blob: c2e0871e6f8b600b23c5432048c1a006beac3849 [file] [log] [blame]
/*
*
* Copyright 2014, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
// 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()
}