added etcd support

pkg/etcd/cluster.go

@@ -0,0 +1,55 @@
+package etcd
+
+import (
+	"errors"
+
+	"git.giftfish.de/ston1th/vipman/pkg/cluster"
+	//"go.etcd.io/etcd/clientv3"
+	"github.com/coreos/etcd/clientv3"
+	"github.com/go-logr/logr"
+)
+
+type Cluster struct {
+	logr.Logger
+	cluster.KV
+	cli *clientv3.Client
+
+	stepdown  chan struct{}
+	stop      chan struct{}
+	done      chan struct{}
+	callbacks cluster.Callbacks
+
+	id            string
+	keyID         string
+	session       bool
+	cancelSession func()
+}
+
+func NewCluster(log logr.Logger) cluster.Cluster {
+	return &Cluster{
+		Logger:   log,
+		KV:       &kv{},
+		stepdown: make(chan struct{}, 1),
+		stop:     make(chan struct{}, 1),
+		done:     make(chan struct{}, 1),
+	}
+}
+
+func (c *Cluster) SetCallbacks(callbacks cluster.Callbacks) error {
+	c.callbacks = callbacks
+	return c.checkConfig()
+}
+
+func (c *Cluster) ID() string {
+	return c.id
+}
+
+func (c *Cluster) checkConfig() error {
+	if c.callbacks.Leader == nil {
+		return errors.New("Leader callback is nil")
+	}
+	if c.callbacks.Follower == nil {
+		return errors.New("Follower callback is nil")
+	}
+	return nil
+}

