Refactor commands.

server/remove_command.go

@@ -0,0 +1,68 @@
+package server
+
+import (
+	"encoding/binary"
+	"path"
+
+	"github.com/coreos/etcd/store"
+	"github.com/coreos/go-raft"
+)
+
+func init() {
+	raft.RegisterCommand(&RemoveCommand{})
+}
+
+// The RemoveCommand removes a server from the cluster.
+type RemoveCommand struct {
+	Name string `json:"name"`
+}
+
+// The name of the remove command in the log
+func (c *RemoveCommand) CommandName() string {
+	return "etcd:remove"
+}
+
+// Remove a server from the cluster
+func (c *RemoveCommand) Apply(server *raft.Server) (interface{}, error) {
+	s, _ := server.StateMachine().(*store.Store)
+	r, _ := server.Context().(*RaftServer)
+
+	// remove machine in etcd storage
+	key := path.Join("_etcd/machines", c.Name)
+
+	_, err := s.Delete(key, false, server.CommitIndex(), server.Term())
+	// delete from stats
+	delete(r.followersStats.Followers, c.Name)
+
+	if err != nil {
+		return []byte{0}, err
+	}
+
+	// remove peer in raft
+	err = server.RemovePeer(c.Name)
+
+	if err != nil {
+		return []byte{0}, err
+	}
+
+	if c.Name == server.Name() {
+		// the removed node is this node
+
+		// if the node is not replaying the previous logs
+		// and the node has sent out a join request in this
+		// start. It is sure that this node received a new remove
+		// command and need to be removed
+		if server.CommitIndex() > r.joinIndex && r.joinIndex != 0 {
+			debugf("server [%s] is removed", server.Name())
+			os.Exit(0)
+		} else {
+			// else ignore remove
+			debugf("ignore previous remove command.")
+		}
+	}
+
+	b := make([]byte, 8)
+	binary.PutUvarint(b, server.CommitIndex())
+
+	return b, err
+}