server: drop Internal option

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

.github/generate.sh

@@ -1,15 +0,0 @@
-#!/bin/bash -e
-
-find . -type f -name '*.pb.*.go' -o -name '*.pb.go' -a ! -name 'message.pb.go' -delete
-PROTOS=$(find . -type f -name '*.proto' | grep -v proto/google/api)
-
-mkdir -p proto/google/api
-curl -s -o proto/google/api/annotations.proto -L https://raw.githubusercontent.com/googleapis/googleapis/master/google/api/annotations.proto
-curl -s -o proto/google/api/http.proto -L https://raw.githubusercontent.com/googleapis/googleapis/master/google/api/http.proto
-
-for PROTO in $PROTOS; do
-  echo $PROTO
-  protoc -I./proto -I. -I$(dirname $PROTO) --go-grpc_out=paths=source_relative:. --go_out=paths=source_relative:. --micro_out=paths=source_relative:. $PROTO
-done
-
-rm -r proto

generate.go

@@ -1,3 +0,0 @@
-package micro
-
-//go:generate ./.github/generate.sh

go.mod

@@ -9,5 +9,5 @@ require (
 	github.com/imdario/mergo v0.3.12
 	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/silas/dag v0.0.0-20210121180416-41cf55125c34
-	golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4
+	golang.org/x/net v0.0.0-20210415231046-e915ea6b2b7d
 )

go.sum

@@ -10,12 +10,12 @@ github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaR
 github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/silas/dag v0.0.0-20210121180416-41cf55125c34 h1:vBfVmA5mZhsQa2jr1FOL9nfA37N/jnbBmi5XUfviVTI=
 github.com/silas/dag v0.0.0-20210121180416-41cf55125c34/go.mod h1:7RTUFBdIRC9nZ7/3RyRNH1bdqIShrDejd1YbLwgPS+I=
-golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4 h1:4nGaVu0QrbjT/AK2PRLuQfQuh6DJve+pELhqTdAj3x0=
-golang.org/x/net v0.0.0-20210405180319-a5a99cb37ef4/go.mod h1:p54w0d4576C0XHj96bSt6lcn1PtDYWL6XObtHCRCNQM=
+golang.org/x/net v0.0.0-20210415231046-e915ea6b2b7d h1:BgJvlyh+UqCUaPlscHJ+PN8GcpfrFdr7NHjd1JL0+Gs=
+golang.org/x/net v0.0.0-20210415231046-e915ea6b2b7d/go.mod h1:9tjilg8BloeKEkVJvy7fQ90B1CfIiPueXVOjqfkSzI8=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
-golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v2 v2.3.0 h1:clyUAQHOM3G0M3f5vQj7LuJrETvjVot3Z5el9nffUtU=

register/extractor.go

@@ -3,7 +3,6 @@ package register
 import (
 	"fmt"
 	"reflect"
-	"strings"
 	"unicode"
 	"unicode/utf8"
 
@@ -11,12 +10,12 @@ import (
 )
 
 // ExtractValue from reflect.Type from specified depth
-func ExtractValue(v reflect.Type, d int) *Value {
+func ExtractValue(v reflect.Type, d int) string {
 	if d == 3 {
-		return nil
+		return ""
 	}
 	if v == nil {
-		return nil
+		return ""
 	}
 
 	if v.Kind() == reflect.Ptr {
@@ -25,7 +24,7 @@ func ExtractValue(v reflect.Type, d int) *Value {
 
 	// slices and maps don't have a defined name
 	if (v.Kind() == reflect.Slice || v.Kind() == reflect.Map) || len(v.Name()) == 0 {
-		return nil
+		return ""
 	}
 
 	// get the rune character
@@ -33,58 +32,10 @@ func ExtractValue(v reflect.Type, d int) *Value {
 
 	// crude check for is unexported field
 	if unicode.IsLower(a) {
-		return nil
+		return ""
 	}
 
