From 2c4d4713f2d7439d12d76619932879cb6df0f668 Mon Sep 17 00:00:00 2001
From: Trent Mick <trentm@gmail.com>
Date: Wed, 31 Oct 2012 22:46:05 -0700
Subject: [PATCH] issue #48: make dtrace-provider presence optional (disabled
 dtrace probes)

dtrace-provider is still in *dependencies* to strongly encourage
installing it. However I want bunyan.js to be useable for basic
usage standalone.
---
 lib/bunyan.js | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/lib/bunyan.js b/lib/bunyan.js
index bbb2984..4a0d6ec 100644
--- a/lib/bunyan.js
+++ b/lib/bunyan.js
@@ -25,7 +25,11 @@ var os = require('os');
 var fs = require('fs');
 var util = require('util');
 var assert = require('assert');
-var dtrace = require('dtrace-provider');
+try {
+  var dtrace = require('dtrace-provider');
+} catch (e) {
+  dtrace = null;
+}
 var EventEmitter = require('events').EventEmitter;
 
 
@@ -48,7 +52,7 @@ function objCopy(obj) {
 
 var format = util.format;
 if (!format) {
-  // If not node 0.6, then use its `util.format`:
+  // If node < 0.6, then use its `util.format`:
   // <https://github.com/joyent/node/blob/master/lib/util.js#L22>:
   var inspect = util.inspect;
   var formatRegExp = /%[sdj%]/g;
@@ -157,8 +161,9 @@ var levelFromName = {
   'fatal': FATAL
 };
 
+// Dtrace probes.
 var dtp = undefined;
-var probes = {};
+var probes = dtrace && {};
 
 /**
  * Resolve a level number, name (upper or lowercase) to a level number value.
@@ -302,7 +307,7 @@ function Logger(options, _childOptions, _childSimple) {
     this.fields = {};
   }
 
-  if (!dtp) {
+  if (!dtp && dtrace) {
     dtp = dtrace.createDTraceProvider('bunyan');
 
     for (var level in levelFromName) {
@@ -768,7 +773,7 @@ function mkLogEmitter(minLevel) {
       rec = mkRecord(msgArgs);
       str = this._emit(rec);
     }
-    probes[minLevel].fire(function () {
+    probes && probes[minLevel].fire(function () {
         return [ str ||
           (rec && log._emit(rec, true)) ||
           log._emit(mkRecord(msgArgs), true) ];