feat: Add VertexAiCodeExecutor

core/src/main/java/com/google/adk/codeexecutors/VertexAiCodeExecutor.java

@@ -0,0 +1,248 @@
+/*
+ * Copyright 2025 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.codeexecutors;
+
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.adk.agents.InvocationContext;
+import com.google.adk.codeexecutors.CodeExecutionUtils.CodeExecutionInput;
+import com.google.adk.codeexecutors.CodeExecutionUtils.CodeExecutionResult;
+import com.google.adk.codeexecutors.CodeExecutionUtils.File;
+import com.google.cloud.aiplatform.v1beta1.ExecuteExtensionRequest;
+import com.google.cloud.aiplatform.v1beta1.ExecuteExtensionResponse;
+import com.google.cloud.aiplatform.v1beta1.ExtensionExecutionServiceClient;
+import com.google.cloud.aiplatform.v1beta1.ExtensionExecutionServiceSettings;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.protobuf.ListValue;
+import com.google.protobuf.Struct;
+import com.google.protobuf.Value;
+import java.io.IOException;
+import java.net.URLConnection;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+/**
+ * A code executor that uses Vertex Code Interpreter Extension to execute code.
+ *
+ * <p>Attributes: resourceName: If set, load the existing resource name of the code interpreter
+ * extension instead of creating a new one. Format:
+ * projects/123/locations/us-central1/extensions/456
+ *
+ * <p>Follow https://cloud.google.com/vertex-ai/generative-ai/docs/extensions/code-interpreter for
+ * setup.
+ */
+public final class VertexAiCodeExecutor extends BaseCodeExecutor {
+  private static final Logger logger = Logger.getLogger(VertexAiCodeExecutor.class.getName());
+
+  private static final ImmutableList<String> SUPPORTED_IMAGE_TYPES =
+      ImmutableList.of("png", "jpg", "jpeg");
+  private static final ImmutableList<String> SUPPORTED_DATA_FILE_TYPES = ImmutableList.of("csv");
+
+  private static final String IMPORTED_LIBRARIES =
+      "import io\n"
+          + "import math\n"
+          + "import re\n"
+          + "\n"
+          + "import matplotlib.pyplot as plt\n"
+          + "import numpy as np\n"
+          + "import pandas as pd\n"
+          + "import scipy\n"
+          + "\n"
+          + "def crop(s: str, max_chars: int = 64) -> str:\n"
+          + "  \"\"\"Crops a string to max_chars characters.\"\"\"\n"
+          + "  return s[: max_chars - 3] + '...' if len(s) > max_chars else s\n"
+          + "\n"
+          + "\n"
+          + "def explore_df(df: pd.DataFrame) -> None:\n"
+          + "  \"\"\"Prints some information about a pandas DataFrame.\"\"\"\n"
+          + "\n"
+          + "  with pd.option_context(\n"
+          + "      'display.max_columns', None, 'display.expand_frame_repr', False\n"
+          + "  ):\n"
+          + "    # Print the column names to never encounter KeyError when selecting one.\n"
+          + "    df_dtypes = df.dtypes\n"
+          + "\n"
+          + "    # Obtain information about data types and missing values.\n"
+          + "    df_nulls = (len(df) - df.isnull().sum()).apply(\n"
+          + "        lambda x: f'{x} / {df.shape[0]} non-null'\n"
+          + "    )\n"
+          + "\n"
+          + "    # Explore unique total values in columns using `.unique()`.\n"
+          + "    df_unique_count = df.apply(lambda x: len(x.unique()))\n"
+          + "\n"
+          + "    # Explore unique values in columns using `.unique()`.\n"
+          + "    df_unique = df.apply(lambda x: crop(str(list(x.unique()))))\n"
+          + "\n"
+          + "    df_info = pd.concat(\n"
+          + "        (\n"
+          + "            df_dtypes.rename('Dtype'),\n"
+          + "            df_nulls.rename('Non-Null Count'),\n"
+          + "            df_unique_count.rename('Unique Values Count'),\n"
+          + "            df_unique.rename('Unique Values'),\n"
+          + "        ),\n"
+          + "        axis=1,\n"
+          + "    )\n"
+          + "    df_info.index.name = 'Columns'\n"
+          + "    print(f\"\"\"Total rows: {df.shape[0]}\n"
+          + "Total columns: {df.shape[1]}\n"
+          + "\n"
+          + "{df_info}\"\"\")";
+
+  private final String resourceName;
+  private final ExtensionExecutionServiceClient codeInterpreterExtension;
+
+  /**
+   * Initializes the VertexAiCodeExecutor.
+   *
+   * @param resourceName If set, load the existing resource name of the code interpreter extension
+   *     instead of creating a new one. Format: projects/123/locations/us-central1/extensions/456
+   */
+  public VertexAiCodeExecutor(String resourceName) {
+    String resolvedResourceName = resourceName;
+    if (resolvedResourceName == null || resolvedResourceName.isEmpty()) {
+      resolvedResourceName = System.getenv("CODE_INTERPRETER_EXTENSION_NAME");
+    }
+
+    if (resolvedResourceName == null || resolvedResourceName.isEmpty()) {
+      logger.warning(
+          "No resource name found for Vertex AI Code Interpreter. It will not be available.");
+      this.resourceName = null;
+      this.codeInterpreterExtension = null;
+    } else {
+      this.resourceName = resolvedResourceName;
+      try {
+        String[] parts = this.resourceName.split("/");
