Port killTree and killTreeForcibly to ZIO 2.0 branch (#209)

* Add `killTree` and `killTreeForcibly`

* Fix yaml indentation

* Fix tests

* Fix test script permissions

* Fix flaky test

* Try different implementation for killTree

* Fix tests

* Switch to another implementation of killTree

.github/workflows/ci.yml

@@ -23,6 +23,8 @@ jobs:
           fetch-depth: 0
       - name: Setup Scala and Java
         uses: olafurpg/setup-scala@v13
+        with:
+          java-version: [email protected]
       - name: Cache scala dependencies
         uses: coursier/cache-action@v6
       - name: Lint code
@@ -36,6 +38,8 @@ jobs:
         uses: actions/[email protected]
       - name: Setup Scala and Java
         uses: olafurpg/setup-scala@v13
+        with:
+          java-version: [email protected]
       - name: Cache scala dependencies
         uses: coursier/cache-action@v6
       - name: Check Document Generation
@@ -47,7 +51,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: ['adopt@1.8', 'adopt@1.11']
+        java: ['[email protected]']
         scala: ['2.11.12', '2.12.15', '2.13.7', '3.1.0']
     steps:
       - name: Checkout current branch
@@ -80,7 +84,9 @@ jobs:
         uses: actions/[email protected]
         with:
           fetch-depth: 0
-      - name: Setup Scala and Java 
+      - name: Setup Scala and Java
+        with:
+          java-version: [email protected]
         uses: olafurpg/setup-scala@v13
       - name: Cache scala dependencies
         uses: coursier/cache-action@v6

.github/workflows/site.yml

@@ -15,6 +15,8 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: olafurpg/setup-scala@v13
+        with:
+          java-version: [email protected]
       - run: sbt docs/docusaurusPublishGhpages
         env:
           GIT_DEPLOY_KEY: ${{ secrets.GIT_DEPLOY_KEY }}

build.sbt

@@ -31,8 +31,10 @@ logo :=
      |               | |
      |               |_|
      |
-     |   ${version.value}
-     |   
+     | ${version.value}
+     |
+     | Scala ${scalaVersion.value}
+     |
      |""".stripMargin
 logoColor := scala.Console.RED
 usefulTasks := Seq(

project/BuildHelper.scala

@@ -60,7 +60,8 @@ object BuildHelper {
     "-Ywarn-numeric-widen",
     "-Ywarn-value-discard",
     "-Xlint:_,-type-parameter-shadow",
-    "-Xsource:2.13"
+    "-Xsource:2.13",
+    "-target:jvm-1.8"
   )
 
   private def extraOptions(scalaVersion: String) =

src/main/scala/zio/process/Process.scala

@@ -19,6 +19,7 @@ import zio.ZIO.{ attemptBlockingCancelable, attemptBlockingInterrupt }
 import zio.{ ExitCode, UIO, ZIO }
 
 import java.lang.{ Process => JProcess }
+import scala.jdk.CollectionConverters._
 
 final case class Process(private val process: JProcess) {
 
@@ -71,6 +72,48 @@ final case class Process(private val process: JProcess) {
       ()
     }
 
+  /**
+   * Kills the entire process tree and will wait until completed. Equivalent to SIGTERM on Unix platforms.
+   *
+   * Note: This method requires JDK 9+
+   */
+  def killTree: ZIO[Any, CommandError, Unit] =
+    execute { process =>
+      val descendants = process.descendants().iterator().asScala.toSeq
+      descendants.foreach(_.destroy())
+
+      process.destroy()
+      process.waitFor()
+
+      descendants.foreach { p =>
+        if (p.isAlive) {
+          p.onExit().get // `ProcessHandle` doesn't have waitFor
+          ()
+        }
+      }
+    }
+
+  /**
+   * Kills the entire process tree and will wait until completed. Equivalent to SIGKILL on Unix platforms.
+   *
+   * Note: This method requires JDK 9+
+   */
+  def killTreeForcibly: ZIO[Any, CommandError, Unit] =
+    execute { process =>
+      val descendants = process.descendants().iterator().asScala.toSeq
+      descendants.foreach(_.destroyForcibly())
+
+      process.destroyForcibly()
+      process.waitFor()
+
+      descendants.foreach { p =>
+        if (p.isAlive) {
+          p.onExit().get // `ProcessHandle` doesn't have waitFor
+          ()
+        }
+      }
+    }
+
   /**
    * Return the exit code of this process if it is zero. If non-zero, it will fail with `CommandError.NonZeroErrorCode`.
    */

