Add sync => go-sync

sync/leader/consul/consul.go

@@ -0,0 +1,158 @@
+package consul
+
+import (
+	"fmt"
+	"log"
+	"net"
+	"os"
+	"path"
+	"sync"
+
+	"github.com/hashicorp/consul/api"
+	"github.com/hashicorp/consul/api/watch"
+	"github.com/micro/go-micro/sync/leader"
+)
+
+type consulLeader struct {
+	opts leader.Options
+	c    *api.Client
+}
+
+type consulElected struct {
+	c    *api.Client
+	l    *api.Lock
+	id   string
+	key  string
+	opts leader.ElectOptions
+
+	mtx sync.RWMutex
+	rv  <-chan struct{}
+}
+
+func (c *consulLeader) Elect(id string, opts ...leader.ElectOption) (leader.Elected, error) {
+	var options leader.ElectOptions
+	for _, o := range opts {
+		o(&options)
+	}
+
+	key := path.Join("micro/leader", c.opts.Group)
+
+	lc, err := c.c.LockOpts(&api.LockOptions{
+		Key:   key,
+		Value: []byte(id),
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	rv, err := lc.Lock(nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return &consulElected{
+		c:    c.c,
+		key:  key,
+		rv:   rv,
+		id:   id,
+		l:    lc,
+		opts: options,
+	}, nil
+}
+
+func (c *consulLeader) Follow() chan string {
+	ch := make(chan string, 1)
+
+	key := path.Join("/micro/leader", c.opts.Group)
+
+	p, err := watch.Parse(map[string]interface{}{
+		"type": "key",
+		"key":  key,
+	})
+	if err != nil {
+		return ch
+	}
+	p.Handler = func(idx uint64, raw interface{}) {
+		if raw == nil {
+			return // ignore
+		}
+		v, ok := raw.(*api.KVPair)
+		if !ok || v == nil {
+			return // ignore
+		}
+		ch <- string(v.Value)
+	}
+
+	go p.RunWithClientAndLogger(c.c, log.New(os.Stdout, "consul: ", log.Lshortfile))
+	return ch
+}
+
+func (c *consulLeader) String() string {
+	return "consul"
+}
+
+func (c *consulElected) Id() string {
+	return c.id
+}
+
+func (c *consulElected) Reelect() error {
+	rv, err := c.l.Lock(nil)
+	if err != nil {
+		return err
+	}
+
+	c.mtx.Lock()
+	c.rv = rv
+	c.mtx.Unlock()
+	return nil
+}
+
+func (c *consulElected) Revoked() chan bool {
+	ch := make(chan bool, 1)
+	c.mtx.RLock()
+	rv := c.rv
+	c.mtx.RUnlock()
+
+	go func() {
+		<-rv
+		ch <- true
+		close(ch)
+	}()
+
+	return ch
+}
+
+func (c *consulElected) Resign() error {
+	return c.l.Unlock()
+}
+
+func NewLeader(opts ...leader.Option) leader.Leader {
+	options := leader.Options{
+		Group: "default",
+	}
+	for _, o := range opts {
+		o(&options)
+	}
+
+	config := api.DefaultConfig()
+
+	// set host
+	// config.Host something
+	// check if there are any addrs
+	if len(options.Nodes) > 0 {
+		addr, port, err := net.SplitHostPort(options.Nodes[0])
+		if ae, ok := err.(*net.AddrError); ok && ae.Err == "missing port in address" {
+			port = "8500"
+			config.Address = fmt.Sprintf("%s:%s", addr, port)
+		} else if err == nil {
+			config.Address = fmt.Sprintf("%s:%s", addr, port)
+		}
+	}
+
+	client, _ := api.NewClient(config)
+
+	return &consulLeader{
+		opts: options,
+		c:    client,
+	}
+}