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fsm.go
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fsm.go
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package consul
import (
"errors"
"fmt"
"io"
"log"
"time"
"github.com/armon/go-metrics"
"github.com/hashicorp/consul/consul/state"
"github.com/hashicorp/consul/consul/structs"
"github.com/hashicorp/go-msgpack/codec"
"github.com/hashicorp/raft"
)
// msgpackHandle is a shared handle for encoding/decoding msgpack payloads
var msgpackHandle = &codec.MsgpackHandle{}
// consulFSM implements a finite state machine that is used
// along with Raft to provide strong consistency. We implement
// this outside the Server to avoid exposing this outside the package.
type consulFSM struct {
logOutput io.Writer
logger *log.Logger
path string
state *state.StateStore
gc *state.TombstoneGC
}
// consulSnapshot is used to provide a snapshot of the current
// state in a way that can be accessed concurrently with operations
// that may modify the live state.
type consulSnapshot struct {
state *state.StateSnapshot
}
// snapshotHeader is the first entry in our snapshot
type snapshotHeader struct {
// LastIndex is the last index that affects the data.
// This is used when we do the restore for watchers.
LastIndex uint64
}
// NewFSMPath is used to construct a new FSM with a blank state
func NewFSM(gc *state.TombstoneGC, logOutput io.Writer) (*consulFSM, error) {
stateNew, err := state.NewStateStore(gc)
if err != nil {
return nil, err
}
fsm := &consulFSM{
logOutput: logOutput,
logger: log.New(logOutput, "", log.LstdFlags),
state: stateNew,
gc: gc,
}
return fsm, nil
}
// State is used to return a handle to the current state
func (c *consulFSM) State() *state.StateStore {
return c.state
}
func (c *consulFSM) Apply(log *raft.Log) interface{} {
buf := log.Data
msgType := structs.MessageType(buf[0])
// Check if this message type should be ignored when unknown. This is
// used so that new commands can be added with developer control if older
// versions can safely ignore the command, or if they should crash.
ignoreUnknown := false
if msgType&structs.IgnoreUnknownTypeFlag == structs.IgnoreUnknownTypeFlag {
msgType &= ^structs.IgnoreUnknownTypeFlag
ignoreUnknown = true
}
switch msgType {
case structs.RegisterRequestType:
return c.applyRegister(buf[1:], log.Index)
case structs.DeregisterRequestType:
return c.applyDeregister(buf[1:], log.Index)
case structs.KVSRequestType:
return c.applyKVSOperation(buf[1:], log.Index)
case structs.SessionRequestType:
return c.applySessionOperation(buf[1:], log.Index)
case structs.ACLRequestType:
return c.applyACLOperation(buf[1:], log.Index)
case structs.TombstoneRequestType:
return c.applyTombstoneOperation(buf[1:], log.Index)
case structs.CoordinateBatchUpdateType:
return c.applyCoordinateBatchUpdate(buf[1:], log.Index)
case structs.PreparedQueryRequestType:
return c.applyPreparedQueryOperation(buf[1:], log.Index)
default:
if ignoreUnknown {
c.logger.Printf("[WARN] consul.fsm: ignoring unknown message type (%d), upgrade to newer version", msgType)
return nil
} else {
panic(fmt.Errorf("failed to apply request: %#v", buf))
}
}
}
func (c *consulFSM) applyRegister(buf []byte, index uint64) interface{} {
defer metrics.MeasureSince([]string{"consul", "fsm", "register"}, time.Now())
var req structs.RegisterRequest
if err := structs.Decode(buf, &req); err != nil {
panic(fmt.Errorf("failed to decode request: %v", err))
}
// Apply all updates in a single transaction
if err := c.state.EnsureRegistration(index, &req); err != nil {
c.logger.Printf("[INFO] consul.fsm: EnsureRegistration failed: %v", err)
return err
}
return nil
}
func (c *consulFSM) applyDeregister(buf []byte, index uint64) interface{} {
defer metrics.MeasureSince([]string{"consul", "fsm", "deregister"}, time.Now())
var req structs.DeregisterRequest
if err := structs.Decode(buf, &req); err != nil {
panic(fmt.Errorf("failed to decode request: %v", err))
}
// Either remove the service entry or the whole node
if req.ServiceID != "" {
if err := c.state.DeleteService(index, req.Node, req.ServiceID); err != nil {
c.logger.Printf("[INFO] consul.fsm: DeleteNodeService failed: %v", err)
return err
}
} else if req.CheckID != "" {
