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Diffstat (limited to 'vendor/google.golang.org/grpc/resolver/resolver.go')
| -rw-r--r-- | vendor/google.golang.org/grpc/resolver/resolver.go | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/resolver/resolver.go b/vendor/google.golang.org/grpc/resolver/resolver.go new file mode 100644 index 000000000..e9fa8e33d --- /dev/null +++ b/vendor/google.golang.org/grpc/resolver/resolver.go @@ -0,0 +1,260 @@ +/* + * + * 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" + + "google.golang.org/grpc/attributes" + "google.golang.org/grpc/credentials" + "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 load balancing policy. + Attributes *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{} +} + +// 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) + // 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. e.g. "dns://some_authority/foo.bar" will be parsed +// into &Target{Scheme: "dns", Authority: "some_authority", Endpoint: "foo.bar"} +// +// If the target does not contain a scheme, we will apply the default scheme, and set the Target to +// be the full target string. e.g. "foo.bar" will be parsed into +// &Target{Scheme: resolver.GetDefaultScheme(), Endpoint: "foo.bar"}. +// +// If the parsed scheme is not registered (i.e. no corresponding resolver available to resolve the +// endpoint), we set the Scheme to be the default scheme, and set the Endpoint to be the full target +// string. e.g. target string "unknown_scheme://authority/endpoint" will be parsed into +// &Target{Scheme: resolver.GetDefaultScheme(), Endpoint: "unknown_scheme://authority/endpoint"}. +type Target struct { + Scheme string + Authority string + Endpoint string +} + +// 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) +} |