route/vendor/google.golang.org/grpc/naming/naming.go

60 lines
2.0 KiB
Go

/*
*
* Copyright 2014 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 naming defines the naming API and related data structures for gRPC.
// The interface is EXPERIMENTAL and may be suject to change.
package naming
// Operation defines the corresponding operations for a name resolution change.
type Operation uint8
const (
// Add indicates a new address is added.
Add Operation = iota
// Delete indicates an exisiting address is deleted.
Delete
)
// Update defines a name resolution update. Notice that it is not valid having both
// empty string Addr and nil Metadata in an Update.
type Update struct {
// Op indicates the operation of the update.
Op Operation
// Addr is the updated address. It is empty string if there is no address update.
Addr string
// Metadata is the updated metadata. It is nil if there is no metadata update.
// Metadata is not required for a custom naming implementation.
Metadata interface{}
}
// Resolver creates a Watcher for a target to track its resolution changes.
type Resolver interface {
// Resolve creates a Watcher for target.
Resolve(target string) (Watcher, error)
}
// Watcher watches for the updates on the specified target.
type Watcher interface {
// Next blocks until an update or error happens. It may return one or more
// updates. The first call should get the full set of the results. It should
// return an error if and only if Watcher cannot recover.
Next() ([]*Update, error)
// Close closes the Watcher.
Close()
}