package redis import ( "context" "crypto/tls" "errors" "fmt" "net" "net/url" "runtime" "strconv" "strings" "time" "github.com/go-redis/redis/v8/internal" "github.com/go-redis/redis/v8/internal/pool" "go.opentelemetry.io/otel/label" "go.opentelemetry.io/otel/trace" ) // Limiter is the interface of a rate limiter or a circuit breaker. type Limiter interface { // Allow returns nil if operation is allowed or an error otherwise. // If operation is allowed client must ReportResult of the operation // whether it is a success or a failure. Allow() error // ReportResult reports the result of the previously allowed operation. // nil indicates a success, non-nil error usually indicates a failure. ReportResult(result error) } // Options keeps the settings to setup redis connection. type Options struct { // The network type, either tcp or unix. // Default is tcp. Network string // host:port address. Addr string // Dialer creates new network connection and has priority over // Network and Addr options. Dialer func(ctx context.Context, network, addr string) (net.Conn, error) // Hook that is called when new connection is established. OnConnect func(ctx context.Context, cn *Conn) error // Use the specified Username to authenticate the current connection // with one of the connections defined in the ACL list when connecting // to a Redis 6.0 instance, or greater, that is using the Redis ACL system. Username string // Optional password. Must match the password specified in the // requirepass server configuration option (if connecting to a Redis 5.0 instance, or lower), // or the User Password when connecting to a Redis 6.0 instance, or greater, // that is using the Redis ACL system. Password string // Database to be selected after connecting to the server. DB int // Maximum number of retries before giving up. // Default is 3 retries. MaxRetries int // Minimum backoff between each retry. // Default is 8 milliseconds; -1 disables backoff. MinRetryBackoff time.Duration // Maximum backoff between each retry. // Default is 512 milliseconds; -1 disables backoff. MaxRetryBackoff time.Duration // Dial timeout for establishing new connections. // Default is 5 seconds. DialTimeout time.Duration // Timeout for socket reads. If reached, commands will fail // with a timeout instead of blocking. Use value -1 for no timeout and 0 for default. // Default is 3 seconds. ReadTimeout time.Duration // Timeout for socket writes. If reached, commands will fail // with a timeout instead of blocking. // Default is ReadTimeout. WriteTimeout time.Duration // Maximum number of socket connections. // Default is 10 connections per every CPU as reported by runtime.NumCPU. PoolSize int // Minimum number of idle connections which is useful when establishing // new connection is slow. MinIdleConns int // Connection age at which client retires (closes) the connection. // Default is to not close aged connections. MaxConnAge time.Duration // Amount of time client waits for connection if all connections // are busy before returning an error. // Default is ReadTimeout + 1 second. PoolTimeout time.Duration // Amount of time after which client closes idle connections. // Should be less than server's timeout. // Default is 5 minutes. -1 disables idle timeout check. IdleTimeout time.Duration // Frequency of idle checks made by idle connections reaper. // Default is 1 minute. -1 disables idle connections reaper, // but idle connections are still discarded by the client // if IdleTimeout is set. IdleCheckFrequency time.Duration // Enables read only queries on slave nodes. readOnly bool // TLS Config to use. When set TLS will be negotiated. TLSConfig *tls.Config // Limiter interface used to implemented circuit breaker or rate limiter. Limiter Limiter } func (opt *Options) init() { if opt.Addr == "" { opt.Addr = "localhost:6379" } if opt.Network == "" { if