[SDK Sentinel] Retry automatic dev server port collisions

temporal-testing/src/main/java/io/temporal/testing/internal/devserver/TemporalDevServerLauncher.java

@@ -22,22 +22,50 @@
 import java.util.ArrayList;
 import java.util.Deque;
 import java.util.List;
+import java.util.Locale;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.function.IntSupplier;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
 /** Internal ProcessBuilder-based Temporal dev-server launcher. */
 public final class TemporalDevServerLauncher {
+  private static final int AUTOMATIC_PORT_ATTEMPTS = 3;
   private static final int LOG_TAIL_LINES = 200;
   private static final long GRACEFUL_SHUTDOWN_SECONDS = 10;
 
   private TemporalDevServerLauncher() {}
 
   public static RunningServer start(
       @Nonnull String namespace, @Nonnull TemporalDevServerOptions options) {
+    return start(namespace, options, () -> reservePort(options.getIp()));
+  }
+
+  static RunningServer start(
+      @Nonnull String namespace,
+      @Nonnull TemporalDevServerOptions options,
+      @Nonnull IntSupplier automaticPortSupplier) {
     Path executable = TemporalDevServerDownloader.prepare(options);
-    int port = options.getPort() == null ? reservePort(options.getIp()) : options.getPort();
+    if (options.getPort() != null) {
+      return start(executable, namespace, options, options.getPort());
+    }
+    for (int attempt = 1; ; attempt++) {
+      try {
+        return start(executable, namespace, options, automaticPortSupplier.getAsInt());
+      } catch (IllegalStateException failure) {
+        if (attempt == AUTOMATIC_PORT_ATTEMPTS || !isAddressAlreadyInUse(failure)) {
+          throw failure;
+        }
+      }
+    }
+  }
+
+  private static RunningServer start(
+      @Nonnull Path executable,
+      @Nonnull String namespace,
+      @Nonnull TemporalDevServerOptions options,
+      int port) {
     String target = targetHost(options.getIp()) + ":" + port;
     List<String> command = buildCommand(executable, namespace, options, port);
 
@@ -247,6 +275,16 @@ private static String renderCommand(@Nonnull List<String> command) {
     return rendered.toString();
   }
 
+  private static boolean isAddressAlreadyInUse(@Nonnull IllegalStateException failure) {
+    String message = failure.getMessage();
+    if (message == null) {
+      return false;
+    }
+    String normalizedMessage = message.toLowerCase(Locale.ROOT);
+    return normalizedMessage.contains("address already in use")
+        || normalizedMessage.contains("only one usage of each socket address");
+  }
+
   private static int reservePort(@Nonnull String ip) {
     try (ServerSocket socket = new ServerSocket(0, 0, InetAddress.getByName(ip))) {
       socket.setReuseAddress(true);

temporal-testing/src/test/java/io/temporal/testing/internal/devserver/TemporalDevServerLauncherIntegrationTest.java

@@ -0,0 +1,61 @@
+package io.temporal.testing.internal.devserver;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import io.temporal.testing.TemporalDevServerOptions;
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.ServerSocket;
+import java.nio.file.Path;
+import java.time.Duration;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.IntSupplier;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.EnabledIfSystemProperty;
+import org.junit.jupiter.api.io.TempDir;
+
+/**
+ * Integration coverage for automatic port collision recovery using the pinned real Temporal CLI.
+ */
+@EnabledIfSystemProperty(named = SdkJavaTestServerProfile.ACTIVE_PROPERTY, matches = "true")
+class TemporalDevServerLauncherIntegrationTest {
+  private static Path temporalCli;
+
+  @TempDir Path tempDirectory;
+
+  @BeforeAll
+  static void prepareTemporalCli() {
+    temporalCli = SdkJavaTestServerProfile.prepare();
+  }
+
+  @Test
+  void automaticPortCollisionIsRetried() throws IOException {
+    try (ServerSocket occupiedPort = new ServerSocket(0, 0, InetAddress.getByName("127.0.0.1"))) {
+      AtomicInteger selections = new AtomicInteger();
+      IntSupplier ports =
+          () -> {
+            if (selections.getAndIncrement() == 0) {
+              return occupiedPort.getLocalPort();
+            }
+            try (ServerSocket availablePort =
+                new ServerSocket(0, 0, InetAddress.getByName("127.0.0.1"))) {
+              return availablePort.getLocalPort();
+            } catch (IOException e) {
+              throw new IllegalStateException(e);
+            }
+          };
+      TemporalDevServerOptions options =
+          TemporalDevServerOptions.newBuilder()
+              .setExistingPath(temporalCli.toString())
+              .setStartupTimeout(Duration.ofSeconds(60))
+              .setLogFile(tempDirectory.resolve("server.log").toString())
+              .build();
+
+      try (TemporalDevServerLauncher.RunningServer ignored =
+          TemporalDevServerLauncher.start("default", options, ports)) {
+        assertEquals(2, selections.get());
+      }
+    }
+  }
+}