feat: update retries and implement Retryable

.gitignore

@@ -9,6 +9,7 @@ target/
 
 # Intellij
 *.iml
+*.factorypath
 .idea/
 
 # VS Code

credentials/java/com/google/auth/Credentials.java

@@ -129,7 +129,9 @@ protected final void blockingGetToCallback(URI uri, RequestMetadataCallback call
    *
    * @param uri URI of the entry point for the request.
    * @return The request metadata used for populating headers or other context.
-   * @throws IOException if there was an error getting up-to-date access.
+   * @throws IOException if there was an error getting up-to-date access. The exception should
+   *     implement {@link Retryable} and {@code isRetryable()} will return true if the operation may
+   *     be retried.
    */
   public abstract Map<String, List<String>> getRequestMetadata(URI uri) throws IOException;
 

credentials/java/com/google/auth/Retryable.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ *    * Neither the name of Google LLC nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.google.auth;
+
+// an interface to identify retryable errors
+public interface Retryable {
+  /**
+   * A flag indicating whether the error is retryable
+   *
+   * @return true if related error is retryable, false otherwise
+   */
+  boolean isRetryable();
+
+  /**
+   * Gets a number of performed retries for related HttpRequest
+   *
+   * @return a number of performed retries
+   */
+  int getRetryCount();
+}

oauth2_http/java/com/google/auth/oauth2/GoogleAuthException.java

@@ -0,0 +1,157 @@
+/*
+ * Copyright 2022 Google LLC
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *
+ *    * Neither the name of Google LLC nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package com.google.auth.oauth2;
+
+import com.google.api.client.http.HttpResponseException;
+import com.google.auth.Retryable;
+import java.io.IOException;
+
+/**
+ * Base class for the standard Auth error response. It extends a default exception while keeping
+ * Json response format
+ */
+class GoogleAuthException extends IOException implements Retryable {
+
+  private final boolean isRetryable;
+  private final int retryCount;
+
+  /**
+   * Constructor with all parameters
+   *
+   * @param isRetryable A retry status for the related HTTP request
+   * @param retryCount A number of retries performed for the related HTTP request
+   * @param message The detail message (which is saved for later retrieval by the {@link
+   *     #getMessage()} method)
+   * @param cause The cause (which is saved for later retrieval by the {@link #getCause()} method).
+   *     (A null value is permitted, and indicates that the cause is nonexistent or unknown.)
+   */
+  GoogleAuthException(boolean isRetryable, int retryCount, String message, Throwable cause) {
+    super(message, cause);
+    this.isRetryable = isRetryable;
+    this.retryCount = retryCount;
+  }
+
+  /**
+   * Constructor with message defaulted to the cause
+   *
+   * @param isRetryable A retry status for the related HTTP request
+   * @param retryCount A number of retries performed for the related HTTP request
+   * @param cause The cause (which is saved for later retrieval by the {@link #getCause()} method).
+   *     (A null value is permitted, and indicates that the cause is nonexistent or unknown.) If the
+   *     cause has retry information, it is going to be skipped in favor of the {@code retryCount}
+   *     parameter
+   */
+  GoogleAuthException(boolean isRetryable, int retryCount, Throwable cause) {
+    super(cause);
+    this.isRetryable = isRetryable;
+    this.retryCount = retryCount;
+  }
+
+  /**
+   * Constructor without explicit retry count.
+   *
+   * @param isRetryable A retry status for the related HTTP request
+   * @param cause The cause (which is saved for later retrieval by the {@link #getCause()} method).
+   *     (A null value is permitted, and indicates that the cause is nonexistent or unknown.)
+   */
+  GoogleAuthException(boolean isRetryable, Throwable cause) {
+    super(cause);
+    this.isRetryable = isRetryable;
+    this.retryCount = 0;
+  }
+
+  /**
+   * Constructor without retry info
+   *
+   * @param cause The cause (which is saved for later retrieval by the {@link #getCause()} method).
+   *     (A null value is permitted, and indicates that the cause is nonexistent or unknown.)
+   */
+  GoogleAuthException(Throwable cause) {
+    this(false, cause);
+  }
+
+  /** A default Constructor */
+  GoogleAuthException() {
+    super();
+    this.isRetryable = false;
+    this.retryCount = 0;
+  }
+
+  /**
+   * Creates an instance of the exception based on {@link HttpResponseException} and a custom error
+   * message.
+   *
+   * @see #createWithTokenEndpointResponseException(HttpResponseException, String)
+   * @param responseException an instance of {@link HttpResponseException}
+   * @param message The detail message (which is saved for later retrieval by the {@link
+   *     #getMessage()} method)
+   * @return new instance of {@link GoogleAuthException}
+   */
+  static GoogleAuthException createWithTokenEndpointResponseException(
+      HttpResponseException responseException, String message) {
+    int responseStatus = responseException.getStatusCode();
+    boolean isRetryable =
+        OAuth2Utils.TOKEN_ENDPOINT_RETRYABLE_STATUS_CODES.contains(responseStatus);
+    int retryCount = responseException.getAttemptCount() - 1;
+
+    if (message == null) {
+      return new GoogleAuthException(isRetryable, retryCount, responseException);
+    } else {
+      return new GoogleAuthException(isRetryable, retryCount, message, responseException);
+    }
+  }
+
+  /**
+   * Creates an instance of the exception based on {@link HttpResponseException} returned by Google
+   * token endpoint. It uses response status code information to populate the {@code #isRetryable}
+   * property and a number of performed attempts to populate the {@code #retryCount} property
+   *
+   * @param responseException an instance of {@link HttpResponseException}
+   * @return new instance of {@link GoogleAuthException}
+   */
+  static GoogleAuthException createWithTokenEndpointResponseException(
+      HttpResponseException responseException) {
+    return GoogleAuthException.createWithTokenEndpointResponseException(responseException, null);
+  }
+
+  /** Returns true if the error is retryable, false otherwise */
+  @Override
+  public boolean isRetryable() {
+    return isRetryable;
+  }
+
+  /** Returns number of reties performed for the related HTTP request */
+  @Override
+  public int getRetryCount() {
+    return retryCount;
+  }
+}