if err := c.state.DeleteCheck(index, req.Node, req.CheckID); err != nil {
c.logger.Printf("[INFO] consul.fsm: DeleteNodeCheck failed: %v", err)
return err
}
} else {
if err := c.state.DeleteNode(index, req.Node); err != nil {
c.logger.Printf("[INFO] consul.fsm: DeleteNode failed: %v", err)
return err
}
}
return nil
}
func (c *consulFSM) applyKVSOperation(buf []byte, index uint64) interface{} {
var req structs.KVSRequest
if err := structs.Decode(buf, &req); err != nil {
panic(fmt.Errorf("failed to decode request: %v", err))
}
defer metrics.MeasureSince([]string{"consul", "fsm", "kvs", string(req.Op)}, time.Now())
switch req.Op {
case structs.KVSSet:
return c.state.KVSSet(index, &req.DirEnt)
case structs.KVSDelete:
return c.state.KVSDelete(index, req.DirEnt.Key)
case structs.KVSDeleteCAS:
act, err := c.state.KVSDeleteCAS(index, req.DirEnt.ModifyIndex, req.DirEnt.Key)
if err != nil {
return err
} else {
return act
}
case structs.KVSDeleteTree:
return c.state.KVSDeleteTree(index, req.DirEnt.Key)
case structs.KVSCAS:
act, err := c.state.KVSSetCAS(index, &req.DirEnt)
if err != nil {
return err
} else {
return act
}
case structs.KVSLock:
act, err := c.state.KVSLock(index, &req.DirEnt)
if err != nil {
return err
} else {
return act
}
case structs.KVSUnlock:
act, err := c.state.KVSUnlock(index, &req.DirEnt)
if err != nil {
return err
} else {
return act
}
default:
err := errors.New(fmt.Sprintf("Invalid KVS operation '%s'", req.Op))
c.logger.Printf("[WARN] consul.fsm: %v", err)
return err
}
}
func (c *consulFSM) applySessionOperation(buf []byte, index uint64) interface{} {
var req structs.SessionRequest
if err := structs.Decode(buf, &req); err != nil {
panic(fmt.Errorf("failed to decode request: %v", err))
}
defer metrics.MeasureSince([]string{"consul", "fsm", "session", string(req.Op)}, time.Now())
switch req.Op {
case structs.SessionCreate:
if err := c.state.SessionCreate(index, &req.Session); err != nil {
return err
} else {
return req.Session.ID
}
case structs.SessionDestroy:
return c.state.SessionDestroy(index, req.Session.ID)
default:
c.logger.Printf("[WARN] consul.fsm: Invalid Session operation '%s'", req.Op)
return fmt.Errorf("Invalid Session operation '%s'", req.Op)
}
}
func (c *consulFSM) applyACLOperation(buf []byte, index uint64) interface{} {
var req structs.ACLRequest
if err := structs.Decode(buf, &req); err != nil {
panic(fmt.Errorf("failed to decode request: %v", err))
}
defer metrics.MeasureSince([]string{"consul", "fsm", "acl", string(req.Op)}, time.Now())
switch req.Op {
case structs.ACLForceSet, structs.ACLSet:
if err := c.state.ACLSet(index, &req.ACL); err != nil {
return err
} else {
return req.ACL.ID
}
case structs.ACLDelete:
return c.state.ACLDelete(index, req.ACL.ID)
default:
c.logger.Printf("[WARN] consul.fsm: Invalid ACL operation '%s'", req.Op)
return fmt.Errorf("Invalid ACL operation '%s'", req.Op)
}
}
func (c *consulFSM) applyTombstoneOperation(buf []byte, index uint64) interface{} {
var req structs.TombstoneRequest
if err := structs.Decode(buf, &req); err != nil {
panic(fmt.Errorf("failed to decode request: %v", err))
}
defer metrics.MeasureSince([]string{"consul", "fsm", "tombstone", string(req.Op)}, time.Now())
switch req.Op {
case structs.TombstoneReap:
return c.state.ReapTombstones(req.ReapIndex)
default:
c.logger.Printf("[WARN] consul.fsm: Invalid Tombstone operation '%s'", req.Op)
return fmt.Errorf("Invalid Tombstone operation '%s'", req.Op)
}
}
// applyCoordinateBatchUpdate processes a batch of coordinate updates and applies
// them in a single underlying transaction. This interface isn't 1:1 with the outer
// update interface that the coordinate endpoint exposes, so we made it single
// purpose and avoided the opcode convention.
func (c *consulFSM) applyCoordinateBatchUpdate(buf []byte, index uint64) interface{} {
var updates structs.Coordinates
if err := structs.Decode(buf, &updates); err != nil {
panic(fmt.Errorf("failed to decode batch updates: %v", err))
}
defer metrics.MeasureSince([]string{"consul", "fsm", "coordinate", "batch-update"}, time.Now())
if err := c.state.CoordinateBatchUpdate(index, updates); err != nil {
return err
}
return nil
}
// applyPreparedQueryOperation applies the given prepared query operation to the
// state store.