strings.HasPrefix(opt.Addr, "/") { opt.Network = "unix" } else { opt.Network = "tcp" } } if opt.DialTimeout == 0 { opt.DialTimeout = 5 * time.Second } if opt.Dialer == nil { opt.Dialer = func(ctx context.Context, network, addr string) (net.Conn, error) { netDialer := &net.Dialer{ Timeout: opt.DialTimeout, KeepAlive: 5 * time.Minute, } if opt.TLSConfig == nil { return netDialer.DialContext(ctx, network, addr) } return tls.DialWithDialer(netDialer, network, addr, opt.TLSConfig) } } if opt.PoolSize == 0 { opt.PoolSize = 10 * runtime.NumCPU() } switch opt.ReadTimeout { case -1: opt.ReadTimeout = 0 case 0: opt.ReadTimeout = 3 * time.Second } switch opt.WriteTimeout { case -1: opt.WriteTimeout = 0 case 0: opt.WriteTimeout = opt.ReadTimeout } if opt.PoolTimeout == 0 { opt.PoolTimeout = opt.ReadTimeout + time.Second } if opt.IdleTimeout == 0 { opt.IdleTimeout = 5 * time.Minute } if opt.IdleCheckFrequency == 0 { opt.IdleCheckFrequency = time.Minute } if opt.MaxRetries == -1 { opt.MaxRetries = 0 } else if opt.MaxRetries == 0 { opt.MaxRetries = 3 } 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 *Options) clone() *Options { clone := *opt return &clone } // ParseURL parses an URL into Options that can be used to connect to Redis. // Scheme is required. // There are two connection types: by tcp socket and by unix socket. // Tcp connection: // redis://:@:/ // Unix connection: // unix://:@?db= func ParseURL(redisURL string) (*Options, error) { u, err := url.Parse(redisURL) if err != nil { return nil, err } switch u.Scheme { case "redis", "rediss": return setupTCPConn(u) case "unix": return setupUnixConn(u) default: return nil, fmt.Errorf("redis: invalid URL scheme: %s", u.Scheme) } } func setupTCPConn(u *url.URL) (*Options, error) { o := &Options{Network: "tcp"} o.Username, o.Password = getUserPassword(u) if len(u.Query()) > 0 { return nil, errors.New("redis: no options supported") } h, p, err := net.SplitHostPort(u.Host) if err != nil { h = u.Host } if h == "" { h = "localhost" } if p == "" { p = "6379" } o.Addr = net.JoinHostPort(h, p) f := strings.FieldsFunc(u.Path, func(r rune) bool { return r == '/' }) switch len(f) { case 0: o.DB = 0 case 1: if o.DB, err = strconv.Atoi(f[0]); err != nil { return nil, fmt.Errorf("redis: invalid database number: %q", f[0]) } default: return nil, fmt.Errorf("redis: invalid URL path: %s", u.Path) } if u.Scheme == "rediss" { o.TLSConfig = &tls.Config{ServerName: h} } return o, nil } func setupUnixConn(u *url.URL) (*Options, error) { o := &Options{ Network: "unix", } if strings.TrimSpace(u.Path) == "" { // path is required with unix connection return nil, errors.New("redis: empty unix socket path") } o.Addr = u.Path o.Username, o.Password = getUserPassword(u) dbStr := u.Query().Get("db") if dbStr == "" { return o, nil // if database is not set, connect to 0 db. } db, err := strconv.Atoi(dbStr) if err != nil { return nil, fmt.Errorf("redis: invalid database number: %s", err) } o.DB = db return o, nil } func getUserPassword(u *url.URL) (string, string) { var user, password string if u.User != nil { user = u.User.Username() if p, ok := u.User.Password(); ok { password = p } } return user, password } func newConnPool(opt *Options) *pool.ConnPool { return pool.NewConnPool(&pool.Options{ Dialer: func(ctx context.Context) (net.Conn, error) { var conn net.Conn err := internal.WithSpan(ctx, "redis.dial", func(ctx context.Context, span trace.Span) error { span.SetAttributes( label.String("db.connection_string", opt.Addr), ) var err error conn, err = opt.Dialer(ctx, opt.Network, opt.Addr) if err != nil { _ = internal.RecordError(ctx, span, err) } return err }) return conn, err }, PoolSize: opt.PoolSize, MinIdleConns: opt.MinIdleConns, MaxConnAge: opt.MaxConnAge, PoolTimeout: opt.PoolTimeout, IdleTimeout: opt.IdleTimeout, IdleCheckFrequency: opt.IdleCheckFrequency, }) }