feat: Add GcsOffloader for asynchronously uploading content to Google Cloud Storage

core/src/main/java/com/google/adk/plugins/agentanalytics/BigQueryAgentAnalyticsPlugin.java

@@ -253,7 +253,10 @@ private Completable logEvent(
       parseFuture =
           state
               .getParser()
-              .parse(content)
+              .parse(
+                  content,
+                  traceIds.traceId(),
+                  traceIds.spanId() != null ? traceIds.spanId() : "no_span")
               .thenAccept(
                   parsedContent -> {
                     row.put(

core/src/main/java/com/google/adk/plugins/agentanalytics/GcsOffloader.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.adk.plugins.agentanalytics;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.auth.Credentials;
+import com.google.cloud.storage.BlobId;
+import com.google.cloud.storage.BlobInfo;
+import com.google.cloud.storage.Storage;
+import com.google.cloud.storage.StorageOptions;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.Executor;
+import java.util.concurrent.RejectedExecutionException;
+import org.jspecify.annotations.Nullable;
+
+/** Offloads content to GCS. */
+class GcsOffloader {
+  private final Storage storage;
+  private final String bucketName;
+  private final Executor executor;
+  private final boolean isStorageOverride;
+
+  GcsOffloader(
+      String projectId,
+      String bucketName,
+      Executor executor,
+      @Nullable Credentials credentials,
+      @Nullable Storage storageOverride) {
+    if (storageOverride != null) {
+      this.isStorageOverride = true;
+      this.storage = storageOverride;
+    } else {
+      this.isStorageOverride = false;
+      StorageOptions.Builder builder = StorageOptions.newBuilder().setProjectId(projectId);
+      if (credentials != null) {
+        builder.setCredentials(credentials);
+      }
+      this.storage = builder.build().getService();
+    }
+    this.bucketName = bucketName;
+    this.executor = executor;
+  }
+
+  /** Async wrapper around blocking GCS upload for binary data. */
+  CompletableFuture<String> uploadContent(byte[] data, String contentType, String path) {
+    try {
+      return CompletableFuture.supplyAsync(
+          () -> {
+            BlobId blobId = BlobId.of(bucketName, path);
+            BlobInfo blobInfo = BlobInfo.newBuilder(blobId).setContentType(contentType).build();
+            storage.create(blobInfo, data);
+            return String.format("gs://%s/%s", bucketName, path);
+          },
+          executor);
+    } catch (RejectedExecutionException e) {
+      return CompletableFuture.failedFuture(e);
+    }
+  }
+
+  /** Async wrapper around blocking GCS upload for text data. */
+  CompletableFuture<String> uploadContent(String data, String contentType, String path) {
+    try {
+      return CompletableFuture.supplyAsync(() -> data.getBytes(UTF_8), executor)
+          .thenCompose(bytes -> uploadContent(bytes, contentType, path));
+    } catch (RejectedExecutionException e) {
+      return CompletableFuture.failedFuture(e);
+    }
+  }
+
+  String getBucketName() {
+    return bucketName;
+  }
+
+  void close() throws Exception {
+    if (storage != null && !isStorageOverride) {
+      storage.close();
+    }
+  }
+}

core/src/main/java/com/google/adk/plugins/agentanalytics/MimeTypeMapper.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.adk.plugins.agentanalytics;
+
+import com.google.common.collect.ImmutableMap;
+
+/** Utility to map MIME types to file extensions. */
+final class MimeTypeMapper {
+  private static final ImmutableMap<String, String> MIME_TO_EXT =
+      ImmutableMap.<String, String>builder()
+          // Images
+          .put("image/jpeg", ".jpg")
+          .put("image/png", ".png")
+          .put("image/gif", ".gif")
+          .put("image/webp", ".webp")
+          .put("image/bmp", ".bmp")
+          .put("image/tiff", ".tiff")
+          // Audio
+          .put("audio/mpeg", ".mp3")
+          .put("audio/ogg", ".ogg")
+          .put("audio/wav", ".wav")
+          .put("audio/x-wav", ".wav")
+          .put("audio/webm", ".webm")
+          .put("audio/aac", ".aac")
+          .put("audio/midi", ".mid")
+          .put("audio/x-m4a", ".m4a")
+          // Video
+          .put("video/mp4", ".mp4")
+          .put("video/mpeg", ".mpeg")
+          .put("video/ogg", ".ogv")
+          .put("video/webm", ".webm")
+          .put("video/avi", ".avi")
+          .put("video/x-msvideo", ".avi")
+          .put("video/quicktime", ".mov")
+          .buildOrThrow();
+
+  private MimeTypeMapper() {}
+
+  /**
+   * Returns the file extension (including the dot) for the given MIME type. Returns an empty string
+   * if the MIME type is unknown.
+   */
+  static String getExtension(String mimeType) {
+    return MIME_TO_EXT.getOrDefault(mimeType, "");
+  }
+}