oauth2_http/java/com/google/auth/oauth2/GoogleCredentials.java

@@ -243,8 +243,8 @@ public boolean createScopedRequired() {
   }
 
   /**
-   * If the credentials support scopes, creates a copy of the the identity with the specified
-   * scopes; otherwise, returns the same instance.
+   * If the credentials support scopes, creates a copy of the identity with the specified scopes;
+   * otherwise, returns the same instance.
    *
    * @param scopes Collection of scopes to request.
    * @return GoogleCredentials with requested scopes.
@@ -254,9 +254,8 @@ public GoogleCredentials createScoped(Collection<String> scopes) {
   }
 
   /**
-   * If the credentials support scopes, creates a copy of the the identity with the specified scopes
-   * and default scopes; otherwise, returns the same instance. This is mainly used by client
-   * libraries.
+   * If the credentials support scopes, creates a copy of the identity with the specified scopes and
+   * default scopes; otherwise, returns the same instance. This is mainly used by client libraries.
    *
    * @param scopes Collection of scopes to request.
    * @param defaultScopes Collection of default scopes to request.
@@ -268,8 +267,8 @@ public GoogleCredentials createScoped(
   }
 
   /**
-   * If the credentials support scopes, creates a copy of the the identity with the specified
-   * scopes; otherwise, returns the same instance.
+   * If the credentials support scopes, creates a copy of the identity with the specified scopes;
+   * otherwise, returns the same instance.
    *
    * @param scopes Collection of scopes to request.
    * @return GoogleCredentials with requested scopes.
@@ -278,6 +277,17 @@ public GoogleCredentials createScoped(String... scopes) {
     return createScoped(ImmutableList.copyOf(scopes));
   }
 
+  /**
+   * If the credentials support automatic retries, creates a copy of the identity with the provided
+   * retry strategy
+   *
+   * @param defaultRetriesEnabled a flag enabling or disabling default retries
+   * @return GoogleCredentials with the new default retries configuration.
+   */
+  public GoogleCredentials createWithCustomRetryStrategy(boolean defaultRetriesEnabled) {
+    return this;
+  }
+
   /**
    * If the credentials support domain-wide delegation, creates a copy of the identity so that it
    * impersonates the specified user; otherwise, returns the same instance.

oauth2_http/java/com/google/auth/oauth2/OAuth2Utils.java

@@ -50,8 +50,11 @@
 import java.math.BigDecimal;
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.Map;
+import java.util.Set;
 
 /** Internal utilities for the com.google.auth.oauth2 namespace. */
 class OAuth2Utils {
@@ -74,6 +77,11 @@ class OAuth2Utils {
 
   static final String BEARER_PREFIX = AuthHttpConstants.BEARER + " ";
 
+  // Includes expected server errors from Google token endpoint
+  // Other 5xx codes are either not used or retries are unlikely to succeed
+  public static final Set<Integer> TOKEN_ENDPOINT_RETRYABLE_STATUS_CODES =
+      new HashSet<>(Arrays.asList(500, 503, 408, 429));
+
   static class DefaultHttpTransportFactory implements HttpTransportFactory {
 
     public HttpTransport create() {

oauth2_http/java/com/google/auth/oauth2/OAuthException.java

@@ -33,14 +33,13 @@
 
 import static com.google.common.base.Preconditions.checkNotNull;
 
-import java.io.IOException;
 import javax.annotation.Nullable;
 
 /**
  * Encapsulates the standard OAuth error response. See
  * https://tools.ietf.org/html/rfc6749#section-5.2.
  */
-class OAuthException extends IOException {
+class OAuthException extends GoogleAuthException {
 
   private final String errorCode;
   @Nullable private final String errorDescription;