... by embedding something like `If-Match: <etag>` semantics in the
symlink.
When creating a symlink, users may now specify an optional
X-Symlink-Target-Etag header. If present, the etag of the final object
returned to the client will be checked; if it does not match the
X-Symlink-Target-Etag header, a 409 Conflict error will be returned to
the client.
Note that, unlike "dynamic symlink" behavior, the target object must
exist with the matching Etag for the "static symlink" to be created.
Since we're validating the Etag anyway, we also set the content-type of
the symlink to match if the client didn't otherwise specifiy and send
the etag & content-length along to the container listing as well.
Bonus goodness:
- Tighten assertions on Content-Location
- Get rid of swift.source-sniffing by making versioned_writes
symlink-aware ('cause I'm going to want to make it symlink-aware
later anyway)
- Allow middlewares left of symlink to set their own
Container-Update-Override-Etag when creating a symlink
- Set dynamic symlink content type if client doesn't supply something
Co-Authored-By: Clay Gerrard <clay.gerrard@gmail.com>
Change-Id: I179ea6180d31146bb947061c69b1807c59529ac8
1abc9c4f9d