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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 | 158 |
1 files changed, 158 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..145cf477e --- /dev/null +++ b/vendor/google.golang.org/grpc/resolver/resolver.go @@ -0,0 +1,158 @@ +/* + * + * 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 + +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. +type AddressType uint8 + +const ( + // Backend indicates the address is for a backend server. + Backend AddressType = iota + // GRPCLB indicates the address is for a grpclb load balancer. + GRPCLB +) + +// Address represents a server the client connects to. +// This is the EXPERIMENTAL API and may be changed or extended in the future. +type Address struct { + // Addr is the server address on which a connection will be established. + Addr string + // Type is the type of this address. + Type AddressType + // ServerName is the name of this address. + // + // e.g. if Type is GRPCLB, ServerName should be the name of the remote load + // balancer, not the name of the backend. + ServerName string + // Metadata is the information associated with Addr, which may be used + // to make load balancing decision. + Metadata interface{} +} + +// BuildOption includes additional information for the builder to create +// the resolver. +type BuildOption struct { + // DisableServiceConfig indicates whether resolver should fetch service config data. + DisableServiceConfig bool +} + +// 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 { + // 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. + 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. + NewServiceConfig(serviceConfig string) +} + +// Target represents a target for gRPC, as specified in: +// https://github.com/grpc/grpc/blob/master/doc/naming.md. +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 BuildOption) (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 +} + +// ResolveNowOption includes additional information for ResolveNow. +type ResolveNowOption 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(ResolveNowOption) + // 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) +} |