feat(gax): add resumable upload error classification and retry algorithm

sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/ResumableUploadCommand.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright 2026 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.api.gax.rpc;
+
+import org.jspecify.annotations.NullMarked;
+
+/** Enumeration of the supported resumable upload wire commands. */
+@NullMarked
+enum ResumableUploadCommand {
+  START,
+  UPLOAD,
+  FINALIZE,
+  UPLOAD_FINALIZE,
+  QUERY
+}

sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/ResumableUploadErrorClassifier.java

@@ -0,0 +1,137 @@
+/*
+ * Copyright 2026 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.api.gax.rpc;
+
+import com.google.common.collect.ImmutableMap;
+import java.io.IOException;
+import java.util.Objects;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Classifies exceptions encountered during resumable upload commands to determine whether/how to
+ * recover.
+ */
+@NullMarked
+final class ResumableUploadErrorClassifier {
+
+  enum Category {
+    /** An errored command that can be retried directly. */
+    TRANSIENT,
+
+    /** An errored command that requires status from the server before recovery. */
+    RECOVERABLE,
+
+    /** An errored command that immediately fails the upload operation. */
+    FATAL
+  }
+
+  private static final ImmutableMap<Integer, Category> HTTP_STATUS_MAP =
+      ImmutableMap.<Integer, Category>builder()
+          .put(408, Category.TRANSIENT)
+          .put(429, Category.TRANSIENT)
+          .put(500, Category.TRANSIENT)
+          .put(502, Category.TRANSIENT)
+          .put(503, Category.TRANSIENT)
+          .put(504, Category.TRANSIENT)
+          .put(400, Category.RECOVERABLE)
+          .put(409, Category.RECOVERABLE)
+          .put(412, Category.RECOVERABLE)
+          .put(416, Category.RECOVERABLE)
+          .build();
+
+  private ResumableUploadErrorClassifier() {}
+
+  /**
+   * Classifies an exception for the given upload command according to resumable upload protocol
+   * rules.
+   *
+   * @param t the error to classify
+   * @param command the upload command that produced the error
+   * @return the classified error category
+   */
+  static Category classify(Throwable t, ResumableUploadCommand command) {
+    Objects.requireNonNull(t, "t must not be null");
+    Objects.requireNonNull(command, "command must not be null");
+
+    if (!(t instanceof ApiException)) {
+      return Category.FATAL;
+    }
+    ApiException apiException = (ApiException) t;
+    StatusCode statusCode = apiException.getStatusCode();
+
+    // HttpJsonApiExceptionFactory wraps non-HTTP errors as UNKNOWN.
+    if (statusCode.getCode() == StatusCode.Code.UNKNOWN) {
+      if (apiException.getCause() instanceof IOException) {
+        return Category.TRANSIENT;
+      }
+      return Category.FATAL;
+    }
+
+    Category category = HTTP_STATUS_MAP.getOrDefault(statusCode.getTransportCode(), Category.FATAL);
+    if (category == Category.RECOVERABLE && !isRecoverableCommand(command)) {
+      return Category.FATAL;
+    }
+    return category;
+  }
+
+  /**
+   * Classifies a missing upload status response header based on the wire command.
+   *
+   * @param command the upload command that received a response lacking the status header
+   * @return the classified error category
+   */
+  static Category classifyMissingStatusHeader(ResumableUploadCommand command) {
+    Objects.requireNonNull(command, "command must not be null");
+    switch (command) {
+      case START:
+        return Category.TRANSIENT;
+      case UPLOAD:
+      case FINALIZE:
+      case UPLOAD_FINALIZE:
+        return Category.RECOVERABLE;
+      case QUERY:
+      default:
+        return Category.FATAL;
+    }
+  }
+
+  private static boolean isRecoverableCommand(ResumableUploadCommand command) {
+    switch (command) {
+      case UPLOAD:
+      case FINALIZE:
+      case UPLOAD_FINALIZE:
+        return true;
+      case START:
+      case QUERY:
+      default:
+        return false;
+    }
+  }
+}

sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/ResumableUploadResultRetryAlgorithm.java

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+/*
+ * Copyright 2026 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.api.gax.rpc;
+
+import static com.google.api.gax.rpc.ResumableUploadErrorClassifier.Category.TRANSIENT;
+
+import com.google.api.gax.retrying.BasicResultRetryAlgorithm;
+import com.google.api.gax.rpc.ResumableUploadErrorClassifier.Category;
+import java.util.Objects;
+import org.jspecify.annotations.NullMarked;
+import org.jspecify.annotations.Nullable;
+
+/**
+ * An adapter that integrates {@link ResumableUploadErrorClassifier} into GAX retrying machinery.
+ *
+ * <p>Only transient errors should retry with an identical request; other recoverable errors will
+ * need to query the upload server to determine the appropriate next request.
+ *
+ * @param <ResponseT> the response type of the upload attempt
+ */
+@NullMarked
+final class ResumableUploadResultRetryAlgorithm<ResponseT>
+    extends BasicResultRetryAlgorithm<ResponseT> {
+
+  private final ResumableUploadCommand command;
+
+  ResumableUploadResultRetryAlgorithm(ResumableUploadCommand command) {
+    this.command = Objects.requireNonNull(command);
+  }
+
+  @Override
+  public boolean shouldRetry(
+      @Nullable Throwable previousThrowable, @Nullable ResponseT previousResponse) {
+    // Successful commands should not retry.
+    if (previousThrowable == null) {
+      return false;
+    }
+    // Transient errors are retried directly with the identical request, others are not.
+    Category category = ResumableUploadErrorClassifier.classify(previousThrowable, command);
+    return category == TRANSIENT;
+  }
+}