feat: initial tracing support (#1623)

vendor/google.golang.org/grpc/resolver/map.go

@@ -0,0 +1,138 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package resolver
+
+type addressMapEntry struct {
+	addr  Address
+	value interface{}
+}
+
+// AddressMap is a map of addresses to arbitrary values taking into account
+// Attributes.  BalancerAttributes are ignored, as are Metadata and Type.
+// Multiple accesses may not be performed concurrently.  Must be created via
+// NewAddressMap; do not construct directly.
+type AddressMap struct {
+	// The underlying map is keyed by an Address with fields that we don't care
+	// about being set to their zero values. The only fields that we care about
+	// are `Addr`, `ServerName` and `Attributes`. Since we need to be able to
+	// distinguish between addresses with same `Addr` and `ServerName`, but
+	// different `Attributes`, we cannot store the `Attributes` in the map key.
+	//
+	// The comparison operation for structs work as follows:
+	//  Struct values are comparable if all their fields are comparable. Two
+	//  struct values are equal if their corresponding non-blank fields are equal.
+	//
+	// The value type of the map contains a slice of addresses which match the key
+	// in their `Addr` and `ServerName` fields and contain the corresponding value
+	// associated with them.
+	m map[Address]addressMapEntryList
+}
+
+func toMapKey(addr *Address) Address {
+	return Address{Addr: addr.Addr, ServerName: addr.ServerName}
+}
+
+type addressMapEntryList []*addressMapEntry
+
+// NewAddressMap creates a new AddressMap.
+func NewAddressMap() *AddressMap {
+	return &AddressMap{m: make(map[Address]addressMapEntryList)}
+}
+
+// find returns the index of addr in the addressMapEntry slice, or -1 if not
+// present.
+func (l addressMapEntryList) find(addr Address) int {
+	for i, entry := range l {
+		// Attributes are the only thing to match on here, since `Addr` and
+		// `ServerName` are already equal.
+		if entry.addr.Attributes.Equal(addr.Attributes) {
+			return i
+		}
+	}
+	return -1
+}
+
+// Get returns the value for the address in the map, if present.
+func (a *AddressMap) Get(addr Address) (value interface{}, ok bool) {
+	addrKey := toMapKey(&addr)
+	entryList := a.m[addrKey]
+	if entry := entryList.find(addr); entry != -1 {
+		return entryList[entry].value, true
+	}
+	return nil, false
+}
+
+// Set updates or adds the value to the address in the map.
+func (a *AddressMap) Set(addr Address, value interface{}) {
+	addrKey := toMapKey(&addr)
+	entryList := a.m[addrKey]
+	if entry := entryList.find(addr); entry != -1 {
+		entryList[entry].value = value
+		return
+	}
+	a.m[addrKey] = append(entryList, &addressMapEntry{addr: addr, value: value})
+}
+
+// Delete removes addr from the map.
+func (a *AddressMap) Delete(addr Address) {
+	addrKey := toMapKey(&addr)
+	entryList := a.m[addrKey]
+	entry := entryList.find(addr)
+	if entry == -1 {
+		return
+	}
+	if len(entryList) == 1 {
+		entryList = nil
+	} else {
+		copy(entryList[entry:], entryList[entry+1:])
+		entryList = entryList[:len(entryList)-1]
+	}
+	a.m[addrKey] = entryList
+}
+
+// Len returns the number of entries in the map.
+func (a *AddressMap) Len() int {
+	ret := 0
+	for _, entryList := range a.m {
+		ret += len(entryList)
+	}
+	return ret
+}
+
+// Keys returns a slice of all current map keys.
+func (a *AddressMap) Keys() []Address {
+	ret := make([]Address, 0, a.Len())
+	for _, entryList := range a.m {
+		for _, entry := range entryList {
+			ret = append(ret, entry.addr)
+		}
+	}
+	return ret
+}
+
+// Values returns a slice of all current map values.
+func (a *AddressMap) Values() []interface{} {
+	ret := make([]interface{}, 0, a.Len())
+	for _, entryList := range a.m {
+		for _, entry := range entryList {
+			ret = append(ret, entry.value)
+		}
+	}
+	return ret
+}

vendor/google.golang.org/grpc/resolver/resolver.go

@@ -0,0 +1,308 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package resolver defines APIs for name resolution in gRPC.
+// All APIs in this package are experimental.
+package resolver
+
+import (
+	"context"
+	"net"
+	"net/url"
+	"strings"
+
+	"google.golang.org/grpc/attributes"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/internal/pretty"
+	"google.golang.org/grpc/serviceconfig"
+)
+
+var (
+	// m is a map from scheme to resolver builder.
+	m = make(map[string]Builder)
+	// defaultScheme is the default scheme to use.
+	defaultScheme = "passthrough"
+)
+
+// TODO(bar) install dns resolver in init(){}.
+
+// Register registers the resolver builder to the resolver map. b.Scheme will be
+// used as the scheme registered with this builder.
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. If multiple Resolvers are
+// registered with the same name, the one registered last will take effect.
