Prometheus endpoint (#5256)

* Add prometheus collector and route

* dep ensure -add github.com/prometheus/client_golang/prometheus

* dep ensure -update github.com/golang/protobuf

* add metrics to reserved usernames

* add comment head in metrics package

* fix style imports

* add metrics settings

* add bearer token check

* mapping metrics configs

* fix lint

* update config cheat sheet

* update conf sample, typo fix

vendor/github.com/golang/protobuf/proto/extensions.go

@@ -38,6 +38,7 @@ package proto
 import (
 	"errors"
 	"fmt"
+	"io"
 	"reflect"
 	"strconv"
 	"sync"
@@ -52,14 +53,111 @@ type ExtensionRange struct {
 	Start, End int32 // both inclusive
 }
 
-// extendableProto is an interface implemented by any protocol buffer that may be extended.
+// extendableProto is an interface implemented by any protocol buffer generated by the current
+// proto compiler that may be extended.
 type extendableProto interface {
+	Message
+	ExtensionRangeArray() []ExtensionRange
+	extensionsWrite() map[int32]Extension
+	extensionsRead() (map[int32]Extension, sync.Locker)
+}
+
+// extendableProtoV1 is an interface implemented by a protocol buffer generated by the previous
+// version of the proto compiler that may be extended.
+type extendableProtoV1 interface {
 	Message
 	ExtensionRangeArray() []ExtensionRange
 	ExtensionMap() map[int32]Extension
 }
 
-var extendableProtoType = reflect.TypeOf((*extendableProto)(nil)).Elem()
+// extensionAdapter is a wrapper around extendableProtoV1 that implements extendableProto.
+type extensionAdapter struct {
+	extendableProtoV1
+}
+
+func (e extensionAdapter) extensionsWrite() map[int32]Extension {
+	return e.ExtensionMap()
+}
+
+func (e extensionAdapter) extensionsRead() (map[int32]Extension, sync.Locker) {
+	return e.ExtensionMap(), notLocker{}
+}
+
+// notLocker is a sync.Locker whose Lock and Unlock methods are nops.
+type notLocker struct{}
+
+func (n notLocker) Lock()   {}
+func (n notLocker) Unlock() {}
+
+// extendable returns the extendableProto interface for the given generated proto message.
+// If the proto message has the old extension format, it returns a wrapper that implements
+// the extendableProto interface.
+func extendable(p interface{}) (extendableProto, error) {
+	switch p := p.(type) {
+	case extendableProto:
+		if isNilPtr(p) {
+			return nil, fmt.Errorf("proto: nil %T is not extendable", p)
+		}
+		return p, nil
+	case extendableProtoV1:
+		if isNilPtr(p) {
+			return nil, fmt.Errorf("proto: nil %T is not extendable", p)
+		}
+		return extensionAdapter{p}, nil
+	}
+	// Don't allocate a specific error containing %T:
+	// this is the hot path for Clone and MarshalText.
+	return nil, errNotExtendable
+}
+
+var errNotExtendable = errors.New("proto: not an extendable proto.Message")
+
+func isNilPtr(x interface{}) bool {
+	v := reflect.ValueOf(x)
+	return v.Kind() == reflect.Ptr && v.IsNil()
+}
+
+// XXX_InternalExtensions is an internal representation of proto extensions.
+//
+// Each generated message struct type embeds an anonymous XXX_InternalExtensions field,
+// thus gaining the unexported 'extensions' method, which can be called only from the proto package.
+//
+// The methods of XXX_InternalExtensions are not concurrency safe in general,
+// but calls to logically read-only methods such as has and get may be executed concurrently.
+type XXX_InternalExtensions struct {
+	// The struct must be indirect so that if a user inadvertently copies a
+	// generated message and its embedded XXX_InternalExtensions, they
+	// avoid the mayhem of a copied mutex.
+	//
+	// The mutex serializes all logically read-only operations to p.extensionMap.
+	// It is up to the client to ensure that write operations to p.extensionMap are
+	// mutually exclusive with other accesses.
+	p *struct {
+		mu           sync.Mutex
+		extensionMap map[int32]Extension
+	}
+}
+
+// extensionsWrite returns the extension map, creating it on first use.
+func (e *XXX_InternalExtensions) extensionsWrite() map[int32]Extension {
+	if e.p == nil {
+		e.p = new(struct {
+			mu           sync.Mutex
+			extensionMap map[int32]Extension
+		})
+		e.p.extensionMap = make(map[int32]Extension)
+	}
+	return e.p.extensionMap
+}
+
+// extensionsRead returns the extensions map for read-only use.  It may be nil.
+// The caller must hold the returned mutex's lock when accessing Elements within the map.
+func (e *XXX_InternalExtensions) extensionsRead() (map[int32]Extension, sync.Locker) {
+	if e.p == nil {
+		return nil, nil
+	}
+	return e.p.extensionMap, &e.p.mu
+}
 
