fix: Improve performance of NetHttpRequest write timeouts by providin…

…g a possibility to use custom threadpool

google-http-client/src/main/java/com/google/api/client/http/HttpRequest.java

@@ -32,6 +32,7 @@
 import java.util.Properties;
 import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
+import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
 import java.util.concurrent.FutureTask;
@@ -153,6 +154,12 @@ public final class HttpRequest {
   /** Timeout in milliseconds to set POST/PUT data or {@code 0} for an infinite timeout. */
   private int writeTimeout = 0;
 
+  /**
+   * Custom executor used to handle write timeouts, enabled by {@link #writeTimeout}.
+   * By default, a new thread is created per each request.
+   */
+  private ExecutorService writeTimeoutExecutor;
+
   /** HTTP unsuccessful (non-2XX) response handler or {@code null} for none. */
   private HttpUnsuccessfulResponseHandler unsuccessfulResponseHandler;
 
@@ -490,6 +497,17 @@ public HttpRequest setWriteTimeout(int writeTimeout) {
   }
 
   /**
+   * Sets custom executor used to handle write timeouts, enabled by {@link #setWriteTimeout(int)}.
+   * By default, a new thread is created per each request.
+   *
+   * @since 1.40.2
+   */
+  public HttpRequest setWriteTimeoutExecutor(ExecutorService writeTimeoutExecutor) {
+    this.writeTimeoutExecutor = writeTimeoutExecutor;
+    return this;
+  }
+
+    /**
    * Returns the HTTP request headers.
    *
    * @since 1.5
@@ -1003,6 +1021,7 @@ public HttpResponse execute() throws IOException {
       // execute
       lowLevelHttpRequest.setTimeout(connectTimeout, readTimeout);
       lowLevelHttpRequest.setWriteTimeout(writeTimeout);
+      lowLevelHttpRequest.setWriteTimeoutExecutor(writeTimeoutExecutor);
 
       // switch tracing scope to current span
       @SuppressWarnings("MustBeClosedChecker")

google-http-client/src/main/java/com/google/api/client/http/LowLevelHttpRequest.java

@@ -16,6 +16,7 @@
 
 import com.google.api.client.util.StreamingContent;
 import java.io.IOException;
+import java.util.concurrent.ExecutorService;
 
 /**
  * Low-level HTTP request.
@@ -158,6 +159,16 @@ public void setTimeout(int connectTimeout, int readTimeout) throws IOException {
    */
   public void setWriteTimeout(int writeTimeout) throws IOException {}
 
+  /**
+   * Sets custom timeout executor for POST/PUT requests.
+   *
+   * <p>Default implementation uses a new thread per each {@link #execute()} call.
+   *
+   * @param writeTimeoutExecutor custom timeout executor to use
+   * @since 1.40.2
+   */
+  public void setWriteTimeoutExecutor(ExecutorService writeTimeoutExecutor) {}
+
   /** Executes the request and returns a low-level HTTP response object. */
   public abstract LowLevelHttpResponse execute() throws IOException;
 }

google-http-client/src/main/java/com/google/api/client/http/javanet/NetHttpRequest.java

@@ -36,6 +36,7 @@ final class NetHttpRequest extends LowLevelHttpRequest {
 
   private final HttpURLConnection connection;
   private int writeTimeout;
+  private ExecutorService writeTimeoutExecutor;
 
   /** @param connection HTTP URL connection */
   NetHttpRequest(HttpURLConnection connection) {
@@ -65,6 +66,11 @@ public void setWriteTimeout(int writeTimeout) throws IOException {
     this.writeTimeout = writeTimeout;
   }
 
+  @Override
+  public void setWriteTimeoutExecutor(ExecutorService writeTimeoutExecutor) {
+    this.writeTimeoutExecutor = writeTimeoutExecutor;
+  }
+
   interface OutputWriter {
     void write(OutputStream outputStream, StreamingContent content) throws IOException;
   }
@@ -184,9 +190,13 @@ public Boolean call() throws IOException {
             }
           };
 
-      final ExecutorService executor = Executors.newSingleThreadExecutor();
+      final boolean externalWriteTimeoutExecutor = writeTimeoutExecutor != null;
+      final ExecutorService executor = externalWriteTimeoutExecutor ? writeTimeoutExecutor : Executors.newSingleThreadExecutor();
       final Future<Boolean> future = executor.submit(new FutureTask<Boolean>(writeContent), null);
-      executor.shutdown();
+
+      if (!externalWriteTimeoutExecutor) {
+        executor.shutdown();
+      }
 
       try {
         future.get(writeTimeout, TimeUnit.MILLISECONDS);
@@ -197,7 +207,8 @@ public Boolean call() throws IOException {
       } catch (TimeoutException e) {
         throw new IOException("Socket write timed out", e);
       }
-      if (!executor.isTerminated()) {
+
+      if (!externalWriteTimeoutExecutor && !executor.isTerminated()) {
         executor.shutdown();
       }
     }

google-http-client/src/test/java/com/google/api/client/http/javanet/NetHttpRequestTest.java

@@ -15,8 +15,11 @@
 import java.io.OutputStream;
 import java.net.URL;
 import java.nio.charset.StandardCharsets;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import java.util.concurrent.TimeoutException;
 import org.junit.Test;
+import javax.annotation.Nullable;
 
 public class NetHttpRequestTest {
 
@@ -44,7 +47,7 @@ public void testHangingWrite() throws InterruptedException {
           @Override
           public void run() {
             try {
-              postWithTimeout(0);
+              postWithTimeout(0, null);
             } catch (IOException e) {
               // expected to be interrupted
               assertEquals(e.getCause().getClass(), InterruptedException.class);
@@ -63,9 +66,9 @@ public void run() {
   }
 
   @Test(timeout = 1000)
-  public void testOutputStreamWriteTimeout() throws Exception {
+  public void testOutputStreamWriteTimeout() {
     try {
-      postWithTimeout(100);
+      postWithTimeout(100, null);
       fail("should have timed out");
     } catch (IOException e) {
       assertEquals(e.getCause().getClass(), TimeoutException.class);
@@ -74,10 +77,25 @@ public void testOutputStreamWriteTimeout() throws Exception {
     }
   }
 
-  private static void postWithTimeout(int timeout) throws Exception {
+  @Test(timeout = 1000)
+  public void testOutputStreamWriteTimeoutWithCustomExecutor() {
+    ExecutorService customWriteTimeoutExecutor = Executors.newSingleThreadExecutor();
+    try {
+      postWithTimeout(100, customWriteTimeoutExecutor);
+      fail("should have timed out");
+    } catch (IOException e) {
+      assertEquals(e.getCause().getClass(), TimeoutException.class);
+      assertFalse(customWriteTimeoutExecutor.isTerminated());
+    } catch (Exception e) {
+      fail("Expected an IOException not a " + e.getCause().getClass().getName());
+    }
+  }
+
+  private static void postWithTimeout(int timeout, @Nullable ExecutorService writeTimeoutExecutor) throws Exception {
     MockHttpURLConnection connection = new MockHttpURLConnection(new URL(HttpTesting.SIMPLE_URL));
     connection.setRequestMethod("POST");
     NetHttpRequest request = new NetHttpRequest(connection);
+    request.setWriteTimeoutExecutor(writeTimeoutExecutor);
     InputStream is = NetHttpRequestTest.class.getClassLoader().getResourceAsStream("file.txt");
     HttpContent content = new InputStreamContent("text/plain", is);
     request.setStreamingContent(content);