forgejo/vendor/github.com/go-redis/redis/v7/ring.go
zeripath 7f8e3192cd
Allow common redis and leveldb connections (#12385)
* Allow common redis and leveldb connections

Prevents multiple reopening of redis and leveldb connections to the same
place by sharing connections.

Further allows for more configurable redis connection type using the
redisURI and a leveldbURI scheme.

Signed-off-by: Andrew Thornton <art27@cantab.net>

* add unit-test

Signed-off-by: Andrew Thornton <art27@cantab.net>

* as per @lunny

Signed-off-by: Andrew Thornton <art27@cantab.net>

* add test

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Update modules/cache/cache_redis.go

* Update modules/queue/queue_disk.go

* Update modules/cache/cache_redis.go

* Update modules/cache/cache_redis.go

* Update modules/queue/unique_queue_disk.go

* Update modules/queue/queue_disk.go

* Update modules/queue/unique_queue_disk.go

* Update modules/session/redis.go

Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Lauris BH <lauris@nix.lv>
2020-09-28 00:09:46 +03:00

726 lines
16 KiB
Go
Vendored

package redis
import (
"context"
"errors"
"fmt"
"math/rand"
"strconv"
"sync"
"sync/atomic"
"time"
"github.com/go-redis/redis/v7/internal"
"github.com/go-redis/redis/v7/internal/consistenthash"
"github.com/go-redis/redis/v7/internal/hashtag"
"github.com/go-redis/redis/v7/internal/pool"
)
// Hash is type of hash function used in consistent hash.
type Hash consistenthash.Hash
var errRingShardsDown = errors.New("redis: all ring shards are down")
// RingOptions are used to configure a ring client and should be
// passed to NewRing.
type RingOptions struct {
// Map of name => host:port addresses of ring shards.
Addrs map[string]string
// Map of name => password of ring shards, to allow different shards to have
// different passwords. It will be ignored if the Password field is set.
Passwords map[string]string
// Frequency of PING commands sent to check shards availability.
// Shard is considered down after 3 subsequent failed checks.
HeartbeatFrequency time.Duration
// Hash function used in consistent hash.
// Default is crc32.ChecksumIEEE.
Hash Hash
// Number of replicas in consistent hash.
// Default is 100 replicas.
//
// Higher number of replicas will provide less deviation, that is keys will be
// distributed to nodes more evenly.
//
// Following is deviation for common nreplicas:
// --------------------------------------------------------
// | nreplicas | standard error | 99% confidence interval |
// | 10 | 0.3152 | (0.37, 1.98) |
// | 100 | 0.0997 | (0.76, 1.28) |
// | 1000 | 0.0316 | (0.92, 1.09) |
// --------------------------------------------------------
//
// See https://arxiv.org/abs/1406.2294 for reference
HashReplicas int
// NewClient creates a shard client with provided name and options.
NewClient func(name string, opt *Options) *Client
// Optional hook that is called when a new shard is created.
OnNewShard func(*Client)
// Following options are copied from Options struct.
OnConnect func(*Conn) error
DB int
Password string
MaxRetries int
MinRetryBackoff time.Duration
MaxRetryBackoff time.Duration
DialTimeout time.Duration
ReadTimeout time.Duration
WriteTimeout time.Duration
PoolSize int
MinIdleConns int
MaxConnAge time.Duration
PoolTimeout time.Duration
IdleTimeout time.Duration
IdleCheckFrequency time.Duration
}
func (opt *RingOptions) init() {
if opt.HeartbeatFrequency == 0 {
opt.HeartbeatFrequency = 500 * time.Millisecond
}
if opt.HashReplicas == 0 {
opt.HashReplicas = 100
}
switch opt.MinRetryBackoff {
case -1:
opt.MinRetryBackoff = 0
case 0:
opt.MinRetryBackoff = 8 * time.Millisecond
}
switch opt.MaxRetryBackoff {
case -1:
opt.MaxRetryBackoff = 0
case 0:
opt.MaxRetryBackoff = 512 * time.Millisecond
}
}
func (opt *RingOptions) clientOptions(shard string) *Options {
return &Options{
OnConnect: opt.OnConnect,
DB: opt.DB,
Password: opt.getPassword(shard),
DialTimeout: opt.DialTimeout,
ReadTimeout: opt.ReadTimeout,
WriteTimeout: opt.WriteTimeout,
PoolSize: opt.PoolSize,
MinIdleConns: opt.MinIdleConns,
MaxConnAge: opt.MaxConnAge,
