feat: support gemini (#237)

Author: k11kirky

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 4.2.0 - 2025-05-22
+
+Add support for google gemini
+
 ## 4.1.0 - 2025-05-22
 
 Moved ai openai package to a composition approach over inheritance.

posthog/ai/gemini/__init__.py

@@ -0,0 +1,11 @@
+from .gemini import Client
+
+
+# Create a genai-like module for perfect drop-in replacement
+class _GenAI:
+    Client = Client
+
+
+genai = _GenAI()
+
+__all__ = ["Client", "genai"]

posthog/ai/gemini/gemini.py

@@ -0,0 +1,336 @@
+import os
+import time
+import uuid
+from typing import Any, Dict, Optional
+
+try:
+    from google import genai
+except ImportError:
+    raise ModuleNotFoundError("Please install the Google Gemini SDK to use this feature: 'pip install google-genai'")
+
+from posthog.ai.utils import call_llm_and_track_usage, get_model_params, with_privacy_mode
+from posthog.client import Client as PostHogClient
+
+
+class Client:
+    """
+    A drop-in replacement for genai.Client that automatically sends LLM usage events to PostHog.
+
+    Usage:
+        client = Client(
+            api_key="your_api_key",
+            posthog_client=posthog_client,
+            posthog_distinct_id="default_user",  # Optional defaults
+            posthog_properties={"team": "ai"}    # Optional defaults
+        )
+        response = client.models.generate_content(
+            model="gemini-2.0-flash",
+            contents=["Hello world"],
+            posthog_distinct_id="specific_user"  # Override default
+        )
+    """
+
+    def __init__(
+        self,
+        api_key: Optional[str] = None,
+        posthog_client: Optional[PostHogClient] = None,
+        posthog_distinct_id: Optional[str] = None,
+        posthog_properties: Optional[Dict[str, Any]] = None,
+        posthog_privacy_mode: bool = False,
+        posthog_groups: Optional[Dict[str, Any]] = None,
+        **kwargs,
+    ):
+        """
+        Args:
+            api_key: Google AI API key. If not provided, will use GOOGLE_API_KEY or API_KEY environment variable
+            posthog_client: PostHog client for tracking usage
+            posthog_distinct_id: Default distinct ID for all calls (can be overridden per call)
+            posthog_properties: Default properties for all calls (can be overridden per call)
+            posthog_privacy_mode: Default privacy mode for all calls (can be overridden per call)
+            posthog_groups: Default groups for all calls (can be overridden per call)
+            **kwargs: Additional arguments (for future compatibility)
+        """
+        if posthog_client is None:
+            raise ValueError("posthog_client is required for PostHog tracking")
+
+        self.models = Models(
+            api_key=api_key,
+            posthog_client=posthog_client,
+            posthog_distinct_id=posthog_distinct_id,
+            posthog_properties=posthog_properties,
+            posthog_privacy_mode=posthog_privacy_mode,
+            posthog_groups=posthog_groups,
+            **kwargs,
+        )
+
+
+class Models:
+    """
+    Models interface that mimics genai.Client().models with PostHog tracking.
+    """
+
+    _ph_client: PostHogClient  # Not None after __init__ validation
+
+    def __init__(
+        self,
+        api_key: Optional[str] = None,
+        posthog_client: Optional[PostHogClient] = None,
+        posthog_distinct_id: Optional[str] = None,
+        posthog_properties: Optional[Dict[str, Any]] = None,
+        posthog_privacy_mode: bool = False,
+        posthog_groups: Optional[Dict[str, Any]] = None,
+        **kwargs,
+    ):
+        """
+        Args:
+            api_key: Google AI API key. If not provided, will use GOOGLE_API_KEY or API_KEY environment variable
+            posthog_client: PostHog client for tracking usage
+            posthog_distinct_id: Default distinct ID for all calls
+            posthog_properties: Default properties for all calls
+            posthog_privacy_mode: Default privacy mode for all calls
+            posthog_groups: Default groups for all calls
+            **kwargs: Additional arguments (for future compatibility)
+        """
+        if posthog_client is None:
+            raise ValueError("posthog_client is required for PostHog tracking")
+
+        self._ph_client = posthog_client
+
+        # Store default PostHog settings
+        self._default_distinct_id = posthog_distinct_id
+        self._default_properties = posthog_properties or {}
