450 lines
11 KiB
Go
450 lines
11 KiB
Go
package consul
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import (
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"log"
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"time"
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"github.com/hashicorp/consul/consul/structs"
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"github.com/hashicorp/go-msgpack/codec"
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"github.com/hashicorp/raft"
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)
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// consulFSM implements a finite state machine that is used
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// along with Raft to provide strong consistency. We implement
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// this outside the Server to avoid exposing this outside the package.
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type consulFSM struct {
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logOutput io.Writer
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logger *log.Logger
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path string
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state *StateStore
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}
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// consulSnapshot is used to provide a snapshot of the current
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// state in a way that can be accessed concurrently with operations
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// that may modify the live state.
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type consulSnapshot struct {
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state *StateSnapshot
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}
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// snapshotHeader is the first entry in our snapshot
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type snapshotHeader struct {
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// LastIndex is the last index that affects the data.
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// This is used when we do the restore for watchers.
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LastIndex uint64
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}
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// NewFSMPath is used to construct a new FSM with a blank state
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func NewFSM(path string, logOutput io.Writer) (*consulFSM, error) {
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// Create a temporary path for the state store
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tmpPath, err := ioutil.TempDir(path, "state")
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if err != nil {
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return nil, err
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}
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// Create a state store
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state, err := NewStateStorePath(tmpPath, logOutput)
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if err != nil {
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return nil, err
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}
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fsm := &consulFSM{
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logOutput: logOutput,
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logger: log.New(logOutput, "", log.LstdFlags),
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path: path,
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state: state,
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}
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return fsm, nil
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}
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// Close is used to cleanup resources associated with the FSM
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func (c *consulFSM) Close() error {
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return c.state.Close()
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}
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// State is used to return a handle to the current state
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func (c *consulFSM) State() *StateStore {
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return c.state
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}
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func (c *consulFSM) Apply(log *raft.Log) interface{} {
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buf := log.Data
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switch structs.MessageType(buf[0]) {
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case structs.RegisterRequestType:
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return c.decodeRegister(buf[1:], log.Index)
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case structs.DeregisterRequestType:
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return c.applyDeregister(buf[1:], log.Index)
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case structs.KVSRequestType:
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return c.applyKVSOperation(buf[1:], log.Index)
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case structs.SessionRequestType:
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return c.applySessionOperation(buf[1:], log.Index)
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case structs.ACLRequestType:
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return c.applyACLOperation(buf[1:], log.Index)
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default:
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panic(fmt.Errorf("failed to apply request: %#v", buf))
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}
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}
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func (c *consulFSM) decodeRegister(buf []byte, index uint64) interface{} {
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var req structs.RegisterRequest
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if err := structs.Decode(buf, &req); err != nil {
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panic(fmt.Errorf("failed to decode request: %v", err))
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}
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return c.applyRegister(&req, index)
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}
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func (c *consulFSM) applyRegister(req *structs.RegisterRequest, index uint64) interface{} {
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// Apply all updates in a single transaction
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if err := c.state.EnsureRegistration(index, req); err != nil {
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c.logger.Printf("[INFO] consul.fsm: EnsureRegistration failed: %v", err)
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return err
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}
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return nil
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}
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func (c *consulFSM) applyDeregister(buf []byte, index uint64) interface{} {
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var req structs.DeregisterRequest
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if err := structs.Decode(buf, &req); err != nil {
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panic(fmt.Errorf("failed to decode request: %v", err))
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}
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// Either remove the service entry or the whole node
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if req.ServiceID != "" {
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if err := c.state.DeleteNodeService(index, req.Node, req.ServiceID); err != nil {
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c.logger.Printf("[INFO] consul.fsm: DeleteNodeService failed: %v", err)
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return err
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}
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} else if req.CheckID != "" {
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if err := c.state.DeleteNodeCheck(index, req.Node, req.CheckID); err != nil {
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c.logger.Printf("[INFO] consul.fsm: DeleteNodeCheck failed: %v", err)
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return err
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}
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} else {
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if err := c.state.DeleteNode(index, req.Node); err != nil {
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c.logger.Printf("[INFO] consul.fsm: DeleteNode failed: %v", err)
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return err
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}
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}
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return nil
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}
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func (c *consulFSM) applyKVSOperation(buf []byte, index uint64) interface{} {
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var req structs.KVSRequest
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if err := structs.Decode(buf, &req); err != nil {
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panic(fmt.Errorf("failed to decode request: %v", err))
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}
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switch req.Op {
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case structs.KVSSet:
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return c.state.KVSSet(index, &req.DirEnt)
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case structs.KVSDelete:
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return c.state.KVSDelete(index, req.DirEnt.Key)
