CODEWITHSUNDEEP
scalaakka
joesan
joesan

Reputation: 15385

Akka thread safety with Futures

I have an actor that has a mutable state. In my receive method, I pattern match the messages and call some service that would return a Future. This Future would modify the state in my Actor instance. Is this state not thread safe? Since the Future would be executing in a different thread, is the state in my Actor this guaranteed to be thread safe?

Upvotes: 2

Views: 667

Answers (1)

Akos Krivachy
Akos Krivachy

Reputation: 4966

No that will not be threadsafe as you correctly assumed. Futures run on any thread that the execution context provides.

The way to solve this is to pipe it back to the same actor. All actor's inputs must always be messages. You can find the documentation here.

Some example code:

import akka.pattern.pipe

//... inside the Actor somewhere:
val futureResult: Future[YourType] = something.thatReturnsAFuture()
futureResult.pipeTo(self)

And then amend your receive block so the result will be processed after the future completes and it is sent back to this actor:

case result: YourType => //...

Upvotes: 10

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