Add wiretap/wiretapContext to FlowWithContext/SourceWithContext

docs/src/main/paradox/release-notes/releases-1.1.md

@@ -43,6 +43,7 @@ The Stream API has been updated to add some extra functions.
 * added extra retry operators that allow users to provide a predicate to decide whether to retry based on the exception ([PR1269](https://github.com/apache/pekko/pull/1269))
 * add optionalVia/unsafeOptionalDataVia operators ([PR1422](https://github.com/apache/pekko/pull/1422))
 * add alsoTo/alsoToContext operators to `SourceWithContext`/`FlowWithContext` ([PR-1443](https://github.com/apache/pekko/pull/1443))
+* add wireTap/wireTapContext operators to `SourceWithContext`/`FlowWithContext` ([PR-1446](https://github.com/apache/pekko/pull/1446))
 
 The Stream Testkit Java DSL has some extra functions.
 

stream-tests/src/test/scala/org/apache/pekko/stream/scaladsl/FlowWithContextSpec.scala

@@ -126,6 +126,50 @@ class FlowWithContextSpec extends StreamSpec {
         }
     }
 
+    "pass through all data when using wireTap" in {
+      val listBuffer = new ListBuffer[String]()
+      Source(Vector(Message("A", 1L), Message("B", 2L), Message("D", 3L), Message("C", 4L)))
+        .asSourceWithContext(_.offset)
+        .via(
+          FlowWithContext.fromTuples(Flow.fromFunction[(Message, Long), (String, Long)] { case (data, offset) =>
+            (data.data.toLowerCase, offset)
+          }).wireTap(Sink.foreach(string => listBuffer.+=(string)))
+        )
+        .toMat(TestSink.probe[(String, Long)])(Keep.right)
+        .run()
+        .request(4)
+        .expectNext(("a", 1L))
+        .expectNext(("b", 2L))
+        .expectNext(("d", 3L))
+        .expectNext(("c", 4L))
+        .expectComplete()
+        .within(10.seconds) {
+          listBuffer should contain atLeastOneElementOf List("a", "b", "d", "c")
+        }
+    }
+
+    "pass through all data when using wireTapContext" in {
+      val listBuffer = new ListBuffer[Long]()
+      Source(Vector(Message("A", 1L), Message("B", 2L), Message("D", 3L), Message("C", 4L)))
+        .asSourceWithContext(_.offset)
+        .via(
+          FlowWithContext.fromTuples(Flow.fromFunction[(Message, Long), (String, Long)] { case (data, offset) =>
+            (data.data.toLowerCase, offset)
+          }).wireTapContext(Sink.foreach(offset => listBuffer.+=(offset)))
+        )
+        .toMat(TestSink.probe[(String, Long)])(Keep.right)
+        .run()
+        .request(4)
+        .expectNext(("a", 1L))
+        .expectNext(("b", 2L))
+        .expectNext(("d", 3L))
+        .expectNext(("c", 4L))
+        .expectComplete()
+        .within(10.seconds) {
+          listBuffer should contain atLeastOneElementOf List(1L, 2L, 3L, 4L)
+        }
+    }
+
     "keep the same order for data and context when using unsafeDataVia" in {
       val data = List(("1", 1), ("2", 2), ("3", 3), ("4", 4))
 

stream-tests/src/test/scala/org/apache/pekko/stream/scaladsl/SourceWithContextSpec.scala

@@ -115,6 +115,44 @@ class SourceWithContextSpec extends StreamSpec {
         }
     }
 
+    "pass through all data when using wireTap" in {
+      val listBuffer = new ListBuffer[Message]()
+      val messages = Vector(Message("A", 1L), Message("B", 2L), Message("D", 3L), Message("C", 4L))
+      Source(messages)
+        .asSourceWithContext(_.offset)
+        .wireTap(Sink.foreach(message => listBuffer.+=(message)))
+        .toMat(TestSink.probe[(Message, Long)])(Keep.right)
+        .run()
+        .request(4)
+        .expectNext((Message("A", 1L), 1L))
+        .expectNext((Message("B", 2L), 2L))
+        .expectNext((Message("D", 3L), 3L))
+        .expectNext((Message("C", 4L), 4L))
+        .expectComplete()
+        .within(10.seconds) {
+          listBuffer.toVector should contain atLeastOneElementOf messages
+        }
+    }
+
+    "pass through all data when using wireTapContext" in {
+      val listBuffer = new ListBuffer[Long]()
+      val messages = Vector(Message("A", 1L), Message("B", 2L), Message("D", 3L), Message("C", 4L))
+      Source(messages)
+        .asSourceWithContext(_.offset)
+        .wireTapContext(Sink.foreach(offset => listBuffer.+=(offset)))
+        .toMat(TestSink.probe[(Message, Long)])(Keep.right)
+        .run()
+        .request(4)
+        .expectNext((Message("A", 1L), 1L))
+        .expectNext((Message("B", 2L), 2L))
+        .expectNext((Message("D", 3L), 3L))
+        .expectNext((Message("C", 4L), 4L))
+        .expectComplete()
+        .within(10.seconds) {
+          listBuffer.toVector should contain atLeastOneElementOf (messages.map(_.offset))
+        }
+    }
+
     "pass through contexts via a FlowWithContext" in {
 
