github.com/macb/etcd@v0.3.1-0.20140227003422-a60481c6b1a0/server/remove_command.go (about)

     1  package server
     2  
     3  import (
     4  	"encoding/binary"
     5  	"os"
     6  
     7  	"github.com/coreos/etcd/log"
     8  	"github.com/coreos/etcd/third_party/github.com/coreos/raft"
     9  )
    10  
    11  func init() {
    12  	raft.RegisterCommand(&RemoveCommand{})
    13  }
    14  
    15  // The RemoveCommand removes a server from the cluster.
    16  type RemoveCommand struct {
    17  	Name string `json:"name"`
    18  }
    19  
    20  // The name of the remove command in the log
    21  func (c *RemoveCommand) CommandName() string {
    22  	return "etcd:remove"
    23  }
    24  
    25  // Remove a server from the cluster
    26  func (c *RemoveCommand) Apply(context raft.Context) (interface{}, error) {
    27  	ps, _ := context.Server().Context().(*PeerServer)
    28  
    29  	// Remove node from the shared registry.
    30  	err := ps.registry.Unregister(c.Name)
    31  
    32  	// Delete from stats
    33  	delete(ps.followersStats.Followers, c.Name)
    34  
    35  	if err != nil {
    36  		log.Debugf("Error while unregistering: %s (%v)", c.Name, err)
    37  		return []byte{0}, err
    38  	}
    39  
    40  	// Remove peer in raft
    41  	err = context.Server().RemovePeer(c.Name)
    42  	if err != nil {
    43  		log.Debugf("Unable to remove peer: %s (%v)", c.Name, err)
    44  		return []byte{0}, err
    45  	}
    46  
    47  	if c.Name == context.Server().Name() {
    48  		// the removed node is this node
    49  
    50  		// if the node is not replaying the previous logs
    51  		// and the node has sent out a join request in this
    52  		// start. It is sure that this node received a new remove
    53  		// command and need to be removed
    54  		if context.CommitIndex() > ps.joinIndex && ps.joinIndex != 0 {
    55  			log.Debugf("server [%s] is removed", context.Server().Name())
    56  			os.Exit(0)
    57  		} else {
    58  			// else ignore remove
    59  			log.Debugf("ignore previous remove command.")
    60  		}
    61  	}
    62  
    63  	b := make([]byte, 8)
    64  	binary.PutUvarint(b, context.CommitIndex())
    65  
    66  	return b, err
    67  }