-	arg := &Value{
-		Name: v.Name(),
-		Type: v.Name(),
-	}
-
-	switch v.Kind() {
-	case reflect.Struct:
-		for i := 0; i < v.NumField(); i++ {
-			f := v.Field(i)
-			val := ExtractValue(f.Type, d+1)
-			if val == nil {
-				continue
-			}
-
-			// if we can find a json tag use it
-			if tags := f.Tag.Get("json"); len(tags) > 0 {
-				parts := strings.Split(tags, ",")
-				if parts[0] == "-" || parts[0] == "omitempty" {
-					continue
-				}
-				val.Name = parts[0]
-			}
-
-			// if there's no name default it
-			if len(val.Name) == 0 {
-				val.Name = v.Field(i).Name
-			}
-
-			arg.Values = append(arg.Values, val)
-		}
-	case reflect.Slice:
-		p := v.Elem()
-		if p.Kind() == reflect.Ptr {
-			p = p.Elem()
-		}
-		arg.Type = "[]" + p.Name()
-	case reflect.Map:
-		p := v.Elem()
-		if p.Kind() == reflect.Ptr {
-			p = p.Elem()
-		}
-		key := v.Key()
-		if key.Kind() == reflect.Ptr {
-			key = key.Elem()
-		}
-		arg.Type = fmt.Sprintf("map[%s]%s", key.Name(), p.Name())
-	}
-
-	return arg
+	return v.Name()
 }
 
 // ExtractEndpoint extract *Endpoint from reflect.Method
@@ -116,7 +67,7 @@ func ExtractEndpoint(method reflect.Method) *Endpoint {
 
 	request := ExtractValue(reqType, 0)
 	response := ExtractValue(rspType, 0)
-	if request == nil || response == nil {
+	if request == "" || response == "" {
 		return nil
 	}
 
@@ -135,7 +86,7 @@ func ExtractEndpoint(method reflect.Method) *Endpoint {
 }
 
 // ExtractSubValue exctact *Value from reflect.Type
-func ExtractSubValue(typ reflect.Type) *Value {
+func ExtractSubValue(typ reflect.Type) string {
 	var reqType reflect.Type
 	switch typ.NumIn() {
 	case 1:
@@ -145,7 +96,7 @@ func ExtractSubValue(typ reflect.Type) *Value {
 	case 3:
 		reqType = typ.In(2)
 	default:
-		return nil
+		return ""
 	}
 	return ExtractValue(reqType, 0)
 }

register/extractor_test.go

@@ -36,28 +36,21 @@ func TestExtractEndpoint(t *testing.T) {
 		t.Fatalf("Expected handler Test, got %s", endpoints[0].Name)
 	}
 
-	if endpoints[0].Request == nil {
+	if endpoints[0].Request == "" {
 		t.Fatal("Expected non nil Request")
 	}
 
-	if endpoints[0].Response == nil {
+	if endpoints[0].Response == "" {
 		t.Fatal("Expected non nil Request")
 	}
 
-	if endpoints[0].Request.Name != "TestRequest" {
-		t.Fatalf("Expected TestRequest got %s", endpoints[0].Request.Name)
+	if endpoints[0].Request != "TestRequest" {
+		t.Fatalf("Expected TestRequest got %s", endpoints[0].Request)
 	}
 
-	if endpoints[0].Response.Name != "TestResponse" {
-		t.Fatalf("Expected TestResponse got %s", endpoints[0].Response.Name)
-	}
-
-	if endpoints[0].Request.Type != "TestRequest" {
-		t.Fatalf("Expected TestRequest type got %s", endpoints[0].Request.Type)
-	}
-
-	if endpoints[0].Response.Type != "TestResponse" {
-		t.Fatalf("Expected TestResponse type got %s", endpoints[0].Response.Type)
+	if endpoints[0].Response != "TestResponse" {
+		t.Fatalf("Expected TestResponse got %s", endpoints[0].Response)
 	}
 
