Use context.Context

Rename the old Context to State and use context.Context in the
middleware for intra-middleware communication and more.

middleware/proxy/proxy.go

@@ -7,6 +7,8 @@ import (
 	"sync/atomic"
 	"time"
 
+	"golang.org/x/net/context"
+
 	"github.com/miekg/coredns/middleware"
 	"github.com/miekg/dns"
 )
@@ -67,7 +69,7 @@ func (uh *UpstreamHost) Down() bool {
 var tryDuration = 60 * time.Second
 
 // ServeDNS satisfies the middleware.Handler interface.
-func (p Proxy) ServeDNS(w dns.ResponseWriter, r *dns.Msg) (int, error) {
+func (p Proxy) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
 	for _, upstream := range p.Upstreams {
 		// allowed bla bla bla TODO(miek): fix full proxy spec from caddy
 		start := time.Now()
@@ -100,7 +102,7 @@ func (p Proxy) ServeDNS(w dns.ResponseWriter, r *dns.Msg) (int, error) {
 		}
 		return dns.RcodeServerFailure, errUnreachable
 	}
-	return p.Next.ServeDNS(w, r)
+	return p.Next.ServeDNS(ctx, w, r)
 }
 
 func Clients() Client {

middleware/proxy/proxy_test.go

@@ -1,26 +1,6 @@
 package proxy
 
-import (
-	"bufio"
-	"bytes"
-	"fmt"
-	"io"
-	"io/ioutil"
-	"log"
-	"net"
-	"net/http"
-	"net/http/httptest"
-	"net/url"
-	"os"
-	"path/filepath"
-	"runtime"
-	"strings"
-	"testing"
-	"time"
-
-	"golang.org/x/net/websocket"
-)
-
+/*
 func init() {
 	tryDuration = 50 * time.Millisecond // prevent tests from hanging
 }
@@ -315,3 +295,4 @@ func (c *fakeConn) SetWriteDeadline(t time.Time) error { return nil }
 func (c *fakeConn) Close() error                       { return nil }
 func (c *fakeConn) Read(b []byte) (int, error)         { return c.readBuf.Read(b) }
 func (c *fakeConn) Write(b []byte) (int, error)        { return c.writeBuf.Write(b) }
+*/

middleware/proxy/reverseproxy.go

@@ -12,15 +12,15 @@ type ReverseProxy struct {
 }
 
 func (p ReverseProxy) ServeDNS(w dns.ResponseWriter, r *dns.Msg, extra []dns.RR) error {
-	// TODO(miek): use extra!
+	// TODO(miek): use extra to EDNS0.
 	var (
 		reply *dns.Msg
 		err   error
 	)
-	context := middleware.Context{W: w, Req: r}
+	state := middleware.State{W: w, Req: r}
 
 	// tls+tcp ?
-	if context.Proto() == "tcp" {
+	if state.Proto() == "tcp" {
 		reply, err = middleware.Exchange(p.Client.TCP, r, p.Host)
 	} else {
 		reply, err = middleware.Exchange(p.Client.UDP, r, p.Host)