+        self._default_privacy_mode = posthog_privacy_mode
+        self._default_groups = posthog_groups
+
+        # Handle API key - try parameter first, then environment variables
+        if api_key is None:
+            api_key = os.environ.get("GOOGLE_API_KEY") or os.environ.get("API_KEY")
+
+        if api_key is None:
+            raise ValueError(
+                "API key must be provided either as parameter or via GOOGLE_API_KEY/API_KEY environment variable"
+            )
+
+        self._client = genai.Client(api_key=api_key)
+        self._base_url = "https://generativelanguage.googleapis.com"
+
+    def _merge_posthog_params(
+        self,
+        call_distinct_id: Optional[str],
+        call_trace_id: Optional[str],
+        call_properties: Optional[Dict[str, Any]],
+        call_privacy_mode: Optional[bool],
+        call_groups: Optional[Dict[str, Any]],
+    ):
+        """Merge call-level PostHog parameters with client defaults."""
+        # Use call-level values if provided, otherwise fall back to defaults
+        distinct_id = call_distinct_id if call_distinct_id is not None else self._default_distinct_id
+        privacy_mode = call_privacy_mode if call_privacy_mode is not None else self._default_privacy_mode
+        groups = call_groups if call_groups is not None else self._default_groups
+
+        # Merge properties: default properties + call properties (call properties override)
+        properties = dict(self._default_properties)
+        if call_properties:
+            properties.update(call_properties)
+
+        if call_trace_id is None:
+            call_trace_id = str(uuid.uuid4())
+
+        return distinct_id, call_trace_id, properties, privacy_mode, groups
+
+    def generate_content(
+        self,
+        model: str,
+        contents,
+        posthog_distinct_id: Optional[str] = None,
+        posthog_trace_id: Optional[str] = None,
+        posthog_properties: Optional[Dict[str, Any]] = None,
+        posthog_privacy_mode: Optional[bool] = None,
+        posthog_groups: Optional[Dict[str, Any]] = None,
+        **kwargs: Any,
+    ):
+        """
+        Generate content using Gemini's API while tracking usage in PostHog.
+
+        This method signature exactly matches genai.Client().models.generate_content()
+        with additional PostHog tracking parameters.
+
+        Args:
+            model: The model to use (e.g., 'gemini-2.0-flash')
+            contents: The input content for generation
+            posthog_distinct_id: ID to associate with the usage event (overrides client default)
+            posthog_trace_id: Trace UUID for linking events (auto-generated if not provided)
+            posthog_properties: Extra properties to include in the event (merged with client defaults)
+            posthog_privacy_mode: Whether to redact sensitive information (overrides client default)
+            posthog_groups: Group analytics properties (overrides client default)
+            **kwargs: Arguments passed to Gemini's generate_content
+        """
+        # Merge PostHog parameters
+        distinct_id, trace_id, properties, privacy_mode, groups = self._merge_posthog_params(
+            posthog_distinct_id, posthog_trace_id, posthog_properties, posthog_privacy_mode, posthog_groups
+        )
+
+        kwargs_with_contents = {"model": model, "contents": contents, **kwargs}
+
+        return call_llm_and_track_usage(
+            distinct_id,
+            self._ph_client,
+            "gemini",
+            trace_id,
+            properties,
+            privacy_mode,
+            groups,
+            self._base_url,
+            self._client.models.generate_content,
+            **kwargs_with_contents,
+        )
+
+    def _generate_content_streaming(
+        self,
+        model: str,
+        contents,
+        distinct_id: Optional[str],
+        trace_id: Optional[str],
+        properties: Optional[Dict[str, Any]],
+        privacy_mode: bool,
+        groups: Optional[Dict[str, Any]],
+        **kwargs: Any,
+    ):
+        start_time = time.time()
+        usage_stats: Dict[str, int] = {"input_tokens": 0, "output_tokens": 0}
+        accumulated_content = []
+
+        kwargs_without_stream = {"model": model, "contents": contents, **kwargs}
+        response = self._client.models.generate_content_stream(**kwargs_without_stream)
+
+        def generator():
+            nonlocal usage_stats
+            nonlocal accumulated_content  # noqa: F824
+            try:
+                for chunk in response:
