open-consul/agent/consul/fsm/fsm.go

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package fsm
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import (
"fmt"
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"io"
"sync"
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"time"
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pkg refactor command/agent/* -> agent/* command/consul/* -> agent/consul/* command/agent/command{,_test}.go -> command/agent{,_test}.go command/base/command.go -> command/base.go command/base/* -> command/* commands.go -> command/commands.go The script which did the refactor is: ( cd $GOPATH/src/github.com/hashicorp/consul git mv command/agent/command.go command/agent.go git mv command/agent/command_test.go command/agent_test.go git mv command/agent/flag_slice_value{,_test}.go command/ git mv command/agent . git mv command/base/command.go command/base.go git mv command/base/config_util{,_test}.go command/ git mv commands.go command/ git mv consul agent rmdir command/base/ gsed -i -e 's|package agent|package command|' command/agent{,_test}.go gsed -i -e 's|package agent|package command|' command/flag_slice_value{,_test}.go gsed -i -e 's|package base|package command|' command/base.go command/config_util{,_test}.go gsed -i -e 's|package main|package command|' command/commands.go gsed -i -e 's|base.Command|BaseCommand|' command/commands.go gsed -i -e 's|agent.Command|AgentCommand|' command/commands.go gsed -i -e 's|\tCommand:|\tBaseCommand:|' command/commands.go gsed -i -e 's|base\.||' command/commands.go gsed -i -e 's|command\.||' command/commands.go gsed -i -e 's|command|c|' main.go gsed -i -e 's|range Commands|range command.Commands|' main.go gsed -i -e 's|Commands: Commands|Commands: command.Commands|' main.go gsed -i -e 's|base\.BoolValue|BoolValue|' command/operator_autopilot_set.go gsed -i -e 's|base\.DurationValue|DurationValue|' command/operator_autopilot_set.go gsed -i -e 's|base\.StringValue|StringValue|' command/operator_autopilot_set.go gsed -i -e 's|base\.UintValue|UintValue|' command/operator_autopilot_set.go gsed -i -e 's|\bCommand\b|BaseCommand|' command/base.go gsed -i -e 's|BaseCommand Options|Command Options|' command/base.go gsed -i -e 's|base.Command|BaseCommand|' command/*.go gsed -i -e 's|c\.Command|c.BaseCommand|g' command/*.go gsed -i -e 's|\tCommand:|\tBaseCommand:|' command/*_test.go gsed -i -e 's|base\.||' command/*_test.go gsed -i -e 's|\bCommand\b|AgentCommand|' command/agent{,_test}.go gsed -i -e 's|cmd.AgentCommand|cmd.BaseCommand|' command/agent.go gsed -i -e 's|cli.AgentCommand = new(Command)|cli.Command = new(AgentCommand)|' command/agent_test.go gsed -i -e 's|exec.AgentCommand|exec.Command|' command/agent_test.go gsed -i -e 's|exec.BaseCommand|exec.Command|' command/agent_test.go gsed -i -e 's|NewTestAgent|agent.NewTestAgent|' command/agent_test.go gsed -i -e 's|= TestConfig|= agent.TestConfig|' command/agent_test.go gsed -i -e 's|: RetryJoin|: agent.RetryJoin|' command/agent_test.go gsed -i -e 's|\.\./\.\./|../|' command/config_util_test.go gsed -i -e 's|\bverifyUniqueListeners|VerifyUniqueListeners|' agent/config{,_test}.go command/agent.go gsed -i -e 's|\bserfLANKeyring\b|SerfLANKeyring|g' agent/{agent,keyring,testagent}.go command/agent.go gsed -i -e 's|\bserfWANKeyring\b|SerfWANKeyring|g' agent/{agent,keyring,testagent}.go command/agent.go gsed -i -e 's|\bNewAgent\b|agent.New|g' command/agent{,_test}.go gsed -i -e 's|\bNewAgent|New|' agent/{acl_test,agent,testagent}.go gsed -i -e 's|\bAgent\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|\bBool\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|\bConfig\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|\bDefaultConfig\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|\bDevConfig\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|\bMergeConfig\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|\bReadConfigPaths\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|\bParseMetaPair\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|\bSerfLANKeyring\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|\bSerfWANKeyring\b|agent.&|g' command/agent{,_test}.go gsed -i -e 's|circonus\.agent|circonus|g' command/agent{,_test}.go gsed -i -e 's|logger\.agent|logger|g' command/agent{,_test}.go gsed -i -e 's|metrics\.agent|metrics|g' command/agent{,_test}.go gsed -i -e 's|// agent.Agent|// agent|' command/agent{,_test}.go gsed -i -e 's|a\.agent\.Config|a.Config|' command/agent{,_test}.go gsed -i -e 's|agent\.AppendSliceValue|AppendSliceValue|' command/{configtest,validate}.go gsed -i -e 's|consul/consul|agent/consul|' GNUmakefile gsed -i -e 's|\.\./test|../../test|' agent/consul/server_test.go # fix imports f=$(grep -rl 'github.com/hashicorp/consul/command/agent' * | grep '\.go') gsed -i -e 's|github.com/hashicorp/consul/command/agent|github.com/hashicorp/consul/agent|' $f goimports -w $f f=$(grep -rl 'github.com/hashicorp/consul/consul' * | grep '\.go') gsed -i -e 's|github.com/hashicorp/consul/consul|github.com/hashicorp/consul/agent/consul|' $f goimports -w $f goimports -w command/*.go main.go )
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"github.com/hashicorp/consul/agent/consul/state"
"github.com/hashicorp/consul/agent/structs"
"github.com/hashicorp/consul/logging"
"github.com/hashicorp/go-hclog"
"github.com/hashicorp/go-msgpack/codec"
"github.com/hashicorp/go-raftchunking"
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"github.com/hashicorp/raft"
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)
// command is a command method on the FSM.
