middleware/log: allows logging based on response classes (#325)

Add the ability to add a class of responses to be logged; success,
denial or error. The default is to log everything (all).

Fixes #258

middleware/cache/README.md

@@ -20,7 +20,7 @@ Or if you want more control:
 
 ~~~ txt
 cache [ttl] [zones...] {
-    noerror capacity [ttl]
+    success capacity [ttl]
     denial capacity [ttl]
 }
 ~~~

middleware/cache/cache.go

@@ -60,7 +60,7 @@ type ResponseWriter struct {
 // WriteMsg implements the dns.ResponseWriter interface.
 func (c *ResponseWriter) WriteMsg(res *dns.Msg) error {
 	do := false
-	mt, opt := response.Classify(res)
+	mt, opt := response.Typify(res)
 	if opt != nil {
 		do = opt.Do()
 	}
@@ -93,7 +93,7 @@ func (c *ResponseWriter) set(m *dns.Msg, key string, mt response.Type, duration
 	}
 
 	switch mt {
-	case response.Success, response.Delegation:
+	case response.NoError, response.Delegation:
 		i := newItem(m, duration)
 		c.pcache.Add(key, i)
 

middleware/cache/cache_test.go

@@ -94,7 +94,7 @@ func TestCache(t *testing.T) {
 		m = cacheMsg(m, tc)
 		do := tc.in.Do
 
-		mt, _ := response.Classify(m)
+		mt, _ := response.Typify(m)
 		k := key(m, mt, do)
 		crr.set(m, k, mt, c.pttl)
 

middleware/cache/item.go

@@ -87,7 +87,7 @@ func setMsgTTL(m *dns.Msg, ttl uint32) {
 }
 
 func minMsgTTL(m *dns.Msg, mt response.Type) time.Duration {
-	if mt != response.Success && mt != response.NameError && mt != response.NoData {
+	if mt != response.NoError && mt != response.NameError && mt != response.NoData {
 		return 0
 	}
 
@@ -98,7 +98,7 @@ func minMsgTTL(m *dns.Msg, mt response.Type) time.Duration {
 			if r.Header().Rrtype == dns.TypeSOA {
 				return time.Duration(r.(*dns.SOA).Minttl) * time.Second
 			}
-		case response.Success, response.Delegation:
+		case response.NoError, response.Delegation:
 			if r.Header().Ttl < uint32(minTTL.Seconds()) {
 				minTTL = time.Duration(r.Header().Ttl) * time.Second
 			}