From 81d027eca78c00aed4638d40989c9afc41cae588 Mon Sep 17 00:00:00 2001
From: TJ Holowaychuk <tj@vision-media.ca>
Date: Tue, 26 Nov 2013 21:37:22 -0800
Subject: [PATCH] add DEBUG usage docs. Closes #41

---
 docs/guide.md | 22 +++++++++++++++++++---
 1 file changed, 19 insertions(+), 3 deletions(-)

diff --git a/docs/guide.md b/docs/guide.md
index f93302f..bed48e3 100644
--- a/docs/guide.md
+++ b/docs/guide.md
@@ -92,7 +92,7 @@ function logger(format){
       .replace(':url', this.url);
 
     console.log(str);
-    
+
     yield next;
   }
 }
@@ -103,8 +103,7 @@ app.use(logger(':method :url'));
 
 ### Named middleware
 
-  Naming middleware is optional, however it's useful for debugging purposes to
-  assign a name.
+  Naming middleware is optional, however it's useful for debugging purposes to assign a name.
 
 ```js
 function logger(format){
@@ -136,3 +135,20 @@ app.use(function *(){
 });
 ```
 
+## Debugging Koa
+
+  Koa along with many of the libraries it's built with support the __DEBUG__ environment variable from [debug](https://github.com/visionmedia/debug) which provides simple conditional logging.
+
+  For example
+  to see all koa-specific debugging information just pass `DEBUG=koa*` and upon boot you'll see the list of middleware used, among other things.
+
+```
+$ DEBUG=koa* node --harmony examples/simple
+  koa:application use responseTime +0ms
+  koa:application use logger +4ms
+  koa:application use contentLength +0ms
+  koa:application use notfound +0ms
+  koa:application use response +0ms
+  koa:application listen +0ms
+```
+