зеркало из https://github.com/github/vitess-gh.git
74 строки
2.3 KiB
Go
74 строки
2.3 KiB
Go
// Copyright 2014, Google Inc. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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/*
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Package etcdtopo implements topo.Server with etcd as the backend.
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We expect the following behavior from the etcd client library:
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- Get and Delete return EcodeKeyNotFound if the node doesn't exist.
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- Create returns EcodeNodeExist if the node already exists.
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- Intermediate directories are always created automatically if necessary.
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- CompareAndSwap returns EcodeKeyNotFound if the node doesn't exist already.
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It returns EcodeTestFailed if the provided version index doesn't match.
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We follow these conventions within this package:
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- Call convertError(err) on any errors returned from the etcd client library.
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Functions defined in this package can be assumed to have already converted
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errors as necessary.
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*/
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package etcdtopo
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import (
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"sync"
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"github.com/youtube/vitess/go/vt/topo"
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)
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// Server is the implementation of topo.Server for etcd.
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type Server struct {
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// _global is a client configured to talk to a list of etcd instances
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// representing the global etcd cluster. It should be accessed with the
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// Server.getGlobal() method, which will initialize _global on first
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// invocation with the list of global addresses from the command-line flag.
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_global Client
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_globalOnce sync.Once
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// _cells contains clients configured to talk to a list of etcd instances
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// representing local etcd clusters. These should be accessed with the
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// Server.getCell() method, which will read the list of addresses for that
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// cell from the global cluster and create clients as needed.
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_cells map[string]*cellClient
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_cellsMutex sync.Mutex
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// newClient is the function this server uses to create a new Client.
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newClient func(machines []string) Client
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}
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// Close implements topo.Server.
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func (s *Server) Close() {
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}
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// GetKnownCells implements topo.Server.
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func (s *Server) GetKnownCells() ([]string, error) {
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resp, err := s.getGlobal().Get(cellsDirPath, true /* sort */, false /* recursive */)
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if err != nil {
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return nil, convertError(err)
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}
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return getNodeNames(resp)
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}
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// NewServer returns a new etcdtopo.Server.
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func NewServer() *Server {
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return &Server{
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_cells: make(map[string]*cellClient),
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newClient: newEtcdClient,
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}
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}
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func init() {
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topo.RegisterServer("etcd", NewServer())
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}
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