func (c *consulFSM) applyPreparedQueryOperation(buf []byte, index uint64) interface{} {
var req structs.PreparedQueryRequest
if err := structs.Decode(buf, &req); err != nil {
panic(fmt.Errorf("failed to decode request: %v", err))
}
defer metrics.MeasureSince([]string{"consul", "fsm", "prepared-query", string(req.Op)}, time.Now())
switch req.Op {
case structs.PreparedQueryCreate, structs.PreparedQueryUpdate:
return c.state.PreparedQuerySet(index, req.Query)
case structs.PreparedQueryDelete:
return c.state.PreparedQueryDelete(index, req.Query.ID)
default:
c.logger.Printf("[WARN] consul.fsm: Invalid PreparedQuery operation '%s'", req.Op)
return fmt.Errorf("Invalid PreparedQuery operation '%s'", req.Op)
}
}
func (c *consulFSM) Snapshot() (raft.FSMSnapshot, error) {
defer func(start time.Time) {
c.logger.Printf("[INFO] consul.fsm: snapshot created in %v", time.Now().Sub(start))
}(time.Now())
return &consulSnapshot{c.state.Snapshot()}, nil
}
func (c *consulFSM) Restore(old io.ReadCloser) error {
defer old.Close()
// Create a new state store
stateNew, err := state.NewStateStore(c.gc)
if err != nil {
return err
}
c.state = stateNew
// Set up a new restore transaction
restore := c.state.Restore()
defer restore.Abort()
// Create a decoder
dec := codec.NewDecoder(old, msgpackHandle)
// Read in the header
var header snapshotHeader
if err := dec.Decode(&header); err != nil {
return err
}
// Populate the new state
msgType := make([]byte, 1)
for {
// Read the message type
_, err := old.Read(msgType)
if err == io.EOF {
break
} else if err != nil {
return err
}
// Decode
switch structs.MessageType(msgType[0]) {
case structs.RegisterRequestType:
var req structs.RegisterRequest
if err := dec.Decode(&req); err != nil {
return err
}
if err := restore.Registration(header.LastIndex, &req); err != nil {
return err
}
case structs.KVSRequestType:
var req structs.DirEntry
if err := dec.Decode(&req); err != nil {
return err
}
if err := restore.KVS(&req); err != nil {
return err
}
case structs.TombstoneRequestType:
var req structs.DirEntry
if err := dec.Decode(&req); err != nil {
return err
}
// For historical reasons, these are serialized in the
// snapshots as KV entries. We want to keep the snapshot
// format compatible with pre-0.6 versions for now.
stone := &state.Tombstone{
Key: req.Key,
Index: req.ModifyIndex,
}
if err := restore.Tombstone(stone); err != nil {
return err
}
case structs.SessionRequestType:
var req structs.Session
if err := dec.Decode(&req); err != nil {
return err
}
if err := restore.Session(&req); err != nil {
return err
}
case structs.ACLRequestType:
var req structs.ACL
if err := dec.Decode(&req); err != nil {
return err
}
if err := restore.ACL(&req); err != nil {
return err
}
case structs.CoordinateBatchUpdateType:
var req structs.Coordinates
if err := dec.Decode(&req); err != nil {
return err
}
if err := restore.Coordinates(header.LastIndex, req); err != nil {
return err
}
case structs.PreparedQueryRequestType:
var req structs.PreparedQuery
if err := dec.Decode(&req); err != nil {
return err
}
if err := restore.PreparedQuery(&req); err != nil {
return err
}
default:
return fmt.Errorf("Unrecognized msg type: %v", msgType)
}
}
restore.Commit()
return nil
}
func (s *consulSnapshot) Persist(sink raft.SnapshotSink) error {
defer metrics.MeasureSince([]string{"consul", "fsm", "persist"}, time.Now())
// Register the nodes
encoder := codec.NewEncoder(sink, msgpackHandle)
// Write the header
header := snapshotHeader{
LastIndex: s.state.LastIndex(),
}
if err := encoder.Encode(&header); err != nil {
sink.Cancel()
return err
}
if err := s.persistNodes(sink, encoder); err != nil {
sink.Cancel()
return err
}
if err := s.persistSessions(sink, encoder); err != nil {
sink.Cancel()
return err
}
if err := s.persistACLs(sink, encoder); err != nil {
sink.Cancel()
return err
}
if err := s.persistKVs(sink, encoder); err != nil {
sink.Cancel()
return err
}
if err := s.persistTombstones(sink, encoder); err != nil {
sink.Cancel()
return err
}
