Update api/config.py

api/config.py

@@ -1,36 +1,100 @@
-# config.py
+# api/config.py
 import os
 from typing import List, Dict
+
+import httpx
 from openai import OpenAI
 from langchain_openai import ChatOpenAI, OpenAIEmbeddings
 
-# ---------- 环境变量 & OpenAI API Key ----------
-OPENAI_API_KEY = os.getenv("OPENAI_API_KEY")
+# ============================
+# Environment & Core Settings
+# ============================
+
+OPENAI_API_KEY = (os.getenv("OPENAI_API_KEY") or "").strip()
 if not OPENAI_API_KEY:
-    raise RuntimeError(
-        "OPENAI_API_KEY is not set. Please go to Settings → Secrets and add it."
-    )
+    raise RuntimeError("OPENAI_API_KEY is not set. Please go to Settings → Secrets and add it.")
+
+# Optional: allow overriding base URL (useful for gateways / proxies)
+OPENAI_BASE_URL = (os.getenv("OPENAI_BASE_URL") or "").strip() or None
+
+# Models
+DEFAULT_MODEL = (os.getenv("CLARE_DEFAULT_MODEL") or "gpt-4.1-mini").strip()
+EMBEDDING_MODEL = (os.getenv("CLARE_EMBEDDING_MODEL") or "text-embedding-3-small").strip()
+
+# Timeout (seconds) - single source of truth
+OPENAI_TIMEOUT_SECONDS = float(os.getenv("CLARE_OPENAI_TIMEOUT_SECONDS", "20").strip())
+
+# Connection pooling / keep-alive
+HTTP_MAX_CONNECTIONS = int(os.getenv("CLARE_HTTP_MAX_CONNECTIONS", "20").strip())
+HTTP_MAX_KEEPALIVE = int(os.getenv("CLARE_HTTP_MAX_KEEPALIVE", "10").strip())
+HTTP_KEEPALIVE_EXPIRY = float(os.getenv("CLARE_HTTP_KEEPALIVE_EXPIRY", "30").strip())
 
-# ---------- 模型配置（一定要在用之前定义） ----------
-DEFAULT_MODEL = "gpt-4.1-mini"
-EMBEDDING_MODEL = "text-embedding-3-small"
+# Network retries (transport-level)
+HTTP_RETRIES = int(os.getenv("CLARE_HTTP_RETRIES", "2").strip())
 
-# ---------- OpenAI 原生 Client（老代码还在用） ----------
-client = OpenAI(api_key=OPENAI_API_KEY)
 
-# ---------- LangChain 封装的 LLM & Embedding ----------
-# 以后如果你想用 LangChain 的 ChatOpenAI / OpenAIEmbeddings，可以直接用这两个
+# ============================
+# Shared HTTP client (singleton)
+# ============================
+
+# httpx Timeout object (connect/read/write/pool)
+_httpx_timeout = httpx.Timeout(
+    timeout=OPENAI_TIMEOUT_SECONDS,
+    connect=min(10.0, OPENAI_TIMEOUT_SECONDS),
+    read=OPENAI_TIMEOUT_SECONDS,
+    write=OPENAI_TIMEOUT_SECONDS,
+    pool=min(10.0, OPENAI_TIMEOUT_SECONDS),
+)
+
+_limits = httpx.Limits(
+    max_connections=HTTP_MAX_CONNECTIONS,
+    max_keepalive_connections=HTTP_MAX_KEEPALIVE,
+    keepalive_expiry=HTTP_KEEPALIVE_EXPIRY,
+)
+
+# A single httpx client reused across the process
+_http_client = httpx.Client(
+    timeout=_httpx_timeout,
+    limits=_limits,
+    headers={
+        # Helps some proxies; safe default
+        "Connection": "keep-alive",
+    },
+    follow_redirects=True,
+)
+
+# ============================
+# OpenAI SDK client (singleton)
+# ============================
+
+# Keep naming as `client` to avoid touching call sites
+client = OpenAI(
+    api_key=OPENAI_API_KEY,
+    base_url=OPENAI_BASE_URL,
+    http_client=_http_client,
+    max_retries=HTTP_RETRIES,
+)
+
+# ============================
+# LangChain wrappers (optional)
+# ============================
+
+# If you use LangChain later, reuse the same timeout policy
 llm_default = ChatOpenAI(
     model=DEFAULT_MODEL,
     temperature=0.5,
-    timeout=20,
+    timeout=OPENAI_TIMEOUT_SECONDS,
+    # Note: LangChain uses its own http stack; keep it simple.
 )
 
 embedding_client = OpenAIEmbeddings(
     model=EMBEDDING_MODEL,
 )
 
-# ---------- 默认 GenAI 课程大纲 ----------
+# ============================
+# Default course outline
+# ============================
+
 DEFAULT_COURSE_TOPICS: List[str] = [
     "Week 0 – Welcome & What is Generative AI; course outcomes LO1–LO5.",
     "Week 1 – Foundations of GenAI: LLMs, Transformer & self-attention, perplexity.",
@@ -45,7 +109,10 @@ DEFAULT_COURSE_TOPICS: List[str] = [
     "Week 10 – Responsible AI; risks, governance, EU AI Act-style ideas.",
 ]
 
-# ---------- 学习模式 ----------
+# ============================
+# Learning modes
+# ============================
+
 LEARNING_MODES: List[str] = [
     "Concept Explainer",
     "Socratic Tutor",
@@ -82,7 +149,10 @@ LEARNING_MODE_INSTRUCTIONS: Dict[str, str] = {
     ),
 }
 
-# ---------- 上传文件类型 ----------
+# ============================
+# Upload doc types
+# ============================
+
 DOC_TYPES: List[str] = [
     "Syllabus",
     "Lecture Slides / PPT",
@@ -90,7 +160,10 @@ DOC_TYPES: List[str] = [
     "Other Course Document",
 ]
 
-# ---------- Clare 的基础 System Prompt ----------
+# ============================
+# Clare system prompt
+# ============================
+
 CLARE_SYSTEM_PROMPT = """
 You are Clare, an AI teaching assistant for Hanbridge University.