Package etcd
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Variables ¶
var ( // ErrNoKey indicates a client method needs a key but receives none. ErrNoKey = errors.New("no key provided") // ErrNoValue indicates a client method needs a value but receives none. ErrNoValue = errors.New("no value provided") )
type Client ¶
Client is a wrapper around the etcd client.
type Client interface { // GetEntries queries the given prefix in etcd and returns a slice // containing the values of all keys found, recursively, underneath that // prefix. GetEntries(prefix string) ([]string, error) // WatchPrefix watches the given prefix in etcd for changes. When a change // is detected, it will signal on the passed channel. Clients are expected // to call GetEntries to update themselves with the latest set of complete // values. WatchPrefix will always send an initial sentinel value on the // channel after establishing the watch, to ensure that clients always // receive the latest set of values. WatchPrefix will block until the // context passed to the NewClient constructor is terminated. WatchPrefix(prefix string, ch chan struct{}) // Register a service with etcd. Register(s Service) error // Deregister a service with etcd. Deregister(s Service) error }
func NewClient ¶
func NewClient(ctx context.Context, machines []string, options ClientOptions) (Client, error)
NewClient returns Client with a connection to the named machines. It will return an error if a connection to the cluster cannot be made. The parameter machines needs to be a full URL with schemas. e.g. "http://localhost:2379" will work, but "localhost:2379" will not.
type ClientOptions ¶
ClientOptions defines options for the etcd client. All values are optional. If any duration is not specified, a default of 3 seconds will be used.
type ClientOptions struct { Cert string Key string CACert string DialTimeout time.Duration DialKeepAlive time.Duration HeaderTimeoutPerRequest time.Duration }
type Registrar ¶
Registrar registers service instance liveness information to etcd.
type Registrar struct {
// contains filtered or unexported fields
}
func NewRegistrar ¶
func NewRegistrar(client Client, service Service, logger log.Logger) *Registrar
NewRegistrar returns a etcd Registrar acting on the provided catalog registration (service).
func (*Registrar) Deregister ¶
func (r *Registrar) Deregister()
Deregister implements the sd.Registrar interface. Call it when you want your service to be deregistered from etcd, typically just prior to shutdown.
func (*Registrar) Register ¶
func (r *Registrar) Register()
Register implements the sd.Registrar interface. Call it when you want your service to be registered in etcd, typically at startup.
type Service ¶
Service holds the instance identifying data you want to publish to etcd. Key must be unique, and value is the string returned to subscribers, typically called the "instance" string in other parts of package sd.
type Service struct { Key string // unique key, e.g. "/service/foobar/1.2.3.4:8080" Value string // returned to subscribers, e.g. "http://1.2.3.4:8080" TTL *TTLOption DeleteOptions *etcd.DeleteOptions }
type Subscriber ¶
Subscriber yield endpoints stored in a certain etcd keyspace. Any kind of change in that keyspace is watched and will update the Subscriber endpoints.
type Subscriber struct {
// contains filtered or unexported fields
}
func NewSubscriber ¶
func NewSubscriber(c Client, prefix string, factory sd.Factory, logger log.Logger) (*Subscriber, error)
NewSubscriber returns an etcd subscriber. It will start watching the given prefix for changes, and update the endpoints.
func (*Subscriber) Endpoints ¶
func (s *Subscriber) Endpoints() ([]endpoint.Endpoint, error)
Endpoints implements the Subscriber interface.
func (*Subscriber) Stop ¶
func (s *Subscriber) Stop()
Stop terminates the Subscriber.
type TTLOption ¶
TTLOption allow setting a key with a TTL. This option will be used by a loop goroutine which regularly refreshes the lease of the key.
type TTLOption struct {
// contains filtered or unexported fields
}
func NewTTLOption ¶
func NewTTLOption(heartbeat, ttl time.Duration) *TTLOption
NewTTLOption returns a TTLOption that contains proper TTL settings. Heartbeat is used to refresh the lease of the key periodically; its value should be at least 500ms. TTL defines the lease of the key; its value should be significantly greater than heartbeat.
Good default values might be 3s heartbeat, 10s TTL.