Add IORuntime#liveFiberSnapshot

core/shared/src/main/scala/cats/effect/FiberInfo.scala

@@ -0,0 +1,47 @@
+/*
+ * Copyright 2020-2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cats.effect
+
+import cats.effect.tracing.Tracing
+
+final case class FiberInfo(fiber: Fiber[IO, _, _], state: FiberState, trace: FiberTrace) {
+  def pretty = {
+    val id = System.identityHashCode(fiber).toHexString
+    val trace = fiber match {
+      case ioFiber: IOFiber[_] => ioFiber.prettyPrintTrace()
+      case _ => ""
+    }
+    val prefixedTrace = if (trace.isEmpty) "" else "\n" + trace
+    s"cats.effect.IOFiber@$id $state$prefixedTrace"
+  }
+}
+
+sealed abstract class FiberState(override val toString: String)
+    extends Product
+    with Serializable
+
+object FiberState {
+  case object Running extends FiberState("RUNNING")
+  case object Blocked extends FiberState("BLOCKED")
+  case object Yielding extends FiberState("YIELDING")
+  case object Waiting extends FiberState("WAITING")
+  case object Active extends FiberState("ACTIVE")
+}
+
+final case class FiberTrace(frames: List[StackTraceElement]) {
+  def pretty: String = Tracing.prettyPrint(frames)
+}

core/shared/src/main/scala/cats/effect/IORuntimeMetrics.scala

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2020-2022 Typelevel
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package cats.effect
+
+final case class IORuntimeMetrics(
+    enqueued: Int,
+    foreign: Int,
+    waiting: Int,
+    workers: List[IORuntimeWorkerMetrics])
+
+final case class IORuntimeWorkerMetrics(index: Int, enqueued: Int)

core/shared/src/main/scala/cats/effect/tracing/Tracing.scala

@@ -141,9 +141,10 @@ private[effect] object Tracing extends TracingPlatform {
       .collect { case ev: TracingEvent.StackTrace => getOpAndCallSite(ev.getStackTrace) }
       .filter(_ ne null)
 
-  def prettyPrint(events: RingBuffer): String = {
-    val frames = getFrames(events)
+  def prettyPrint(events: RingBuffer): String =
+    prettyPrint(getFrames(events))
 
+  def prettyPrint(frames: List[StackTraceElement]): String =
     frames
       .zipWithIndex
       .map {
@@ -152,5 +153,5 @@ private[effect] object Tracing extends TracingPlatform {
           s" $junc $frame"
       }
       .mkString(System.lineSeparator())
-  }
+
 }