type command func(buf []byte, index uint64) interface{}
// unboundCommand is a command method on the FSM, not yet bound to an FSM
// instance.
type unboundCommand func(c *FSM, buf []byte, index uint64) interface{}
// commands is a map from message type to unbound command.
var commands map[structs.MessageType]unboundCommand
// registerCommand registers a new command with the FSM, which should be done
// at package init() time.
func registerCommand(msg structs.MessageType, fn unboundCommand) {
if commands == nil {
commands = make(map[structs.MessageType]unboundCommand)
}
if commands[msg] != nil {
panic(fmt.Errorf("Message %d is already registered", msg))
}
commands[msg] = fn
}
// FSM implements a finite state machine that is used
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// along with Raft to provide strong consistency. We implement
// this outside the Server to avoid exposing this outside the package.
type FSM struct {
logger hclog.Logger
path string
// apply is built off the commands global and is used to route apply
// operations to their appropriate handlers.
apply map[structs.MessageType]command
// stateLock is only used to protect outside callers to State() from
// racing with Restore(), which is called by Raft (it puts in a totally
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// new state store). Everything internal here is synchronized by the
// Raft side, so doesn't need to lock this.
stateLock sync.RWMutex
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state *state.Store
gc *state.TombstoneGC
chunker *raftchunking.ChunkingFSM
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}
// New is used to construct a new FSM with a blank state.
func New(gc *state.TombstoneGC, logger hclog.Logger) (*FSM, error) {
if logger == nil {
logger = hclog.New(&hclog.LoggerOptions{})
}
stateNew, err := state.NewStateStore(gc)
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if err != nil {
return nil, err
}
fsm := &FSM{
logger: logger.Named(logging.FSM),
apply: make(map[structs.MessageType]command),
state: stateNew,
gc: gc,
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}
// Build out the apply dispatch table based on the registered commands.
for msg, fn := range commands {
thisFn := fn
fsm.apply[msg] = func(buf []byte, index uint64) interface{} {
return thisFn(fsm, buf, index)
}
}
fsm.chunker = raftchunking.NewChunkingFSM(fsm, nil)
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return fsm, nil
}
func (c *FSM) ChunkingFSM() *raftchunking.ChunkingFSM {
return c.chunker
}
// State is used to return a handle to the current state
func (c *FSM) State() *state.Store {
c.stateLock.RLock()
defer c.stateLock.RUnlock()
return c.state
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}
func (c *FSM) Apply(log *raft.Log) interface{} {
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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
}
// Apply based on the dispatch table, if possible.
if fn := c.apply[msgType]; fn != nil {
return fn(buf[1:], log.Index)
}
// Otherwise, see if it's safe to ignore. If not, we have to panic so
// that we crash and our state doesn't diverge.
if ignoreUnknown {
c.logger.Warn("ignoring unknown message type, upgrade to newer version", "type", msgType)
return nil
}
panic(fmt.Errorf("failed to apply request: %#v", buf))
}
func (c *FSM) Snapshot() (raft.FSMSnapshot, error) {
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defer func(start time.Time) {
c.logger.Info("snapshot created", "duration", time.Since(start).String())
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}(time.Now())
chunkState, err := c.chunker.CurrentState()
if err != nil {
return nil, err
}
return &snapshot{
state: c.state.Snapshot(),
chunkState: chunkState,
}, nil
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}
// Restore streams in the snapshot and replaces the current state store with a
// new one based on the snapshot if all goes OK during the restore.
func (c *FSM) Restore(old io.ReadCloser) error {
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defer old.Close()
// Create a new state store.
stateNew, err := state.NewStateStore(c.gc)
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if err != nil {
return err
}
// Set up a new restore transaction
restore := stateNew.Restore()
defer restore.Abort()
// Create a decoder
dec := codec.NewDecoder(old, structs.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
msg := structs.MessageType(msgType[0])
switch {
case msg == structs.ChunkingStateType:
chunkState := &raftchunking.State{
ChunkMap: make(raftchunking.ChunkMap),
}
if err := dec.Decode(chunkState); err != nil {
return err
}
if err := c.chunker.RestoreState(chunkState); err != nil {
return err
}
case restorers[msg] != nil:
fn := restorers[msg]
if err := fn(&header, restore, dec); err != nil {
return err
}
default:
return fmt.Errorf("Unrecognized msg type %d", msg)
}
}
restore.Commit()
// External code might be calling State(), so we need to synchronize
// here to make sure we swap in the new state store atomically.
c.stateLock.Lock()
stateOld := c.state
c.state = stateNew
c.stateLock.Unlock()
// Signal that the old state store has been abandoned. This is required
// because we don't operate on it any more, we just throw it away, so
// blocking queries won't see any changes and need to be woken up.
stateOld.Abandon()
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return nil
}