+        if (parts.length < 4 || !parts[2].equals("locations")) {
+          throw new IllegalArgumentException("Invalid resource name format: " + this.resourceName);
+        }
+        String location = parts[3];
+        String endpoint = String.format("%s-aiplatform.googleapis.com:443", location);
+        ExtensionExecutionServiceSettings settings =
+            ExtensionExecutionServiceSettings.newBuilder().setEndpoint(endpoint).build();
+        this.codeInterpreterExtension = ExtensionExecutionServiceClient.create(settings);
+      } catch (IOException e) {
+        logger.log(Level.SEVERE, "Failed to create ExtensionExecutionServiceClient", e);
+        throw new IllegalStateException("Failed to create ExtensionExecutionServiceClient", e);
+      }
+    }
+  }
+
+  @Override
+  public CodeExecutionResult executeCode(
+      InvocationContext invocationContext, CodeExecutionInput codeExecutionInput) {
+    // Execute the code.
+    Map<String, Object> codeExecutionResult =
+        executeCodeInterpreter(
+            getCodeWithImports(codeExecutionInput.code()),
+            codeExecutionInput.inputFiles(),
+            codeExecutionInput.executionId());
+
+    // Save output file as artifacts.
+    List<File> savedFiles = new ArrayList<>();
+    if (codeExecutionResult.containsKey("output_files")) {
+      @SuppressWarnings("unchecked")
+      List<Map<String, String>> outputFiles =
+          (List<Map<String, String>>) codeExecutionResult.get("output_files");
+      for (Map<String, String> outputFile : outputFiles) {
+        String fileName = outputFile.get("name");
+        String content = outputFile.get("contents"); // This is a base64 string.
+        String fileType = fileName.substring(fileName.lastIndexOf('.') + 1);
+        String mimeType;
+        if (SUPPORTED_IMAGE_TYPES.contains(fileType)) {
+          mimeType = "image/" + fileType;
+        } else if (SUPPORTED_DATA_FILE_TYPES.contains(fileType)) {
+          mimeType = "text/" + fileType;
+        } else {
+          mimeType = URLConnection.guessContentTypeFromName(fileName);
+        }
+        savedFiles.add(File.builder().name(fileName).content(content).mimeType(mimeType).build());
+      }
+    }
+
+    // Collect the final result.
+    return CodeExecutionResult.builder()
+        .stdout((String) codeExecutionResult.getOrDefault("execution_result", ""))
+        .stderr((String) codeExecutionResult.getOrDefault("execution_error", ""))
+        .outputFiles(savedFiles)
+        .build();
+  }
+
+  private Map<String, Object> executeCodeInterpreter(
+      String code, List<File> inputFiles, Optional<String> sessionId) {
+    if (codeInterpreterExtension == null) {
+      logger.warning(
+          "Vertex AI Code Interpreter execution is not available. Returning empty result.");
+      return ImmutableMap.of(
+          "execution_result", "", "execution_error", "", "output_files", new ArrayList<>());
+    }
+
+    // Build operationParams
+    Struct.Builder paramsBuilder = Struct.newBuilder();
+    paramsBuilder.putFields("query", Value.newBuilder().setStringValue(code).build());
+    if (inputFiles != null && !inputFiles.isEmpty()) {
+      ListValue.Builder listBuilder = ListValue.newBuilder();
+      for (File f : inputFiles) {
+        Struct.Builder fileStructBuilder = Struct.newBuilder();
+        fileStructBuilder.putFields("name", Value.newBuilder().setStringValue(f.name()).build());
+        fileStructBuilder.putFields(
+            "contents", Value.newBuilder().setStringValue(f.content()).build());
+        listBuilder.addValues(Value.newBuilder().setStructValue(fileStructBuilder.build()));
+      }
+      paramsBuilder.putFields(
+          "files", Value.newBuilder().setListValue(listBuilder.build()).build());
+    }
+    sessionId.ifPresent(
+        s -> paramsBuilder.putFields("session_id", Value.newBuilder().setStringValue(s).build()));
+
+    ExecuteExtensionRequest request =
+        ExecuteExtensionRequest.newBuilder()
+            .setName(this.resourceName)
+            .setOperationId("generate_and_execute")
+            .setOperationParams(paramsBuilder.build())
+            .build();
+
+    ExecuteExtensionResponse response = codeInterpreterExtension.executeExtension(request);
+    String jsonOutput = response.getContent();
+    if (jsonOutput == null || jsonOutput.isEmpty()) {
+      return ImmutableMap.of(
+          "execution_result", "", "execution_error", "", "output_files", new ArrayList<>());
+    }
+
+    try {
+      ObjectMapper mapper = new ObjectMapper();
+      return mapper.readValue(jsonOutput, new TypeReference<Map<String, Object>>() {});
+    } catch (IOException e) {
+      logger.log(Level.SEVERE, "Failed to parse JSON from code interpreter: " + jsonOutput, e);
+      return ImmutableMap.of(
+          "execution_result",
+          "",
+          "execution_error",
+          "Failed to parse extension response: " + e.getMessage(),
+          "output_files",
+          new ArrayList<>());
+    }
+  }
+
+  private String getCodeWithImports(String code) {
+    return String.format("%s\n\n%s", IMPORTED_LIBRARIES, code);
+  }
+}