+	t.Logf("XXX %#+v\n", endpoints[0])
 }

register/memory.go

@@ -490,15 +490,6 @@ func recordToService(r *record, domain string) *Service {
 
 	endpoints := make([]*Endpoint, len(r.Endpoints))
 	for i, e := range r.Endpoints {
-		request := new(Value)
-		if e.Request != nil {
-			*request = *e.Request
-		}
-		response := new(Value)
-		if e.Response != nil {
-			*response = *e.Response
-		}
-
 		metadata := make(map[string]string, len(e.Metadata))
 		for k, v := range e.Metadata {
 			metadata[k] = v
@@ -506,8 +497,8 @@ func recordToService(r *record, domain string) *Service {
 
 		endpoints[i] = &Endpoint{
 			Name:     e.Name,
-			Request:  request,
-			Response: response,
+			Request:  e.Request,
+			Response: e.Response,
 			Metadata: metadata,
 		}
 	}

register/register.go

@@ -59,19 +59,12 @@ type Node struct {
 
 // Endpoint holds endpoint register info
 type Endpoint struct {
-	Request  *Value            `json:"request"`
-	Response *Value            `json:"response"`
+	Request  string            `json:"request"`
+	Response string            `json:"response"`
 	Metadata metadata.Metadata `json:"metadata"`
 	Name     string            `json:"name"`
 }
 
-// Value holds additional kv stuff
-type Value struct {
-	Name   string   `json:"name"`
-	Type   string   `json:"type"`
-	Values []*Value `json:"values"`
-}
-
 // Option func signature
 type Option func(*Options)
 

server/noop.go

@@ -160,22 +160,16 @@ func (n *noopServer) Register() error {
 	n.RLock()
 	// Maps are ordered randomly, sort the keys for consistency
 	var handlerList []string
-	for n, e := range n.handlers {
-		// Only advertise non internal handlers
-		if !e.Options().Internal {
+	for n, _ := range n.handlers {
 		handlerList = append(handlerList, n)
 	}
-	}
 
 	sort.Strings(handlerList)
 
 	var subscriberList []*subscriber
 	for e := range n.subscribers {
-		// Only advertise non internal subscribers
-		if !e.Options().Internal {
 		subscriberList = append(subscriberList, e)
 	}
-	}
 	sort.Slice(subscriberList, func(i, j int) bool {
 		return subscriberList[i].topic > subscriberList[j].topic
 	})

server/options.go

@@ -325,8 +325,6 @@ type HandlerOptions struct {
 	Context context.Context
 	// Metadata for hondler
 	Metadata map[string]metadata.Metadata
-	// Internal flag limits exporting to other nodes via register
-	Internal bool
 }
 
 // NewHandlerOptions creates new HandlerOptions
@@ -354,8 +352,6 @@ type SubscriberOptions struct {
 	Queue string
 	// AutoAck flag for auto ack messages after processing
 	AutoAck bool
-	// Internal flag limit exporting info via register
-	Internal bool
 	// BodyOnly flag specifies that message without headers
 	BodyOnly bool
 }
@@ -382,23 +378,6 @@ func EndpointMetadata(name string, md metadata.Metadata) HandlerOption {
 	}
 }
 
-// InternalHandler options specifies that a handler is not advertised
-// to the discovery system. In the future this may also limit request
-// to the internal network or authorised user.
-func InternalHandler(b bool) HandlerOption {
-	return func(o *HandlerOptions) {
-		o.Internal = b
-	}
-}
-
-// InternalSubscriber options specifies that a subscriber is not advertised
-// to the discovery system.
-func InternalSubscriber(b bool) SubscriberOption {
-	return func(o *SubscriberOptions) {
-		o.Internal = b
-	}
-}
-
 // DisableAutoAck will disable auto acking of messages
 // after they have been handled.
 func DisableAutoAck() SubscriberOption {

