Cleanup: put middleware helper functions in pkgs (#245)

Move all (almost all) Go files in middleware into their
own packages. This makes for better naming and discoverability.

Lot of changes elsewhere to make this change.

The middleware.State was renamed to request.Request which is better,
but still does not cover all use-cases. It was also moved out middleware
because it is used by `dnsserver` as well.

A pkg/dnsutil packages was added for shared, handy, dns util functions.

All normalize functions are now put in normalize.go

1 files changed, 16 insertions, 15 deletions

diff --git a/middleware/cache/cache.go b/middleware/cache/cache.go
index fd804d445..bd29a815c 100644
--- a/middleware/cache/cache.go
+++ b/middleware/cache/cache.go
@@ -6,6 +6,7 @@ import (
 	"time"
 
 	"github.com/miekg/coredns/middleware"
+	"github.com/miekg/coredns/middleware/pkg/response"
 
 	"github.com/miekg/dns"
 	gcache "github.com/patrickmn/go-cache"
@@ -23,7 +24,7 @@ func NewCache(ttl int, zones []string, next middleware.Handler) Cache {
 	return Cache{Next: next, Zones: zones, cache: gcache.New(defaultDuration, purgeDuration), cap: time.Duration(ttl) * time.Second}
 }
 
-func cacheKey(m *dns.Msg, t middleware.MsgType, do bool) string {
+func cacheKey(m *dns.Msg, t response.Type, do bool) string {
 	if m.Truncated {
 		return ""
 	}
@@ -31,15 +32,15 @@ func cacheKey(m *dns.Msg, t middleware.MsgType, do bool) string {
 	qtype := m.Question[0].Qtype
 	qname := strings.ToLower(m.Question[0].Name)
 	switch t {
-	case middleware.Success:
+	case response.Success:
 		fallthrough
-	case middleware.Delegation:
+	case response.Delegation:
 		return successKey(qname, qtype, do)
-	case middleware.NameError:
+	case response.NameError:
 		return nameErrorKey(qname, do)
-	case middleware.NoData:
+	case response.NoData:
 		return noDataKey(qname, qtype, do)
-	case middleware.OtherError:
+	case response.OtherError:
 		return ""
 	}
 	return ""
@@ -57,7 +58,7 @@ func NewCachingResponseWriter(w dns.ResponseWriter, cache *gcache.Cache, cap tim
 
 func (c *CachingResponseWriter) WriteMsg(res *dns.Msg) error {
 	do := false
-	mt, opt := middleware.Classify(res)
+	mt, opt := response.Classify(res)
 	if opt != nil {
 		do = opt.Do()
 	}
@@ -72,7 +73,7 @@ func (c *CachingResponseWriter) WriteMsg(res *dns.Msg) error {
 	return c.ResponseWriter.WriteMsg(res)
 }
 
-func (c *CachingResponseWriter) set(m *dns.Msg, key string, mt middleware.MsgType) {
+func (c *CachingResponseWriter) set(m *dns.Msg, key string, mt response.Type) {
 	if key == "" {
 		log.Printf("[ERROR] Caching called with empty cache key")
 		return
@@ -80,21 +81,21 @@ func (c *CachingResponseWriter) set(m *dns.Msg, key string, mt middleware.MsgTyp
 
 	duration := c.cap
 	switch mt {
-	case middleware.Success, middleware.Delegation:
+	case response.Success, response.Delegation:
 		if c.cap == 0 {
 			duration = minTtl(m.Answer, mt)
 		}
 		i := newItem(m, duration)
 
 		c.cache.Set(key, i, duration)
-	case middleware.NameError, middleware.NoData:
+	case response.NameError, response.NoData:
 		if c.cap == 0 {
 			duration = minTtl(m.Ns, mt)
 		}
 		i := newItem(m, duration)
 
 		c.cache.Set(key, i, duration)
-	case middleware.OtherError:
+	case response.OtherError:
 		// don't cache these
 	default:
 		log.Printf("[WARNING] Caching called with unknown middleware MsgType: %d", mt)
@@ -112,19 +113,19 @@ func (c *CachingResponseWriter) Hijack() {
 	return
 }
 
-func minTtl(rrs []dns.RR, mt middleware.MsgType) time.Duration {
-	if mt != middleware.Success && mt != middleware.NameError && mt != middleware.NoData {
+func minTtl(rrs []dns.RR, mt response.Type) time.Duration {
+	if mt != response.Success && mt != response.NameError && mt != response.NoData {
 		return 0
 	}
 
 	minTtl := maxTtl
 	for _, r := range rrs {
 		switch mt {
-		case middleware.NameError, middleware.NoData:
+		case response.NameError, response.NoData:
 			if r.Header().Rrtype == dns.TypeSOA {
 				return time.Duration(r.(*dns.SOA).Minttl) * time.Second
 			}
-		case middleware.Success, middleware.Delegation:
+		case response.Success, response.Delegation:
 			if r.Header().Ttl < minTtl {
 				minTtl = r.Header().Ttl
 			}