pkg/etcd/etcd.go

@@ -0,0 +1,217 @@
+package etcd
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"time"
+
+	"git.giftfish.de/ston1th/vipman/pkg/config"
+	"git.giftfish.de/ston1th/vipman/pkg/util"
+	"github.com/coreos/etcd/clientv3"
+	"go.uber.org/zap"
+	"go.uber.org/zap/zapcore"
+	//"go.etcd.io/etcd/clientv3"
+	"go.etcd.io/etcd/clientv3/concurrency"
+)
+
+func (c *Cluster) Start(etcdcfg *config.Config) error {
+	err := c.checkConfig()
+	if err != nil {
+		return err
+	}
+	cfg := etcdcfg.Cluster.Etcd
+	var level zapcore.Level
+	err = level.Set(cfg.LogLevel)
+	if err != nil {
+		return err
+	}
+	al := zap.NewAtomicLevel()
+	al.SetLevel(level)
+	var tlsConfig *tls.Config
+	if cfg.TLS != nil {
+		ca, err := config.LoadCertPool(cfg.TLS.CA)
+		if err != nil {
+			return err
+		}
+		tlsConfig = &tls.Config{
+			MinVersion:         tls.VersionTLS12,
+			InsecureSkipVerify: cfg.TLS.Insecure,
+			RootCAs:            ca,
+		}
+	}
+
+	c.cli, err = clientv3.New(clientv3.Config{
+		Endpoints:   cfg.Endpoints,
+		TLS:         tlsConfig,
+		DialTimeout: time.Second * 5,
+		Username:    cfg.Username,
+		Password:    cfg.Password,
+		LogConfig: &zap.Config{
+			Level:             al,
+			Encoding:          "console",
+			DisableCaller:     true,
+			DisableStacktrace: true,
+			EncoderConfig:     zap.NewDevelopmentEncoderConfig(),
+			OutputPaths:       []string{"stderr"},
+			ErrorOutputPaths:  []string{"stderr"},
+		},
+	})
+	if err != nil {
+		return err
+	}
+
+	ctxSsession, cancelSession := context.WithCancel(context.Background())
+	c.cancelSession = cancelSession
+	s, err := concurrency.NewSession(c.cli,
+		concurrency.WithContext(ctxSsession),
+		concurrency.WithTTL(10),
+	)
+	if err != nil {
+		return err
+	}
+	c.session = true
+
+	prefix := cfg.Prefix + "/" + cfg.ClusterName
+	c.id = fmt.Sprintf("%x", s.Lease())
+	c.keyID = fmt.Sprintf("%s/%s", prefix, c.id)
+
+	e := concurrency.NewElection(s, prefix)
+	ctxCampaign, cancelCampaign := context.WithCancel(context.Background())
+	go func() {
+		errc := make(chan error, 1)
+		for {
+			go func() {
+				errc <- e.Campaign(ctxCampaign, "leader")
+			}()
+			select {
+			case err := <-errc:
+				if err != nil {
+					time.Sleep(time.Second)
+				}
+			case <-ctxCampaign.Done():
+				return
+			}
+		}
+	}()
+
+	t := time.NewTicker(time.Second)
+	ctx, cancel := context.WithCancel(context.Background())
+	ctxObserve, cancelObserve := context.WithCancel(context.Background())
+	leading := false
+	following := false
+	leaderChan := c.observe(ctxObserve, e.Observe(ctxObserve))
+	for {
+		if !leading && c.leaderID(e.Leader(ctxObserve)) == c.keyID {
+			leading = true
+			go c.leader(ctx)
+		} else if !following && !leading {
+			following = true
+			go c.follower(ctx)
+		}
+
+		select {
+		case <-t.C:
+		case leader := <-leaderChan:
+			if leader {
+				if following {
+					cancel()
+					following = false
+					ctx, cancel = context.WithCancel(context.Background())
+				}
+				if !leading {
+					leading = true
+					go c.leader(ctx)
+				}
+			} else {
+				if leading {
+					cancel()
+					leading = false
+					ctx, cancel = context.WithCancel(context.Background())
+				}
+				if !following {
+					following = true
+					go c.follower(ctx)
+				}
+			}
+		case <-c.stepdown:
+			cancel()
+			ctx, cancel = context.WithCancel(context.Background())
+			ctxResign, _ := context.WithTimeout(context.Background(), time.Second*2)
+			e.Resign(ctxResign)
+		case <-c.stop:
+			t.Stop()
+			cancelObserve()
+			cancelCampaign()
+			cancel()
+			if leading {
+				ctxResign, _ := context.WithTimeout(context.Background(), time.Second*2)
+				e.Resign(ctxResign)
+			}
+			s.Close()
+			close(c.done)
+			return nil
+		}
+	}
+	return nil
+}
+
+func (c *Cluster) leaderID(r *clientv3.GetResponse, err error) string {
+	if err != nil {
+		return ""
+	}
+	if len(r.Kvs) == 0 {
+		return ""
+	}
+	return string(r.Kvs[0].Key)
+}
+
+func (c *Cluster) observe(ctx context.Context, resp <-chan clientv3.GetResponse) <-chan bool {
+	leader := make(chan bool)
+	go func() {
+		for {
+			select {
+			case r := <-resp:
+				if c.leaderID(&r, nil) == c.keyID {
+					leader <- true
+				} else {
+					leader <- false
+				}
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+	return leader
+}
+
+func (c *Cluster) Stepdown() {
+	select {
+	case c.stepdown <- struct{}{}:
+	case <-time.After(time.Second * 2):
+	}
+}
+
+func (c *Cluster) Stop() {
+	if !c.session {
+		c.cancelSession()
+		return
+	}
+	close(c.stop)
+	<-c.done
+	c.cli.Close()
+}
+
+func (c *Cluster) leader(ctx context.Context) {
+	defer func() {
+		util.HandleCrash()
+	}()
+	c.callbacks.Leader(ctx, c)
+}
+
+func (c *Cluster) follower(ctx context.Context) {
+	defer func() {
+		util.HandleCrash()
+	}()
+	c.callbacks.Follower(ctx, c)
+}

pkg/etcd/kv.go

@@ -0,0 +1,18 @@
+package etcd
+
+//TODO
+
+type kv struct {
+}
+
+func (kv *kv) Get(k string) []byte {
+	return nil
+}
+
+func (kv *kv) Set(k string, v []byte) error {
+	return nil
+}
+
+func (kv *kv) Delete(k string) error {
+	return nil
+}