Not sure why this is proving so difficult.. pointers are hard? [Was
tempted to rollback all tweaks here, but the original issue we're fixing
it too important to not have a proper fix].
But we need to make a copy of the message at the earliest point in the
handler because we are changing it (adding an opt rr). If we do this on
the original message (which is a pointer) we change it (obvs). When
undoing those changes we do work on a copy.
Re: testing. There isn't a explicit test for this, so I've added on to
the top-level test/ directory, which indeed makes the issue visible:
master:
~~~
go test -v -run=TestLookupCacheWithoutEdns
=== RUN TestLookupCacheWithoutEdns
cache_test.go:154: Expected no OPT RR, but got:
;; OPT PSEUDOSECTION:
; EDNS: version 0; flags: do; udp: 2048
--- FAIL: TestLookupCacheWithoutEdns (0.01s)
FAIL
~~~
This branch:
~~~
% go test -v -run=TestLookupCacheWithoutEdns
=== RUN TestLookupCacheWithoutEdns
--- PASS: TestLookupCacheWithoutEdns (0.01s)
PASS
ok github.com/coredns/coredns/test 0.109s
~~~
Signed-off-by: Miek Gieben <miek@miek.nl>
By checking state.Do() were are checking if the request had DO, but
we are _always_ adding Do now - do we need to save the DO from the
ORIGINAL request, which must be done in the ResponseWriter.
Also skip OPT records in filterDNSSEC as we can't set the TTL on those
records, this prevents writing a number to OPT's MBZ.
Note none of the tests have changed and still PASS. This is due to
the fact that CoreDNSServerAndPorts isn't a full server as we start in
main, it lacks the scrubwriter for instance. This is not bad per se, but
should be documented in the test code.
Signed-off-by: Miek Gieben <miek@miek.nl>
* cache: default to DNSSEC
This change does away with the DNS/DNSSEC distinction the cache
currently makes. Cache will always make coredns perform a DNSSEC query
and store that result. If a client just needs plain DNS, the DNSSEC
records are stripped from the response.
It should also be more memory efficient, because we store a reply once
and not one DNS and another for DNSSEC.
Fixes: #3836
Signed-off-by: Miek Gieben <miek@miek.nl>
* Change OPT RR when one is present in the msg.
Signed-off-by: Miek Gieben <miek@miek.nl>
* Fix comment for isDNSSEC
Signed-off-by: Miek Gieben <miek@miek.nl>
* Update plugin/cache/handler.go
Co-authored-by: Chris O'Haver <cohaver@infoblox.com>
* Update plugin/cache/item.go
Co-authored-by: Chris O'Haver <cohaver@infoblox.com>
* Code review; fix comment for isDNSSEC
Signed-off-by: Miek Gieben <miek@miek.nl>
* Update doc and set AD to false
Set Authenticated Data to false when DNSSEC was not wanted. Also update
the readme with the new behavior.
Signed-off-by: Miek Gieben <miek@miek.nl>
* Update plugin/cache/handler.go
Co-authored-by: Chris O'Haver <cohaver@infoblox.com>
Co-authored-by: Chris O'Haver <cohaver@infoblox.com>
* - ensure plugins that use prometheus.MustRegister, re-register after reload
- removing once.Do on the startup function was simplest way to do it.
* - fix underscored names (advice of bot)
* - tune existing UT for reload, and add a test verifying failing reload does not prevent correct registering for metrics
* - ensure different ports for tests that can run in same time ..
Every plugin needs to deal with EDNS0 and should call Scrub to make a
message fit the client's buffer. Move this functionality into the server
and wrapping the ResponseWriter into a ScrubWriter that handles these
bits for us. Result:
Less code and faster, because multiple chained plugins could all be
calling scrub and SizeAndDo - now there is just one place.
Most tests in file/* and dnssec/* needed adjusting because in those unit
tests you don't see OPT RRs anymore. The DNSSEC signer was also looking
at the returned OPT RR to see if it needed to sign - as those are now
added by the server (and thus later), this needed to change slightly.
Scrub itself still exist (for backward compat reasons), but has been
made a noop. Scrub has been renamed to scrub as it should not be used by
external plugins.
Fixes: #2010
Signed-off-by: Miek Gieben <miek@miek.nl>
The default dns.Response implementation of a dns.ResponseWriter will
panic if RemoteAddr() is called after the connection to the client has
been closed already. The current cache implementation doesn't create a
new request+responsewriter during an asynchronous prefetch, but
piggybacks on the request triggering the prefetch.
This change copies the RemoteAddr first, so that it's safe to use it
later during the actual prefetch request.
A better implementation would be to completely decouple the prefetch
request from the client triggering a request.
* plugin/cache: per server metrics
Use per server metrics in the cache plugin as well. This required
some plumbing changes. Also use request.Request more.
* fix cherry-pick
* global: move to context
Move from golang.org/x/net/context to std lib's context.
Change done with:
for i in $(grep -l '/context' **/*.go); do sed -e 's|golang.org/x/net/context|context|' -i $i; echo $i; done
for i in **/*.go; do goimports -w $i; done
* drop from dns.pb.go as well
* plugin/{cache,forward,proxy}: don't allow responses that are bogus
Responses that are not matching what we've been querying for should be
dropped. They are converted into FormErrs by forward and proxy; as a 2nd
backstop cache will also not cache these.
* plug
* add explicit test
* Improve plugin/cache metrics
* Add coredns_cache_prefetch_total metric to track number of prefetches.
* Remove unnecessary Cache.get() call which would incorrectly increment
cache counters.
* Initialize all counters and gauges at zero.
* Allow prefetching of a single request per ttl
The original implementation didn't allow prefetching queries which are
only requested once during the duration of a TTL. The minimum amount of
queries which had to be seen was therefore capped at 2.
This change also implements a real prefetch test. The existing test was
a noop and always passed regardless of any prefetch implementation.
* Fix prefetching for items with a short TTL
The default prefetch threshold (percentage) is 10% of the lifetime of a
cache item. With the previous implementation, this disabled prefetching
for all items with a TTL < 10s (the resulting percentage would be 0, at
which point a cached item is already discarded).
This change uses a time based threshold calculation and ensures that
a prefetch is triggered at a TTL of 1 at the latest.
* Fix wrong duration reporting of cached responses
The logging and metrics plugins (among others) included the duration of
a cache prefetch in the request latency of client request. This change
fixes this wrong reporting and executes the prefetch request in a
goroutine in the background.
After initial startup, see if prometheus is loaded and if so, register
our metrics with it.
Stop doing the init() func and just use the sync.Once so we don't double
registrer our metrics.
Cache would let the first response through and would then cap subsequent
ones to whatever the cache duration was. This would lead to huge drops
in TTL values: 3600 -> 20 for instance, which is not only bad, but can
mess up your careful TTL planning business.
This PR fixes that and applies the cache duration to all replies. As a
bonus I could remove a time.Sleep() from the cache test and just check
for the cache duration as the TTL on the reply.
Fixes#1038
* Rename middleware to plugin
first pass; mostly used 'sed', few spots where I manually changed
text.
This still builds a coredns binary.
* fmt error
* Rename AddMiddleware to AddPlugin
* Readd AddMiddleware to remain backwards compat
2017-09-14 09:36:06 +01:00
Renamed from middleware/cache/handler.go (Browse further)
