Add decoder attempt instance

core/src/main/scala/dev/profunktor/fs2rabbit/effects/EnvelopeDecoder.scala

@@ -15,13 +15,14 @@
  */
 
 package dev.profunktor.fs2rabbit.effects
-import cats.{Applicative, ApplicativeThrow}
+import cats.{Applicative, ApplicativeError, ApplicativeThrow, MonadError}
 import cats.data.Kleisli
 import dev.profunktor.fs2rabbit.model.{AmqpFieldValue, AmqpProperties, ExchangeName, RoutingKey}
 import dev.profunktor.fs2rabbit.model.AmqpFieldValue._
 import cats.implicits._
 
-object EnvelopeDecoder {
+object EnvelopeDecoder extends EnvelopeDecoderInstances {
+
   def apply[F[_], A](implicit e: EnvelopeDecoder[F, A]): EnvelopeDecoder[F, A] = e
 
   def properties[F[_]: Applicative]: EnvelopeDecoder[F, AmqpProperties] =
@@ -81,3 +82,16 @@ object EnvelopeDecoder {
   ): EnvelopeDecoder[F, Option[A]] =
     Kleisli(_.properties.headers.get(name).traverse(h => F.catchNonFatal(pf(h))))
 }
+
+sealed trait EnvelopeDecoderInstances {
+
+  implicit def decoderAttempt[F[_], E: ApplicativeError[F, *], A](implicit
+      decoder: EnvelopeDecoder[F, A]
+  ): EnvelopeDecoder[F, Either[E, A]] =
+    decoder.attempt
+
+  implicit def decoderOption[F[_], E: ApplicativeError[F, *], A](implicit
+      decoder: EnvelopeDecoder[F, A]
+  ): EnvelopeDecoder[F, Option[A]] =
+    decoder.attempt.map(_.toOption)
+}

core/src/test/scala/dev/profunktor/fs2rabbit/effects/EnvelopeDecoderSpec.scala

@@ -31,11 +31,14 @@ import cats.effect.unsafe.implicits.global
 
 class EnvelopeDecoderSpec extends AsyncFunSuite {
 
+  import EnvelopeDecoder._
   // Available instances of EnvelopeDecoder for any ApplicativeError[F, Throwable]
   EnvelopeDecoder[Either[Throwable, *], String]
   EnvelopeDecoder[SyncIO, String]
   EnvelopeDecoder[EitherT[IO, String, *], String]
   EnvelopeDecoder[Try, String]
+  EnvelopeDecoder[Try, Option[String]]
+  EnvelopeDecoder[Try, Either[Throwable, String]]
 
   test("should decode a UTF-8 string") {
     val msg = "hello world!"
@@ -86,4 +89,32 @@ class EnvelopeDecoderSpec extends AsyncFunSuite {
       .unsafeToFuture()
   }
 
+  test("should decode a UTF-8 string - Attempt") {
+    val msg = "hello world!"
+    val raw = msg.getBytes(StandardCharsets.UTF_8)
+
+    EnvelopeDecoder[IO, Either[Throwable, String]]
+      .run(
+        AmqpEnvelope(DeliveryTag(0L), raw, AmqpProperties.empty, ExchangeName("test"), RoutingKey("test.route"), false)
+      )
+      .flatMap { result =>
+        IO(assert(result == Right(msg)))
+      }
+      .unsafeToFuture()
+  }
+
+  test("should decode a UTF-8 string - Attempt option") {
+    val msg = "hello world!"
+    val raw = msg.getBytes(StandardCharsets.UTF_8)
+
+    EnvelopeDecoder[IO, Option[String]]
+      .run(
+        AmqpEnvelope(DeliveryTag(0L), raw, AmqpProperties.empty, ExchangeName("test"), RoutingKey("test.route"), false)
+      )
+      .flatMap { result =>
+        IO(assert(result == Option(msg)))
+      }
+      .unsafeToFuture()
+  }
+
 }