core/src/main/java/com/google/adk/events/Event.java

@@ -24,6 +24,7 @@
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 import com.google.adk.JsonBaseModel;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.genai.types.Content;
 import com.google.genai.types.FinishReason;
@@ -237,14 +238,28 @@ public final ImmutableList<FunctionResponse> functionResponses() {
         .collect(toImmutableList());
   }
 
+  /** Returns whether the event has a trailing code execution result. */
+  @JsonIgnore
+  public final boolean hasTrailingCodeExecutionResult() {
+    return content()
+        .flatMap(Content::parts)
+        .filter(parts -> !parts.isEmpty())
+        .map(parts -> Iterables.getLast(parts))
+        .flatMap(part -> part.codeExecutionResult())
+        .isPresent();
+  }
+
   /** Returns true if this is a final response. */
   @JsonIgnore
   public final boolean finalResponse() {
     if (actions().skipSummarization().orElse(false)
         || (longRunningToolIds().isPresent() && !longRunningToolIds().get().isEmpty())) {
       return true;
     }
-    return functionCalls().isEmpty() && functionResponses().isEmpty() && !partial().orElse(false);
+    return functionCalls().isEmpty()
+        && functionResponses().isEmpty()
+        && !partial().orElse(false)
+        && !hasTrailingCodeExecutionResult();
   }
 
   /**

core/src/main/java/com/google/adk/flows/llmflows/AutoFlow.java

@@ -29,8 +29,9 @@ public class AutoFlow extends SingleFlow {
           .add(new AgentTransfer())
           .build();
 
-  /** No additional response processors. */
-  private static final ImmutableList<ResponseProcessor> RESPONSE_PROCESSORS = ImmutableList.of();
+  /** Only base response processors. */
+  private static final ImmutableList<ResponseProcessor> RESPONSE_PROCESSORS =
+      ImmutableList.copyOf(SingleFlow.RESPONSE_PROCESSORS);
 
   public AutoFlow() {
     this(/* maxSteps= */ Optional.empty());

core/src/main/java/com/google/adk/flows/llmflows/CodeExecution.java

@@ -294,7 +294,7 @@ private static Flowable<Event> runPostProcessor(
     }
     String codeStr = codeStrOptional.get();
     responseContent = responseContentBuilder.build();
-    llmResponseBuilder.content(Content.builder().build());
+    llmResponseBuilder.content(Optional.empty());
 
     Event codeEvent =
         Event.builder()

core/src/main/java/com/google/adk/flows/llmflows/SingleFlow.java

@@ -20,7 +20,7 @@
 import java.util.List;
 import java.util.Optional;
 
-/** Basic LLM flow with fixed request processors and no response post-processing. */
+/** Basic LLM flow with fixed request and response processors. */
 public class SingleFlow extends BaseLlmFlow {
   // TODO: We should eventually remove this class since it complicates things.
 

core/src/main/java/com/google/adk/models/LlmResponse.java

@@ -109,6 +109,8 @@ static LlmResponse.Builder jacksonBuilder() {
     @JsonProperty("content")
     public abstract Builder content(Content content);
 
+    public abstract Builder content(Optional<Content> content);
+
     @JsonProperty("interrupted")
     public abstract Builder interrupted(@Nullable Boolean interrupted);