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.
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
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
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.