feat: add llm cache diagnostics

src/services/llm_service.py

@@ -6,6 +6,8 @@
 
 from typing import Any, Dict, List, Tuple
 
+import hashlib
+import inspect
 import json
 
 from src.common.data_models.embedding_service_data_models import EmbeddingResult
@@ -26,6 +28,7 @@ from src.llm_models.payload_content.message import Message, MessageBuilder, Role
 from src.llm_models.payload_content.tool_option import ToolCall
 from src.llm_models.utils_model import LLMOrchestrator
 from src.services.embedding_service import EmbeddingServiceClient
+from src.services.llm_cache_stats import record_llm_cache_usage
 from src.services.service_task_resolver import (
     get_available_models as _get_available_models,
     resolve_task_name as _resolve_task_name,
@@ -46,7 +49,7 @@ class LLMServiceClient:
     - `embed_text`（兼容入口，推荐改用 `EmbeddingServiceClient`）
     """
 
-    def __init__(self, task_name: str, request_type: str = "") -> None:
+    def __init__(self, task_name: str, request_type: str = "", session_id: str = "") -> None:
         """初始化 LLM 服务门面。
 
         Args:
@@ -55,6 +58,7 @@ class LLMServiceClient:
         """
         self.task_name = _resolve_task_name(task_name)
         self.request_type = request_type
+        self.session_id = str(session_id or "").strip()
         self._orchestrator = LLMOrchestrator(task_name=self.task_name, request_type=request_type)
 
     @staticmethod
@@ -85,6 +89,70 @@ class LLMServiceClient:
             return LLMImageOptions()
         return options
 
+    @staticmethod
+    def _serialize_message_for_cache_stats(message: Message) -> Dict[str, Any]:
+        parts: list[dict[str, Any]] = []
+        for part in message.parts:
+            if hasattr(part, "text"):
+                parts.append({"type": "text", "text": part.text})
+                continue
+
+            image_base64 = getattr(part, "image_base64", "")
+            image_digest = hashlib.sha256(image_base64.encode("utf-8")).hexdigest() if image_base64 else ""
+            parts.append(
+                {
+                    "type": "image",
+                    "format": getattr(part, "image_format", ""),
+                    "size": len(image_base64),
+                    "sha256": image_digest,
+                }
+            )
+
+        return {
+            "role": str(message.role.value if hasattr(message.role, "value") else message.role),
+            "parts": parts,
+            "tool_call_id": message.tool_call_id,
+            "tool_name": message.tool_name,
+            "tool_calls": [
+                {
+                    "id": tool_call.call_id,
+                    "name": tool_call.func_name,
+                    "arguments": tool_call.args,
+                    "extra_content": tool_call.extra_content,
+                }
+                for tool_call in (message.tool_calls or [])
+            ],
+        }
+
+    @classmethod
+    def _build_cache_stats_prompt_text(
+        cls,
+        *,
+        messages: List[Message],
+        tool_options: Any,
+        response_format: Any,
+    ) -> str:
+        payload = {
+            "messages": [cls._serialize_message_for_cache_stats(message) for message in messages],
+            "tool_options": tool_options or [],
+            "response_format": response_format,
+        }
+        return json.dumps(payload, ensure_ascii=False, sort_keys=True, default=str)
+
+    def _record_cache_stats(self, result: LLMResponseResult, prompt_text: str | None = None) -> None:
+        """记录当前调用的 prompt cache 统计。"""
+
+        record_llm_cache_usage(
+            task_name=self.task_name,
+            request_type=self.request_type,
+            model_name=result.model_name,
+            session_id=self.session_id,
+            prompt_tokens=result.prompt_tokens,
+            prompt_cache_hit_tokens=result.prompt_cache_hit_tokens,
+            prompt_cache_miss_tokens=result.prompt_cache_miss_tokens,
+            prompt_text=prompt_text,
+        )
+
     async def generate_response(
         self,
         prompt: str,
@@ -100,7 +168,12 @@ class LLMServiceClient:
             LLMResponseResult: 统一文本生成结果。
         """
         active_options = self._normalize_generation_options(options)
-        return await self._orchestrator.generate_response_async(
+        prompt_text = self._build_cache_stats_prompt_text(
+            messages=[MessageBuilder().add_text_content(prompt).build()],
+            tool_options=active_options.tool_options,
+            response_format=active_options.response_format,
+        )
+        result = await self._orchestrator.generate_response_async(
             prompt=prompt,
             temperature=active_options.temperature,
             max_tokens=active_options.max_tokens,
@@ -109,6 +182,8 @@ class LLMServiceClient:
             raise_when_empty=active_options.raise_when_empty,
             interrupt_flag=active_options.interrupt_flag,
         )
+        self._record_cache_stats(result, prompt_text=prompt_text)
+        return result
 
     async def generate_response_with_messages(
         self,
@@ -125,8 +200,22 @@ class LLMServiceClient:
             LLMResponseResult: 统一文本生成结果。
         """
         active_options = self._normalize_generation_options(options)
-        return await self._orchestrator.generate_response_with_message_async(
-            message_factory=message_factory,
+        prompt_text_holder: dict[str, str] = {}
+
+        def cache_stats_message_factory(client: BaseClient, model_info: Any = None) -> List[Message]:
+            if len(inspect.signature(message_factory).parameters) >= 2:
+                messages = message_factory(client, model_info)
+            else:
+                messages = message_factory(client)
+            prompt_text_holder["prompt_text"] = self._build_cache_stats_prompt_text(
+                messages=messages,
+                tool_options=active_options.tool_options,
+                response_format=active_options.response_format,
+            )
+            return messages
+
+        result = await self._orchestrator.generate_response_with_message_async(
+            message_factory=cache_stats_message_factory,
             temperature=active_options.temperature,
             max_tokens=active_options.max_tokens,
             tools=active_options.tool_options,
@@ -134,6 +223,8 @@ class LLMServiceClient:
             raise_when_empty=active_options.raise_when_empty,
             interrupt_flag=active_options.interrupt_flag,
         )
+        self._record_cache_stats(result, prompt_text=prompt_text_holder.get("prompt_text"))
+        return result
 
     async def generate_response_for_image(
         self,
@@ -154,7 +245,30 @@ class LLMServiceClient:
             LLMResponseResult: 统一文本生成结果。
         """
         active_options = self._normalize_image_options(options)
-        return await self._orchestrator.generate_response_for_image(
+        image_digest = hashlib.sha256(image_base64.encode("utf-8")).hexdigest() if image_base64 else ""
+        prompt_text = json.dumps(
+            {
+                "messages": [
+                    {
+                        "role": "user",
+                        "parts": [
+                            {"type": "text", "text": prompt},
+                            {
+                                "type": "image",
+                                "format": image_format,
+                                "size": len(image_base64),
+                                "sha256": image_digest,
+                            },
+                        ],
+                    }
+                ],
+                "tool_options": [],
+                "response_format": None,
+            },
+            ensure_ascii=False,
+            sort_keys=True,
+        )
+        result = await self._orchestrator.generate_response_for_image(
             prompt=prompt,
             image_base64=image_base64,
             image_format=image_format,
@@ -162,6 +276,8 @@ class LLMServiceClient:
             max_tokens=active_options.max_tokens,
             interrupt_flag=active_options.interrupt_flag,
         )
+        self._record_cache_stats(result, prompt_text=prompt_text)
+        return result
 
     async def transcribe_audio(self, voice_base64: str) -> LLMAudioTranscriptionResult:
         """执行音频转写请求。