util/reflect/struct.go

@@ -0,0 +1,398 @@
+package reflect
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+	"reflect"
+	"regexp"
+	"strings"
+)
+
+var (
+	// ErrInvalidParam specifies invalid url query params
+	ErrInvalidParam = errors.New("invalid url query param provided")
+)
+
+var (
+	bracketSplitter = regexp.MustCompile(`\[|\]`)
+)
+
+// StructFields returns slice of struct fields
+func StructFields(src interface{}) ([]reflect.StructField, error) {
+	var fields []reflect.StructField
+
+	sv := reflect.ValueOf(src)
+	if sv.Kind() == reflect.Ptr {
+		sv = sv.Elem()
+	}
+	if sv.Kind() != reflect.Struct {
+		return nil, ErrInvalidStruct
+	}
+
+	typ := sv.Type()
+	for idx := 0; idx < typ.NumField(); idx++ {
+		fld := typ.Field(idx)
+		val := sv.Field(idx)
+		if !val.CanSet() || len(fld.PkgPath) != 0 {
+			continue
+		}
+		if val.Kind() == reflect.Struct {
+			infields, err := StructFields(val.Interface())
+			if err != nil {
+				return nil, err
+			}
+			fields = append(fields, infields...)
+		} else {
+			fields = append(fields, fld)
+		}
+	}
+
+	return fields, nil
+}
+
+// CopyDefaults for a from b
+// a and b should be pointers to the same kind of struct
+func CopyDefaults(a, b interface{}) {
+	pt := reflect.TypeOf(a)
+	t := pt.Elem()
+	va := reflect.ValueOf(a).Elem()
+	vb := reflect.ValueOf(b).Elem()
+	for i := 0; i < t.NumField(); i++ {
+		aField := va.Field(i)
+		if aField.CanSet() {
+			bField := vb.Field(i)
+			aField.Set(bField)
+		}
+	}
+}
+
+// CopyFrom sets the public members of a from b
+// a and b should be pointers to structs
+// a can be a different type from b
+// Only the Fields which have the same name and assignable type on a
+// and b will be set.
+func CopyFrom(a, b interface{}) {
+	ta := reflect.TypeOf(a).Elem()
+	tb := reflect.TypeOf(b).Elem()
+	va := reflect.ValueOf(a).Elem()
+	vb := reflect.ValueOf(b).Elem()
+	for i := 0; i < tb.NumField(); i++ {
+		bField := vb.Field(i)
+		tbField := tb.Field(i)
+		name := tbField.Name
+		aField := va.FieldByName(name)
+		taField, found := ta.FieldByName(name)
+		if found && aField.IsValid() && bField.IsValid() && aField.CanSet() && tbField.Type.AssignableTo(taField.Type) {
+			aField.Set(bField)
+		}
+	}
+}
+
+func StructURLValues(src interface{}, pref string, tags []string) (url.Values, error) {
+	data := url.Values{}
+
+	sv := reflect.ValueOf(src)
+	if sv.Kind() == reflect.Ptr {
+		sv = sv.Elem()
+	}
+	if sv.Kind() != reflect.Struct {
+		return nil, ErrInvalidStruct
+	}
+
+	typ := sv.Type()
+	for idx := 0; idx < typ.NumField(); idx++ {
+		fld := typ.Field(idx)
+		val := sv.Field(idx)
+		if !val.CanSet() || len(fld.PkgPath) != 0 || !val.IsValid() {
+			continue
+		}
+
+		var t *tag
+		for _, tn := range tags {
+			ts, ok := fld.Tag.Lookup(tn)
+			if !ok {
+				continue
+			}
+
+			tp := strings.Split(ts, ",")
+			// special
+			switch tn {
+			case "protobuf": // special
+				t = &tag{key: tn, name: tp[3][5:], opts: append(tp[:3], tp[4:]...)}
+			default:
+				t = &tag{key: tn, name: tp[0], opts: tp[1:]}
+			}
+			if t.name != "" {
+				break
+			}
+		}
+
+		if t.name == "" {
+			// fallback to lowercase
+			t.name = strings.ToLower(fld.Name)
+		}
+		if pref != "" {
+			t.name = pref + "." + t.name
+		}
+
+		if !val.IsValid() || val.IsZero() {
+			continue
+		}
+
+		switch val.Kind() {
+		case reflect.Struct, reflect.Ptr:
+			if val.IsNil() {
+				continue
+			}
+			ndata, err := StructURLValues(val.Interface(), t.name, tags)