       def flowWithContext[T] = FlowWithContext[T, Long]

stream/src/main/mima-filters/1.0.x.backwards.excludes/pr-1446-wireTap-wireTapContext-source-flow-with-context.backwards.excludes

@@ -0,0 +1,2 @@
+    ProblemFilters.exclude[ReversedMissingMethodProblem]("org.apache.pekko.stream.scaladsl.FlowWithContextOps.wireTap")
+    ProblemFilters.exclude[ReversedMissingMethodProblem]("org.apache.pekko.stream.scaladsl.FlowWithContextOps.wireTapContext")

stream/src/main/scala/org/apache/pekko/stream/scaladsl/FlowWithContext.scala

@@ -144,6 +144,12 @@ final class FlowWithContext[-In, -CtxIn, +Out, +CtxOut, +Mat](delegate: Flow[(In
   override def alsoToContext(that: Graph[SinkShape[CtxOut], _]): Repr[Out, CtxOut] =
     FlowWithContext.fromTuples(delegate.alsoTo(Sink.contramapImpl(that, (in: (Out, CtxOut)) => in._2)))
 
+  override def wireTap(that: Graph[SinkShape[Out], _]): Repr[Out, CtxOut] =
+    FlowWithContext.fromTuples(delegate.wireTap(Sink.contramapImpl(that, (in: (Out, CtxOut)) => in._1)))
+
+  override def wireTapContext(that: Graph[SinkShape[CtxOut], _]): Repr[Out, CtxOut] =
+    FlowWithContext.fromTuples(delegate.wireTap(Sink.contramapImpl(that, (in: (Out, CtxOut)) => in._2)))
+
   /**
    * Context-preserving variant of [[pekko.stream.scaladsl.Flow.withAttributes]].
    *

stream/src/main/scala/org/apache/pekko/stream/scaladsl/FlowWithContextOps.scala

@@ -104,6 +104,22 @@ trait FlowWithContextOps[+Out, +Ctx, +Mat] {
    */
   def alsoToContext(that: Graph[SinkShape[Ctx], _]): Repr[Out, Ctx]
 
+  /**
+   * Data variant of [[pekko.stream.scaladsl.FlowOps.wireTap]]
+   *
+   * @see [[pekko.stream.scaladsl.FlowOps.wireTap]]
+   * @since 1.1.0
+   */
+  def wireTap(that: Graph[SinkShape[Out], _]): Repr[Out, Ctx]
+
+  /**
+   * Context variant of [[pekko.stream.scaladsl.FlowOps.wireTap]]
+   *
+   * @see [[pekko.stream.scaladsl.FlowOps.wireTap]]
+   * @since 1.1.0
+   */
+  def wireTapContext(that: Graph[SinkShape[Ctx], _]): Repr[Out, Ctx]
+
   /**
    * Context-preserving variant of [[pekko.stream.scaladsl.FlowOps.map]].
    *

stream/src/main/scala/org/apache/pekko/stream/scaladsl/SourceWithContext.scala

@@ -161,6 +161,12 @@ final class SourceWithContext[+Out, +Ctx, +Mat] private[stream] (delegate: Sourc
   override def alsoToContext(that: Graph[SinkShape[Ctx], _]): Repr[Out, Ctx] =
     SourceWithContext.fromTuples(delegate.alsoTo(Sink.contramapImpl(that, (in: (Out, Ctx)) => in._2)))
 
+  override def wireTap(that: Graph[SinkShape[Out], _]): Repr[Out, Ctx] =
+    SourceWithContext.fromTuples(delegate.wireTap(Sink.contramapImpl(that, (in: (Out, Ctx)) => in._1)))
+
+  override def wireTapContext(that: Graph[SinkShape[Ctx], _]): Repr[Out, Ctx] =
+    SourceWithContext.fromTuples(delegate.wireTap(Sink.contramapImpl(that, (in: (Out, Ctx)) => in._2)))
+
   /**
    * Connect this [[pekko.stream.scaladsl.SourceWithContext]] to a [[pekko.stream.scaladsl.Sink]] and run it.
    * The returned value is the materialized value of the `Sink`.