Merge pull request #54 from arifamirani/master

Add support for GELF logging using UDP

README.md

@@ -220,6 +220,24 @@ This was mainly created for [cluster](https://github.com/LearnBoost/cluster), bu
       .listen(3000);
 </pre>
 
+## gelf logger
+
+A gelf logger has been added to log4js, by [arifamirani](https://github.com/arifamirani). This allows log4js to log to [GELF](http://www.graylog2.org/about/gelf) compatible servers such as [Graylog](http://www.graylog2.org/). This is currently configuration based and needs the following configuration to be added to log4j.json. For example:
+
+<pre>
+  {
+    "appenders": [  
+      {
+        "type": "gelf",
+        "host": "logs.mydomain.com", //defaults to localhost
+        "hostname":"mrs-dev", //defaults to the value returned by os.hostname()
+        "port": "12201", //defaults to 12201
+        "facility": "myapp" //defaults to nodejs-server
+      }
+    }
+  }
+</pre>
+
 ## author (of this node version)
 
 Gareth Jones (csausdev - gareth.jones@sensis.com.au)

lib/appenders/gelf.js

@@ -0,0 +1,98 @@
+var compress = require('compress-buffer').compress;
+var layouts = require('../layouts');
+var levels = require('../levels');
+var dgram = require('dgram');
+var util = require('util');
+
+/**
+ * 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 logEventBuffer = [];
+
+    LOG_EMERG=0;    // system is unusable
+    LOG_ALERT=1;    // action must be taken immediately
+    LOG_CRIT=2;     // critical conditions
+    LOG_ERR=3;      // error conditions
+    LOG_ERROR=3;    // because people WILL typo
+    LOG_WARNING=4;  // warning conditions
+    LOG_NOTICE=5;   // normal, but significant, condition
+    LOG_INFO=6;     // informational message
+    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;
+
+    host = host || 'localhost';
+    port = port || 12201;
+    hostname = hostname || require('os').hostname();
+    facility = facility || 'nodejs-server';
+    layout = layout || layouts.patternLayout('%m');
+
+    var client = dgram.createSocket("udp4");
+
+    process.on('exit', function() {
+        if (client) client.close();
+    });
+
+    function preparePacket(loggingEvent) {
+        var msg = {};
+        msg.full_message = layout(loggingEvent);
+        msg.short_message = msg.full_message;
+
+        msg.version="1.0";
+        msg.timestamp = msg.timestamp || new Date().getTime() / 1000 >> 0;
+        msg.host = hostname;
+        msg.level = levelMapping[loggingEvent.level || levels.DEBUG];
+        msg.facility = facility;
+        return msg;
+    }
+
+    function flushBuffer() {
+        while (logEventBuffer.length > 0) {
+            var message = preparePacket(logEventBuffer.shift());
+            var packet = compress(new Buffer(JSON.stringify(message)));
+            if (packet.length > 8192) {
+                util.debug("Message packet length (" + packet.length + ") is larger than 8k. Not sending");
+            } else {
+                sendPacket(packet);
+            }
+        }
+    }
+
+    function sendPacket(packet) {
+        try {
+            client.send(packet, 0, packet.length, port, host);
+        } catch(e) {}
+    }
+
+    return function(loggingEvent) {
+        logEventBuffer.push(loggingEvent);
+        flushBuffer();
+    };
+}
+
+function configure(config) {
+    var layout;
+    if (config.layout) {
+        layout = layouts.layout(config.layout.type, config.layout);
+    }
+    return gelfAppender(layout, config.host, config.port, config.hostname, config.facility);
+}
+
+exports.name = "gelf";
+exports.appender = gelfAppender;
+exports.configure = configure;

package.json

@@ -22,7 +22,8 @@
        "lib": "lib"
    },
    "dependencies": {
-       "async": "0.1.15"
+       "async": "0.1.15",
+       "compress-buffer": ">= 0.5.0"
    },
    "devDependencies": {
        "vows": ">=0.5.2",

test/gelfAppender.js

@@ -0,0 +1,31 @@
+var vows = require('vows')
+, log4js = require('../lib/log4js')
+, assert = require('assert')
+, util = require('util')
+, dgram = require("dgram");
+
+log4js.configure({ "appenders": [{"type": "gelf"}] }, undefined);
+
+vows.describe('log4js gelfAppender').addBatch({
+
+    'with default gelfAppender settings': {
+        topic: function() {
+            var logger = log4js.getLogger();
+
+            //Start local dgram server to act as GELF server
+            var server = dgram.createSocket("udp4");
+            //Assert as soon as message arrives
+            server.on("message", this.callback);
+            //Send a fake message as soon as server is ready
+            server.on("listening", function () {
+              logger.info("This should be a packet of size 161 bytes at the server");
+            });
+
+            //Listen on default values
+            server.bind(12201, 'localhost');
+        },
+        'should receive log messages at the local gelf server': function(err, packet) {
+            assert.ok(packet.size > 0, "Recevied blank message");
+        }
+    }
+}).export(module);