= Cloud PyPI -- Example CDN =

In order to test drive a PyPI CDN, we've setup an example CDN on Amazon Cloudfront for pypi.python.org.

 * https://d1t66zoqn9vlte.cloudfront.net/simple/

== Settings ==

These are the settings:

 * Origin: pypi.python.org
 * Default Root Object: pypi
 * Origin Protocol Policy: HTTP OnlyMatch Viewer
 * Viewer Protocol Policy: HTTPS Only
 * Minimum TTL: 3600
 * No forwarding of cookies or query strings

As a result, the CDN is only available over HTTPS (there's no redirect in place) and the content is fetched from PyPI using HTTPS as well.

The TTL is set to a low value for testing purposes. For a deployment, the value can be set to a much higher value for the package pages; and a lower value for the /simple/ index itself.

''Note:'' Without cache headers in the PyPI response (it currently doesn't send cache headers), the default TTL for the cache retention is 24h, according to the Amazon documentation.

== Example fetching the /simple/ index ==

First request:

{{{
200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 1323539
Connection: keep-alive
Server: nginx/1.1.19
Date: Thu, 28 Feb 2013 13:56:22 GMT
Strict-Transport-Security: max-age=86400
X-Amz-Cf-Id: vXAxMoustlCxyzFAVjjg3EUJG5OgP-ALefiF1mbvbJlW9ZsHCxtdLg==
Via: 1.0 3dee24f419c49cc32df542a9410fda87.cloudfront.net (CloudFront)
X-Cache: Miss from cloudfront
}}}

Second request:

{{{
200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 1323539
Connection: keep-alive
Server: nginx/1.1.19
Date: Thu, 28 Feb 2013 13:56:22 GMT
Strict-Transport-Security: max-age=86400
Age: 337
X-Amz-Cf-Id: -2COLjgkKLDF83jrr0iFahyAO4UGOMB0hXNM_ROMFJQpII1goFyi-A==
Via: 1.0 3dee24f419c49cc32df542a9410fda87.cloudfront.net (CloudFront)
X-Cache: Hit from cloudfront
}}}

== Issues found in the experiment ==

 * The URL is not easy to remember

 It's possible to setup a nicer URL for the CDN, but even then, the URL will still read {{{something.cloudfront.net}}}. Unfortunately, we cannot use CNAMEs for this, e.g. use pypi-cdn.python.org as name, since the HTTPS verification would not work with this URL.

 It would be possible to install a redirect from pypi-cdn.python.org to the something.cloudfront.net URL - at a cost: if the redirector is down, the CDN would not be reachable via the nicer URL.