+			if err != nil {
+				return ndata, err
+			}
+			for k, v := range ndata {
+				data[k] = v
+			}
+		default:
+			switch val.Kind() {
+			case reflect.Slice:
+				for i := 0; i < val.Len(); i++ {
+					va := val.Index(i)
+					//if va.Type().Elem().Kind() != reflect.Ptr {
+					if va.Kind() != reflect.Ptr {
+						data.Set(t.name, fmt.Sprintf("%v", va.Interface()))
+						continue
+					}
+					switch va.Type().Elem().String() {
+					case "wrapperspb.BoolValue", "wrapperspb.BytesValue", "wrapperspb.StringValue":
+						if eva := reflect.Indirect(va).FieldByName("Value"); eva.IsValid() {
+							data.Add(t.name, fmt.Sprintf("%v", eva.Interface()))
+						}
+					case "wrapperspb.DoubleValue", "wrapperspb.FloatValue":
+						if eva := reflect.Indirect(va).FieldByName("Value"); eva.IsValid() {
+							data.Add(t.name, fmt.Sprintf("%v", eva.Interface()))
+						}
+					case "wrapperspb.Int32Value", "wrapperspb.Int64Value":
+						if eva := reflect.Indirect(va).FieldByName("Value"); eva.IsValid() {
+							data.Add(t.name, fmt.Sprintf("%v", eva.Interface()))
+						}
+					case "wrapperspb.UInt32Value", "wrapperspb.UInt64Value":
+						if eva := reflect.Indirect(va).FieldByName("Value"); eva.IsValid() {
+							data.Add(t.name, fmt.Sprintf("%v", eva.Interface()))
+						}
+					default:
+						data.Add(t.name, fmt.Sprintf("%v", val.Index(i).Interface()))
+					}
+				}
+			default:
+				data.Set(t.name, fmt.Sprintf("%v", val.Interface()))
+			}
+		}
+	}
+	return data, nil
+}
+
+// URLMap returns map of url query params
+func URLMap(query string) (map[string]interface{}, error) {
+	var (
+		mp interface{} = make(map[string]interface{})
+	)
+
+	params := strings.Split(query, "&")
+
+	for _, part := range params {
+		tm, err := queryToMap(part)
+		if err != nil {
+			return nil, err
+		}
+		mp = merge(mp, tm)
+	}
+
+	return mp.(map[string]interface{}), nil
+}
+
+// FlattenMap expand key.subkey to nested map
+func FlattenMap(a map[string]interface{}) map[string]interface{} {
+	// preprocess map
+	nb := make(map[string]interface{}, len(a))
+	for k, v := range a {
+		ps := strings.Split(k, ".")
+		if len(ps) == 1 {
+			nb[k] = v
+			continue
+		}
+		em := make(map[string]interface{})
+		em[ps[len(ps)-1]] = v
+		for i := len(ps) - 2; i > 0; i-- {
+			nm := make(map[string]interface{})
+			nm[ps[i]] = em
+			em = nm
+		}
+		if vm, ok := nb[ps[0]]; ok {
+			// nested map
+			nm := vm.(map[string]interface{})
+			for vk, vv := range em {
+				nm[vk] = vv
+			}
+			nb[ps[0]] = nm
+		} else {
+			nb[ps[0]] = em
+		}
+	}
+	return nb
+}
+
+/*
+	case reflect.String:
+		fn := func(c rune) bool { return c == ',' || c == ';' || c == ' ' }
+		slice := strings.FieldsFunc(vb.String(), fn)
+		if va.IsNil() {
+			va.Set(reflect.MakeSlice(va.Type(), len(slice), len(slice)))
+		}
+*/
+
+func btSplitter(str string) []string {
+	r := bracketSplitter.Split(str, -1)
+	for idx, s := range r {
+		if len(s) == 0 {
+			if len(r) > idx+1 {
+				copy(r[idx:], r[idx+1:])
+				r = r[:len(r)-1]
+			}
+		}
+	}
+	return r
+}
+
+// queryToMap turns something like a[b][c]=4 into
+//   map[string]interface{}{
+//     "a": map[string]interface{}{
+// 		  "b": map[string]interface{}{
+// 			  "c": 4,
+// 		  },
+// 	  },
+//   }
+func queryToMap(param string) (map[string]interface{}, error) {
+	rawKey, rawValue, err := splitKeyAndValue(param)
+	if err != nil {
+		return nil, err
+	}
+	rawValue, err = url.QueryUnescape(rawValue)
+	if err != nil {
