add go mysql redis sample

Signed-off-by: vishal979 <shantapowertech2@gmail.com>

go-mysql-redis/vendor/gopkg.in/redis.v5/sentinel.go

@@ -0,0 +1,335 @@
+package redis
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"strings"
+	"sync"
+	"time"
+
+	"gopkg.in/redis.v5/internal"
+	"gopkg.in/redis.v5/internal/pool"
+)
+
+//------------------------------------------------------------------------------
+
+// FailoverOptions are used to configure a failover client and should
+// be passed to NewFailoverClient.
+type FailoverOptions struct {
+	// The master name.
+	MasterName string
+	// A seed list of host:port addresses of sentinel nodes.
+	SentinelAddrs []string
+
+	// Following options are copied from Options struct.
+
+	Password string
+	DB       int
+
+	MaxRetries int
+
+	DialTimeout  time.Duration
+	ReadTimeout  time.Duration
+	WriteTimeout time.Duration
+
+	PoolSize           int
+	PoolTimeout        time.Duration
+	IdleTimeout        time.Duration
+	IdleCheckFrequency time.Duration
+}
+
+func (opt *FailoverOptions) options() *Options {
+	return &Options{
+		Addr: "FailoverClient",
+
+		DB:       opt.DB,
+		Password: opt.Password,
+
+		MaxRetries: opt.MaxRetries,
+
+		DialTimeout:  opt.DialTimeout,
+		ReadTimeout:  opt.ReadTimeout,
+		WriteTimeout: opt.WriteTimeout,
+
+		PoolSize:           opt.PoolSize,
+		PoolTimeout:        opt.PoolTimeout,
+		IdleTimeout:        opt.IdleTimeout,
+		IdleCheckFrequency: opt.IdleCheckFrequency,
+	}
+}
+
+// NewFailoverClient returns a Redis client that uses Redis Sentinel
+// for automatic failover. It's safe for concurrent use by multiple
+// goroutines.
+func NewFailoverClient(failoverOpt *FailoverOptions) *Client {
+	opt := failoverOpt.options()
+	opt.init()
+
+	failover := &sentinelFailover{
+		masterName:    failoverOpt.MasterName,
+		sentinelAddrs: failoverOpt.SentinelAddrs,
+
+		opt: opt,
+	}
+
+	client := Client{
+		baseClient: baseClient{
+			opt:      opt,
+			connPool: failover.Pool(),
+
+			onClose: func() error {
+				return failover.Close()
+			},
+		},
+	}
+	client.cmdable.process = client.Process
+
+	return &client
+}
+
+//------------------------------------------------------------------------------
+
+type sentinelClient struct {
+	cmdable
+	baseClient
+}
+
+func newSentinel(opt *Options) *sentinelClient {
+	opt.init()
+	client := sentinelClient{
+		baseClient: baseClient{
+			opt:      opt,
+			connPool: newConnPool(opt),
+		},
+	}
+	client.cmdable = cmdable{client.Process}
+	return &client
+}
+
+func (c *sentinelClient) PubSub() *PubSub {
+	return &PubSub{
+		base: baseClient{
+			opt:      c.opt,
+			connPool: pool.NewStickyConnPool(c.connPool.(*pool.ConnPool), false),
+		},
+	}
+}
+
+func (c *sentinelClient) GetMasterAddrByName(name string) *StringSliceCmd {
+	cmd := NewStringSliceCmd("SENTINEL", "get-master-addr-by-name", name)
+	c.Process(cmd)
+	return cmd
+}
+
+func (c *sentinelClient) Sentinels(name string) *SliceCmd {
+	cmd := NewSliceCmd("SENTINEL", "sentinels", name)
+	c.Process(cmd)
+	return cmd
+}
+
+type sentinelFailover struct {
+	masterName    string
+	sentinelAddrs []string
+
+	opt *Options
+
+	pool     *pool.ConnPool
+	poolOnce sync.Once
+
+	mu       sync.RWMutex
+	sentinel *sentinelClient
+}
+
+func (d *sentinelFailover) Close() error {
+	return d.resetSentinel()
+}
+
+func (d *sentinelFailover) dial() (net.Conn, error) {
+	addr, err := d.MasterAddr()
+	if err != nil {
+		return nil, err
+	}
+	return net.DialTimeout("tcp", addr, d.opt.DialTimeout)
+}
+
+func (d *sentinelFailover) Pool() *pool.ConnPool {
+	d.poolOnce.Do(func() {
+		d.opt.Dialer = d.dial
+		d.pool = newConnPool(d.opt)
+	})
+	return d.pool
+}
+
+func (d *sentinelFailover) MasterAddr() (string, error) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+
+	// Try last working sentinel.
+	if d.sentinel != nil {
+		addr, err := d.sentinel.GetMasterAddrByName(d.masterName).Result()
+		if err != nil {
+			internal.Logf("sentinel: GetMasterAddrByName %q failed: %s", d.masterName, err)
+			d._resetSentinel()