PoolTimeout: opt.PoolTimeout,
IdleTimeout: opt.IdleTimeout,
IdleCheckFrequency: opt.IdleCheckFrequency,
}
}
func (opt *RingOptions) getPassword(shard string) string {
if opt.Password == "" {
return opt.Passwords[shard]
}
return opt.Password
}
//------------------------------------------------------------------------------
type ringShard struct {
Client *Client
down int32
}
func (shard *ringShard) String() string {
var state string
if shard.IsUp() {
state = "up"
} else {
state = "down"
}
return fmt.Sprintf("%s is %s", shard.Client, state)
}
func (shard *ringShard) IsDown() bool {
const threshold = 3
return atomic.LoadInt32(&shard.down) >= threshold
}
func (shard *ringShard) IsUp() bool {
return !shard.IsDown()
}
// Vote votes to set shard state and returns true if state was changed.
func (shard *ringShard) Vote(up bool) bool {
if up {
changed := shard.IsDown()
atomic.StoreInt32(&shard.down, 0)
return changed
}
if shard.IsDown() {
return false
}
atomic.AddInt32(&shard.down, 1)
return shard.IsDown()
}
//------------------------------------------------------------------------------
type ringShards struct {
opt *RingOptions
mu sync.RWMutex
hash *consistenthash.Map
shards map[string]*ringShard // read only
list []*ringShard // read only
len int
closed bool
}
func newRingShards(opt *RingOptions) *ringShards {
return &ringShards{
opt: opt,
hash: newConsistentHash(opt),
shards: make(map[string]*ringShard),
}
}
func (c *ringShards) Add(name string, cl *Client) {
shard := &ringShard{Client: cl}
c.hash.Add(name)
c.shards[name] = shard
c.list = append(c.list, shard)
}
func (c *ringShards) List() []*ringShard {
c.mu.RLock()
list := c.list
c.mu.RUnlock()
return list
}
func (c *ringShards) Hash(key string) string {
c.mu.RLock()
hash := c.hash.Get(key)
c.mu.RUnlock()
return hash
}
func (c *ringShards) GetByKey(key string) (*ringShard, error) {
key = hashtag.Key(key)
c.mu.RLock()
if c.closed {
c.mu.RUnlock()
return nil, pool.ErrClosed
}
hash := c.hash.Get(key)
if hash == "" {
c.mu.RUnlock()
return nil, errRingShardsDown
}
shard := c.shards[hash]
c.mu.RUnlock()
return shard, nil
}
func (c *ringShards) GetByHash(name string) (*ringShard, error) {
if name == "" {
return c.Random()
}
c.mu.RLock()
shard := c.shards[name]
c.mu.RUnlock()
return shard, nil
}
func (c *ringShards) Random() (*ringShard, error) {
return c.GetByKey(strconv.Itoa(rand.Int()))
}
// heartbeat monitors state of each shard in the ring.
func (c *ringShards) Heartbeat(frequency time.Duration) {
ticker := time.NewTicker(frequency)
defer ticker.Stop()
for range ticker.C {
var rebalance bool
c.mu.RLock()
if c.closed {
c.mu.RUnlock()
break
}
shards := c.list
c.mu.RUnlock()
for _, shard := range shards {
err := shard.Client.Ping().Err()
if shard.Vote(err == nil || err == pool.ErrPoolTimeout) {
internal.Logger.Printf("ring shard state changed: %s", shard)
rebalance = true
}
}
if rebalance {
c.rebalance()
}
}
}
// rebalance removes dead shards from the Ring.
func (c *ringShards) rebalance() {
c.mu.RLock()
shards := c.shards
c.mu.RUnlock()
hash := newConsistentHash(c.opt)
var shardsNum int
for name, shard := range shards {
if shard.IsUp() {
hash.Add(name)
shardsNum++
}
}
c.mu.Lock()
c.hash = hash
c.len = shardsNum
c.mu.Unlock()
}
func (c *ringShards) Len() int {
c.mu.RLock()
l := c.len
c.mu.RUnlock()
return l
}
func (c *ringShards) Close() error {
c.mu.Lock()
defer c.mu.Unlock()
if c.closed {
return nil
}
c.closed = true
var firstErr error
for _, shard := range c.shards {
if err := shard.Client.Close(); err != nil && firstErr == nil {
firstErr = err
}
}
c.hash = nil
c.shards = nil
c.list = nil
return firstErr
}
//------------------------------------------------------------------------------
type ring struct {
opt *RingOptions
shards *ringShards
cmdsInfoCache *cmdsInfoCache //nolint:structcheck
}
// Ring is a Redis client that uses consistent hashing to distribute
// keys across multiple Redis servers (shards). It's safe for
// concurrent use by multiple goroutines.
//
// Ring monitors the state of each shard and removes dead shards from