+		return nil, err
+	}
+	rawKey, err = url.QueryUnescape(rawKey)
+	if err != nil {
+		return nil, err
+	}
+
+	pieces := btSplitter(rawKey)
+	key := pieces[0]
+
+	// If len==1 then rawKey has no [] chars and we can just
+	// decode this as key=value into {key: value}
+	if len(pieces) == 1 {
+		return map[string]interface{}{
+			key: rawValue,
+		}, nil
+	}
+
+	// If len > 1 then we have something like a[b][c]=2
+	// so we need to turn this into {"a": {"b": {"c": 2}}}
+	// To do this we break our key into two pieces:
+	//   a and b[c]
+	// and then we set {"a": queryToMap("b[c]", value)}
+	ret := make(map[string]interface{})
+	ret[key], err = queryToMap(buildNewKey(rawKey) + "=" + rawValue)
+	if err != nil {
+		return nil, err
+	}
+
+	// When URL params have a set of empty brackets (eg a[]=1)
+	// it is assumed to be an array. This will get us the
+	// correct value for the array item and return it as an
+	// []interface{} so that it can be merged properly.
+	if pieces[1] == "" {
+		temp := ret[key].(map[string]interface{})
+		ret[key] = []interface{}{temp[""]}
+	}
+	return ret, nil
+}
+
+// buildNewKey will take something like:
+// origKey = "bar[one][two]"
+// pieces = [bar one two ]
+// and return "one[two]"
+func buildNewKey(origKey string) string {
+	pieces := btSplitter(origKey)
+
+	ret := origKey[len(pieces[0])+1:]
+	ret = ret[:len(pieces[1])] + ret[len(pieces[1])+1:]
+	return ret
+}
+
+// splitKeyAndValue splits a URL param at the last equal
+// sign and returns the two strings. If no equal sign is
+// found, the ErrInvalidParam error is returned.
+func splitKeyAndValue(param string) (string, string, error) {
+	li := strings.LastIndex(param, "=")
+	if li == -1 {
+		return "", "", ErrInvalidParam
+	}
+	return param[:li], param[li+1:], nil
+}
+
+// merge merges a with b if they are either both slices
+// or map[string]interface{} types. Otherwise it returns b.
+func merge(a interface{}, b interface{}) interface{} {
+	if av, aok := a.(map[string]interface{}); aok {
+		if bv, bok := b.(map[string]interface{}); bok {
+			return mergeMapIface(av, bv)
+		}
+	}
+	if av, aok := a.([]interface{}); aok {
+		if bv, bok := b.([]interface{}); bok {
+			return mergeSliceIface(av, bv)
+		}
+	}
+
+	va := reflect.ValueOf(a)
+	vb := reflect.ValueOf(b)
+	if (va.Type().Kind() == reflect.Slice) && (va.Type().Elem().Kind() == vb.Type().Kind() || vb.Type().ConvertibleTo(va.Type().Elem())) {
+		va = reflect.Append(va, vb.Convert(va.Type().Elem()))
+		return va.Interface()
+	}
+
+	return b
+}
+
+// mergeMap merges a with b, attempting to merge any nested
+// values in nested maps but eventually overwriting anything
+// in a that can't be merged with whatever is in b.
+func mergeMapIface(a map[string]interface{}, b map[string]interface{}) map[string]interface{} {
+	for bK, bV := range b {
+		if aV, ok := a[bK]; ok {
+			if (reflect.ValueOf(aV).Type().Kind() == reflect.ValueOf(bV).Type().Kind()) ||
+				((reflect.ValueOf(aV).Type().Kind() == reflect.Slice) && reflect.ValueOf(aV).Type().Elem().Kind() == reflect.ValueOf(bV).Type().Kind()) {
+				nV := []interface{}{aV, bV}
+				a[bK] = nV
+			} else {
+				a[bK] = merge(a[bK], bV)
+			}
+		} else {
+			a[bK] = bV
+		}
+	}
+	return a
+}
+
+// mergeSlice merges a with b and returns the result.
+func mergeSliceIface(a []interface{}, b []interface{}) []interface{} {
+	a = append(a, b...)
+	return a
+}
+
+type tag struct {
+	key  string
+	name string
+	opts []string
+}