if err := s.persistPreparedQueries(sink, encoder); err != nil {
sink.Cancel()
return err
}
return nil
}
func (s *consulSnapshot) persistNodes(sink raft.SnapshotSink,
encoder *codec.Encoder) error {
// Get all the nodes
nodes, err := s.state.Nodes()
if err != nil {
return err
}
// Register each node
for node := nodes.Next(); node != nil; node = nodes.Next() {
n := node.(*structs.Node)
req := structs.RegisterRequest{
Node: n.Node,
Address: n.Address,
}
// Register the node itself
sink.Write([]byte{byte(structs.RegisterRequestType)})
if err := encoder.Encode(&req); err != nil {
return err
}
// Register each service this node has
services, err := s.state.Services(n.Node)
if err != nil {
return err
}
for service := services.Next(); service != nil; service = services.Next() {
sink.Write([]byte{byte(structs.RegisterRequestType)})
req.Service = service.(*structs.ServiceNode).ToNodeService()
if err := encoder.Encode(&req); err != nil {
return err
}
}
// Register each check this node has
req.Service = nil
checks, err := s.state.Checks(n.Node)
if err != nil {
return err
}
for check := checks.Next(); check != nil; check = checks.Next() {
sink.Write([]byte{byte(structs.RegisterRequestType)})
req.Check = check.(*structs.HealthCheck)
if err := encoder.Encode(&req); err != nil {
return err
}
}
}
// Save the coordinates separately since they are not part of the
// register request interface. To avoid copying them out, we turn
// them into batches with a single coordinate each.
coords, err := s.state.Coordinates()
if err != nil {
return err
}
for coord := coords.Next(); coord != nil; coord = coords.Next() {
sink.Write([]byte{byte(structs.CoordinateBatchUpdateType)})
updates := structs.Coordinates{coord.(*structs.Coordinate)}
if err := encoder.Encode(&updates); err != nil {
return err
}
}
return nil
}
func (s *consulSnapshot) persistSessions(sink raft.SnapshotSink,
encoder *codec.Encoder) error {
sessions, err := s.state.Sessions()
if err != nil {
return err
}
for session := sessions.Next(); session != nil; session = sessions.Next() {
sink.Write([]byte{byte(structs.SessionRequestType)})
if err := encoder.Encode(session.(*structs.Session)); err != nil {
return err
}
}
return nil
}
func (s *consulSnapshot) persistACLs(sink raft.SnapshotSink,
encoder *codec.Encoder) error {
acls, err := s.state.ACLs()
if err != nil {
return err
}
for acl := acls.Next(); acl != nil; acl = acls.Next() {
sink.Write([]byte{byte(structs.ACLRequestType)})
if err := encoder.Encode(acl.(*structs.ACL)); err != nil {
return err
}
}
return nil
}
func (s *consulSnapshot) persistKVs(sink raft.SnapshotSink,
encoder *codec.Encoder) error {
entries, err := s.state.KVs()
if err != nil {
return err
}
for entry := entries.Next(); entry != nil; entry = entries.Next() {
sink.Write([]byte{byte(structs.KVSRequestType)})
if err := encoder.Encode(entry.(*structs.DirEntry)); err != nil {
return err
}
}
return nil
}
func (s *consulSnapshot) persistTombstones(sink raft.SnapshotSink,
encoder *codec.Encoder) error {
stones, err := s.state.Tombstones()
if err != nil {
return err
}
for stone := stones.Next(); stone != nil; stone = stones.Next() {
sink.Write([]byte{byte(structs.TombstoneRequestType)})
// For historical reasons, these are serialized in the snapshots
// as KV entries. We want to keep the snapshot format compatible
// with pre-0.6 versions for now.
s := stone.(*state.Tombstone)
fake := &structs.DirEntry{
Key: s.Key,
RaftIndex: structs.RaftIndex{
ModifyIndex: s.Index,
},
}
if err := encoder.Encode(fake); err != nil {
return err
}
}
return nil
}
func (s *consulSnapshot) persistPreparedQueries(sink raft.SnapshotSink,
encoder *codec.Encoder) error {
queries, err := s.state.PreparedQueries()
if err != nil {
return err
}
for query := queries.Next(); query != nil; query = queries.Next() {
sink.Write([]byte{byte(structs.PreparedQueryRequestType)})
if err := encoder.Encode(query.(*structs.PreparedQuery)); err != nil {
return err
}
}
return nil
}
func (s *consulSnapshot) Release() {
s.state.Close()
}