Closes elastic#2471 - Add logging to a file

- Refactored the JSONStream to be a through stream
- Closes elastic#2471
- Refactored how we handle JSONStreams. They now need to be piped to the
  destination

package.json

@@ -56,7 +56,8 @@
     "request": "^2.40.0",
     "requirefrom": "^0.2.0",
     "semver": "^4.2.0",
-    "serve-favicon": "~2.2.0"
+    "serve-favicon": "~2.2.0",
+    "through": "^2.3.6"
   },
   "devDependencies": {
     "connect": "~2.19.5",

src/server/bin/kibana.js

@@ -18,6 +18,7 @@ program.option('-c, --config <path>', 'Path to the config file');
 program.option('-p, --port <port>', 'The port to bind to', parseInt);
 program.option('-q, --quiet', 'Turns off logging');
 program.option('-H, --host <host>', 'The host to bind to');
+program.option('-l, --log-file <path>', 'The file to log to');
 program.option('--plugins <path>', 'Path to scan for plugins');
 program.parse(process.argv);
 
@@ -49,6 +50,10 @@ if (program.quiet) {
   config.quiet = program.quiet;
 }
 
+if (program.logFile) {
+  config.log_file = program.logFile;
+}
+
 if (program.host) {
   config.host = program.host;
 }

src/server/config/index.js

@@ -45,7 +45,8 @@ var config = module.exports = {
   kibana                  : kibana,
   package                 : require(packagePath),
   htpasswd                : htpasswdPath,
-  buildNum                : '@@buildNum'
+  buildNum                : '@@buildNum',
+  log_file                : kibana.log_file || null
 };
 
 config.plugins = listPlugins(config);

src/server/config/kibana.yml

@@ -49,3 +49,6 @@ verify_ssl: true
 # Set the path to where you would like the process id file to be created.
 # pid_file: /var/run/kibana.pid
 
+# If you would like to send the log output to a file you can set the path below. 
+# This will also turn off the STDOUT log output.
+# log_file: ./kibana.log

src/server/lib/JSONStream.js → src/server/lib/createJSONStream.js

@@ -1,6 +1,5 @@
 var _ = require('lodash');
-var Writable = require('stream').Writable;
-var util = require('util');
+var through = require('through');
 
 var levels = {
   10: 'trace',
@@ -11,14 +10,7 @@ var levels = {
   60: 'fatal'
 };
 
-function JSONStream(options) {
-  options = options || {};
-  Writable.call(this, options);
-}
-
-util.inherits(JSONStream, Writable);
-
-JSONStream.prototype._write = function (entry, encoding, callback) {
+function write(entry) {
   entry = JSON.parse(entry.toString('utf8'));
   var env = process.env.NODE_ENV || 'development';
 
@@ -36,8 +28,13 @@ JSONStream.prototype._write = function (entry, encoding, callback) {
     if (!output.message) output.message = output.error.message;
   }
 
-  process.stdout.write(JSON.stringify(output) + "\n");
-  callback();
-};
+  this.queue(JSON.stringify(output) + '\n');
+}
+
+function end() {
+  this.queue(null);
+}
 
-module.exports = JSONStream;
+module.exports = function () {
+  return through(write, end);
+};

src/server/lib/logger.js

@@ -2,18 +2,33 @@ var _ = require('lodash');
 var morgan = require('morgan');
 var env = process.env.NODE_ENV || 'development';
 var bunyan = require('bunyan');
+var fs = require('fs');
 var StdOutStream = require('./StdOutStream');
-var JSONStream = require('./JSONStream');
+var createJSONStream = require('./createJSONStream');
 var config = require('../config');
-var stream = { stream: new JSONStream() };
 var streams = [];
 
+// Set the default stream based on the enviroment. If we are on development then
+// then we are going to create a pretty stream. Everytyhing else will get the 
+// JSON stream to stdout.
+var defaultStream;
 if (env === 'development') {
-  stream.stream = new StdOutStream();
+  defaultStream = new StdOutStream();
+} else {
+  defaultStream = createJSONStream()
+    .pipe(process.stdout);
 }
 
-if (!config.quiet) {
-  streams.push(stream);
+// If we are not being oppressed and we are not sending the output to a log file
+// push the default stream to the list of streams
+if (!config.quiet && !config.log_file) {
+  streams.push({ stream: defaultStream });
+}
+
+// Send the stream to a file using the json format.
+if (config.log_file) {
+  var fileStream = fs.createWriteStream(config.log_file);
+  streams.push({ stream: createJSONStream().pipe(fileStream) });
 }
 
 var logger = module.exports = bunyan.createLogger({