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