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case structs.KVSDeleteTree:
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return c.state.KVSDeleteTree(index, req.DirEnt.Key)
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case structs.KVSCAS:
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act, err := c.state.KVSCheckAndSet(index, &req.DirEnt)
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if err != nil {
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return err
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} else {
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return act
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}
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case structs.KVSLock:
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act, err := c.state.KVSLock(index, &req.DirEnt)
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if err != nil {
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return err
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} else {
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return act
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}
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case structs.KVSUnlock:
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act, err := c.state.KVSUnlock(index, &req.DirEnt)
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if err != nil {
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return err
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} else {
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return act
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}
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default:
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err := errors.New(fmt.Sprintf("Invalid KVS operation '%s'", req.Op))
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c.logger.Printf("[WARN] consul.fsm: %v", err)
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return err
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}
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}
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func (c *consulFSM) applySessionOperation(buf []byte, index uint64) interface{} {
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var req structs.SessionRequest
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if err := structs.Decode(buf, &req); err != nil {
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panic(fmt.Errorf("failed to decode request: %v", err))
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}
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switch req.Op {
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case structs.SessionCreate:
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if err := c.state.SessionCreate(index, &req.Session); err != nil {
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return err
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} else {
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return req.Session.ID
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}
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case structs.SessionDestroy:
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return c.state.SessionDestroy(index, req.Session.ID)
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default:
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c.logger.Printf("[WARN] consul.fsm: Invalid Session operation '%s'", req.Op)
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return fmt.Errorf("Invalid Session operation '%s'", req.Op)
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}
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}
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func (c *consulFSM) applyACLOperation(buf []byte, index uint64) interface{} {
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var req structs.ACLRequest
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if err := structs.Decode(buf, &req); err != nil {
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panic(fmt.Errorf("failed to decode request: %v", err))
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}
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switch req.Op {
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case structs.ACLForceSet:
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fallthrough
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case structs.ACLSet:
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if err := c.state.ACLSet(index, &req.ACL); err != nil {
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return err
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} else {
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return req.ACL.ID
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}
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case structs.ACLDelete:
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return c.state.ACLDelete(index, req.ACL.ID)
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default:
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c.logger.Printf("[WARN] consul.fsm: Invalid ACL operation '%s'", req.Op)
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return fmt.Errorf("Invalid ACL operation '%s'", req.Op)
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}
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}
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func (c *consulFSM) Snapshot() (raft.FSMSnapshot, error) {
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defer func(start time.Time) {
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c.logger.Printf("[INFO] consul.fsm: snapshot created in %v", time.Now().Sub(start))
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}(time.Now())
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// Create a new snapshot
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snap, err := c.state.Snapshot()
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if err != nil {
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return nil, err
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}
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return &consulSnapshot{snap}, nil
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}
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func (c *consulFSM) Restore(old io.ReadCloser) error {
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defer old.Close()
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// Create a temporary path for the state store
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tmpPath, err := ioutil.TempDir(c.path, "state")
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if err != nil {
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return err
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}
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// Create a new state store
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state, err := NewStateStorePath(tmpPath, c.logOutput)
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if err != nil {
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return err
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}
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c.state.Close()
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c.state = state
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// Create a decoder
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dec := codec.NewDecoder(old, msgpackHandle)
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// Read in the header
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var header snapshotHeader
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if err := dec.Decode(&header); err != nil {
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return err
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}
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// Populate the new state
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msgType := make([]byte, 1)
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for {
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// Read the message type
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_, err := old.Read(msgType)
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if err == io.EOF {
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break
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} else if err != nil {
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return err
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}
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// Decode
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switch structs.MessageType(msgType[0]) {
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case structs.RegisterRequestType:
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var req structs.RegisterRequest
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if err := dec.Decode(&req); err != nil {
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return err
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}
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c.applyRegister(&req, header.LastIndex)
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case structs.KVSRequestType:
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var req structs.DirEntry
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if err := dec.Decode(&req); err != nil {
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return err
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}
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if err := c.state.KVSRestore(&req); err != nil {
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return err
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}
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case structs.SessionRequestType:
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var req structs.Session
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if err := dec.Decode(&req); err != nil {
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return err
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}
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if err := c.state.SessionRestore(&req); err != nil {