+		} else {
+			addr := net.JoinHostPort(addr[0], addr[1])
+			internal.Logf("sentinel: %q addr is %s", d.masterName, addr)
+			return addr, nil
+		}
+	}
+
+	for i, sentinelAddr := range d.sentinelAddrs {
+		sentinel := newSentinel(&Options{
+			Addr: sentinelAddr,
+
+			DialTimeout:  d.opt.DialTimeout,
+			ReadTimeout:  d.opt.ReadTimeout,
+			WriteTimeout: d.opt.WriteTimeout,
+
+			PoolSize:    d.opt.PoolSize,
+			PoolTimeout: d.opt.PoolTimeout,
+			IdleTimeout: d.opt.IdleTimeout,
+		})
+		masterAddr, err := sentinel.GetMasterAddrByName(d.masterName).Result()
+		if err != nil {
+			internal.Logf("sentinel: GetMasterAddrByName %q failed: %s", d.masterName, err)
+			sentinel.Close()
+			continue
+		}
+
+		// Push working sentinel to the top.
+		d.sentinelAddrs[0], d.sentinelAddrs[i] = d.sentinelAddrs[i], d.sentinelAddrs[0]
+
+		d.setSentinel(sentinel)
+		addr := net.JoinHostPort(masterAddr[0], masterAddr[1])
+		internal.Logf("sentinel: %q addr is %s", d.masterName, addr)
+		return addr, nil
+	}
+
+	return "", errors.New("redis: all sentinels are unreachable")
+}
+
+func (d *sentinelFailover) setSentinel(sentinel *sentinelClient) {
+	d.discoverSentinels(sentinel)
+	d.sentinel = sentinel
+	go d.listen(sentinel)
+}
+
+func (d *sentinelFailover) resetSentinel() error {
+	d.mu.Lock()
+	err := d._resetSentinel()
+	d.mu.Unlock()
+	return err
+}
+
+func (d *sentinelFailover) _resetSentinel() error {
+	var err error
+	if d.sentinel != nil {
+		err = d.sentinel.Close()
+		d.sentinel = nil
+	}
+	return err
+}
+
+func (d *sentinelFailover) discoverSentinels(sentinel *sentinelClient) {
+	sentinels, err := sentinel.Sentinels(d.masterName).Result()
+	if err != nil {
+		internal.Logf("sentinel: Sentinels %q failed: %s", d.masterName, err)
+		return
+	}
+	for _, sentinel := range sentinels {
+		vals := sentinel.([]interface{})
+		for i := 0; i < len(vals); i += 2 {
+			key := vals[i].(string)
+			if key == "name" {
+				sentinelAddr := vals[i+1].(string)
+				if !contains(d.sentinelAddrs, sentinelAddr) {
+					internal.Logf(
+						"sentinel: discovered new %q sentinel: %s",
+						d.masterName, sentinelAddr,
+					)
+					d.sentinelAddrs = append(d.sentinelAddrs, sentinelAddr)
+				}
+			}
+		}
+	}
+}
+
+// closeOldConns closes connections to the old master after failover switch.
+func (d *sentinelFailover) closeOldConns(newMaster string) {
+	// Good connections that should be put back to the pool. They
+	// can't be put immediately, because pool.PopFree will return them
+	// again on next iteration.
+	cnsToPut := make([]*pool.Conn, 0)
+
+	for {
+		cn := d.pool.PopFree()
+		if cn == nil {
+			break
+		}
+		if cn.RemoteAddr().String() != newMaster {
+			err := fmt.Errorf(
+				"sentinel: closing connection to the old master %s",
+				cn.RemoteAddr(),
+			)
+			internal.Logf(err.Error())
+			d.pool.Remove(cn, err)
+		} else {
+			cnsToPut = append(cnsToPut, cn)
+		}
+	}
+
+	for _, cn := range cnsToPut {
+		d.pool.Put(cn)
+	}
+}
+
+func (d *sentinelFailover) listen(sentinel *sentinelClient) {
+	var pubsub *PubSub
+	for {
+		if pubsub == nil {
+			pubsub = sentinel.PubSub()
+
+			if err := pubsub.Subscribe("+switch-master"); err != nil {
+				internal.Logf("sentinel: Subscribe failed: %s", err)
+				pubsub.Close()
+				d.resetSentinel()
+				return
+			}
+		}
+
+		msg, err := pubsub.ReceiveMessage()
+		if err != nil {
+			internal.Logf("sentinel: ReceiveMessage failed: %s", err)
+			pubsub.Close()
+			d.resetSentinel()
+			return
+		}
+
+		switch msg.Channel {
+		case "+switch-master":
+			parts := strings.Split(msg.Payload, " ")
+			if parts[0] != d.masterName {
+				internal.Logf("sentinel: ignore new %s addr", parts[0])
+				continue
+			}
+
+			addr := net.JoinHostPort(parts[3], parts[4])
+			internal.Logf(
+				"sentinel: new %q addr is %s",
+				d.masterName, addr,
+			)
+
+			d.closeOldConns(addr)
+		}
+	}
+}
+
+func contains(slice []string, str string) bool {
+	for _, s := range slice {
+		if s == str {
+			return true
+		}
+	}
+	return false
+}