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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,122 @@ | ||
| package dcs | ||
|
|
||
| import ( | ||
| "fmt" | ||
| "log/slog" | ||
| "math/rand" | ||
| "net" | ||
| "sync" | ||
| "time" | ||
| ) | ||
|
|
||
| type RandomHostProvider struct { | ||
| lock sync.Mutex | ||
| servers []string | ||
| resolved []string | ||
| tried map[string]struct{} | ||
| logger *slog.Logger | ||
| lastLookup time.Time | ||
| lookupTTL time.Duration | ||
| } | ||
|
|
||
| func NewRandomHostProvider(config *RandomHostProviderConfig, logger *slog.Logger) *RandomHostProvider { | ||
| return &RandomHostProvider{ | ||
| lookupTTL: config.LookupTTL, | ||
| logger: logger, | ||
| tried: make(map[string]struct{}), | ||
| } | ||
| } | ||
|
|
||
| func (rhp *RandomHostProvider) Init(servers []string) error { | ||
| rhp.lock.Lock() | ||
| defer rhp.lock.Unlock() | ||
|
|
||
| rhp.servers = servers | ||
|
|
||
| err := rhp.resolveHosts() | ||
|
|
||
| if err != nil { | ||
| return fmt.Errorf("failed to init zk host provider %v", err) | ||
| } | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| func (rhp *RandomHostProvider) resolveHosts() error { | ||
| resolved := []string{} | ||
| for _, server := range rhp.servers { | ||
| host, port, err := net.SplitHostPort(server) | ||
| if err != nil { | ||
| return err | ||
| } | ||
| addrs, err := net.LookupHost(host) | ||
| if err != nil { | ||
| rhp.logger.Error(fmt.Sprintf("unable to resolve %s", host), "error", err) | ||
| } | ||
| for _, addr := range addrs { | ||
| resolved = append(resolved, net.JoinHostPort(addr, port)) | ||
| } | ||
| } | ||
|
|
||
| if len(resolved) == 0 { | ||
| return fmt.Errorf("no hosts resolved for %q", rhp.servers) | ||
| } | ||
|
|
||
| rhp.lastLookup = time.Now() | ||
| rhp.resolved = resolved | ||
|
|
||
| rand.Shuffle(len(rhp.resolved), func(i, j int) { rhp.resolved[i], rhp.resolved[j] = rhp.resolved[j], rhp.resolved[i] }) | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| func (rhp *RandomHostProvider) Len() int { | ||
| rhp.lock.Lock() | ||
| defer rhp.lock.Unlock() | ||
| return len(rhp.resolved) | ||
| } | ||
|
|
||
| func (rhp *RandomHostProvider) Next() (server string, retryStart bool) { | ||
| rhp.lock.Lock() | ||
| defer rhp.lock.Unlock() | ||
| lastTime := time.Since(rhp.lastLookup) | ||
| needRetry := false | ||
| if lastTime > rhp.lookupTTL { | ||
| err := rhp.resolveHosts() | ||
| if err != nil { | ||
| rhp.logger.Error("resolve zk hosts failed", "error", err) | ||
| } | ||
| } | ||
|
|
||
| notTried := []string{} | ||
|
|
||
| for _, addr := range rhp.resolved { | ||
| if _, ok := rhp.tried[addr]; !ok { | ||
| notTried = append(notTried, addr) | ||
| } | ||
| } | ||
|
|
||
| var selected string | ||
|
|
||
| if len(notTried) == 0 { | ||
| needRetry = true | ||
| for k := range rhp.tried { | ||
| delete(rhp.tried, k) | ||
| } | ||
| selected = rhp.resolved[rand.Intn(len(rhp.resolved))] | ||
| } else { | ||
| selected = notTried[rand.Intn(len(notTried))] | ||
| } | ||
|
|
||
| rhp.tried[selected] = struct{}{} | ||
|
|
||
| return selected, needRetry | ||
| } | ||
|
|
||
| func (rhp *RandomHostProvider) Connected() { | ||
| rhp.lock.Lock() | ||
| defer rhp.lock.Unlock() | ||
| for k := range rhp.tried { | ||
| delete(rhp.tried, k) | ||
| } | ||
| } |