 // ExtensionDesc represents an extension specification.
 // Used in generated code from the protocol compiler.
@@ -69,6 +167,7 @@ type ExtensionDesc struct {
 	Field         int32       // field number
 	Name          string      // fully-qualified name of extension, for text formatting
 	Tag           string      // protobuf tag style
+	Filename      string      // name of the file in which the extension is defined
 }
 
 func (ed *ExtensionDesc) repeated() bool {
@@ -92,8 +191,13 @@ type Extension struct {
 }
 
 // SetRawExtension is for testing only.
-func SetRawExtension(base extendableProto, id int32, b []byte) {
-	base.ExtensionMap()[id] = Extension{enc: b}
+func SetRawExtension(base Message, id int32, b []byte) {
+	epb, err := extendable(base)
+	if err != nil {
+		return
+	}
+	extmap := epb.extensionsWrite()
+	extmap[id] = Extension{enc: b}
 }
 
 // isExtensionField returns true iff the given field number is in an extension range.
@@ -108,9 +212,13 @@ func isExtensionField(pb extendableProto, field int32) bool {
 
 // checkExtensionTypes checks that the given extension is valid for pb.
 func checkExtensionTypes(pb extendableProto, extension *ExtensionDesc) error {
+	var pbi interface{} = pb
 	// Check the extended type.
-	if a, b := reflect.TypeOf(pb), reflect.TypeOf(extension.ExtendedType); a != b {
-		return errors.New("proto: bad extended type; " + b.String() + " does not extend " + a.String())
+	if ea, ok := pbi.(extensionAdapter); ok {
+		pbi = ea.extendableProtoV1
+	}
+	if a, b := reflect.TypeOf(pbi), reflect.TypeOf(extension.ExtendedType); a != b {
+		return fmt.Errorf("proto: bad extended type; %v does not extend %v", b, a)
 	}
 	// Check the range.
 	if !isExtensionField(pb, extension.Field) {
@@ -155,80 +263,62 @@ func extensionProperties(ed *ExtensionDesc) *Properties {
 	return prop
 }
 
-// encodeExtensionMap encodes any unmarshaled (unencoded) extensions in m.
-func encodeExtensionMap(m map[int32]Extension) error {
-	for k, e := range m {
-		if e.value == nil || e.desc == nil {
-			// Extension is only in its encoded form.
-			continue
-		}
-
-		// We don't skip extensions that have an encoded form set,
-		// because the extension value may have been mutated after
-		// the last time this function was called.
-
-		et := reflect.TypeOf(e.desc.ExtensionType)
-		props := extensionProperties(e.desc)
-
-		p := NewBuffer(nil)
-		// If e.value has type T, the encoder expects a *struct{ X T }.
-		// Pass a *T with a zero field and hope it all works out.
-		x := reflect.New(et)
-		x.Elem().Set(reflect.ValueOf(e.value))
-		if err := props.enc(p, props, toStructPointer(x)); err != nil {
-			return err
-		}
-		e.enc = p.buf
-		m[k] = e
-	}
-	return nil
-}
-
-func sizeExtensionMap(m map[int32]Extension) (n int) {
-	for _, e := range m {
-		if e.value == nil || e.desc == nil {
-			// Extension is only in its encoded form.
-			n += len(e.enc)
-			continue
-		}
-
-		// We don't skip extensions that have an encoded form set,
-		// because the extension value may have been mutated after
-		// the last time this function was called.
-
-		et := reflect.TypeOf(e.desc.ExtensionType)
-		props := extensionProperties(e.desc)
-
-		// If e.value has type T, the encoder expects a *struct{ X T }.
-		// Pass a *T with a zero field and hope it all works out.
-		x := reflect.New(et)
-		x.Elem().Set(reflect.ValueOf(e.value))
-		n += props.size(props, toStructPointer(x))
-	}
-	return
-}
-
 // HasExtension returns whether the given extension is present in pb.
-func HasExtension(pb extendableProto, extension *ExtensionDesc) bool {
+func HasExtension(pb Message, extension *ExtensionDesc) bool {
 	// TODO: Check types, field numbers, etc.?
-	_, ok := pb.ExtensionMap()[extension.Field]
+	epb, err := extendable(pb)
+	if err != nil {
+		return false
+	}
+	extmap, mu := epb.extensionsRead()
+	if extmap == nil {
+		return false
+	}
+	mu.Lock()
+	_, ok := extmap[extension.Field]
+	mu.Unlock()
 	return ok
 }
 