// the ring. When a shard comes online it is added back to the ring. This
// gives you maximum availability and partition tolerance, but no
// consistency between different shards or even clients. Each client
// uses shards that are available to the client and does not do any
// coordination when shard state is changed.
//
// Ring should be used when you need multiple Redis servers for caching
// and can tolerate losing data when one of the servers dies.
// Otherwise you should use Redis Cluster.
type Ring struct {
*ring
cmdable
hooks
ctx context.Context
}
func NewRing(opt *RingOptions) *Ring {
opt.init()
ring := Ring{
ring: &ring{
opt: opt,
shards: newRingShards(opt),
},
ctx: context.Background(),
}
ring.cmdsInfoCache = newCmdsInfoCache(ring.cmdsInfo)
ring.cmdable = ring.Process
for name, addr := range opt.Addrs {
shard := newRingShard(opt, name, addr)
ring.shards.Add(name, shard)
}
go ring.shards.Heartbeat(opt.HeartbeatFrequency)
return &ring
}
func newRingShard(opt *RingOptions, name, addr string) *Client {
clopt := opt.clientOptions(name)
clopt.Addr = addr
var shard *Client
if opt.NewClient != nil {
shard = opt.NewClient(name, clopt)
} else {
shard = NewClient(clopt)
}
if opt.OnNewShard != nil {
opt.OnNewShard(shard)
}
return shard
}
func (c *Ring) Context() context.Context {
return c.ctx
}
func (c *Ring) WithContext(ctx context.Context) *Ring {
if ctx == nil {
panic("nil context")
}
clone := *c
clone.cmdable = clone.Process
clone.hooks.lock()
clone.ctx = ctx
return &clone
}
// Do creates a Cmd from the args and processes the cmd.
func (c *Ring) Do(args ...interface{}) *Cmd {
return c.DoContext(c.ctx, args...)
}
func (c *Ring) DoContext(ctx context.Context, args ...interface{}) *Cmd {
cmd := NewCmd(args...)
_ = c.ProcessContext(ctx, cmd)
return cmd
}
func (c *Ring) Process(cmd Cmder) error {
return c.ProcessContext(c.ctx, cmd)
}
func (c *Ring) ProcessContext(ctx context.Context, cmd Cmder) error {
return c.hooks.process(ctx, cmd, c.process)
}
// Options returns read-only Options that were used to create the client.
func (c *Ring) Options() *RingOptions {
return c.opt
}
func (c *Ring) retryBackoff(attempt int) time.Duration {
return internal.RetryBackoff(attempt, c.opt.MinRetryBackoff, c.opt.MaxRetryBackoff)
}
// PoolStats returns accumulated connection pool stats.
func (c *Ring) PoolStats() *PoolStats {
shards := c.shards.List()
var acc PoolStats
for _, shard := range shards {
s := shard.Client.connPool.Stats()
acc.Hits += s.Hits
acc.Misses += s.Misses
acc.Timeouts += s.Timeouts
acc.TotalConns += s.TotalConns
acc.IdleConns += s.IdleConns
}
return &acc
}
// Len returns the current number of shards in the ring.
func (c *Ring) Len() int {
return c.shards.Len()
}
// Subscribe subscribes the client to the specified channels.
func (c *Ring) Subscribe(channels ...string) *PubSub {
if len(channels) == 0 {
panic("at least one channel is required")
}
shard, err := c.shards.GetByKey(channels[0])
if err != nil {
//TODO: return PubSub with sticky error
panic(err)
}
return shard.Client.Subscribe(channels...)
}
// PSubscribe subscribes the client to the given patterns.
func (c *Ring) PSubscribe(channels ...string) *PubSub {
if len(channels) == 0 {
panic("at least one channel is required")
}
shard, err := c.shards.GetByKey(channels[0])
if err != nil {
//TODO: return PubSub with sticky error
panic(err)
}
return shard.Client.PSubscribe(channels...)
}
// ForEachShard concurrently calls the fn on each live shard in the ring.
// It returns the first error if any.
func (c *Ring) ForEachShard(fn func(client *Client) error) error {
shards := c.shards.List()
var wg sync.WaitGroup
errCh := make(chan error, 1)
for _, shard := range shards {
if shard.IsDown() {
continue
}
wg.Add(1)
go func(shard *ringShard) {
defer wg.Done()
err := fn(shard.Client)
if err != nil {
select {
case errCh <- err:
default:
}
}
}(shard)
}
wg.Wait()
select {
case err := <-errCh:
return err
default:
return nil
}
}
func (c *Ring) cmdsInfo() (map[string]*CommandInfo, error) {
shards := c.shards.List()
firstErr := errRingShardsDown
