Remove the word middleware (#1067)

* Rename middleware to plugin

first pass; mostly used 'sed', few spots where I manually changed
text.

This still builds a coredns binary.

* fmt error

* Rename AddMiddleware to AddPlugin

* Readd AddMiddleware to remain backwards compat

plugin/dnssec/setup.go

@@ -0,0 +1,128 @@
+package dnssec
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/coredns/coredns/core/dnsserver"
+	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/pkg/cache"
+
+	"github.com/mholt/caddy"
+)
+
+func init() {
+	caddy.RegisterPlugin("dnssec", caddy.Plugin{
+		ServerType: "dns",
+		Action:     setup,
+	})
+}
+
+func setup(c *caddy.Controller) error {
+	zones, keys, capacity, err := dnssecParse(c)
+	if err != nil {
+		return plugin.Error("dnssec", err)
+	}
+
+	ca := cache.New(capacity)
+	dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
+		return New(zones, keys, next, ca)
+	})
+
+	// Export the capacity for the metrics. This only happens once, because this is a re-load change only.
+	cacheCapacity.WithLabelValues("signature").Set(float64(capacity))
+
+	return nil
+}
+
+func dnssecParse(c *caddy.Controller) ([]string, []*DNSKEY, int, error) {
+	zones := []string{}
+
+	keys := []*DNSKEY{}
+
+	capacity := defaultCap
+	for c.Next() {
+		// dnssec [zones...]
+		zones = make([]string, len(c.ServerBlockKeys))
+		copy(zones, c.ServerBlockKeys)
+		args := c.RemainingArgs()
+		if len(args) > 0 {
+			zones = args
+		}
+
+		for c.NextBlock() {
+			switch c.Val() {
+			case "key":
+				k, e := keyParse(c)
+				if e != nil {
+					return nil, nil, 0, e
+				}
+				keys = append(keys, k...)
+			case "cache_capacity":
+				if !c.NextArg() {
+					return nil, nil, 0, c.ArgErr()
+				}
+				value := c.Val()
+				cacheCap, err := strconv.Atoi(value)
+				if err != nil {
+					return nil, nil, 0, err
+				}
+				capacity = cacheCap
+			}
+
+		}
+	}
+	for i := range zones {
+		zones[i] = plugin.Host(zones[i]).Normalize()
+	}
+
+	// Check if each keys owner name can actually sign the zones we want them to sign
+	for _, k := range keys {
+		kname := plugin.Name(k.K.Header().Name)
+		ok := false
+		for i := range zones {
+			if kname.Matches(zones[i]) {
+				ok = true
+				break
+			}
+		}
+		if !ok {
+			return zones, keys, capacity, fmt.Errorf("key %s (keyid: %d) can not sign any of the zones", string(kname), k.keytag)
+		}
+	}
+
+	return zones, keys, capacity, nil
+}
+
+func keyParse(c *caddy.Controller) ([]*DNSKEY, error) {
+	keys := []*DNSKEY{}
+
+	if !c.NextArg() {
+		return nil, c.ArgErr()
+	}
+	value := c.Val()
+	if value == "file" {
+		ks := c.RemainingArgs()
+		if len(ks) == 0 {
+			return nil, c.ArgErr()
+		}
+
+		for _, k := range ks {
+			base := k
+			// Kmiek.nl.+013+26205.key, handle .private or without extension: Kmiek.nl.+013+26205
+			if strings.HasSuffix(k, ".key") {
+				base = k[:len(k)-4]
+			}
+			if strings.HasSuffix(k, ".private") {
+				base = k[:len(k)-8]
+			}
+			k, err := ParseKeyFile(base+".key", base+".private")
+			if err != nil {
+				return nil, err
+			}
+			keys = append(keys, k)
+		}
+	}
+	return keys, nil
+}