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return err
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}
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case structs.ACLRequestType:
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var req structs.ACL
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if err := dec.Decode(&req); err != nil {
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return err
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}
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if err := c.state.ACLRestore(&req); err != nil {
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return err
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}
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default:
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return fmt.Errorf("Unrecognized msg type: %v", msgType)
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}
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}
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return nil
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}
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func (s *consulSnapshot) Persist(sink raft.SnapshotSink) error {
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// Register the nodes
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encoder := codec.NewEncoder(sink, msgpackHandle)
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// Write the header
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header := snapshotHeader{
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LastIndex: s.state.LastIndex(),
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}
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if err := encoder.Encode(&header); err != nil {
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sink.Cancel()
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return err
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}
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if err := s.persistNodes(sink, encoder); err != nil {
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sink.Cancel()
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return err
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}
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if err := s.persistSessions(sink, encoder); err != nil {
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sink.Cancel()
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return err
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}
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if err := s.persistACLs(sink, encoder); err != nil {
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sink.Cancel()
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return err
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}
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if err := s.persistKV(sink, encoder); err != nil {
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sink.Cancel()
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return err
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}
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return nil
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}
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func (s *consulSnapshot) persistNodes(sink raft.SnapshotSink,
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encoder *codec.Encoder) error {
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// Get all the nodes
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nodes := s.state.Nodes()
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// Register each node
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var req structs.RegisterRequest
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for i := 0; i < len(nodes); i++ {
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req = structs.RegisterRequest{
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Node: nodes[i].Node,
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Address: nodes[i].Address,
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}
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// Register the node itself
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sink.Write([]byte{byte(structs.RegisterRequestType)})
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if err := encoder.Encode(&req); err != nil {
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return err
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}
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// Register each service this node has
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services := s.state.NodeServices(nodes[i].Node)
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for _, srv := range services.Services {
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req.Service = srv
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sink.Write([]byte{byte(structs.RegisterRequestType)})
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if err := encoder.Encode(&req); err != nil {
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return err
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}
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}
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// Register each check this node has
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req.Service = nil
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checks := s.state.NodeChecks(nodes[i].Node)
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for _, check := range checks {
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req.Check = check
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sink.Write([]byte{byte(structs.RegisterRequestType)})
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if err := encoder.Encode(&req); err != nil {
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return err
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}
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}
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}
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return nil
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}
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func (s *consulSnapshot) persistSessions(sink raft.SnapshotSink,
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encoder *codec.Encoder) error {
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sessions, err := s.state.SessionList()
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if err != nil {
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return err
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}
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for _, s := range sessions {
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sink.Write([]byte{byte(structs.SessionRequestType)})
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if err := encoder.Encode(s); err != nil {
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return err
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}
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}
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return nil
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}
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func (s *consulSnapshot) persistACLs(sink raft.SnapshotSink,
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encoder *codec.Encoder) error {
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acls, err := s.state.ACLList()
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if err != nil {
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return err
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}
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for _, s := range acls {
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sink.Write([]byte{byte(structs.ACLRequestType)})
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if err := encoder.Encode(s); err != nil {
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return err
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}
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}
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return nil
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}
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func (s *consulSnapshot) persistKV(sink raft.SnapshotSink,
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encoder *codec.Encoder) error {
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streamCh := make(chan interface{}, 256)
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errorCh := make(chan error)
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go func() {
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if err := s.state.KVSDump(streamCh); err != nil {
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errorCh <- err
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}
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}()
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for {
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select {
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case raw := <-streamCh:
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if raw == nil {
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return nil
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}
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sink.Write([]byte{byte(structs.KVSRequestType)})
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if err := encoder.Encode(raw); err != nil {
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return err
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}
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case err := <-errorCh:
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return err
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}
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}
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}
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func (s *consulSnapshot) Release() {
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s.state.Close()
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}
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