plugin/forward: Allow Proxy to be used outside of forward plugin. (#5951)

* plugin/forward: Move Proxy into pkg/plugin/proxy, to allow forward.Proxy to be used outside of forward plugin.

Signed-off-by: Patrick Downey <patrick.downey@dioadconsulting.com>

plugin/pkg/proxy/persistent_test.go

@@ -0,0 +1,109 @@
+package proxy
+
+import (
+	"testing"
+	"time"
+
+	"github.com/coredns/coredns/plugin/pkg/dnstest"
+
+	"github.com/miekg/dns"
+)
+
+func TestCached(t *testing.T) {
+	s := dnstest.NewServer(func(w dns.ResponseWriter, r *dns.Msg) {
+		ret := new(dns.Msg)
+		ret.SetReply(r)
+		w.WriteMsg(ret)
+	})
+	defer s.Close()
+
+	tr := newTransport(s.Addr)
+	tr.Start()
+	defer tr.Stop()
+
+	c1, cache1, _ := tr.Dial("udp")
+	c2, cache2, _ := tr.Dial("udp")
+
+	if cache1 || cache2 {
+		t.Errorf("Expected non-cached connection")
+	}
+
+	tr.Yield(c1)
+	tr.Yield(c2)
+	c3, cached3, _ := tr.Dial("udp")
+	if !cached3 {
+		t.Error("Expected cached connection (c3)")
+	}
+	if c2 != c3 {
+		t.Error("Expected c2 == c3")
+	}
+
+	tr.Yield(c3)
+
+	// dial another protocol
+	c4, cached4, _ := tr.Dial("tcp")
+	if cached4 {
+		t.Errorf("Expected non-cached connection (c4)")
+	}
+	tr.Yield(c4)
+}
+
+func TestCleanupByTimer(t *testing.T) {
+	s := dnstest.NewServer(func(w dns.ResponseWriter, r *dns.Msg) {
+		ret := new(dns.Msg)
+		ret.SetReply(r)
+		w.WriteMsg(ret)
+	})
+	defer s.Close()
+
+	tr := newTransport(s.Addr)
+	tr.SetExpire(100 * time.Millisecond)
+	tr.Start()
+	defer tr.Stop()
+
+	c1, _, _ := tr.Dial("udp")
+	c2, _, _ := tr.Dial("udp")
+	tr.Yield(c1)
+	time.Sleep(10 * time.Millisecond)
+	tr.Yield(c2)
+
+	time.Sleep(120 * time.Millisecond)
+	c3, cached, _ := tr.Dial("udp")
+	if cached {
+		t.Error("Expected non-cached connection (c3)")
+	}
+	tr.Yield(c3)
+
+	time.Sleep(120 * time.Millisecond)
+	c4, cached, _ := tr.Dial("udp")
+	if cached {
+		t.Error("Expected non-cached connection (c4)")
+	}
+	tr.Yield(c4)
+}
+
+func TestCleanupAll(t *testing.T) {
+	s := dnstest.NewServer(func(w dns.ResponseWriter, r *dns.Msg) {
+		ret := new(dns.Msg)
+		ret.SetReply(r)
+		w.WriteMsg(ret)
+	})
+	defer s.Close()
+
+	tr := newTransport(s.Addr)
+
+	c1, _ := dns.DialTimeout("udp", tr.addr, maxDialTimeout)
+	c2, _ := dns.DialTimeout("udp", tr.addr, maxDialTimeout)
+	c3, _ := dns.DialTimeout("udp", tr.addr, maxDialTimeout)
+
+	tr.conns[typeUDP] = []*persistConn{{c1, time.Now()}, {c2, time.Now()}, {c3, time.Now()}}
+
+	if len(tr.conns[typeUDP]) != 3 {
+		t.Error("Expected 3 connections")
+	}
+	tr.cleanup(true)
+
+	if len(tr.conns[typeUDP]) > 0 {
+		t.Error("Expected no cached connections")
+	}
+}