class MQTT::Pending(T)

• MQTT::Pending(T)
• Reference
• Object

Overview

A single-shot slot for a response we're expecting from the broker.

This replaces the promises that used to carry request/response plumbing. Promise::DeferredPromise#get spawns a fiber and allocates a channel on every call, and Promise.timeout costs another fiber and channel per request. More importantly a promise runs its callbacks inline on whichever fiber resolves it, which made it unsafe to resolve one while holding a lock.

Completion is signalled by closing a channel, which wakes every waiter rather than handing the value to whoever happens to receive first.

Defined in:

mqtt/pending.cr

Constructors

• .new

Instance Method Summary

• #completed? : Bool
• #get(timeout : Time::Span | Nil = nil, description : String = "response") : T

  Blocks the calling fiber until the response arrives.

• #reject(error : Exception) : Nil
• #resolve(value : T) : Nil

Constructor Detail

Instance Method Detail