Hello :wave: ,
We are looking to add monix-bio support to the weaver test framework, in the same way as we have for Monix: disneystreaming/weaver-test#63
To that end, I wondered whether there are documented ways to summon Cats Effect instances like Timer, ContextShift, ConcurrentEffectfor monix-bio's Task.
@bfdesTimer and ContextShift should be available for "free" (e.g. https://github.com/monix/monix-bio/blob/master/core/shared/src/main/scala/monix/bio/IO.scala#L5235 ) and ConcurrentEffect if there is implicit Scheduler in scope (IO.catsEffect(s) could work manually) without doing anything. Did you run into any problems?
implicit def timer: Timer[Task] = Task.timer(scheduler)
implicit def cs: ContextShift[Task] = Task.contextShift(scheduler)is redundant unless this is a different scheduler than the one you pass when running the task
@Avasil :wave: , in case you don't see the notification : we could use a little bit of guidance there :
https://github.com/disneystreaming/weaver-test/pull/83/files#r491327459
Hi! I was trying to make this issue monix/monix-bio#159
If I understand correctly, I should use method whenA from cats.Monad and write like this:
def whenA(cond: Boolean)(action: => IO[E, Unit]): IO[E, Unit] =
MonadIO[E, *].whenA(cond)(action)
But I have problem with parameter catsMonad. I'm trying to use catsParallelAny.monad here, but facing with type mismatch. Should I find another way to define catsMonad? Or may be I chose wrong way at the beginning?
Hello @GKhotyan , thank you for the interest in contributing!
It seems like the signature needs to be final def whenA[E1 >: E](cond: Boolean)(action: => IO[E1, Unit]): IO[E1, Unit] for Applicative[IO[E1, *]].whenA to work.
On the other hand, I would prefer to reimplement it, the implementation is very simple
Ahh, I was wrong with the signature.
For some reason I put it as an IO method instead of companion object but if we also have a variant on IO then it wouldn't take action at all.
On companion object it's simply def when[E](cond: Boolean)(action :=> IO[E, Unit]): IO[E, Unit] regardless of Applicative usage.
BTW, it seems like someone else has already contributed it in the meantime but I have few low hanging fruits in monix/monix if you'd like to look after something else.
If you'd like to contribute to monix-bio in particular, there are some methods that would be nice to have in the API, like ZIO's absorb:
final def absorb(implicit ev: E <:< Throwable): Task[A]
final def absorbWith(f: E => Throwable): Task[A]that is equivalent of redeemCauseWith(c => IO.raiseError(c.toThrowable), x => IO.now(x))
Not sure about the name, if there are no better ideas, we can just settle on absorb.
There are some other methods that I wanted to include in both Monix and Monix BIO, I will create issues for them tomorrow. Feel free to ping me if I don't do that :sweat_smile:
/** Creates a new Task by applying a monadic function to the successful result
- of the source Task, and discard the result.
*/final def flatTap[E1 >: E, B](f: A => IO[E1, B]): IO[E1, A] = { this.flatMap { a => f(a).map(_ => a) } }
but comparing to cats flatTap where F could be List or Option, here F is always IO, so I’m confused. May be this code is not what required?
Hello @WesselVS
Are there plans to integrate the just merged improved tracing from monix?
Yes, I've planned to do this after releasing stack traces for Monix that I want to do within a few days
Also, if I were to take a shot at this myself, what would be a good approach?
It would require copying relevant changes from this PR: https://github.com/monix/monix/pull/1267/filesmonix-bio depends on monix-execution so RingBuffer will be available but the rest needs to be duplicated.
The structure is very similar so integration should be a straightforward but manual task.
Is bio forked from monix, so that I can pull in the master branch from monix into bio?
It's not a fork but it depends on some modules
If you'd like to help out then that would be fantastic
monix-bio release a lot :)
Thanks! Just out of curiosity: I'm seeing this in the monix trace (in the test captures bracket frames of FullStackTracingSuite):
TaskTrace: 13 frames captured
├ apply @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:117)
├ apply @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:117)
├ runToFuture @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:130)
├ <clinit> @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:117)
├ runToFuture @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:130)
├ pure @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:117)
├ runToFuture @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:130)
├ <clinit> @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:117)
├ bracket @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:117)
├ flatMap @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:117)
├ flatMap @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:117)
├ flatMap @ tracing.FullStackTracingSuite$.traced (FullStackTracingSuite.scala:12)
╰ map @ tracing.FullStackTracingSuite$.new (FullStackTracingSuite.scala:120)Why is runToFuture there 3 times? The trace I'm getting in monix-bio lists the runToFuture only 2 times, but I'm trying to figure out why it's there more than once.
1.1.0 with stack traces :) https://github.com/monix/monix-bio/releases/tag/v1.1.0cc @WesselVS
Future[Either[SomeFailure, A]] for many of its operations. I would like transform that into an IO[SomeFailure, A] and work with it until I have to actually serve the data (then runToFuture). I assume whatever used to be a failed Future in the past is a fatal\terminal error in the context of IO... am I getting it right? Is this a supported use case?
Hello @eliavlavi
Your understanding is correct. It's similar with fromTryEither
It's equivalent of IO.deferFuture(f).hideErrors.rethrow.
Unfortunately, there's no built-in operator for that but I think we really need it if you're interested in contributing.
I see that I even implemented TaskFromFutureEither in low-level code but I don't remember why I didn't expose it in the API :sweat_smile:
IO.scala right under def fromFuture to me, but I am not sure where should the test go - TaskFromFutureSuite.scala? new file?)
@WesselVS You can do a conversion like this: https://bio.monix.io/docs/cats-effect#monixevaltask
I have some plans to make Observable easier to use with IO[E, A] (without conversions) but it is not a top priority for me right now