How do I use “writeOutputStream” with an fs2 Stream[IO, Byte]
I am trying to use fs2.io.writeOutputStream for the output to a Java AWS lambda fn. I don't know how to provide the implicit parameter it's looking for:
"no implicits found for parameter cs: ContextShift[IO]"
I found some documentation for creating my own implicit ContextShift object but that seems like overkill for what I'm trying to do.
final def handleRequest(in: InputStream, out: OutputStream, context: Context): Unit = (for {
bytes <- in.compile.toList
str = getString(bytes)
args <- decode(str).raiseIO
_ <- produce(args).to(writeOutputStream(IO(out), global)).compile.drain
} yield Unit).unsafeRunAsyncAndForget() // throws exception in the case of Failure
// ------------------------------------------------
// produce(args: MyCaseClass): fs2.Stream[IO, Byte]
scala aws-lambda fs2
asked Nov 13 '18 at 20:38
codenoodlecodenoodle
377110
add a comment |
I am trying to use fs2.io.writeOutputStream for the output to a Java AWS lambda fn. I don't know how to provide the implicit parameter it's looking for:
"no implicits found for parameter cs: ContextShift[IO]"
I found some documentation for creating my own implicit ContextShift object but that seems like overkill for what I'm trying to do.
final def handleRequest(in: InputStream, out: OutputStream, context: Context): Unit = (for {
bytes <- in.compile.toList
str = getString(bytes)
args <- decode(str).raiseIO
_ <- produce(args).to(writeOutputStream(IO(out), global)).compile.drain
} yield Unit).unsafeRunAsyncAndForget() // throws exception in the case of Failure
// ------------------------------------------------
// produce(args: MyCaseClass): fs2.Stream[IO, Byte]
scala aws-lambda fs2
asked Nov 13 '18 at 20:38
codenoodlecodenoodle
377110
add a comment |
I am trying to use fs2.io.writeOutputStream for the output to a Java AWS lambda fn. I don't know how to provide the implicit parameter it's looking for:
"no implicits found for parameter cs: ContextShift[IO]"
I found some documentation for creating my own implicit ContextShift object but that seems like overkill for what I'm trying to do.
final def handleRequest(in: InputStream, out: OutputStream, context: Context): Unit = (for {
bytes <- in.compile.toList
str = getString(bytes)
args <- decode(str).raiseIO
_ <- produce(args).to(writeOutputStream(IO(out), global)).compile.drain
} yield Unit).unsafeRunAsyncAndForget() // throws exception in the case of Failure
// ------------------------------------------------
// produce(args: MyCaseClass): fs2.Stream[IO, Byte]
scala aws-lambda fs2
asked Nov 13 '18 at 20:38
codenoodlecodenoodle
377110
I am trying to use fs2.io.writeOutputStream for the output to a Java AWS lambda fn. I don't know how to provide the implicit parameter it's looking for:
"no implicits found for parameter cs: ContextShift[IO]"
I found some documentation for creating my own implicit ContextShift object but that seems like overkill for what I'm trying to do.
final def handleRequest(in: InputStream, out: OutputStream, context: Context): Unit = (for {
bytes <- in.compile.toList
str = getString(bytes)
args <- decode(str).raiseIO
_ <- produce(args).to(writeOutputStream(IO(out), global)).compile.drain
} yield Unit).unsafeRunAsyncAndForget() // throws exception in the case of Failure
// ------------------------------------------------
// produce(args: MyCaseClass): fs2.Stream[IO, Byte]
scala aws-lambda fs2
scala aws-lambda fs2
asked Nov 13 '18 at 20:38
codenoodlecodenoodle
377110
asked Nov 13 '18 at 20:38
codenoodlecodenoodle
377110
asked Nov 13 '18 at 20:38
codenoodlecodenoodle
377110
asked Nov 13 '18 at 20:38
codenoodlecodenoodle
377110
asked Nov 13 '18 at 20:38
codenoodlecodenoodle
377110
377110
add a comment |
add a comment |
1 Answer
1
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"By default, Cats Effect can provide instance of ContextShift[IO] that manages thread-pools, but only if there’s an ExecutionContext in scope or if IOApp is used."
-- Cats-effect documentation.
