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/lib.go

@@ -73,7 +73,6 @@ for a protocol buffer variable v:
 When the .proto file specifies `syntax="proto3"`, there are some differences:
 
   - Non-repeated fields of non-message type are values instead of pointers.
-  - Getters are only generated for message and oneof fields.
   - Enum types do not get an Enum method.
 
 The simplest way to describe this is to see an example.
@@ -274,6 +273,67 @@ import (
 	"sync"
 )
 
+// RequiredNotSetError is an error type returned by either Marshal or Unmarshal.
+// Marshal reports this when a required field is not initialized.
+// Unmarshal reports this when a required field is missing from the wire data.
+type RequiredNotSetError struct{ field string }
+
+func (e *RequiredNotSetError) Error() string {
+	if e.field == "" {
+		return fmt.Sprintf("proto: required field not set")
+	}
+	return fmt.Sprintf("proto: required field %q not set", e.field)
+}
+func (e *RequiredNotSetError) RequiredNotSet() bool {
+	return true
+}
+
+type invalidUTF8Error struct{ field string }
+
+func (e *invalidUTF8Error) Error() string {
+	if e.field == "" {
+		return "proto: invalid UTF-8 detected"
+	}
+	return fmt.Sprintf("proto: field %q contains invalid UTF-8", e.field)
+}
+func (e *invalidUTF8Error) InvalidUTF8() bool {
+	return true
+}
+
+// errInvalidUTF8 is a sentinel error to identify fields with invalid UTF-8.
+// This error should not be exposed to the external API as such errors should
+// be recreated with the field information.
+var errInvalidUTF8 = &invalidUTF8Error{}
+
+// isNonFatal reports whether the error is either a RequiredNotSet error
+// or a InvalidUTF8 error.
+func isNonFatal(err error) bool {
+	if re, ok := err.(interface{ RequiredNotSet() bool }); ok && re.RequiredNotSet() {
+		return true
+	}
+	if re, ok := err.(interface{ InvalidUTF8() bool }); ok && re.InvalidUTF8() {
+		return true
+	}
+	return false
+}
+
+type nonFatal struct{ E error }
+
+// Merge merges err into nf and reports whether it was successful.
+// Otherwise it returns false for any fatal non-nil errors.
+func (nf *nonFatal) Merge(err error) (ok bool) {
+	if err == nil {
+		return true // not an error
+	}
+	if !isNonFatal(err) {
+		return false // fatal error
+	}
+	if nf.E == nil {
+		nf.E = err // store first instance of non-fatal error
+	}
+	return true
+}
+
 // Message is implemented by generated protocol buffer messages.
 type Message interface {
 	Reset()
@@ -308,18 +368,9 @@ func GetStats() Stats { return stats }
 // temporary Buffer and are fine for most applications.
 type Buffer struct {
 	buf   []byte // encode/decode byte stream
-	index int    // write point
+	index int    // read point
 
-	// pools of basic types to amortize allocation.
-	bools   []bool
-	uint32s []uint32
-	uint64s []uint64
-
-	// extra pools, only used with pointer_reflect.go
-	int32s   []int32
-	int64s   []int64
-	float32s []float32
-	float64s []float64
+	deterministic bool
 }
 
 // NewBuffer allocates a new Buffer and initializes its internal data to
@@ -344,6 +395,30 @@ func (p *Buffer) SetBuf(s []byte) {
 // Bytes returns the contents of the Buffer.
 func (p *Buffer) Bytes() []byte { return p.buf }
 
+// SetDeterministic sets whether to use deterministic serialization.
+//
+// Deterministic serialization guarantees that for a given binary, equal
+// messages will always be serialized to the same bytes. This implies:
+//
+//   - Repeated serialization of a message will return the same bytes.
+//   - Different processes of the same binary (which may be executing on
+//     different machines) will serialize equal messages to the same bytes.
+//
+// Note that the deterministic serialization is NOT canonical across
+// languages. It is not guaranteed to remain stable over time. It is unstable
+// across different builds with schema changes due to unknown fields.
+// Users who need canonical serialization (e.g., persistent storage in a
+// canonical form, fingerprinting, etc.) should define their own
+// canonicalization specification and implement their own serializer rather
+// than relying on this API.
+//
+// If deterministic serialization is requested, map entries will be sorted
+// by keys in lexographical order. This is an implementation detail and
+// subject to change.
+func (p *Buffer) SetDeterministic(deterministic bool) {
+	p.deterministic = deterministic
+}
+
 /*
  * Helper routines for simplifying the creation of optional fields of basic type.
  */
@@ -832,22 +907,12 @@ func fieldDefault(ft reflect.Type, prop *Properties) (sf *scalarField, nestedMes
 	return sf, false, nil
 }
 
+// mapKeys returns a sort.Interface to be used for sorting the map keys.
 // Map fields may have key types of non-float scalars, strings and enums.
-// The easiest way to sort them in some deterministic order is to use fmt.
-// If this turns out to be inefficient we can always consider other options,
-// such as doing a Schwartzian transform.
-
 func mapKeys(vs []reflect.Value) sort.Interface {
-	s := mapKeySorter{
-		vs: vs,
-		// default Less function: textual comparison
-		less: func(a, b reflect.Value) bool {
-			return fmt.Sprint(a.Interface()) < fmt.Sprint(b.Interface())
-		},
-	}
+	s := mapKeySorter{vs: vs}
 
-	// Type specialization per https://developers.google.com/protocol-buffers/docs/proto#maps;
-	// numeric keys are sorted numerically.
+	// Type specialization per https://developers.google.com/protocol-buffers/docs/proto#maps.
 	if len(vs) == 0 {
 		return s
 	}
@@ -856,6 +921,12 @@ func mapKeys(vs []reflect.Value) sort.Interface {
 		s.less = func(a, b reflect.Value) bool { return a.Int() < b.Int() }
 	case reflect.Uint32, reflect.Uint64:
 		s.less = func(a, b reflect.Value) bool { return a.Uint() < b.Uint() }
+	case reflect.Bool:
+		s.less = func(a, b reflect.Value) bool { return !a.Bool() && b.Bool() } // false < true
+	case reflect.String:
+		s.less = func(a, b reflect.Value) bool { return a.String() < b.String() }
+	default:
+		panic(fmt.Sprintf("unsupported map key type: %v", vs[0].Kind()))
 	}
 
 	return s
@@ -889,6 +960,20 @@ func isProto3Zero(v reflect.Value) bool {
 	return false
 }
 
+// ProtoPackageIsVersion2 is referenced from generated protocol buffer files
+// to assert that that code is compatible with this version of the proto package.
+const ProtoPackageIsVersion2 = true
+
 // ProtoPackageIsVersion1 is referenced from generated protocol buffer files
 // to assert that that code is compatible with this version of the proto package.
 const ProtoPackageIsVersion1 = true
+
+// InternalMessageInfo is a type used internally by generated .pb.go files.
+// This type is not intended to be used by non-generated code.
+// This type is not subject to any compatibility guarantee.
+type InternalMessageInfo struct {
+	marshal   *marshalInfo
+	unmarshal *unmarshalInfo
+	merge     *mergeInfo
+	discard   *discardInfo
+}