for _, shard := range shards {
cmdsInfo, err := shard.Client.Command().Result()
if err == nil {
return cmdsInfo, nil
}
if firstErr == nil {
firstErr = err
}
}
return nil, firstErr
}
func (c *Ring) cmdInfo(name string) *CommandInfo {
cmdsInfo, err := c.cmdsInfoCache.Get()
if err != nil {
return nil
}
info := cmdsInfo[name]
if info == nil {
internal.Logger.Printf("info for cmd=%s not found", name)
}
return info
}
func (c *Ring) cmdShard(cmd Cmder) (*ringShard, error) {
cmdInfo := c.cmdInfo(cmd.Name())
pos := cmdFirstKeyPos(cmd, cmdInfo)
if pos == 0 {
return c.shards.Random()
}
firstKey := cmd.stringArg(pos)
return c.shards.GetByKey(firstKey)
}
func (c *Ring) process(ctx context.Context, cmd Cmder) error {
err := c._process(ctx, cmd)
if err != nil {
cmd.SetErr(err)
return err
}
return nil
}
func (c *Ring) _process(ctx context.Context, cmd Cmder) error {
var lastErr error
for attempt := 0; attempt <= c.opt.MaxRetries; attempt++ {
if attempt > 0 {
if err := internal.Sleep(ctx, c.retryBackoff(attempt)); err != nil {
return err
}
}
shard, err := c.cmdShard(cmd)
if err != nil {
return err
}
lastErr = shard.Client.ProcessContext(ctx, cmd)
if lastErr == nil || !isRetryableError(lastErr, cmd.readTimeout() == nil) {
return lastErr
}
}
return lastErr
}
func (c *Ring) Pipelined(fn func(Pipeliner) error) ([]Cmder, error) {
return c.Pipeline().Pipelined(fn)
}
func (c *Ring) Pipeline() Pipeliner {
pipe := Pipeline{
ctx: c.ctx,
exec: c.processPipeline,
}
pipe.init()
return &pipe
}
func (c *Ring) processPipeline(ctx context.Context, cmds []Cmder) error {
return c.hooks.processPipeline(ctx, cmds, func(ctx context.Context, cmds []Cmder) error {
return c.generalProcessPipeline(ctx, cmds, false)
})
}
func (c *Ring) TxPipelined(fn func(Pipeliner) error) ([]Cmder, error) {
return c.TxPipeline().Pipelined(fn)
}
func (c *Ring) TxPipeline() Pipeliner {
pipe := Pipeline{
ctx: c.ctx,
exec: c.processTxPipeline,
}
pipe.init()
return &pipe
}
func (c *Ring) processTxPipeline(ctx context.Context, cmds []Cmder) error {
return c.hooks.processPipeline(ctx, cmds, func(ctx context.Context, cmds []Cmder) error {
return c.generalProcessPipeline(ctx, cmds, true)
})
}
func (c *Ring) generalProcessPipeline(
ctx context.Context, cmds []Cmder, tx bool,
) error {
cmdsMap := make(map[string][]Cmder)
for _, cmd := range cmds {
cmdInfo := c.cmdInfo(cmd.Name())
hash := cmd.stringArg(cmdFirstKeyPos(cmd, cmdInfo))
if hash != "" {
hash = c.shards.Hash(hashtag.Key(hash))
}
cmdsMap[hash] = append(cmdsMap[hash], cmd)
}
var wg sync.WaitGroup
for hash, cmds := range cmdsMap {
wg.Add(1)
go func(hash string, cmds []Cmder) {
defer wg.Done()
_ = c.processShardPipeline(ctx, hash, cmds, tx)
}(hash, cmds)
}
wg.Wait()
return cmdsFirstErr(cmds)
}
func (c *Ring) processShardPipeline(
ctx context.Context, hash string, cmds []Cmder, tx bool,
) error {
//TODO: retry?
shard, err := c.shards.GetByHash(hash)
if err != nil {
setCmdsErr(cmds, err)
return err
}
if tx {
err = shard.Client.processTxPipeline(ctx, cmds)
} else {
err = shard.Client.processPipeline(ctx, cmds)
}
return err
}
// Close closes the ring client, releasing any open resources.
//
// It is rare to Close a Ring, as the Ring is meant to be long-lived
// and shared between many goroutines.
func (c *Ring) Close() error {
return c.shards.Close()
}
func (c *Ring) Watch(fn func(*Tx) error, keys ...string) error {
if len(keys) == 0 {
return fmt.Errorf("redis: Watch requires at least one key")
}
var shards []*ringShard
for _, key := range keys {
if key != "" {
shard, err := c.shards.GetByKey(hashtag.Key(key))
if err != nil {
return err
}
shards = append(shards, shard)
}
}
if len(shards) == 0 {
return fmt.Errorf("redis: Watch requires at least one shard")
}
if len(shards) > 1 {
for _, shard := range shards[1:] {
if shard.Client != shards[0].Client {
err := fmt.Errorf("redis: Watch requires all keys to be in the same shard")
return err
}
}
}
return shards[0].Client.Watch(fn, keys...)
}
func newConsistentHash(opt *RingOptions) *consistenthash.Map {
return consistenthash.New(opt.HashReplicas, consistenthash.Hash(opt.Hash))
}