Docker Swarm Code Analysis Note (2)--discovery

This is a creation in Article, where the information may have evolved or changed.

DockerProvides the implementation of the discovery package new backend definition interface ( discovey.go ):

Package Discoveryimport ("Errors" "Time") var (//Errnotsupported was returned when a discovery service was not Su    Pported. errnotsupported = errors.  New ("Discovery Service not supported")//Errnotimplemented was returned when Discovery feature was not implemented//    By Discovery Backend. errnotimplemented = errors. New ("Not implemented in this discovery service")//Watcher provides watching over a cluster for nodes joining and leaving    . Type Watcher Interface {//Watch the discovery for entry changes.    Returns a channel that would receive changes or an error.    Providing a non-nil stopch can is used to stop watching. Watch (stopch <-chan struct{}) (<-chan Entries, <-chan error)}//backend is implemented by Discovery Backends whic    H Manage cluster Entries.type backend interface {//Watcher must is provided by every backend.    Watcher//Initialize The discovery with URIs, a heartbeat, a TTL and optional settings. Initialize (String, time. DUration, time.    Duration, map[string]string) error/Register to the discovery. Register (String) Error}

Watcher interfacenodethe callback function used to join or remove cluster the out-of-time. Initializeused for backend initialization, and Register is used to node join cluster .