* perf(proxy): use mutex-based connection pool
The proxy package (used for example by the forward plugin) utilized
an actor model where a single connManager goroutine managed
connection pooling via unbuffered channels (dial, yield, ret). This
design serialized all connection acquisition and release operations
through a single goroutine, creating a bottleneck under high
concurrency. This was observable as a performance degradation when
using a single upstream backend compared to multiple backends
(which sharded the bottleneck).
Changes:
- Removed dial, yield, and ret channels from the Transport struct.
- Removed the connManager goroutine's request processing loop.
- Implemented Dial() and Yield() using a sync.Mutex to protect the
connection slice, allowing for fast concurrent access without
context switching.
- Downgraded connManager to a simple background cleanup loop that
only handles connection expiration on a ticker.
- Updated plugin/pkg/proxy/connect.go to use direct method calls
instead of channel sends.
- Updated tests to reflect the removal of internal channels.
Benchmarks show that this change eliminates the single-backend
bottleneck. Now a single upstream backend performs on par with
multiple backends, and overall throughput is improved.
The implementation aligns with standard Go patterns for connection
pooling (e.g., net/http.Transport).
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* fix: address PR review for persistent.go
- Named mutex field instead of embedding, to not expose
Lock() and Unlock()
- Move stop check outside of lock in Yield()
- Close() without a separate goroutine
- Change stop channel to struct
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* fix: address code review feedback for conn pool
- Switch from LIFO to FIFO connection selection for source port
diversity, reducing DNS cache poisoning risk (RFC 5452).
- Remove "clear entire cache" optimization as it was LIFO-specific.
FIFO naturally iterates and skips expired connections.
- Remove all goroutines for closing connections; collect connections
while holding lock, close synchronously after releasing lock.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* fix: remove unused error consts
No longer utilised after refactoring the channel based approach.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* feat(forward): add max_idle_conns option
Add configurable connection pool limit for the forward plugin via
the max_idle_conns Corefile option.
Changes:
- Add SetMaxIdleConns to proxy
- Add maxIdleConns field to Forward struct
- Add max_idle_conns parsing in forward plugin setup
- Apply setting to each proxy during configuration
- Update forward plugin README with new option
By default the value is 0 (unbounded). When set, excess
connections returned to the pool are closed immediately
rather than cached.
Also add a yield related test.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* chore(proxy): simple Dial by closing conns inline
Remove toClose slice collection to reduce complexity. Instead close
expired connections directly while iterating. Reduces complexity with
negligible lock-time impact.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* chore: fewer explicit Unlock calls
Cleaner and less chance of forgetting to unlock on new possible
code paths.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
---------
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
Enable intrange linter to enforce modern Go range syntax over
traditional for loops, by converting:
for i := 0; i < n; i++
to:
for i := range n
Adding type conversions where needed for compatibility
with existing uint64 parameters.
Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
* Default to upstream to self
This is a backwards incompatible change.
This is a massive (cleanup) PR where we default to resolving external
names by the coredns process itself, instead of directly forwarding them
to some upstream.
This ignores any arguments `upstream` may have had and makes it depend
on proxy/forward configuration in the Corefile. This allows resolved
upstream names to be cached and we have better healthchecking of the
upstreams. It also means there is only one way to resolve names, by
either using the proxy or forward plugin.
The proxy/forward lookup.go functions have been removed. This also
lessen the dependency on proxy, meaning deprecating proxy will become
easier. Some tests have been removed as well, or moved to the top-level
test directory as they now require a full coredns process instead of
just the plugin.
For the etcd plugin, the entire StubZone resolving is *dropped*! This
was a hacky (but working) solution to say the least. If someone cares
deeply it can be brought back (maybe)?
The pkg/upstream is now very small and almost does nothing. Also the
New() function was changed to return a pointer to upstream.Upstream. It
also returns only one parameter, so any stragglers using it will
encounter a compile error.
All documentation has been adapted. This affected the following plugins:
* etcd
* file
* auto
* secondary
* federation
* template
* route53
A followup PR will make any upstream directives with arguments an error,
right now they are ignored.
Signed-off-by: Miek Gieben <miek@miek.nl>
* Fix etcd build - probably still fails unit test
Signed-off-by: Miek Gieben <miek@miek.nl>
* Slightly smarter lookup check in upstream
Signed-off-by: Miek Gieben <miek@miek.nl>
* Compilez
Signed-off-by: Miek Gieben <miek@miek.nl>
* Clean up tests logging
This cleans up the travis logs so you can see the failures better.
