plugin/forward: fix broken tap plugins when dnstap plugins specified (#5890)

* plugin/forward: fix broken tap plugins when dnstap plugins specified

---------

Signed-off-by: Gerhard Tan <gwohau.tan@gmail.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/plugin/forward/forward_test.go b/plugin/forward/forward_test.go
index b0ef47ba9..b50f4ff22 100644
--- a/plugin/forward/forward_test.go
+++ b/plugin/forward/forward_test.go
@@ -1,7 +1,13 @@
 package forward
 
 import (
+	"strings"
 	"testing"
+
+	"github.com/coredns/caddy"
+	"github.com/coredns/caddy/caddyfile"
+	"github.com/coredns/coredns/core/dnsserver"
+	"github.com/coredns/coredns/plugin/dnstap"
 )
 
 func TestList(t *testing.T) {
@@ -22,3 +28,39 @@ func TestList(t *testing.T) {
 		}
 	}
 }
+
+func TestSetTapPlugin(t *testing.T) {
+	input := `forward . 127.0.0.1
+	dnstap /tmp/dnstap.sock full
+	dnstap tcp://example.com:6000
+	`
+	stanzas := strings.Split(input, "\n")
+	c := caddy.NewTestController("dns", strings.Join(stanzas[1:], "\n"))
+	dnstapSetup, err := caddy.DirectiveAction("dns", "dnstap")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err = dnstapSetup(c); err != nil {
+		t.Fatal(err)
+	}
+	c.Dispenser = caddyfile.NewDispenser("", strings.NewReader(stanzas[0]))
+	if err = setup(c); err != nil {
+		t.Fatal(err)
+	}
+	dnsserver.NewServer("", []*dnsserver.Config{dnsserver.GetConfig(c)})
+	f, ok := dnsserver.GetConfig(c).Handler("forward").(*Forward)
+	if !ok {
+		t.Fatal("Expected a forward plugin")
+	}
+	tap, ok := dnsserver.GetConfig(c).Handler("dnstap").(*dnstap.Dnstap)
+	if !ok {
+		t.Fatal("Expected a dnstap plugin")
+	}
+	f.SetTapPlugin(tap)
+	if len(f.tapPlugins) != 2 {
+		t.Fatalf("Expected: 2 results, got: %v", len(f.tapPlugins))
+	}
+	if f.tapPlugins[0] != tap || tap.Next != f.tapPlugins[1] {
+		t.Error("Unexpected order of dnstap plugins")
+	}
+}