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f4312aef8a
* Fix Dockerfile base Go version Signed-off-by: dusanb94 <dusan.borovcanin@mainflux.com> * Update Go version and dependencies Signed-off-by: dusanb94 <dusan.borovcanin@mainflux.com>
39 lines
1.6 KiB
Go
39 lines
1.6 KiB
Go
package sd
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// Event represents a push notification generated from the underlying service discovery
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// implementation. It contains either a full set of available resource instances, or
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// an error indicating some issue with obtaining information from discovery backend.
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// Examples of errors may include loosing connection to the discovery backend, or
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// trying to look up resource instances using an incorrectly formatted key.
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// After receiving an Event with an error the listenter should treat previously discovered
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// resource instances as stale (although it may choose to continue using them).
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// If the Instancer is able to restore connection to the discovery backend it must push
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// another Event with the current set of resource instances.
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type Event struct {
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Instances []string
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Err error
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}
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// Instancer listens to a service discovery system and notifies registered
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// observers of changes in the resource instances. Every event sent to the channels
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// contains a complete set of instances known to the Instancer. That complete set is
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// sent immediately upon registering the channel, and on any future updates from
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// discovery system.
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type Instancer interface {
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Register(chan<- Event)
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Deregister(chan<- Event)
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Stop()
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}
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// FixedInstancer yields a fixed set of instances.
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type FixedInstancer []string
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// Register implements Instancer.
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func (d FixedInstancer) Register(ch chan<- Event) { ch <- Event{Instances: d} }
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// Deregister implements Instancer.
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func (d FixedInstancer) Deregister(ch chan<- Event) {}
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// Stop implements Instancer.
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func (d FixedInstancer) Stop() {}
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