154 lines
3.7 KiB
Go
154 lines
3.7 KiB
Go
package main
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import (
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"encoding/json"
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"fmt"
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"github.com/coreos/etcd/store"
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"github.com/coreos/go-raft"
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"path"
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"time"
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)
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// A command represents an action to be taken on the replicated state machine.
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type Command interface {
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CommandName() string
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Apply(server *raft.Server) (interface{}, error)
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}
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// Set command
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type SetCommand struct {
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Key string `json:"key"`
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Value string `json:"value"`
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ExpireTime time.Time `json:"expireTime"`
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}
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// The name of the set command in the log
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func (c *SetCommand) CommandName() string {
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return "etcd:set"
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}
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// Set the key-value pair
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func (c *SetCommand) Apply(server *raft.Server) (interface{}, error) {
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return etcdStore.Set(c.Key, c.Value, c.ExpireTime, server.CommitIndex())
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}
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// TestAndSet command
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type TestAndSetCommand struct {
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Key string `json:"key"`
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Value string `json:"value"`
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PrevValue string `json: prevValue`
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ExpireTime time.Time `json:"expireTime"`
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}
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// The name of the testAndSet command in the log
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func (c *TestAndSetCommand) CommandName() string {
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return "testAndSet"
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}
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// Set the key-value pair if the current value of the key equals to the given prevValue
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func (c *TestAndSetCommand) Apply(server *raft.Server) (interface{}, error) {
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return etcdStore.TestAndSet(c.Key, c.PrevValue, c.Value, c.ExpireTime, server.CommitIndex())
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}
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// Get command
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type GetCommand struct {
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Key string `json:"key"`
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}
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// The name of the get command in the log
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func (c *GetCommand) CommandName() string {
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return "etcd:get"
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}
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// Get the value of key
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func (c *GetCommand) Apply(server *raft.Server) (interface{}, error) {
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return etcdStore.Get(c.Key)
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}
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// Delete command
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type DeleteCommand struct {
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Key string `json:"key"`
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}
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// The name of the delete command in the log
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func (c *DeleteCommand) CommandName() string {
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return "etcd:delete"
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}
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// Delete the key
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func (c *DeleteCommand) Apply(server *raft.Server) (interface{}, error) {
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return etcdStore.Delete(c.Key, server.CommitIndex())
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}
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// Watch command
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type WatchCommand struct {
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Key string `json:"key"`
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SinceIndex uint64 `json:"sinceIndex"`
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}
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// The name of the watch command in the log
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func (c *WatchCommand) CommandName() string {
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return "etcd:watch"
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}
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func (c *WatchCommand) Apply(server *raft.Server) (interface{}, error) {
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// create a new watcher
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watcher := store.NewWatcher()
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// add to the watchers list
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etcdStore.AddWatcher(c.Key, watcher, c.SinceIndex)
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// wait for the notification for any changing
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res := <-watcher.C
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if res == nil {
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return nil, fmt.Errorf("Clearing watch")
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}
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return json.Marshal(res)
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}
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// JoinCommand
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type JoinCommand struct {
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Name string `json:"name"`
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Hostname string `json:"hostName"`
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RaftPort int `json:"raftPort"`
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ClientPort int `json:"clientPort"`
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}
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// The name of the join command in the log
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func (c *JoinCommand) CommandName() string {
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return "etcd:join"
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}
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// Join a server to the cluster
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func (c *JoinCommand) Apply(raftServer *raft.Server) (interface{}, error) {
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// check if the join command is from a previous machine, who lost all its previous log.
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response, _ := etcdStore.RawGet(path.Join("_etcd/machines", c.Name))
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if response != nil {
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return []byte("join success"), nil
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}
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// check machine number in the cluster
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num := machineNum()
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if num == maxClusterSize {
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return []byte("join fail"), fmt.Errorf(errors[103])
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}
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// add peer in raft
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err := raftServer.AddPeer(c.Name)
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// add machine in etcd storage
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key := path.Join("_etcd/machines", c.Name)
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value := fmt.Sprintf("%s,%d,%d", c.Hostname, c.RaftPort, c.ClientPort)
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etcdStore.Set(key, value, time.Unix(0, 0), raftServer.CommitIndex())
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return []byte("join success"), err
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}
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func (c *JoinCommand) NodeName() string {
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return c.Name
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}
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