VertexAIGeminiGenerator

Generate text using Google Gemini models through Vertex AI.

Basic Information

• Type: haystack_integrations.components.generators.google_vertex.gemini.VertexAIGeminiGenerator
• Components it can connect with:
  • PromptBuilder: Receives a prompt from PromptBuilder.
  • AnswerBuilder: Sends generated replies to AnswerBuilder.
  • Supports multimodal inputs (text and images).

Deprecation Notice

This integration will be deprecated soon. We recommend using GoogleGenAIChatGenerator instead, which provides unified access to both Gemini Developer API and Vertex AI.

Inputs

Parameter	Type	Default	Description
parts	Variadic[Union[str, ByteStream, Part]]		Prompt for the model.
streaming_callback	Optional[Callable[[StreamingChunk], None]]	None	A callback function that is called when a new token is received from the stream.

Outputs

Parameter	Type	Default	Description
replies	List[str]		A list of generated content.

Overview

VertexAIGeminiGenerator generates text using Google Gemini models through Vertex AI. It supports multimodal inputs including text and images.

This component is designed for text generation, not for chat. If you want chat capabilities, use GoogleGenAIChatGenerator instead.

Authorization

This component authenticates using Google Cloud Application Default Credentials (ADCs). For more information, see the official Google documentation.

Create secrets for GCP_PROJECT_ID and optionally GCP_DEFAULT_REGION. For detailed instructions on creating secrets, see Create Secrets.

Usage Example

This query pipeline uses VertexAIGeminiGenerator to generate text responses:

components:
  bm25_retriever:
    type: haystack_integrations.components.retrievers.opensearch.bm25_retriever.OpenSearchBM25Retriever
    init_parameters:
      document_store:
        type: haystack_integrations.document_stores.opensearch.document_store.OpenSearchDocumentStore
        init_parameters:
          hosts:
          index: 'default'
          max_chunk_bytes: 104857600
          embedding_dim: 768
          return_embedding: false
          method:
          mappings:
          settings:
          create_index: true
          http_auth:
          use_ssl:
          verify_certs:
          timeout:
      top_k: 10
      fuzziness: 0

  PromptBuilder:
    type: haystack.components.builders.prompt_builder.PromptBuilder
    init_parameters:
      template: |
        Given the following information, answer the question.

        Context:
        {% for document in documents %}
        {{ document.content }}
        {% endfor %}

        Question: {{ query }}
      required_variables:
      variables:

  VertexAIGeminiGenerator:
    type: haystack_integrations.components.generators.google_vertex.gemini.VertexAIGeminiGenerator
    init_parameters:
      project_id:
      model: gemini-2.0-flash
      location:
      generation_config:
      safety_settings:
      system_instruction:
      streaming_callback:

  AnswerBuilder:
    type: haystack.components.builders.answer_builder.AnswerBuilder
    init_parameters:
      pattern:
      reference_pattern:

connections:
  - sender: bm25_retriever.documents
    receiver: PromptBuilder.documents
  - sender: PromptBuilder.prompt
    receiver: VertexAIGeminiGenerator.parts
  - sender: VertexAIGeminiGenerator.replies
    receiver: AnswerBuilder.replies
  - sender: bm25_retriever.documents
    receiver: AnswerBuilder.documents

inputs:
  query:
    - bm25_retriever.query
    - PromptBuilder.query
    - AnswerBuilder.query

outputs:
  answers: AnswerBuilder.answers

max_runs_per_component: 100

metadata: {}

Parameters

Init Parameters

These are the parameters you can configure in Pipeline Builder:

Parameter	Type	Default	Description
project_id	Optional[str]	None	ID of the GCP project to use. By default, it is set during Google Cloud authentication.
model	str	gemini-2.0-flash	Name of the model to use. For available models, see Vertex AI models.
location	Optional[str]	None	The default location to use when making API calls. If not set, uses us-central-1.
generation_config	Optional[Union[GenerationConfig, Dict[str, Any]]]	None	The generation config to use. Accepted fields: temperature, top_p, top_k, candidate_count, max_output_tokens, stop_sequences.
safety_settings	Optional[Dict[HarmCategory, HarmBlockThreshold]]	None	The safety settings to use.
system_instruction	Optional[Union[str, ByteStream, Part]]	None	Default system instruction to use for generating content.
streaming_callback	Optional[Callable[[StreamingChunk], None]]	None	A callback function that is called when a new token is received from the stream.

Run Method Parameters

These are the parameters you can configure for the run() method. You can pass these parameters at query time through the API, in Playground, or when running a job.

Parameter	Type	Default	Description
parts	Variadic[Union[str, ByteStream, Part]]		Prompt for the model.
streaming_callback	Optional[Callable[[StreamingChunk], None]]	None	A callback function that is called when a new token is received from the stream.