* cache: add sharded cache implementation
Add Cache impl and a few tests. This cache is 256-way sharded, mainly
so each shard has it's own lock. The main cache structure is a readonly
jump plane into the right shard.
This should remove the single lock contention on the main lock and
provide more concurrent throughput - Obviously this hasn't been tested
or measured.
The key into the cache was made a uint32 (hash.fnv) and the hashing op
is not using strings.ToLower anymore remove any GC in that code path.
* here too
* Minimum shard size
* typos
* blurp
* small cleanups no defer
* typo
* Add freq based on Johns idea
* cherry-pick conflict resolv
* typo
* update from early code review from john
* add prefetch to the cache
* mw/cache: add prefetch
* remove println
* remove comment
* Fix tests
* Test prefetch in setup
* Add start of cache
* try add diff cache options
* Add hacky testcase
* not needed
* allow the use of a percentage for prefetch
If the TTL falls below xx% do a prefetch, if the record was popular.
Some other fixes and correctly prefetch only popular records.
Provide TTL examples for cache middleware. Fixes: #364
Add interaction docs to make non invalidation for cache middleware
clear. Cache might serve stale records. Fixes: #403
* middleware/cache: cache 0 will be capped at 5
cache 0 would return TTL=0 records, up that to the documented minimum of
5 seconds.
* middleware/cache: check for 0 TTL
Handle 0 TTL differently and return an error, we might need to
special case this in the future.
* middleware/metrics: add more metrics
middleware/cache:
Add metrics for number of elements in the cache. Also export the total
size. Update README to detail the new metrics.
middleware/metrics
Move metrics into subpackage called "vars". This breaks the import
cycle and is cleaner. This allows vars.Report to be used in the
the dnsserver to log refused queries.
middleware/metrics: tests
Add tests to the metrics framework. The metrics/test subpackage allows
scraping of the local server. Do a few test scrape of the metrics that
are defined in the metrics middleware.
This also allows metrics integration tests to check if the caching and
dnssec middleware export their metrics correctly.
* update README
* typos
* fix tests
This still needs cleanup, but this is a first pass the cleans some
cruft and documents our style (in middleware.md) and makes all the
docs match that style.
Rename: positive -> success
negative -> denial
There is a third (unused category) which is error. Start using these
new in the caching middleware and later in the logging middleware.
Make the cache memory bounded, by using a LRU cache. Also split the
cache in a positive and negative one - each with its own controls.
Extend the cache stanza to allow for this:
cache {
positive limit [ttl]
negative limit [ttl]
}
is now possible. This also add a cache_test.go in the toplevel test/
directory that exercises the caching path.
Fixes#260
* Add middleware/cache
Add a caching middleware that caches nxdomain, nodata and successful
responses. It differentiates between DNSSEC on normal DNS replies.
Each reply is compress and scrubbed so it will fit the specific client
asking for it.
* first simple test, less exporting of stuff
* more
* Add middleware/cache
Add a caching middleware that caches nxdomain, nodata and successful
responses. It differentiates between DNSSEC on normal DNS replies.
Each reply is compressed and scrubbed so it will fit the specific client
asking for it. The TTL is decremented with the time spend in the cache.
There is syntax that allows you to cap the TTL for all records, no
matter what. This allows for a shortlived cache, just to absorb query
peaks.
+Tests
* cache test infrastructure
* Testing
