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middleware/proxy: make it scale (#287)

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* 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
This commit is contained in:
Miek Gieben
2016-10-08 14:46:22 +01:00
committed by GitHub
parent f29f622ec7
commit a05901f62a
9 changed files with 159 additions and 388 deletions
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29
middleware/proxy/lookup.go
View File

@@ -1,7 +1,6 @@
package proxy
// functions OTHER middleware might want to use to do lookup in the same
// style as the proxy.
// functions other middleware might want to use to do lookup in the same style as the proxy.
import (
"sync/atomic"
@@ -14,7 +13,7 @@ import (
// New create a new proxy with the hosts in host and a Random policy.
func New(hosts []string) Proxy {
p := Proxy{Next: nil, Client: Clients()}
p := Proxy{Next: nil, Client: NewClient()}
upstream := &staticUpstream{
from: "",
@@ -31,7 +30,8 @@ func New(hosts []string) Proxy {
Conns: 0,
Fails: 0,
FailTimeout: upstream.FailTimeout,
Unhealthy: false,
Unhealthy: false,
CheckDown: func(upstream *staticUpstream) UpstreamHostDownFunc {
return func(uh *UpstreamHost) bool {
if uh.Unhealthy {
@@ -54,7 +54,6 @@ func New(hosts []string) Proxy {
// Lookup will use name and type to forge a new message and will send that upstream. It will
// set any EDNS0 options correctly so that downstream will be able to process the reply.
// Lookup is not suitable for forwarding request. Ssee for that.
func (p Proxy) Lookup(state request.Request, name string, tpe uint16) (*dns.Msg, error) {
req := new(dns.Msg)
req.SetQuestion(name, tpe)
@@ -63,18 +62,13 @@ func (p Proxy) Lookup(state request.Request, name string, tpe uint16) (*dns.Msg,
return p.lookup(state, req)
}
// Forward will forward the request to upstream
// Forward forward the request in state as-is. Unlike Lookup that adds EDNS0 suffix to the message.
func (p Proxy) Forward(state request.Request) (*dns.Msg, error) {
return p.lookup(state, state.Req)
}
func (p Proxy) lookup(state request.Request, r *dns.Msg) (*dns.Msg, error) {
var (
reply *dns.Msg
err error
)
for _, upstream := range p.Upstreams {
// allowed bla bla bla TODO(miek): fix full proxy spec from caddy?
start := time.Now()
// Since Select() should give us "up" hosts, keep retrying
@@ -85,15 +79,16 @@ func (p Proxy) lookup(state request.Request, r *dns.Msg) (*dns.Msg, error) {
return nil, errUnreachable
}
// duplicated from proxy.go, but with a twist, we don't write the
// reply back to the client, we return it.
atomic.AddInt64(&host.Conns, 1)
if state.Proto() == "tcp" {
reply, _, err = p.Client.TCP.Exchange(r, host.Name)
} else {
reply, _, err = p.Client.UDP.Exchange(r, host.Name)
}
reply, backendErr := p.Client.ServeDNS(state.W, r, host)
atomic.AddInt64(&host.Conns, -1)
if err == nil {
if backendErr == nil {
return reply, nil
}
timeout := host.FailTimeout