src/test/bash/kill-test/sample-child.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+echo $$
+sleep 30
+echo -n "end: "
+echo $$

src/test/bash/kill-test/sample-parent.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+echo $$
+./sample-child.sh &
+./sample-child.sh &
+sleep 30
+echo -n "end: "
+echo $$

src/test/scala/zio/process/CommandSpec.scala

@@ -7,6 +7,7 @@ import zio.{ durationInt, Chunk, ExitCode, ZIO }
 
 import java.io.File
 import java.nio.charset.StandardCharsets
+import java.util.Optional
 
 // TODO: Add aspects for different OSes? scala.util.Properties.isWin, etc. Also try to make this as OS agnostic as possible in the first place
 object CommandSpec extends ZIOProcessBaseSpec {
@@ -134,6 +135,53 @@ object CommandSpec extends ZIOProcessBaseSpec {
       for {
         exit <- Command("ls").workingDirectory(new File("/some/bad/path")).lines.exit
       } yield assert(exit)(fails(isSubtype[CommandError.WorkingDirectoryMissing](anything)))
-    }
+    },
+    test("kill only kills parent process") {
+      for {
+        process  <- Command("./sample-parent.sh").workingDirectory(new File("src/test/bash/kill-test")).run
+        pids     <- process.stdout.stream
+                      .via(ZPipeline.utf8Decode)
+                      .via(ZPipeline.splitLines)
+                      .take(3)
+                      .runCollect
+                      .map(_.map(_.toInt))
+        _        <- process.kill
+        pidsAlive = pids.map { pid =>
+                      toScalaOption(ProcessHandle.of(pid.toLong)).exists(_.isAlive)
+                    }
+      } yield assertTrue(pidsAlive == Chunk(false, true, true))
+    } @@ TestAspect.nonFlaky(25),
+    test("killTree also kills child processes") {
+      for {
+        process  <- Command("./sample-parent.sh").workingDirectory(new File("src/test/bash/kill-test")).run
+        pids     <- process.stdout.stream
+                      .via(ZPipeline.utf8Decode)
+                      .via(ZPipeline.splitLines)
+                      .take(3)
+                      .runCollect
+                      .map(_.map(_.toInt))
+        _        <- process.killTree
+        pidsAlive = pids.map { pid =>
+                      toScalaOption(ProcessHandle.of(pid.toLong)).exists(_.isAlive)
+                    }
+      } yield assertTrue(pidsAlive == Chunk(false, false, false))
+    } @@ TestAspect.nonFlaky(25),
+    test("killTreeForcibly also kills child processes") {
+      for {
+        process  <- Command("./sample-parent.sh").workingDirectory(new File("src/test/bash/kill-test")).run
+        pids     <- process.stdout.stream
+                      .via(ZPipeline.utf8Decode)
+                      .via(ZPipeline.splitLines)
+                      .take(3)
+                      .runCollect
+                      .map(_.map(_.toInt))
+        _        <- process.killTree
+        pidsAlive = pids.map { pid =>
+                      toScalaOption(ProcessHandle.of(pid.toLong)).exists(_.isAlive)
+                    }
+      } yield assertTrue(pidsAlive == Chunk(false, false, false))
+    } @@ TestAspect.nonFlaky(25)
   )
+
+  private def toScalaOption[A](o: Optional[A]): Option[A] = if (o.isPresent) Some(o.get) else None
 }

src/test/scala/zio/process/ZIOProcessBaseSpec.scala

@@ -4,5 +4,5 @@ import zio.durationInt
 import zio.test._
 
 trait ZIOProcessBaseSpec extends DefaultRunnableSpec {
-  override def aspects = List(TestAspect.timeout(5.seconds))
+  override def aspects = List(TestAspect.timeout(30.seconds))
 }