feat: GenAI - Add support for logprobs and response_logprobs.

PiperOrigin-RevId: 677832804

Author: sasha-gitg

tests/system/vertexai/test_generative_models.py

@@ -257,6 +257,8 @@ def test_generate_content_with_parameters(self, api_endpoint_env_name):
                 candidate_count=1,
                 max_output_tokens=100,
                 stop_sequences=["STOP!"],
+                response_logprobs=True,
+                logprobs=3,
             ),
             safety_settings={
                 generative_models.HarmCategory.HARM_CATEGORY_HATE_SPEECH: generative_models.HarmBlockThreshold.BLOCK_MEDIUM_AND_ABOVE,

tests/unit/vertexai/test_generative_models.py

@@ -585,6 +585,8 @@ def test_generate_content(self, generative_models: generative_models):
                 stop_sequences=["\n\n\n"],
                 presence_penalty=0.0,
                 frequency_penalty=0.0,
+                logprobs=5,
+                response_logprobs=True,
             ),
             safety_settings=[
                 generative_models.SafetySetting(

vertexai/generative_models/_generative_models.py

@@ -1577,6 +1577,8 @@ def __init__(
         response_schema: Optional[Dict[str, Any]] = None,
         seed: Optional[int] = None,
         routing_config: Optional["RoutingConfig"] = None,
+        logprobs: Optional[int] = None,
+        response_logprobs: Optional[bool] = None,
     ):
         r"""Constructs a GenerationConfig object.
 
@@ -1603,6 +1605,8 @@ def __init__(
             response_schema: Output response schema of the genreated candidate text. Only valid when
                 response_mime_type is application/json.
             routing_config: Model routing preference set in the request.
+            logprobs: Logit probabilities.
+            reponse_logprobs: If true, export the logprobs results in response.
 
         Usage:
             ```
@@ -1637,6 +1641,8 @@ def __init__(
             response_mime_type=response_mime_type,
             response_schema=raw_schema,
             seed=seed,
+            logprobs=logprobs,
+            response_logprobs=response_logprobs,
         )
         if routing_config is not None:
             self._raw_generation_config.routing_config = (
@@ -2223,6 +2229,10 @@ def content(self) -> "Content":
     def avg_logprobs(self) -> float:
         return self._raw_candidate.avg_logprobs
 
+    @property
+    def logprobs_result(self) -> gapic_content_types.LogprobsResult:
+        return self._raw_candidate.logprobs_result
+
     @property
     def finish_reason(self) -> gapic_content_types.Candidate.FinishReason:
         return self._raw_candidate.finish_reason