maas.io lacks Cache-Control settings for simplestreams

[jhobbs]

Summary

There are no Cache-Control settings for simplestreams files on maas.io. This means caching proxies in between maas and maas.io might cache incompatible files - like index.json and index.json.gpg - separately, causing signature validation errors.

See: https://bugs.launchpad.net/maas/+bug/1761813

Process

curl -D - https://images.maas.io/ephemeral-v3/daily/streams/v1/index.json.gpg

Note the lack of Cache-Control in the header.

Current and expected result

Currently there is no Cache-Control. I expect there to be Cache-Control along the lines of:

Cache-Control: max-age=0, proxy-revalidate

Screenshot

http://paste.ubuntu.com/p/6Ry5kfdFBf/

[carlaberkers]

fix released on LP