initial commit

pkg/raft/fsm.go

@@ -0,0 +1,99 @@
+package raft
+
+import (
+	"fmt"
+	"io"
+	"time"
+
+	"git.giftfish.de/ston1th/raftbbolt/msgpack"
+	"github.com/hashicorp/raft"
+)
+
+const (
+	retainSnapshotCount = 2
+	raftTimeout         = 10 * time.Second
+)
+
+type Op uint8
+
+const (
+	SET Op = iota
+	DELETE
+)
+
+type raftCmd struct {
+	Op Op
+	K  string
+	V  []byte
+}
+
+type fsm kv
+
+func (f *fsm) Apply(l *raft.Log) interface{} {
+	var c raftCmd
+	if err := msgpack.Unmarshal(l.Data, &c); err != nil {
+		panic(fmt.Sprintf("failed to unmarshal command: %s", err.Error()))
+	}
+
+	switch c.Op {
+	case SET:
+		f.applySet(c.K, c.V)
+	case DELETE:
+		f.applyDelete(c.K)
+	default:
+		panic(fmt.Sprintf("unrecognized command op: %d", c.Op))
+	}
+	return nil
+}
+
+func (f *fsm) Snapshot() (raft.FSMSnapshot, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	m := make(kvm)
+	for k, v := range f.m {
+		m[k] = v
+	}
+	return &fsmSnapshot{m: m}, nil
+}
+
+func (f *fsm) Restore(rc io.ReadCloser) error {
+	o := make(kvm)
+	if err := msgpack.NewDecoder(rc).Decode(&o); err != nil {
+		return err
+	}
+	f.m = o
+	return nil
+}
+
+func (f *fsm) applySet(k string, v []byte) {
+	f.mu.Lock()
+	f.m[k] = v
+	f.mu.Unlock()
+}
+
+func (f *fsm) applyDelete(k string) {
+	f.mu.Lock()
+	delete(f.m, k)
+	f.mu.Unlock()
+}
+
+type fsmSnapshot struct {
+	m kvm
+}
+
+func (f *fsmSnapshot) Persist(sink raft.SnapshotSink) error {
+	err := func() error {
+		err := msgpack.NewEncoder(sink).Encode(f.m)
+		if err != nil {
+			return err
+		}
+		return sink.Close()
+	}()
+
+	if err != nil {
+		sink.Cancel()
+	}
+	return err
+}
+
+func (f *fsmSnapshot) Release() {}