Merge pull request #320 from RichardScothern/docs

doc: document storage middleware.

doc/deploying.md

@@ -3,4 +3,42 @@
 **TODO(stevvooe):** This should discuss various deployment scenarios for
 production-ready deployments. These may be backed by ready-made docker images
 but this should explain how they were created and what considerations were
-present.
+present.
+
+
+# Middleware Configuration
+
+This section describes how to configure storage middleware in the registry to enable layers to be served via a CDN, thus reducing requests to the storage layer.  Currently [Amazon Cloudfront](http://aws.amazon.com/cloudfront/) is supported and must be used in conjunction with the S3 storage driver.
+
+## Cloudfront
+
+## Parameters
+
+`name`: The name of the storage middleware.  Currently `cloudfront` is an accepted value.
+
+`disabled`: This can be set to false to easily disable the middleware.
+
+`options` : A set of key/value options to configure the middleware:
+
+* `baseurl` : The cloudfront base URL
+* `privatekey` : The location of your AWS private key on the filesystem 
+* `keypairid` : The ID of your Cloudfront keypair.
+* `duration` : The duration in minutes for which the URL is valid.  Default is 20.
+
+Note: Cloudfront keys exist separately to other AWS keys.  See [here](http://docs.aws.amazon.com/AWSSecurityCredentials/1.0/AboutAWSCredentials.html#KeyPairs) for more information.
+
+## Example
+
+
+
+```
+middleware:
+    storage:
+        - name: cloudfront
+          disabled: false
+          options:
+             baseurl: http://d111111abcdef8.cloudfront.net
+             privatekey: /path/to/asecret.pem
+             keypairid: asecret
+             duration: 60
+```