From 99ecaf2845e166579bd022f1c04fe7cb78e39511 Mon Sep 17 00:00:00 2001
From: Trent Mick <trentm@gmail.com>
Date: Mon, 30 Jan 2012 12:01:15 -0800
Subject: [PATCH] log.clone

---
 TODO.md       |  9 +++++++--
 hi.js         | 52 +++++++++++++--------------------------------------
 lib/bunyan.js | 50 ++++++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 67 insertions(+), 44 deletions(-)

diff --git a/TODO.md b/TODO.md
index feb73c0..6ebaf4f 100644
--- a/TODO.md
+++ b/TODO.md
@@ -1,10 +1,15 @@
-- node-bunyan and push to priv
-- .bind or equiv with diff name
 - info's siblings
 - `bunyan` cli
 - expand set of fields
+    <https://github.com/Graylog2/graylog2-docs/wiki/GELF>
+    <http://journal.paul.querna.org/articles/2011/12/26/log-for-machines-in-json/>
+    require: facility and hostname
 - renderer support (i.e. repr of a restify request obj)
 - docs
 - feel out usage
+- not sure about `log.info()` for is-enabled. Perhaps `log.isInfo()` because
+  can then use that for `log.isInfo(true)` for 'ring' argument. Separate level
+  and ringLevel.
 - Logger.set to mutate config or `this.fields`
 - Logger.del to remove a field
+- test suite
diff --git a/hi.js b/hi.js
index b4de68e..ec5d726 100644
--- a/hi.js
+++ b/hi.js
@@ -1,4 +1,5 @@
 var Logger = require('./lib/bunyan');
+
 var log = new Logger({facility: "myapp", level: "info"});
 console.log("log.info() is:", log.info())
 log.info("hi");
@@ -9,43 +10,16 @@ log.info({foo:"bar"}, "hi %d", 1, "two", 3);
 
 console.log("\n--\n")
 
+function Wuzzle(options) {
+  this.log = options.log;
+  this.log.info("creating a wuzzle")
+}
+
+Wuzzle.prototype.woos = function () {
+  this.log.info("This wuzzle is woosey.")
+}
+
+var wuzzle = new Wuzzle({log: log.clone({component: "wuzzle"})});
+wuzzle.woos();
+log.info("done with the wuzzle")
 
-//console.log("\n--\n")
-//xxx = console.log;
-//var INFO = 2;
-//
-//function foo() {
-//  console.log("function foo arguments:", arguments)
-//}
-//
-//function Bar() {
-//  this.level = 1;
-//}
-//Bar.prototype.info = function (fields, msg) {
-//  console.log("function info arguments:", arguments)
-//  var msgArgs;
-//  if (arguments.length === 0) {             // `log.info()`
-//    return (this.level <= INFO);
-//  } else if (this.level > INFO) {
-//    return;
-//  } else if (typeof fields === 'string') {  // `log.info(msg, ...)`
-//    fields = null;
-//    msgArgs = Array.prototype.slice.call(arguments);
-//    xxx("msgArgs: ", msgArgs, arguments)
-//  } else {                                  // `log.info(fields, msg, ...)`
-//    msgArgs = Array.prototype.slice.call(arguments, 1);
-//  }
-//  xxx("info start: arguments:", arguments.length, arguments, msgArgs)
-//  //var rec = this._mkRecord(fields, INFO, msgArgs);
-//  //this._emit(rec);
-//}
-//
-//
-//foo()
-//foo("one")
-//foo("one", "two")
-//
-//bar = new Bar();
-//bar.info()
-//bar.info("one")
-//bar.info("one", "two")
diff --git a/lib/bunyan.js b/lib/bunyan.js
index fabff4f..8d933ff 100644
--- a/lib/bunyan.js
+++ b/lib/bunyan.js
@@ -9,12 +9,14 @@
 // "CHANGES.md" (the change log).
 var VERSION = 0;
 
+
 var paul = function paul(s) {     // internal dev/debug logging
   var args = ["PAUL: "+s].concat(Array.prototype.slice.call(arguments, 1));
   console.error.apply(this, args);
 };
 var paul = function paul() {};  // uncomment to turn of debug logging
 
+
 var fs = require('fs');
 var util = require('util');
 
@@ -103,11 +105,14 @@ function Logger(options) {
   if (! this instanceof Logger) {
     return new Logger(options);
   }
+  if (!options) {
+    throw new TypeError("options (object) is required");
+  }
   
   // These are the default fields for log records (minus the attributes
   // removed in this constructor). To allow storing raw log records
-  // (unrendered), `this.fields` must never be mutated. Create a copy, if
-  // necessary.
+  // (unrendered), `this.fields` must never be mutated. Create a copy for
+  // any changes.
   this.fields = objCopy(options);
   
   if (options.stream) {
@@ -127,7 +132,38 @@ function Logger(options) {
   } else {
     this.level = 2; // INFO is default level.
   }
-  paul('Logger default fields:', this.fields);
+  
+  //XXX Non-core fields should go in 'x' sub-object.
+}
+
+
+/**
+ * Clone this logger to a new one, additionally adding the given config
+ * options.
+ *
+ * This can be useful when passing a logger to a sub-component, e.g. a
+ * "wuzzle" component of your service:
+ *
+ *    var wuzzleLog = log.clone({component: "wuzzle"})
+ *    var wuzzle = new Wuzzle({..., log: wuzzleLog})
+ *
+ * Then log records from the wuzzle code will have the same structure as
+ * the app log, *plus the component="wuzzle" field*.
+ *
+ * @param options {Object} Optional. Set of options to apply to the clone.
+ *    Supports the same set of options as the constructor.
+ */
+Logger.prototype.clone = function (options) {
+  paul("keys", Object.keys(this))
+  var cloneOptions = objCopy(this.fields);
+  cloneOptions.level = this.level;
+  cloneOptions.stream = this.stream;
+  if (options) {
+    Object.keys(options).forEach(function(k) {
+      cloneOptions[k] = options[k];
+    });
+  }
+  return new Logger(cloneOptions);
 }
 
 
@@ -145,6 +181,12 @@ Logger.prototype._mkRecord = function (fields, level, msgArgs) {
   return [this.fields, recFields, level, msgArgs];
 }
 
+
+/**
+ * Emit a log record.
+ *
+ * @param rec {log record}
+ */
 Logger.prototype._emit = function (rec) {
   var obj = objCopy(rec[0]);
   var recFields = rec[1];
@@ -160,6 +202,7 @@ Logger.prototype._emit = function (rec) {
   this.stream.write(JSON.stringify(obj) + '\n');
 }
 
+
 /**
  * Usages:
  *    log.info(<object> fields, <string> msg, ...)
@@ -183,6 +226,7 @@ Logger.prototype.info = function () {
   this._emit(rec);
 }
 
+
 module.exports = Logger;