+                    if hasattr(chunk, "usage_metadata") and chunk.usage_metadata:
+                        usage_stats = {
+                            "input_tokens": getattr(chunk.usage_metadata, "prompt_token_count", 0),
+                            "output_tokens": getattr(chunk.usage_metadata, "candidates_token_count", 0),
+                        }
+
+                    if hasattr(chunk, "text") and chunk.text:
+                        accumulated_content.append(chunk.text)
+
+                    yield chunk
+
+            finally:
+                end_time = time.time()
+                latency = end_time - start_time
+                output = "".join(accumulated_content)
+
+                self._capture_streaming_event(
+                    model,
+                    contents,
+                    distinct_id,
+                    trace_id,
+                    properties,
+                    privacy_mode,
+                    groups,
+                    kwargs,
+                    usage_stats,
+                    latency,
+                    output,
+                )
+
+        return generator()
+
+    def _capture_streaming_event(
+        self,
+        model: str,
+        contents,
+        distinct_id: Optional[str],
+        trace_id: Optional[str],
+        properties: Optional[Dict[str, Any]],
+        privacy_mode: bool,
+        groups: Optional[Dict[str, Any]],
+        kwargs: Dict[str, Any],
+        usage_stats: Dict[str, int],
+        latency: float,
+        output: str,
+    ):
+        if trace_id is None:
+            trace_id = str(uuid.uuid4())
+
+        event_properties = {
+            "$ai_provider": "gemini",
+            "$ai_model": model,
+            "$ai_model_parameters": get_model_params(kwargs),
+            "$ai_input": with_privacy_mode(
+                self._ph_client,
+                privacy_mode,
+                self._format_input(contents),
+            ),
+            "$ai_output_choices": with_privacy_mode(
+                self._ph_client,
+                privacy_mode,
+                [{"content": output, "role": "assistant"}],
+            ),
+            "$ai_http_status": 200,
+            "$ai_input_tokens": usage_stats.get("input_tokens", 0),
+            "$ai_output_tokens": usage_stats.get("output_tokens", 0),
+            "$ai_latency": latency,
+            "$ai_trace_id": trace_id,
+            "$ai_base_url": self._base_url,
+            **(properties or {}),
+        }
+
+        if distinct_id is None:
+            event_properties["$process_person_profile"] = False
+
+        if hasattr(self._ph_client, "capture"):
+            self._ph_client.capture(
+                distinct_id=distinct_id,
+                event="$ai_generation",
+                properties=event_properties,
+                groups=groups,
+            )
+
+    def _format_input(self, contents):
+        """Format input contents for PostHog tracking"""
+        if isinstance(contents, str):
+            return [{"role": "user", "content": contents}]
+        elif isinstance(contents, list):
+            formatted = []
+            for item in contents:
+                if isinstance(item, str):
+                    formatted.append({"role": "user", "content": item})
+                elif hasattr(item, "text"):
+                    formatted.append({"role": "user", "content": item.text})
+                else:
+                    formatted.append({"role": "user", "content": str(item)})
+            return formatted
+        else:
+            return [{"role": "user", "content": str(contents)}]
+
+    def generate_content_stream(
+        self,
+        model: str,
+        contents,
+        posthog_distinct_id: Optional[str] = None,
+        posthog_trace_id: Optional[str] = None,
+        posthog_properties: Optional[Dict[str, Any]] = None,
+        posthog_privacy_mode: Optional[bool] = None,
+        posthog_groups: Optional[Dict[str, Any]] = None,
+        **kwargs: Any,
+    ):
+        # Merge PostHog parameters
+        distinct_id, trace_id, properties, privacy_mode, groups = self._merge_posthog_params(
+            posthog_distinct_id, posthog_trace_id, posthog_properties, posthog_privacy_mode, posthog_groups
+        )
+
+        return self._generate_content_streaming(
+            model,
+            contents,
+            distinct_id,
+            trace_id,
+            properties,
+            privacy_mode,
+            groups,
+            **kwargs,
+        )