feat: add AttemptCount to HttpResponseException

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

@@ -1113,7 +1113,9 @@ public HttpResponse execute() throws IOException {
     // throw an exception if unsuccessful response
     if (throwExceptionOnExecuteError && !response.isSuccessStatusCode()) {
       try {
-        throw new HttpResponseException(response);
+        throw new HttpResponseException.Builder(response)
+            .setAttemptCount(numRetries - retriesRemaining)
+            .build();
       } finally {
         response.disconnect();
       }

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

@@ -42,6 +42,9 @@ public class HttpResponseException extends IOException {
   /** HTTP response content or {@code null} for none. */
   private final String content;
 
+  /** Number of attempts performed */
+  private final int attemptCount;
+
   /**
    * Constructor that constructs a detail message from the given HTTP response that includes the
    * status code, status message and HTTP response content.
@@ -73,6 +76,7 @@ protected HttpResponseException(Builder builder) {
     statusMessage = builder.statusMessage;
     headers = builder.headers;
     content = builder.content;
+    attemptCount = builder.attemptCount;
   }
 
   /**
@@ -121,6 +125,15 @@ public final String getContent() {
     return content;
   }
 
+  /**
+   * Returns the attempt count
+   *
+   * @since 1.41
+   */
+  public final int getAttemptCount() {
+    return attemptCount;
+  }
+
   /**
    * Builder.
    *
@@ -145,6 +158,9 @@ public static class Builder {
     /** Detail message to use or {@code null} for none. */
     String message;
 
+    /** Number of attempts performed */
+    int attemptCount;
+
     /**
      * @param statusCode HTTP status code
      * @param statusMessage status message or {@code null}
@@ -260,6 +276,18 @@ public Builder setContent(String content) {
       return this;
     }
 
+    /** Returns the request attempt count */
+    public final int getAttemptCount() {
+      return attemptCount;
+    }
+
+    /** Sets the attempt count for the related HTTP request execution. */
+    public Builder setAttemptCount(int attemptCount) {
+      Preconditions.checkArgument(attemptCount >= 0);
+      this.attemptCount = attemptCount;
+      return this;
+    }
+
     /** Returns a new instance of {@link HttpResponseException} based on this builder. */
     public HttpResponseException build() {
       return new HttpResponseException(this);

google-http-client/src/test/java/com/google/api/client/http/HttpResponseExceptionTest.java

@@ -23,13 +23,15 @@
 import com.google.api.client.testing.http.MockHttpTransport;
 import com.google.api.client.testing.http.MockLowLevelHttpRequest;
 import com.google.api.client.testing.http.MockLowLevelHttpResponse;
+import com.google.api.client.util.ExponentialBackOff;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.ObjectInputStream;
 import java.io.ObjectOutput;
 import java.io.ObjectOutputStream;
 import junit.framework.TestCase;
+import org.junit.Assert;
 import org.junit.function.ThrowingRunnable;
 
 /**
@@ -208,6 +210,8 @@ public void run() throws Throwable {
                 + SIMPLE_GENERIC_URL
                 + LINE_SEPARATOR
                 + "Unable to find resource");
+    // no retries expected
+    assertEquals(1, responseException.getAttemptCount());
   }
 
   public void testInvalidCharset() throws Exception {
@@ -245,6 +249,50 @@ public void run() throws Throwable {
         .isEqualTo("404 Not Found\nGET " + SIMPLE_GENERIC_URL);
   }
 
+  public void testAttemptCountWithBackOff() throws Exception {
+    HttpTransport fakeTransport =
+        new MockHttpTransport() {
+          @Override
+          public LowLevelHttpRequest buildRequest(String method, String url) throws IOException {
+            return new MockLowLevelHttpRequest() {
+              @Override
+              public LowLevelHttpResponse execute() throws IOException {
+                MockLowLevelHttpResponse result = new MockLowLevelHttpResponse();
+                result.setStatusCode(HttpStatusCodes.STATUS_CODE_SERVER_ERROR);
+                result.setReasonPhrase("Error");
+                result.setContent("Unknown Error");
+                return result;
+              }
+            };
+          }
+        };
+    ExponentialBackOff backoff = new ExponentialBackOff.Builder().build();
+    final HttpRequest request =
+        fakeTransport.createRequestFactory().buildGetRequest(new GenericUrl("http://not/used"));
+    request.setUnsuccessfulResponseHandler(
+        new HttpBackOffUnsuccessfulResponseHandler(backoff)
+            .setBackOffRequired(
+                new HttpBackOffUnsuccessfulResponseHandler.BackOffRequired() {
+                  public boolean isRequired(HttpResponse response) {
+                    return true;
+                  }
+                }));
+    request.setNumberOfRetries(1);
+    HttpResponseException responseException =
+        assertThrows(
+            HttpResponseException.class,
+            new ThrowingRunnable() {
+              @Override
+              public void run() throws Throwable {
+                request.execute();
+              }
+            });
+
+    Assert.assertEquals(500, responseException.getStatusCode());
+    // original request and 1 retry - total 2
+    assertEquals(2, responseException.getAttemptCount());
+  }
+
   public void testUnsupportedCharset() throws Exception {
     HttpTransport transport =
         new MockHttpTransport() {