plugin/cache: key cache on Checking Disabled (CD) bit (#6354)

* plugin/cache: key cache on Checking Disabled (CD) bit

Key the cache on CD bit, which effectively separates the entries for
queries with CD disabled or enabled.

Signed-off-by: Grant Spence <gspence@redhat.com>

1 files changed, 0 insertions, 163 deletions

diff --git a/plugin/cache/prefech_test.go b/plugin/cache/prefech_test.go
deleted file mode 100644
index 609956ee9..000000000
--- a/plugin/cache/prefech_test.go
+++ /dev/null
@@ -1,163 +0,0 @@
-package cache
-
-import (
-	"context"
-	"fmt"
-	"testing"
-	"time"
-
-	"github.com/coredns/coredns/plugin"
-	"github.com/coredns/coredns/plugin/pkg/dnstest"
-	"github.com/coredns/coredns/plugin/test"
-
-	"github.com/miekg/dns"
-)
-
-func TestPrefetch(t *testing.T) {
-	tests := []struct {
-		qname         string
-		ttl           int
-		prefetch      int
-		verifications []verification
-	}{
-		{
-			qname:    "hits.reset.example.org.",
-			ttl:      80,
-			prefetch: 1,
-			verifications: []verification{
-				{
-					after:  0 * time.Second,
-					answer: "hits.reset.example.org. 80 IN A 127.0.0.1",
-					fetch:  true,
-				},
-				{
-					after:  73 * time.Second,
-					answer: "hits.reset.example.org.  7 IN A 127.0.0.1",
-					fetch:  true,
-				},
-				{
-					after:  80 * time.Second,
-					answer: "hits.reset.example.org. 73 IN A 127.0.0.2",
-				},
-			},
-		},
-		{
-			qname:    "short.ttl.example.org.",
-			ttl:      5,
-			prefetch: 1,
-			verifications: []verification{
-				{
-					after:  0 * time.Second,
-					answer: "short.ttl.example.org. 5 IN A 127.0.0.1",
-					fetch:  true,
-				},
-				{
-					after:  1 * time.Second,
-					answer: "short.ttl.example.org. 4 IN A 127.0.0.1",
-				},
-				{
-					after:  4 * time.Second,
-					answer: "short.ttl.example.org. 1 IN A 127.0.0.1",
-					fetch:  true,
-				},
-				{
-					after:  5 * time.Second,
-					answer: "short.ttl.example.org. 4 IN A 127.0.0.2",
-				},
-			},
-		},
-		{
-			qname:    "no.prefetch.example.org.",
-			ttl:      30,
-			prefetch: 0,
-			verifications: []verification{
-				{
-					after:  0 * time.Second,
-					answer: "no.prefetch.example.org. 30 IN A 127.0.0.1",
-					fetch:  true,
-				},
-				{
-					after:  15 * time.Second,
-					answer: "no.prefetch.example.org. 15 IN A 127.0.0.1",
-				},
-				{
-					after:  29 * time.Second,
-					answer: "no.prefetch.example.org.  1 IN A 127.0.0.1",
-				},
-				{
-					after:  30 * time.Second,
-					answer: "no.prefetch.example.org. 30 IN A 127.0.0.2",
-					fetch:  true,
-				},
-			},
-		},
-	}
-
-	t0, err := time.Parse(time.RFC3339, "2018-01-01T14:00:00+00:00")
-	if err != nil {
-		t.Fatal(err)
-	}
-	for _, tt := range tests {
-		t.Run(tt.qname, func(t *testing.T) {
-			fetchc := make(chan struct{}, 1)
-
-			c := New()
-			c.prefetch = tt.prefetch
-			c.Next = prefetchHandler(tt.qname, tt.ttl, fetchc)
-
-			req := new(dns.Msg)
-			req.SetQuestion(tt.qname, dns.TypeA)
-			rec := dnstest.NewRecorder(&test.ResponseWriter{})
-
-			for _, v := range tt.verifications {
-				c.now = func() time.Time { return t0.Add(v.after) }
-
-				c.ServeDNS(context.TODO(), rec, req)
-				if v.fetch {
-					select {
-					case <-fetchc:
-						if !v.fetch {
-							t.Fatalf("After %s: want request to trigger a prefetch", v.after)
-						}
-					case <-time.After(time.Second):
-						t.Fatalf("After %s: want request to trigger a prefetch", v.after)
-					}
-				}
-				if want, got := rec.Rcode, dns.RcodeSuccess; want != got {
-					t.Errorf("After %s: want rcode %d, got %d", v.after, want, got)
-				}
-				if want, got := 1, len(rec.Msg.Answer); want != got {
-					t.Errorf("After %s: want %d answer RR, got %d", v.after, want, got)
-				}
-				if want, got := test.A(v.answer).String(), rec.Msg.Answer[0].String(); want != got {
-					t.Errorf("After %s: want answer %s, got %s", v.after, want, got)
-				}
-			}
-		})
-	}
-}
-
-type verification struct {
-	after  time.Duration
-	answer string
-	// fetch defines whether a request is sent to the next handler.
-	fetch bool
-}
-
-// prefetchHandler is a fake plugin implementation which returns a single A
-// record with the given qname and ttl. The returned IP address starts at
-// 127.0.0.1 and is incremented on every request.
-func prefetchHandler(qname string, ttl int, fetchc chan struct{}) plugin.Handler {
-	i := 0
-	return plugin.HandlerFunc(func(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
-		i++
-		m := new(dns.Msg)
-		m.SetQuestion(qname, dns.TypeA)
-		m.Response = true
-		m.Answer = append(m.Answer, test.A(fmt.Sprintf("%s %d IN A 127.0.0.%d", qname, ttl, i)))
-
-		w.WriteMsg(m)
-		fetchc <- struct{}{}
-		return dns.RcodeSuccess, nil
-	})
-}