077ba77ea6
This patch makes four significant changes to the handling of GET
requests for sharding or sharded containers:
- container server GET requests may now result in the entire list of
shard ranges being returned for the 'listing' state regardless of
any request parameter constraints.
- the proxy server may cache that list of shard ranges in memcache
and the requests environ infocache dict, and subsequently use the
cached shard ranges when handling GET requests for the same
container.
- the proxy now caches more container metadata so that it can
synthesize a complete set of container GET response headers from
cache.
- the proxy server now enforces more container GET request validity
checks that were previously only enforced by the backend server,
e.g. checks for valid request parameter values
With this change, when the proxy learns from container metadata
that the container is sharded then it will cache shard
ranges fetched from the backend during a container GET in memcache.
On subsequent container GETs the proxy will use the cached shard
ranges to gather object listings from shard containers, avoiding
further GET requests to the root container until the cached shard
ranges expire from cache.
Cached shard ranges are most useful if they cover the entire object
name space in the container. The proxy therefore uses a new
X-Backend-Override-Shard-Name-Filter header to instruct the container
server to ignore any request parameters that would constrain the
returned shard range listing i.e. 'marker', 'end_marker', 'includes'
and 'reverse' parameters. Having obtained the entire shard range
listing (either from the server or from cache) the proxy now applies
those request parameter constraints itself when constructing the
client response.
When using cached shard ranges the proxy will synthesize response
headers from the container metadata that is also in cache. To enable
the full set of container GET response headers to be synthezised in
this way, the set of metadata that the proxy caches when handling a
backend container GET response is expanded to include various
timestamps.
The X-Newest header may be used to disable looking up shard ranges
in cache.
Change-Id: I5fc696625d69d1ee9218ee2a508a1b9be6cf9685
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| .. | ||
| controllers | ||
| __init__.py | ||
| server.py | ||