Revive reduced servlet smoke test matrix on top of main

.github/workflows/build-common.yml

@@ -15,6 +15,9 @@ on:
       skip-windows-smoke-tests:
         type: boolean
         required: false
+      reduced-smoke-tests:
+        type: boolean
+        required: false
     secrets:
       DEVELOCITY_ACCESS_KEY:
         required: false
@@ -459,6 +462,7 @@ jobs:
           ./gradlew
           :smoke-tests:test
           -PsmokeTestSuite=${{ matrix.smoke-test-suite }}
+          ${{ inputs.reduced-smoke-tests && '-PreducedSmokeTests=true' || '' }}
           ${{ inputs.skip-openj9-tests && matrix.smoke-test-suite != 'websphere' && '-PskipOpenJ9SmokeTests=true' || '' }}
           ${{ inputs.no-build-cache && ' --no-build-cache' || '' }}
 

.github/workflows/build-pull-request.yml

@@ -93,7 +93,12 @@ jobs:
     needs: [resolve-native, resolve-servlet-images]
     uses: ./.github/workflows/reusable-pr-build.yml
     with:
+      # `test native` is applied automatically by .github/labeler.yml when the
+      # PR diff touches native-relevant paths. `test openj9`, `test windows`,
+      # and `test full smoke` are manual force-enables that are picked up on
+      # the next PR sync/open/reopen event.
       skip-native-tests: ${{ !(needs.resolve-native.outputs.run-native-tests == 'true' || contains(github.event.pull_request.labels.*.name, 'test native')) }}
       skip-openj9-tests: ${{ !contains(github.event.pull_request.labels.*.name, 'test openj9') }}
       skip-windows-smoke-tests: ${{ !contains(github.event.pull_request.labels.*.name, 'test windows') }}
+      reduced-smoke-tests: ${{ !contains(github.event.pull_request.labels.*.name, 'test full smoke') }}
       skip-servlet-images: ${{ needs.resolve-servlet-images.outputs.build-servlet-images != 'true' }}

.github/workflows/reusable-pr-build.yml

@@ -14,6 +14,9 @@ on:
       skip-windows-smoke-tests:
         type: boolean
         default: false
+      reduced-smoke-tests:
+        type: boolean
+        default: false
       skip-servlet-images:
         type: boolean
         default: false
@@ -27,6 +30,7 @@ jobs:
     with:
       skip-openj9-tests: ${{ inputs.skip-openj9-tests }}
       skip-windows-smoke-tests: ${{ inputs.skip-windows-smoke-tests }}
+      reduced-smoke-tests: ${{ inputs.reduced-smoke-tests }}
       cache-read-only: true
 
   test-latest-deps:

smoke-tests/build.gradle.kts

@@ -88,6 +88,11 @@ tasks {
     val extensionTestAppTask = project(":smoke-tests:extensions:testapp").tasks.named<Jar>("jar")
     val extensionTestAppJarPath = extensionTestAppTask.flatMap { it.archiveFile }
 
+    val reducedSmokeTests = findProperty("reducedSmokeTests") == "true"
+    if (reducedSmokeTests) {
+      systemProperty("reducedSmokeTests", "true")
+    }
+
     dependsOn(shadowTask, extensionTestAppTask, extensionTask)
 
     doFirst {

smoke-tests/images/servlet/build.gradle.kts

@@ -198,8 +198,8 @@ tasks {
     description = "Builds all Windows Docker images for the test matrix"
   }
 
-  val linuxImages = createDockerTasks(buildLinuxTestImages, false)
-  val windowsImages = createDockerTasks(buildWindowsTestImages, true)
+  val linuxImages = createDockerTasks(buildLinuxTestImages, false, targets)
+  val windowsImages = createDockerTasks(buildWindowsTestImages, true, targets)
 
   val pushLinuxImages by registering(DockerPushImage::class) {
     dependsOn(buildLinuxTestImages)
@@ -376,7 +376,7 @@ fun configureImage(
   return image
 }
 
-fun createDockerTasks(parentTask: TaskProvider<out Task>, isWindows: Boolean): Set<String> {
+fun createDockerTasks(parentTask: TaskProvider<out Task>, isWindows: Boolean, targets: Map<String, List<ImageTarget>>): Set<String> {
   val resultImages = mutableSetOf<String>()
   for ((server, matrices) in targets) {
     val smokeTestServer = findProperty("smokeTestServer")

smoke-tests/src/test/java/io/opentelemetry/smoketest/appserver/AppServerTest.java

@@ -51,6 +51,10 @@ void setUpServer() {
     var jdk = appServer.jdk();
     isWindows = TestContainerManager.useWindowsContainers();
 
+    // In reduced mode (PR builds), only run a representative subset of the full matrix.
+    // The full matrix runs on merge to main.
+    skipIfNotReduced(appServer);
+
     // ibm-semeru-runtimes doesn't publish windows images
     // adoptopenjdk is deprecated and doesn't publish Windows 2022 images
     assumeFalse(isWindows && jdk.endsWith("-openj9"));
@@ -59,6 +63,50 @@ void setUpServer() {
     startWithoutCleanup(new AppServerImage(jdk, serverVersion, isWindows));
   }
 
+  // Reduced smoke test rules for PR builds. The full matrix runs on merge to main.
+  // Tomcat covers all JDKs (hotspot), TomEE covers all JDKs (openj9),
+  // Websphere is already minimal, other servers test only minimum JDK on hotspot.
+  private void skipIfNotReduced(AppServer appServer) {
+    if (!Boolean.getBoolean("reducedSmokeTests")) {
+      return;
+    }
+    String jdk = appServer.jdk();
+    boolean isOpenj9 = jdk.contains("-openj9");
+
+    if (this instanceof TomcatSmokeTest) {
+      assumeFalse(isOpenj9, "Reduced mode: Tomcat runs hotspot only");
+      return;
+    }
+    if (this instanceof TomeeSmokeTest) {
+      assumeTrue(isOpenj9, "Reduced mode: TomEE runs openj9 only");
+      return;
+    }
+    if (this instanceof WebsphereSmokeTest) {
+      return;
+    }
+    // All other servers: hotspot only, minimum JDK per server version
+    assumeFalse(isOpenj9, "Reduced mode: hotspot only");
+    assumeTrue(isMinimumJdk(appServer), "Reduced mode: only minimum JDK per server version");
+  }
+
+  private boolean isMinimumJdk(AppServer appServer) {
+    int myJdk = parseJdkVersion(appServer.jdk());
+    for (Class<?> sibling : getClass().getEnclosingClass().getDeclaredClasses()) {
+      AppServer other = sibling.getAnnotation(AppServer.class);
+      if (other != null
+          && other.version().equals(appServer.version())
+          && !other.jdk().contains("-openj9")
+          && parseJdkVersion(other.jdk()) < myJdk) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  private static int parseJdkVersion(String jdk) {
+    return Integer.parseInt(jdk.split("-")[0]);
+  }
+
   @AfterAll
   void afterAll() {
     stop();