+func Register(b Builder) {
+	m[b.Scheme()] = b
+}
+
+// Get returns the resolver builder registered with the given scheme.
+//
+// If no builder is register with the scheme, nil will be returned.
+func Get(scheme string) Builder {
+	if b, ok := m[scheme]; ok {
+		return b
+	}
+	return nil
+}
+
+// SetDefaultScheme sets the default scheme that will be used. The default
+// default scheme is "passthrough".
+//
+// NOTE: this function must only be called during initialization time (i.e. in
+// an init() function), and is not thread-safe. The scheme set last overrides
+// previously set values.
+func SetDefaultScheme(scheme string) {
+	defaultScheme = scheme
+}
+
+// GetDefaultScheme gets the default scheme that will be used.
+func GetDefaultScheme() string {
+	return defaultScheme
+}
+
+// AddressType indicates the address type returned by name resolution.
+//
+// Deprecated: use Attributes in Address instead.
+type AddressType uint8
+
+const (
+	// Backend indicates the address is for a backend server.
+	//
+	// Deprecated: use Attributes in Address instead.
+	Backend AddressType = iota
+	// GRPCLB indicates the address is for a grpclb load balancer.
+	//
+	// Deprecated: to select the GRPCLB load balancing policy, use a service
+	// config with a corresponding loadBalancingConfig.  To supply balancer
+	// addresses to the GRPCLB load balancing policy, set State.Attributes
+	// using balancer/grpclb/state.Set.
+	GRPCLB
+)
+
+// Address represents a server the client connects to.
+//
+// # Experimental
+//
+// Notice: This type is EXPERIMENTAL and may be changed or removed in a
+// later release.
+type Address struct {
+	// Addr is the server address on which a connection will be established.
+	Addr string
+
+	// ServerName is the name of this address.
+	// If non-empty, the ServerName is used as the transport certification authority for
+	// the address, instead of the hostname from the Dial target string. In most cases,
+	// this should not be set.
+	//
+	// If Type is GRPCLB, ServerName should be the name of the remote load
+	// balancer, not the name of the backend.
+	//
+	// WARNING: ServerName must only be populated with trusted values. It
+	// is insecure to populate it with data from untrusted inputs since untrusted
+	// values could be used to bypass the authority checks performed by TLS.
+	ServerName string
+
+	// Attributes contains arbitrary data about this address intended for
+	// consumption by the SubConn.
+	Attributes *attributes.Attributes
+
+	// BalancerAttributes contains arbitrary data about this address intended
+	// for consumption by the LB policy.  These attribes do not affect SubConn
+	// creation, connection establishment, handshaking, etc.
+	BalancerAttributes *attributes.Attributes
+
+	// Type is the type of this address.
+	//
+	// Deprecated: use Attributes instead.
+	Type AddressType
+
+	// Metadata is the information associated with Addr, which may be used
+	// to make load balancing decision.
+	//
+	// Deprecated: use Attributes instead.
+	Metadata interface{}
+}
+
+// Equal returns whether a and o are identical.  Metadata is compared directly,
+// not with any recursive introspection.
+func (a Address) Equal(o Address) bool {
+	return a.Addr == o.Addr && a.ServerName == o.ServerName &&
+		a.Attributes.Equal(o.Attributes) &&
+		a.BalancerAttributes.Equal(o.BalancerAttributes) &&
+		a.Type == o.Type && a.Metadata == o.Metadata
+}
+
+// String returns JSON formatted string representation of the address.
+func (a Address) String() string {
+	return pretty.ToJSON(a)
+}
+
+// BuildOptions includes additional information for the builder to create
+// the resolver.
+type BuildOptions struct {
+	// DisableServiceConfig indicates whether a resolver implementation should
+	// fetch service config data.
+	DisableServiceConfig bool
+	// DialCreds is the transport credentials used by the ClientConn for
+	// communicating with the target gRPC service (set via
+	// WithTransportCredentials). In cases where a name resolution service
+	// requires the same credentials, the resolver may use this field. In most
+	// cases though, it is not appropriate, and this field may be ignored.
+	DialCreds credentials.TransportCredentials
+	// CredsBundle is the credentials bundle used by the ClientConn for
+	// communicating with the target gRPC service (set via
+	// WithCredentialsBundle). In cases where a name resolution service
+	// requires the same credentials, the resolver may use this field. In most
+	// cases though, it is not appropriate, and this field may be ignored.
+	CredsBundle credentials.Bundle
+	// Dialer is the custom dialer used by the ClientConn for dialling the
+	// target gRPC service (set via WithDialer). In cases where a name
+	// resolution service requires the same dialer, the resolver may use this
+	// field. In most cases though, it is not appropriate, and this field may
+	// be ignored.
+	Dialer func(context.Context, string) (net.Conn, error)
+}
+
+// State contains the current Resolver state relevant to the ClientConn.
+type State struct {
+	// Addresses is the latest set of resolved addresses for the target.
+	Addresses []Address
+
+	// ServiceConfig contains the result from parsing the latest service
+	// config.  If it is nil, it indicates no service config is present or the
+	// resolver does not provide service configs.
+	ServiceConfig *serviceconfig.ParseResult
+
+	// Attributes contains arbitrary data about the resolver intended for
+	// consumption by the load balancing policy.
+	Attributes *attributes.Attributes
+}
+
+// ClientConn contains the callbacks for resolver to notify any updates
+// to the gRPC ClientConn.
+//
+// This interface is to be implemented by gRPC. Users should not need a
+// brand new implementation of this interface. For the situations like
+// testing, the new implementation should embed this interface. This allows
+// gRPC to add new methods to this interface.
+type ClientConn interface {
+	// UpdateState updates the state of the ClientConn appropriately.
+	UpdateState(State) error
+	// ReportError notifies the ClientConn that the Resolver encountered an
+	// error.  The ClientConn will notify the load balancer and begin calling
+	// ResolveNow on the Resolver with exponential backoff.
+	ReportError(error)
+	// NewAddress is called by resolver to notify ClientConn a new list
+	// of resolved addresses.
+	// The address list should be the complete list of resolved addresses.
+	//
+	// Deprecated: Use UpdateState instead.
+	NewAddress(addresses []Address)
+	// NewServiceConfig is called by resolver to notify ClientConn a new
+	// service config. The service config should be provided as a json string.
+	//
+	// Deprecated: Use UpdateState instead.
+	NewServiceConfig(serviceConfig string)
+	// ParseServiceConfig parses the provided service config and returns an
+	// object that provides the parsed config.
+	ParseServiceConfig(serviceConfigJSON string) *serviceconfig.ParseResult
+}
+
+// Target represents a target for gRPC, as specified in:
+// https://github.com/grpc/grpc/blob/master/doc/naming.md.
+// It is parsed from the target string that gets passed into Dial or DialContext
+// by the user. And gRPC passes it to the resolver and the balancer.
+//
+// If the target follows the naming spec, and the parsed scheme is registered
+// with gRPC, we will parse the target string according to the spec. If the
+// target does not contain a scheme or if the parsed scheme is not registered
+// (i.e. no corresponding resolver available to resolve the endpoint), we will
+// apply the default scheme, and will attempt to reparse it.
+//
+// Examples:
+//
+//   - "dns://some_authority/foo.bar"
+//     Target{Scheme: "dns", Authority: "some_authority", Endpoint: "foo.bar"}
+//   - "foo.bar"
+//     Target{Scheme: resolver.GetDefaultScheme(), Endpoint: "foo.bar"}
+//   - "unknown_scheme://authority/endpoint"
+//     Target{Scheme: resolver.GetDefaultScheme(), Endpoint: "unknown_scheme://authority/endpoint"}
+type Target struct {
+	// Deprecated: use URL.Scheme instead.
+	Scheme string
+	// Deprecated: use URL.Host instead.
+	Authority string
+	// URL contains the parsed dial target with an optional default scheme added
+	// to it if the original dial target contained no scheme or contained an
+	// unregistered scheme. Any query params specified in the original dial
+	// target can be accessed from here.
+	URL url.URL
+}
+
+// Endpoint retrieves endpoint without leading "/" from either `URL.Path`
+// or `URL.Opaque`. The latter is used when the former is empty.
+func (t Target) Endpoint() string {
+	endpoint := t.URL.Path
+	if endpoint == "" {
+		endpoint = t.URL.Opaque
+	}
+	// For targets of the form "[scheme]://[authority]/endpoint, the endpoint
+	// value returned from url.Parse() contains a leading "/". Although this is
+	// in accordance with RFC 3986, we do not want to break existing resolver
+	// implementations which expect the endpoint without the leading "/". So, we
+	// end up stripping the leading "/" here. But this will result in an
+	// incorrect parsing for something like "unix:///path/to/socket". Since we
+	// own the "unix" resolver, we can workaround in the unix resolver by using
+	// the `URL` field.
+	return strings.TrimPrefix(endpoint, "/")
+}
+
+// Builder creates a resolver that will be used to watch name resolution updates.
+type Builder interface {
+	// Build creates a new resolver for the given target.
+	//
+	// gRPC dial calls Build synchronously, and fails if the returned error is
+	// not nil.
+	Build(target Target, cc ClientConn, opts BuildOptions) (Resolver, error)
+	// Scheme returns the scheme supported by this resolver.
+	// Scheme is defined at https://github.com/grpc/grpc/blob/master/doc/naming.md.
+	Scheme() string
+}
+
+// ResolveNowOptions includes additional information for ResolveNow.
+type ResolveNowOptions struct{}
+
+// Resolver watches for the updates on the specified target.
+// Updates include address updates and service config updates.
+type Resolver interface {
+	// ResolveNow will be called by gRPC to try to resolve the target name
+	// again. It's just a hint, resolver can ignore this if it's not necessary.
+	//
+	// It could be called multiple times concurrently.
+	ResolveNow(ResolveNowOptions)
+	// Close closes the resolver.
+	Close()
+}
+
+// UnregisterForTesting removes the resolver builder with the given scheme from the
+// resolver map.
+// This function is for testing only.
+func UnregisterForTesting(scheme string) {
+	delete(m, scheme)
+}