When a client sent "X-Delete-After: <n>", the proxy and all object
servers would each compute X-Delete-At as "int(time.time() +
n)". However, since they don't all compute it at exactly the same
time, the objects stored on disk can end up with differing values for
X-Delete-At, and in that case, the object-expirer queue has multiple
entries for the same object (one for each distinct X-Delete-At value).
This commit makes two changes, either one of which is sufficient to
fix the bug.
First, after computing X-Delete-At from X-Delete-After, X-Delete-After
is removed from the request's headers. Thus, the proxy computes
X-Delete-At, and the object servers don't, so there's only a single
value.
Second, computation of X-Delete-At now uses the request's X-Timestamp
instead of time.time(). In the proxy, these values are essentially the
same; the proxy is responsible for setting X-Timestamp. In the object
server, this ensures that all computed X-Delete-At values are
identical, even if the object servers' clocks are not, or if one
object server takes an extra second to respond to a PUT request.
Co-Authored-By: Alistair Coles <alistairncoles@gmail.com>
Change-Id: I9a1b6826c4c553f0442cfe2bb78cdf49508fa4a5
Closes-Bug: 1741371
31c294de79