As plugin/proxy always returns compressed messages, it's important to
set this before calling Scrub(), as some messages will be unnecessarily
truncated otherwise.

HTTP healthchecking will be implicitely activated for proxy upstream
hosts, even if not configured. The README states that not using the
health_check directive will disable HTTP healthchecks though.

It seems to me that the availability of the HealthCheck.Path attribute
is used as indicator whether HTTP healthchecks should be used or not.
The normalizeCheckURL() function didn't check that attribute though,
always returning a CheckURL. This would increase the healthcheck failure
on every third failure in plugin/proxy, without any possibility for the
upstream host to be marked as healthy again. This would eventually
remove all upstream hosts from the serving pool.

This adds the inital top-level OWNERS file. Each plugin should also get
one, but that will be more work.

Ref: #1454

Golint fix to make goreportcard happy
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

This fix uses external context package for server-tls.go
This fix is a follow up to 1468.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

This was used for docker automation or someting?
I don't think there are uses for this, lets remove it.

With Go 1.9 you *can* include the std lib's context package and nothing
breaks. However we never officially made the move (and grpc also doesn't
ues the std lib's one).

Standardize all plugins on using the extern context package.

Fixes #1466

Let caddyfile parser give us the token, the comma sep thing also didn't
work.

Fixes #1446

* plugin.md updates

Talk about return code, logging and other bits.

Also checked the code for fmt.Printf logging, there is none.

Fixes #1449 #1450

* review

* more typos

* Add reload directive

* gofmt

* Fix default jitter and error message

* remove unneeded call to NextArg, add a couple negative setup tests

* Review feedback

* testpr3

* hack

* chop

* tolerate coredns/coredns get fail

* remove TEST from readme

Last release I forgot steps, put them in Makefile.release. Generating
the manual files will be skipped if 'ronn' can't be found.

* Enable forward

* Regen all docs

CoreVersion needs to be documented for golint, but we can't use too much
text because we grep this file for the coredns version.

* move flag blacklisting to main

Doing it in init() is the wrong place or something else changed. Doing
it in main() makes it easy to see *when* this happens.

* keep trapsignals

* plugin/forward: add out of tree forward plugin

This is a simpler proxy than *proxy*, include by default so it is easier
to switch (i.e. no recompile). It lacks features compared to proxy (did I
say it was simpler), but does cache udp and tcp connection, so it is
faster than proxy.

* Muck with the makefile

* Versioning forward now

Enable this Caddy plugin by default. Docs will go up coredns.io for this
as well.

See https://caddyserver.com/docs/on

These test cases became invalid with the fix of message truncation and
don't validate anything.

* Fix truncation of messages longer than permitted by the client

CoreDNS currently doesn't respect the maximum response size advertised
by the client and returns the full answer on a message with the TC bit
set. This breaks client implementations which rely on DNS servers
respecting the advertised size limit, for example the Ruby stdlib
client. It also has negative network performance implications, as large
messages will be split up into multiple UDP packets, even though the
client will discard the truncated response anyway.

While RFC 2181 permits the response of partial RRSets, finding the
correct number of records fitting into the advertised response size is
non-trivial. As clients should ignore truncated messages, this change
simply removes the full RRSet on truncated messages.

* Remove incorrect etcd test assertion

If a client requests a TXT record larger than its advertised buffer
size, a DNS server should _not_ respond with the answer, but truncate
the message and set the TC bit, so that the client can retry using TCP.

In order to track the rollout status of CoreDNS versions, add the common
build_info metric.

See #1400 and the discussion in that bug.

Fixes #1400

Fix the error handling. Log when we have an error during any of the
transfer state. And if there isn't an error transfer the zones.

Also fix the tests in test/ so we, at least, check the initial transfer.

Update the docs to show more about how errors are handled.

Ref #1400

Ignore most of the source code - this should lead to smaller docker
images.

Due to the one-off nature of releases 1.0.4 we need to manually bump
the version in master.

Resolves: #1313

* plugin/dnssec: filter bitmap also for NXDOMAIN responses

We change nxdomain to nodata, so at the point when we receive the
reply it can be nxdomain or nodata. In both cases we should filter the
nsec bitmap.

Change the code and add explicit tests for this.

* More tests

* plugin/health: add lameduck mode

Add a way to configure lameduck more, i.e. set health to false, stop
polling plugins. Then wait for a duration before shutting down. As the
health middleware is configured early on in the plugin list, it will
hold up all other shutdown, meaning we still answer queries.

* Add New

* More tests

* golint

* remove confusing text

* plugin/dnssec: check validityperiod of RRSIGs

Somehow we missed implementing this. If a sig a retrieved from the
cache, but not valid anymore, regenerate it instead of server invalid
signatures.

Fixes #1378

* drop from cache after 3/4 validity

* six days means 6 days

* 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.