Older tests in tests/ would call log.SetOutput(ioutil.Discard) in
a haphazard way. This add log.Discard and put an `init` function in each
package's dir (no way to do this globally). The cleanup in tests/ is
clear.
All plugins also got this init function to have some uniformity and kill
any (future) logging there in the tests as well.
There is a one-off in pkg/healthcheck because that does log.
Signed-off-by: Miek Gieben <miek@miek.nl>
* bring back original log_test.go
Signed-off-by: Miek Gieben <miek@miek.nl>
* suppress logging here as well
Signed-off-by: Miek Gieben <miek@miek.nl>
* 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
* tests: CoreDNSServerAndPorts
Copy from kubernetes.go and renamed to fit the style, adapted almost
all callers.
This is a mechanicl change, no testdata was changed.
* typos
* add proxy tcp
* add truncated for tcp to udp response
* move truncation to scrubbing
* add test that executes upstream over tcp
* middleware/proxy: some tweaks
rename force-tcp to force_tcp to be inline with the rest and use
a dnsOptions struct to put the options in to allow it to be extended.
Add some parse tests as well.
* Fix test and rename dnsOptions Options
* core: add listening for other protocols
Allow CoreDNS to listen for TLS request coming over port 853. This can
be enabled with `tls://` in the config file.
Implement listening for grps:// as well.
a Corefile like:
~~~
. tls://.:1853 {
whoami
tls
}
~~~
Means we listen on 1853 for tls requests, the `tls` config item allows
configuration for TLS parameters. We *might* be tempted to use Caddy's
Let's Encrypt implementation here.
* Refactor coredns/grpc into CoreDNS
This makes gRPC a first class citizen in CoreDNS. Add defines as being
just another server.
* some cleanups
* unexport the servers
* Move protobuf dir
* Hook up TLS properly
* Fix test
* listen for TLS as well. README updates
* disable test, fix package
* fix test
* Fix tests
* Fix remaining test
* Some tests
* Make the test work
* Add grpc test from #580
* fix crash
* Fix tests
* Close conn
* README cleanups
* README
* link RFC
By defining and using an proxy.Exchanger interface we make the proxy
more generic and we can then fold back httproxy into proxy.
This overrides #463 and #473 and should make futures extensions rather
trivial
* Add docs that talk about `protocol` and how to set it.
* middleware/proxy: rename New to NewLookup
It's used as a Lookup mechanism not as a completely new proxy,
reflect that in the name.
* Set maxfails to 3 by default when looking up names.
Most of the changes have been copied
from https://github.com/johnbelamaric/coredns/pull/1/files
Create a small speedup running the tests:
PASS
ok github.com/miekg/coredns/test 10.329s
PASS
ok github.com/miekg/coredns/test 6.079s
Skip the etcd ones. Doing the middleware/*/*_test ones doesn't yield
any speedup as these are still done on a per directory basis.
* middleware/proxy
Use connection pooling for communicating with an upstream, instead of
opening a new socket every time.
This makes the proxy more efficient and allowed for some cleanups.
* Some cleanups
* Some fixes
* more
* Kill pool
* Add nil check
* remove pool
* Add a setup test for middleware/file
This fix adds a setup test for middleware/file so that there is
a basic coverage for the Corefile processing of middleware/file.
This fix is related to 308 (Will look into it).
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>
* middleware/file: use helper function for test
Fixup setup_test.go and use the test.TempFile function to make things
somewhat shorter.
Use clean up the use of testing.T in TempFile - it is not used.
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
Cleanup the errors and removed deadcode along the way. The leaves
some error laying around, mostly about commenting exported identifier.
We should look hard if those really are needed.
Move all (almost all) Go files in middleware into their
own packages. This makes for better naming and discoverability.
Lot of changes elsewhere to make this change.
The middleware.State was renamed to request.Request which is better,
but still does not cover all use-cases. It was also moved out middleware
because it is used by `dnsserver` as well.
A pkg/dnsutil packages was added for shared, handy, dns util functions.
All normalize functions are now put in normalize.go
* Set version to 001
* Remove k8stest, test fails is k8s is not there: touch luck
* Remove server directory: not used anymore
* Disable k8s test (for now)
* gometalinter changes
* Make CoreDNS a server type plugin for Caddy
Remove code we don't need and port all middleware over. Fix all tests
and rework the documentation.
Also make `go generate` build a caddy binary which we then copy into
our directory. This means `go build`-builds remain working as-is.
And new etc instances in each etcd test for better isolation.
Fix more tests and rework test.Server with the newer support Caddy offers.
Fix Makefile to support new mode of operation.
