According to the Apache mod_proxy docs, X-Forwarded-Host can be a
comma-separated list of hosts, to which each proxy appends the requested
host. We want to grab only the first from this comma-separated list
to get the original requested Host when building URLs.
Docker-DCO-1.1-Signed-off-by: Josh Hawn <josh.hawn@docker.com> (github: jlhawn)
Manifests are now fetched by a field called "reference", which may be a tag or
a digest. When using digests to reference a manifest, the data is immutable.
The routes and specification have been updated to allow this.
There are a few caveats to this approach:
1. It may be problematic to rely on data format to differentiate between a tag
and a digest. Currently, they are disjoint but there may modifications on
either side that break this guarantee.
2. The caching characteristics of returned content are very different for
digest versus tag-based references. Digest urls can be cached forever while tag
urls cannot.
Both of these are minimal caveats that we can live with in the future.
Signed-off-by: Stephen J Day <stephen.day@docker.com>
