param host - host to which to send logs (default:localhost)
* @param port - port at which to send logs to (default:12201)
* @param hostname - hostname of the current host (default:os hostname)
* @param facility - facility to log to (default:nodejs-server)
*/
function gelfAppender (layout, host, port, hostname, facility) {
var config, customFields;
if (typeof(host) === 'object') {
config = host;
host = config.host;
port = config.port;
hostname = config.hostname;
facility = config.facility;
customFields = config.customFields;
}
host = host || 'localhost';
port = port || 12201;
hostname = hostname || require('os').hostname();
facility = facility || 'nodejs-server';
layout = layout || layouts.messagePassThroughLayout;
var defaultCustomFields = customFields || {};
var client = dgram.createSocket("udp4");
process.on('exit', function() {
if (client) client.close();
});
/**
* Add custom fields (start with underscore )
* - if the first object passed to the logger contains 'GELF' field,
* copy the underscore fields to the message
* @param loggingEvent
* @param msg
*/
function addCustomFields(loggingEvent, msg){
/* append defaultCustomFields firsts */
Object.keys(defaultCustomFields).forEach(function(key) {
// skip _id field for graylog2, skip keys not starts with UNDERSCORE
if (key.match(/^_/) && key !== "_id") {
msg[key] = defaultCustomFields[key];
}
});
/* append custom fields per message */
var data = loggingEvent.data;
if (!Array.isArray(data) || data.length === 0) return;
var firstData = data[0];
if (!firstData.GELF) return; // identify with GELF field defined
Object.keys(firstData).forEach(function(key) {
// skip _id field for graylog2, skip keys not starts with UNDERSCORE
if (key.match(/^_/) || key !== "_id") {
msg[key] = firstData[key];
}
});
/* the custom field object should be removed, so it will not be looged by the later appenders */
loggingEvent.data.shift();
}
function preparePacket(loggingEvent) {
var msg = {};
addCustomFields(loggingEvent, msg);
msg.full_message = layout(loggingEvent);
msg.short_message = msg.full_message;
msg.version="1.0";
msg.timestamp = msg.timestamp || new Date().getTime() / 1000; // log should use millisecond
msg.host = hostname;
msg.level = levelMapping[loggingEvent.level || levels.DEBUG];
msg.facility = facility;
return msg;
}
function sendPacket(packet) {
try {
client.send(packet, 0, packet.length, port, host);
} catch(e) {}
}
return function(loggingEvent) {
var message = preparePacket(loggingEvent);
zlib.gzip(new Buffer(JSON.stringify(message)), function(err, packet) {
if (err) {
console.error(err.stack);
} else {
if (packet.length > 8192) {
debug("Message packet length (" + packet.length + ") is larger than 8k. Not sending");
} else {
sendPacket(packet);
}
}
});
};
}
function configure(config) {
var layout;
if (config.layout) {
layout = layouts.layout(config.layout.type, config.layout);
}
return gelfAppender(layout, config);
}
exports.appender = gelfAppender;
exports.configure = configure;