feat(generation_service): add image URL extraction and random QA generation logic

runtime/datamate-python/app/module/generation/service/generation_service.py

@@ -1,5 +1,7 @@
 import asyncio
 import json
+import random
+import re
 import uuid
 
 from langchain_core.language_models import BaseChatModel
@@ -36,6 +38,13 @@ def _filter_docs(split_docs, chunk_size):
     return filtered_docs
 
 
+def extract_img_urls(doc):
+    """提取文档中的图片地址"""
+    pattern = r"!\[\]\((.*?)\)"
+    # 查找所有匹配的地址
+    img_urls = re.findall(pattern, doc)
+    return img_urls
+
 class GenerationService:
     def __init__(self, db: AsyncSession):
         self.db = db
@@ -226,6 +235,15 @@ async def _process_single_chunk_qa(
 
         已经进入后续流程的任务（例如其它协程正在生成答案）允许自然执行完。
         """
+        # 随机决定是否对当前 chunk 进行 QA 生成
+        if random.random() > question_cfg.temperature:
+            logger.info(
+                f"Skip QA generation for chunk_index={chunk.chunk_index} in file_task={file_task.id} due to random decision."
+            )
+            # 更新文件任务的 processed_chunks 计数
+            await self._increment_processed_chunks(file_task.id, 1)
+            return False
+
         # 如果没有全局上限配置，维持原有行为
         if max_qa_pairs is not None and max_qa_pairs > 0:
             from sqlalchemy import func
@@ -411,6 +429,11 @@ async def process_single_question(question: str):
                 base_obj["instruction"] = question
                 data_obj = base_obj
 
+            # 提取图片URL
+            img_urls = extract_img_urls(chunk_text)
+            if img_urls:
+                data_obj["img_urls"] = img_urls
+
             record = SynthesisData(
                 id=str(uuid.uuid4()),
                 data=data_obj,