From an ExecutionContext.
import cats.effect.{IO, ContextShift}
import scala.concurrent.ExecutionContext.Implicits.global
val contextShift = IO.contextShift(global)
Using IOApp.
import cats.effect.{IO, IOApp, ContextShift}
object Main extends IOApp {
override def run(args: List[String]): IO[ExitCode] = {
val cs = implicitly[ContextShift[IO]]
}
}
answered Nov 14 '18 at 1:49
Luis Miguel Mejía SuárezLuis Miguel Mejía Suárez
1,793721
Thanks! "IO.contextShift(global)" is exactly what I needed.
– codenoodle
Nov 14 '18 at 14:43
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
"By default, Cats Effect can provide instance of ContextShift[IO] that manages thread-pools, but only if there’s an ExecutionContext in scope or if IOApp is used."
-- Cats-effect documentation.
From an ExecutionContext.
import cats.effect.{IO, ContextShift}
import scala.concurrent.ExecutionContext.Implicits.global
val contextShift = IO.contextShift(global)
Using IOApp.
import cats.effect.{IO, IOApp, ContextShift}
object Main extends IOApp {
override def run(args: List[String]): IO[ExitCode] = {
val cs = implicitly[ContextShift[IO]]
}
}
answered Nov 14 '18 at 1:49
Luis Miguel Mejía SuárezLuis Miguel Mejía Suárez
1,793721
Thanks! "IO.contextShift(global)" is exactly what I needed.
– codenoodle
Nov 14 '18 at 14:43
add a comment |
"By default, Cats Effect can provide instance of ContextShift[IO] that manages thread-pools, but only if there’s an ExecutionContext in scope or if IOApp is used."
-- Cats-effect documentation.
From an ExecutionContext.
import cats.effect.{IO, ContextShift}
import scala.concurrent.ExecutionContext.Implicits.global
val contextShift = IO.contextShift(global)
Using IOApp.
import cats.effect.{IO, IOApp, ContextShift}
object Main extends IOApp {
override def run(args: List[String]): IO[ExitCode] = {
val cs = implicitly[ContextShift[IO]]
}
}
answered Nov 14 '18 at 1:49
Luis Miguel Mejía SuárezLuis Miguel Mejía Suárez
1,793721
Thanks! "IO.contextShift(global)" is exactly what I needed.
– codenoodle
Nov 14 '18 at 14:43
add a comment |
"By default, Cats Effect can provide instance of ContextShift[IO] that manages thread-pools, but only if there’s an ExecutionContext in scope or if IOApp is used."
-- Cats-effect documentation.
From an ExecutionContext.
import cats.effect.{IO, ContextShift}
import scala.concurrent.ExecutionContext.Implicits.global
val contextShift = IO.contextShift(global)
Using IOApp.
import cats.effect.{IO, IOApp, ContextShift}
object Main extends IOApp {
override def run(args: List[String]): IO[ExitCode] = {
val cs = implicitly[ContextShift[IO]]
}
}
answered Nov 14 '18 at 1:49
Luis Miguel Mejía SuárezLuis Miguel Mejía Suárez
1,793721
"By default, Cats Effect can provide instance of ContextShift[IO] that manages thread-pools, but only if there’s an ExecutionContext in scope or if IOApp is used."
-- Cats-effect documentation.
From an ExecutionContext.
import cats.effect.{IO, ContextShift}
import scala.concurrent.ExecutionContext.Implicits.global
val contextShift = IO.contextShift(global)
Using IOApp.
import cats.effect.{IO, IOApp, ContextShift}
object Main extends IOApp {
override def run(args: List[String]): IO[ExitCode] = {
val cs = implicitly[ContextShift[IO]]
}
}
answered Nov 14 '18 at 1:49
Luis Miguel Mejía SuárezLuis Miguel Mejía Suárez
1,793721
answered Nov 14 '18 at 1:49
Luis Miguel Mejía SuárezLuis Miguel Mejía Suárez
1,793721
answered Nov 14 '18 at 1:49
Luis Miguel Mejía SuárezLuis Miguel Mejía Suárez
1,793721
answered Nov 14 '18 at 1:49
Luis Miguel Mejía SuárezLuis Miguel Mejía Suárez
1,793721
1,793721
Thanks! "IO.contextShift(global)" is exactly what I needed.
– codenoodle
Nov 14 '18 at 14:43
add a comment |
Thanks! "IO.contextShift(global)" is exactly what I needed.
– codenoodle
Nov 14 '18 at 14:43
Thanks! "IO.contextShift(global)" is exactly what I needed.
– codenoodle
Nov 14 '18 at 14:43
Thanks! "IO.contextShift(global)" is exactly what I needed.
– codenoodle
Nov 14 '18 at 14:43
add a comment |
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