Report JVM crash logs from CI Visibility smoke tests

dd-java-agent/agent-ci-visibility/civisibility-test-fixtures/src/main/java/datadog/trace/civisibility/CiVisibilitySmokeTest.java

@@ -13,15 +13,21 @@
 import datadog.trace.api.config.TraceInstrumentationConfig;
 import datadog.trace.api.config.TracerConfig;
 import java.io.File;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 import org.junit.jupiter.api.io.TempDir;
 
 public abstract class CiVisibilitySmokeTest {
@@ -40,6 +46,11 @@ public abstract class CiVisibilitySmokeTest {
 
   private static final Map<String, String> DEFAULT_TRACER_CONFIG = defaultJvmArguments();
 
+  private static final Path JVM_CRASH_LOGS_DIR =
+      Paths.get(
+          System.getProperty("datadog.smoketest.builddir", "build"), "reports", "jvm-crash-logs");
+  private static final int JVM_CRASH_LOG_PRINTED_LINES = 60;
+
   @TempDir protected Path prefsDir;
 
   protected static String buildJavaHome() {
@@ -149,6 +160,45 @@ protected String preventJulPrefsFileLock() {
     return "-Djava.util.prefs.userRoot=" + resolved.toAbsolutePath();
   }
 
+  /**
+   * Prints and preserves the JVM fatal error logs ({@code hs_err_pid*.log}) that forked processes
+   * wrote under {@code directory}. Forked JVMs write these logs to their working directory, which
+   * is usually a temporary folder deleted after the test.
+   */
+  protected static void reportJvmCrashLogs(Path directory) {
+    if (directory == null || !Files.isDirectory(directory)) {
+      return;
+    }
+    List<Path> crashLogs;
+    try (Stream<Path> files = Files.walk(directory)) {
+      crashLogs =
+          files
+              .filter(p -> p.getFileName().toString().matches("hs_err_pid\\d+\\.log"))
+              .collect(Collectors.toList());
+    } catch (IOException | UncheckedIOException e) {
+      System.err.println("Failed to look for JVM crash logs in " + directory + ": " + e);
+      return;
+    }
+    for (Path crashLog : crashLogs) {
+      try {
+        Files.createDirectories(JVM_CRASH_LOGS_DIR);
+        Path copy = JVM_CRASH_LOGS_DIR.resolve(crashLog.getFileName());
+        Files.copy(crashLog, copy, StandardCopyOption.REPLACE_EXISTING);
+        try (Stream<String> lines = Files.lines(crashLog, StandardCharsets.ISO_8859_1)) {
+          System.out.println(
+              "JVM crash log "
+                  + crashLog
+                  + " (copied to "
+                  + copy.toAbsolutePath()
+                  + "):\n"
+                  + lines.limit(JVM_CRASH_LOG_PRINTED_LINES).collect(Collectors.joining("\n")));
+        }
+      } catch (IOException | UncheckedIOException e) {
+        System.err.println("Failed to report JVM crash log " + crashLog + ": " + e);
+      }
+    }
+  }
+
   private static Path tempUserPrefsPath() {
     String uniqueId =
         System.currentTimeMillis() + "_" + System.nanoTime() + "_" + Thread.currentThread().getId();

dd-smoke-tests/gradle/src/test/java/datadog/smoketest/AbstractGradleTest.java

@@ -22,6 +22,7 @@
 import java.util.stream.Stream;
 import org.gradle.internal.impldep.org.apache.commons.io.FileUtils;
 import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Assumptions;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.TestInstance;
@@ -53,6 +54,11 @@ void resetMockBackend() {
     mockBackend.reset();
   }
 
+  @AfterEach
+  void reportForkedJvmCrashes() {
+    reportJvmCrashLogs(projectFolder);
+  }
+
   @AfterAll
   void closeMockBackend() throws Exception {
     mockBackend.close();

dd-smoke-tests/maven/src/test/java/datadog/smoketest/MavenSmokeTest.java

@@ -40,6 +40,7 @@
 import java.util.concurrent.TimeoutException;
 import org.apache.maven.wrapper.MavenWrapperMain;
 import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.condition.DisabledIf;
 import org.junit.jupiter.api.condition.EnabledForJreRange;
@@ -81,6 +82,11 @@ void resetMockBackend() {
     mockBackend.reset();
   }
 
+  @AfterEach
+  void reportForkedJvmCrashes() {
+    reportJvmCrashLogs(projectHome);
+  }
+
   @AfterAll
   static void closeMockBackend() throws Exception {
     mockBackend.close();