 // ClearExtension removes the given extension from pb.
-func ClearExtension(pb extendableProto, extension *ExtensionDesc) {
+func ClearExtension(pb Message, extension *ExtensionDesc) {
+	epb, err := extendable(pb)
+	if err != nil {
+		return
+	}
 	// TODO: Check types, field numbers, etc.?
-	delete(pb.ExtensionMap(), extension.Field)
+	extmap := epb.extensionsWrite()
+	delete(extmap, extension.Field)
 }
 
-// GetExtension parses and returns the given extension of pb.
-// If the extension is not present and has no default value it returns ErrMissingExtension.
-func GetExtension(pb extendableProto, extension *ExtensionDesc) (interface{}, error) {
-	if err := checkExtensionTypes(pb, extension); err != nil {
+// GetExtension retrieves a proto2 extended field from pb.
+//
+// If the descriptor is type complete (i.e., ExtensionDesc.ExtensionType is non-nil),
+// then GetExtension parses the encoded field and returns a Go value of the specified type.
+// If the field is not present, then the default value is returned (if one is specified),
+// otherwise ErrMissingExtension is reported.
+//
+// If the descriptor is not type complete (i.e., ExtensionDesc.ExtensionType is nil),
+// then GetExtension returns the raw encoded bytes of the field extension.
+func GetExtension(pb Message, extension *ExtensionDesc) (interface{}, error) {
+	epb, err := extendable(pb)
+	if err != nil {
 		return nil, err
 	}
 
-	emap := pb.ExtensionMap()
+	if extension.ExtendedType != nil {
+		// can only check type if this is a complete descriptor
+		if err := checkExtensionTypes(epb, extension); err != nil {
+			return nil, err
+		}
+	}
+
+	emap, mu := epb.extensionsRead()
+	if emap == nil {
+		return defaultExtensionValue(extension)
+	}
+	mu.Lock()
+	defer mu.Unlock()
 	e, ok := emap[extension.Field]
 	if !ok {
 		// defaultExtensionValue returns the default value or
@@ -247,6 +337,11 @@ func GetExtension(pb extendableProto, extension *ExtensionDesc) (interface{}, er
 		return e.value, nil
 	}
 
+	if extension.ExtensionType == nil {
+		// incomplete descriptor
+		return e.enc, nil
+	}
+
 	v, err := decodeExtension(e.enc, extension)
 	if err != nil {
 		return nil, err
@@ -264,6 +359,11 @@ func GetExtension(pb extendableProto, extension *ExtensionDesc) (interface{}, er
 // defaultExtensionValue returns the default value for extension.
 // If no default for an extension is defined ErrMissingExtension is returned.
 func defaultExtensionValue(extension *ExtensionDesc) (interface{}, error) {
+	if extension.ExtensionType == nil {
+		// incomplete descriptor, so no default
+		return nil, ErrMissingExtension
+	}
+
 	t := reflect.TypeOf(extension.ExtensionType)
 	props := extensionProperties(extension)
 
@@ -298,31 +398,28 @@ func defaultExtensionValue(extension *ExtensionDesc) (interface{}, error) {
 
 // decodeExtension decodes an extension encoded in b.
 func decodeExtension(b []byte, extension *ExtensionDesc) (interface{}, error) {
-	o := NewBuffer(b)
-
 	t := reflect.TypeOf(extension.ExtensionType)
-
-	props := extensionProperties(extension)
+	unmarshal := typeUnmarshaler(t, extension.Tag)
 
 	// t is a pointer to a struct, pointer to basic type or a slice.
-	// Allocate a "field" to store the pointer/slice itself; the
-	// pointer/slice will be stored here. We pass
-	// the address of this field to props.dec.
-	// This passes a zero field and a *t and lets props.dec
-	// interpret it as a *struct{ x t }.
+	// Allocate space to store the pointer/slice.
 	value := reflect.New(t).Elem()
 
+	var err error
 	for {
-		// Discard wire type and field number varint. It isn't needed.
-		if _, err := o.DecodeVarint(); err != nil {
+		x, n := decodeVarint(b)
+		if n == 0 {
+			return nil, io.ErrUnexpectedEOF
+		}
+		b = b[n:]
+		wire := int(x) & 7
+
+		b, err = unmarshal(b, valToPointer(value.Addr()), wire)
+		if err != nil {
 			return nil, err
 		}
 
-		if err := props.dec(o, props, toStructPointer(value.Addr())); err != nil {
-			return nil, err
-		}
-
-		if o.index >= len(o.buf) {
+		if len(b) == 0 {
 			break
 		}
 	}
@@ -332,10 +429,9 @@ func decodeExtension(b []byte, extension *ExtensionDesc) (interface{}, error) {
 // GetExtensions returns a slice of the extensions present in pb that are also listed in es.
 // The returned slice has the same length as es; missing extensions will appear as nil elements.
 func GetExtensions(pb Message, es []*ExtensionDesc) (extensions []interface{}, err error) {
-	epb, ok := pb.(extendableProto)
-	if !ok {
-		err = errors.New("proto: not an extendable proto")
-		return
+	epb, err := extendable(pb)
+	if err != nil {
+		return nil, err
 	}
 	extensions = make([]interface{}, len(es))
 	for i, e := range es {
@@ -350,9 +446,44 @@ func GetExtensions(pb Message, es []*ExtensionDesc) (extensions []interface{}, e
 	return
 }
 
+// ExtensionDescs returns a new slice containing pb's extension descriptors, in undefined order.
+// For non-registered extensions, ExtensionDescs returns an incomplete descriptor containing
+// just the Field field, which defines the extension's field number.
+func ExtensionDescs(pb Message) ([]*ExtensionDesc, error) {
+	epb, err := extendable(pb)
+	if err != nil {
+		return nil, err
+	}
+	registeredExtensions := RegisteredExtensions(pb)
+
+	emap, mu := epb.extensionsRead()
+	if emap == nil {
+		return nil, nil
+	}
+	mu.Lock()
+	defer mu.Unlock()
+	extensions := make([]*ExtensionDesc, 0, len(emap))
+	for extid, e := range emap {
+		desc := e.desc
+		if desc == nil {
+			desc = registeredExtensions[extid]
+			if desc == nil {
+				desc = &ExtensionDesc{Field: extid}
+			}
+		}
+
+		extensions = append(extensions, desc)
+	}
+	return extensions, nil
+}
+
 // SetExtension sets the specified extension of pb to the specified value.
-func SetExtension(pb extendableProto, extension *ExtensionDesc, value interface{}) error {
-	if err := checkExtensionTypes(pb, extension); err != nil {
+func SetExtension(pb Message, extension *ExtensionDesc, value interface{}) error {
+	epb, err := extendable(pb)
+	if err != nil {
+		return err
+	}
+	if err := checkExtensionTypes(epb, extension); err != nil {
 		return err
 	}
 	typ := reflect.TypeOf(extension.ExtensionType)
@@ -368,10 +499,23 @@ func SetExtension(pb extendableProto, extension *ExtensionDesc, value interface{
 		return fmt.Errorf("proto: SetExtension called with nil value of type %T", value)
 	}
 
-	pb.ExtensionMap()[extension.Field] = Extension{desc: extension, value: value}
+	extmap := epb.extensionsWrite()
+	extmap[extension.Field] = Extension{desc: extension, value: value}
 	return nil
 }
 
+// ClearAllExtensions clears all extensions from pb.
+func ClearAllExtensions(pb Message) {
+	epb, err := extendable(pb)
+	if err != nil {
+		return
+	}
+	m := epb.extensionsWrite()
+	for k := range m {
+		delete(m, k)
+	}
+}
+
 // A global registry of extensions.
 // The generated code will register the generated descriptors by calling RegisterExtension.