Calling toStrict on an entity makes it very easy to randomly deadlock the request about akka-http

[akka-ci]

Comment by ktoso
Wednesday Jun 29, 2016 at 21:25 GMT

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Please read this response which explains what you're doing to the server here: http://stackoverflow.com/questions/34641861/akka-http-blocking-in-a-future-blocks-the-server/34645097#34645097

Put a warning in the routing docs not to do this

I agree we should give more guidance, where should we put those docs you think?
Dealing with futures is as simple as *don't block!", and there's the onComplete(future) directive.

Create a 'strict' Directive which does this for you properly (See also #20096)

I like the idea, can you create a ticket specifically for it? Maybe even contribute? It would be rather simple :-)

Fix the code so that this is easily diagnosable/doesn't break

That is hard... I wonder if possible hm.

[akka-ci]

Comment by Joe-Edwards
Tuesday Jul 05, 2016 at 09:51 GMT

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where should we put those docs you think?

Perhaps a warning box at the bottom of the introduction to http://doc.akka.io/docs/akka/2.4.7/scala/http/routing-dsl/routes.html#routes ?

can you create a ticket specifically for it?

Done. I'll think about making some pull requests, but I need to sort out the CLA first.

[akka-ci]

Comment by ktoso
Tuesday Jul 05, 2016 at 12:32 GMT

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Perhaps a warning box at the bottom of the introduction to http://doc.akka.io/docs/akka/2.4.7/scala/http/routing-dsl/routes.html#routes ?

the Await block is scary. Yes, a note is likely a good idea, we could link from it to: akka/akka#20469 (which I'll attempt to merge).

Done. I'll think about making some pull requests, but I need to sort out the CLA first.

That'd be awesome :) Let me know if there's anything I could help out with there.

[catalin-ursachi]

Given there's an extractStrictEntity directive now, is there any more work required for this ticket?

[jrudolph]

Doing some (almost) spring cleaning. Let's close this for now.

Blocking in Akka will lead to bad results in any case. It would be nice if we could offer better tools to troubleshoot situations like this but at least in this case you can get an indication of what is wrong by looking at the stack trace which will show the blocking await call. A better solution is out of scope for Akka HTTP. Maybe at some point we can offer some diagnostics in Akka or Akka Stream directly.