Make sure the clean task doesn't break test fixtures (#43641)

Use a dedicated fixture dir.

.gitignore

@@ -41,3 +41,6 @@ html_docs
 # random old stuff that we should look at the necessity of...
 /tmp/
 eclipse-build
+
+# projects using testfixtures 
+testfixtures_shared/

buildSrc/src/main/java/org/elasticsearch/gradle/testfixtures/TestFixturesPlugin.java

@@ -35,6 +35,9 @@ import org.gradle.api.tasks.TaskContainer;
 import org.gradle.api.tasks.testing.Test;
 
 import java.io.File;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
 import java.util.Collections;
 import java.util.function.BiConsumer;
 
@@ -50,6 +53,10 @@ public class TestFixturesPlugin implements Plugin<Project> {
             "testFixtures", TestFixtureExtension.class, project
         );
 
+        ExtraPropertiesExtension ext = project.getExtensions().getByType(ExtraPropertiesExtension.class);
+        File testfixturesDir = project.file("testfixtures_shared");
+        ext.set("testFixturesDir", testfixturesDir);
+
         if (project.file(DOCKER_COMPOSE_YML).exists()) {
             // convenience boilerplate with build plugin
             // Can't reference tasks that are implemented in Groovy, use reflection  instead
@@ -63,6 +70,14 @@ public class TestFixturesPlugin implements Plugin<Project> {
             Task buildFixture = project.getTasks().create("buildFixture");
             Task pullFixture = project.getTasks().create("pullFixture");
             Task preProcessFixture = project.getTasks().create("preProcessFixture");
+            preProcessFixture.doFirst((task) -> {
+                try {
+                    Files.createDirectories(testfixturesDir.toPath());
+                } catch (IOException e) {
+                    throw new UncheckedIOException(e);
+                }
+            });
+            preProcessFixture.getOutputs().dir(testfixturesDir);
             buildFixture.dependsOn(preProcessFixture);
             pullFixture.dependsOn(preProcessFixture);
             Task postProcessFixture = project.getTasks().create("postProcessFixture");
@@ -90,6 +105,9 @@ public class TestFixturesPlugin implements Plugin<Project> {
                 pullFixture.dependsOn(tasks.getByName("composePull"));
                 tasks.getByName("composeUp").mustRunAfter(preProcessFixture);
                 tasks.getByName("composePull").mustRunAfter(preProcessFixture);
+                tasks.getByName("composeDown").doLast((task) -> {
+                    project.delete(testfixturesDir);
+                });
 
                 configureServiceInfoForTask(
                     postProcessFixture,

test/fixtures/krb5kdc-fixture/build.gradle

@@ -29,14 +29,14 @@ List<String> services = ["peppa", "hdfs"]
 preProcessFixture.doLast {
   // We need to create these up-front because if docker creates them they will be owned by root and we won't be
   // able to clean them up
-  services.each { file("${buildDir}/shared/${it}").mkdirs() }
+  services.each { file("${testFixturesDir}/shared/${it}").mkdirs() }
 }
 
 postProcessFixture {
-    inputs.dir("${buildDir}/shared")
+    inputs.dir("${testFixturesDir}/shared")
     services.each { service ->
-        File confTemplate = file("${buildDir}/shared/${service}/krb5.conf.template")
-        File confFile = file("${buildDir}/shared/${service}/krb5.conf")
+        File confTemplate = file("${testFixturesDir}/shared/${service}/krb5.conf.template")
+        File confFile = file("${testFixturesDir}/shared/${service}/krb5.conf")
         outputs.file(confFile)
         doLast {
             assert confTemplate.exists()
@@ -47,7 +47,7 @@ postProcessFixture {
     }
 }
 
-project.ext.krb5Conf = { service -> file("$buildDir/shared/${service}/krb5.conf") }
-project.ext.krb5Keytabs = { service, fileName -> file("$buildDir/shared/${service}/keytabs/${fileName}") }
+project.ext.krb5Conf = { service -> file("$testFixturesDir/shared/${service}/krb5.conf") }
+project.ext.krb5Keytabs = { service, fileName -> file("$testFixturesDir/shared/${service}/keytabs/${fileName}") }
 
 test.enabled = false

test/fixtures/krb5kdc-fixture/docker-compose.yml

@@ -7,7 +7,7 @@ services:
       dockerfile: Dockerfile
     command: "bash /fixture/src/main/resources/provision/peppa.sh"
     volumes:
-      - ./build/shared/peppa:/fixture/build
+      - ./testfixtures_shared/shared/peppa:/fixture/build
       # containers have bad entropy so mount /dev/urandom. Less secure but this is a test fixture.
       - /dev/urandom:/dev/random
     ports:
@@ -20,7 +20,7 @@ services:
       dockerfile: Dockerfile
     command: "bash /fixture/src/main/resources/provision/hdfs.sh"
     volumes:
-      - ./build/shared/hdfs:/fixture/build
+      - ./testfixtures_shared/shared/hdfs:/fixture/build
       # containers have bad entropy so mount /dev/urandom. Less secure but this is a test fixture.
       - /dev/urandom:/dev/random
     ports: