README에 conda/systemd/Apache 설치 문서 추가

- Miniconda(ncue) 기반 설치/실행 및 systemd 예시 추가
- Apache ProxyPass 설정 및 503 트러블슈팅 절차 정리
- Flask DB pool lazy 생성으로 임포트 단계 장애(503) 완화

Co-authored-by: Cursor <cursoragent@cursor.com>

README.md

@@ -16,33 +16,166 @@ python3 -m http.server 8000
 
 그 후 브라우저에서 `http://localhost:8000`으로 접속합니다.
 
-## 서버(Node) + PostgreSQL 사용자 저장
+## 백엔드(Flask) + PostgreSQL 사용자 저장
 
 로그인 후 사용자 정보를 `ncue_user`에 저장하고(Upsert), 로그인/로그아웃 시간을 기록하며,
 `/api/config/auth`로 Auth0 설정을 공유하려면 백엔드 서버가 필요합니다.
 
 현재 백엔드는 **Python Flask(기본 포트 8023)** 로 제공합니다. (정적 HTML/JS는 그대로 사용 가능)
 
-1) 의존성 설치(Python)
+### 1) DB 테이블 생성(서버에서 1회)
-
-```bash
-python3 -m venv .venv
-source .venv/bin/activate
-pip install -r requirements.txt
-```
-
-2) 테이블 생성
 
 ```bash
 psql -h "$DB_HOST" -p "$DB_PORT" -U "$DB_USER" -d "$DB_NAME" -f db/schema.sql
 ```
 
-3) 서버 실행
+### 2) 실행 방법 A: (로컬/간단) venv로 실행
 
 ```bash
-python flask_app.py
+python3 -m venv .venv
+source .venv/bin/activate
+pip install -r requirements.txt
+PORT=8023 python flask_app.py
 ```
 
+### 3) 실행 방법 B: (운영/권장) Miniconda 환경 `ncue` + gunicorn + systemd
+
+#### B-1) 최초 1회 설치
+
+```bash
+cd /path/to/home
+conda activate ncue
+python -m pip install -r requirements.txt
+python -m pip install gunicorn
+```
+
+#### B-2) 단독 실행(테스트)
+
+```bash
+conda activate ncue
+cd /path/to/home
+gunicorn -w 2 -b 127.0.0.1:8023 flask_app:app
+```
+
+확인:
+
+```bash
+curl -s http://127.0.0.1:8023/healthz
+curl -s http://127.0.0.1:8023/api/config/auth
+```
+
+#### B-3) systemd 서비스(예시)
+
+`/etc/systemd/system/ncue-flask.service`:
+
+```ini
+[Unit]
+Description=NCUE Flask API (gunicorn)
+After=network.target
+
+[Service]
+Type=simple
+User=www-data
+Group=www-data
+WorkingDirectory=/path/to/home
+
+# miniconda 경로는 설치 위치에 맞게 수정하세요.
+ExecStart=/bin/bash -lc 'source /opt/miniconda3/etc/profile.d/conda.sh && conda activate ncue && gunicorn -w 2 -b 127.0.0.1:8023 flask_app:app'
+Restart=always
+RestartSec=3
+
+# .env 대신 systemd Environment로 주입(권장)
+Environment=DB_HOST=ncue.net
+Environment=DB_PORT=5432
+Environment=DB_NAME=ncue
+Environment=DB_USER=ncue
+Environment=DB_PASSWORD=REPLACE_ME
+Environment=TABLE=ncue_user
+Environment=AUTH0_DOMAIN=ncue.net
+Environment=AUTH0_CLIENT_ID=g5RDfax7FZkKzXYvXOgku3Ll8CxuA4IM
+Environment=AUTH0_GOOGLE_CONNECTION=google-oauth2
+Environment=ADMIN_EMAILS=dosangyoon@gmail.com,dsyoon@ncue.net
+Environment=PORT=8023
+
+[Install]
+WantedBy=multi-user.target
+```
+
+적용/재시작:
+
+```bash
+sudo systemctl daemon-reload
+sudo systemctl enable --now ncue-flask
+sudo systemctl restart ncue-flask
+sudo systemctl status ncue-flask --no-pager
+```
+
+로그 확인:
+
+```bash
+sudo journalctl -u ncue-flask -n 200 --no-pager
+```
+
+### 4) Apache 설정(정적은 Apache, `/api/*`만 8023 프록시)
+
+필요 모듈(Ubuntu/Debian):
+
+```bash
+sudo a2enmod proxy proxy_http headers
+sudo systemctl reload apache2
+```
+
+가상호스트 예시:
+
+```apacheconf
+<VirtualHost *:80>
+  ServerName ncue.net
+
+  DocumentRoot /path/to/home
+  <Directory /path/to/home>
+    Require all granted
+  </Directory>
+
+  ProxyPreserveHost On
+  RequestHeader set X-Forwarded-Proto "https"
+
+  ProxyPass        /api/    http://127.0.0.1:8023/api/
+  ProxyPassReverse /api/    http://127.0.0.1:8023/api/
+  ProxyPass        /healthz http://127.0.0.1:8023/healthz
+  ProxyPassReverse /healthz http://127.0.0.1:8023/healthz
+</VirtualHost>
+```
+
+적용:
+
+```bash
+sudo apachectl -t && sudo systemctl reload apache2
+```
+
+### 5) 503(Service Unavailable) 트러블슈팅 체크리스트
+
+브라우저 콘솔에서 503이 뜨면 대부분 **Apache가 127.0.0.1:8023 백엔드로 프록시했는데 백엔드가 응답을 못하는 상태**입니다.
+
+- 백엔드가 살아있는지:
+
+```bash
+curl -i http://127.0.0.1:8023/healthz
+curl -i http://127.0.0.1:8023/api/config/auth
+```
+
+- 서비스 로그:
+
+```bash
+sudo journalctl -u ncue-flask -n 200 --no-pager
+```
+
+- Apache 프록시 로그:
+  - Ubuntu/Debian: `/var/log/apache2/error.log`
+  - RHEL/CentOS: `/var/log/httpd/error_log`
+
+> 참고: `flask_app.py`는 DB가 일시적으로 죽어도 앱 임포트 단계에서 바로 죽지 않도록(DB pool lazy 생성) 개선되어,
+> “백엔드 프로세스가 안 떠서 Apache가 503”인 케이스를 줄였습니다.
+
 기본적으로 `.env`의 `ADMIN_EMAILS`에 포함된 이메일은 `can_manage=true`로 자동 승격됩니다.
 
 ### (선택) 역프록시/분리 배포
@@ -83,3 +216,6 @@ update ncue_user set can_manage = true where email = 'me@example.com';
 - 내보내기: 현재 화면 기준 링크를 JSON으로 다운로드합니다.
 - 가져오기: 내보내기 JSON(배열 또는 `{links:[...]}`)을 다시 불러옵니다.
 
+
+
+## 설치 방

flask_app.py

@@ -24,13 +24,6 @@ def env(name: str, default: str = "") -> str:
     return str(os.getenv(name, default))
 
 
-def must(name: str) -> str:
-    v = env(name).strip()
-    if not v:
-        raise RuntimeError(f"Missing env: {name}")
-    return v
-
-
 _IDENT_RE = re.compile(r"^[a-zA-Z_][a-zA-Z0-9_]*$")
 
 
@@ -51,11 +44,11 @@ def parse_email_csv(s: str) -> list[str]:
 
 PORT = int(env("PORT", "8023") or "8023")
 
-DB_HOST = must("DB_HOST")
+DB_HOST = env("DB_HOST", "").strip()
 DB_PORT = int(env("DB_PORT", "5432") or "5432")
-DB_NAME = must("DB_NAME")
+DB_NAME = env("DB_NAME", "").strip()
-DB_USER = must("DB_USER")
+DB_USER = env("DB_USER", "").strip()
-DB_PASSWORD = must("DB_PASSWORD")
+DB_PASSWORD = env("DB_PASSWORD", "").strip()
 
 TABLE = safe_ident(env("TABLE", "ncue_user") or "ncue_user")
 CONFIG_TABLE = "ncue_app_config"
@@ -71,8 +64,25 @@ AUTH0_GOOGLE_CONNECTION = env("AUTH0_GOOGLE_CONNECTION", "").strip()
 # Optional CORS (for static on different origin)
 CORS_ORIGINS = env("CORS_ORIGINS", "*").strip() or "*"
 
+_POOL: Optional[psycopg2.pool.SimpleConnectionPool] = None
 
-POOL: psycopg2.pool.SimpleConnectionPool = psycopg2.pool.SimpleConnectionPool(
+
+def db_configured() -> bool:
+    return bool(DB_HOST and DB_NAME and DB_USER and DB_PASSWORD)
+
+
+def get_pool() -> psycopg2.pool.SimpleConnectionPool:
+    """
+    Lazy DB pool creation.
+    - prevents app import failure (which causes Apache 503) when DB is temporarily unavailable
+    - /api/config/auth can still work purely from .env without DB
+    """
+    global _POOL
+    if _POOL is not None:
+        return _POOL
+    if not db_configured():
+        raise RuntimeError("db_not_configured")
+    _POOL = psycopg2.pool.SimpleConnectionPool(
         minconn=1,
         maxconn=10,
         host=DB_HOST,
@@ -82,20 +92,23 @@ POOL: psycopg2.pool.SimpleConnectionPool = psycopg2.pool.SimpleConnectionPool(
         password=DB_PASSWORD,
         sslmode="disable",
     )
+    return _POOL
 
 
 def db_exec(sql: str, params: Tuple[Any, ...] = ()) -> None:
-    conn = POOL.getconn()
+    pool = get_pool()
+    conn = pool.getconn()
     try:
         conn.autocommit = True
         with conn.cursor() as cur:
             cur.execute(sql, params)
     finally:
-        POOL.putconn(conn)
+        pool.putconn(conn)
 
 
 def db_one(sql: str, params: Tuple[Any, ...] = ()) -> Optional[tuple]:
-    conn = POOL.getconn()
+    pool = get_pool()
+    conn = pool.getconn()
     try:
         conn.autocommit = True
         with conn.cursor() as cur:
@@ -103,7 +116,7 @@ def db_one(sql: str, params: Tuple[Any, ...] = ()) -> Optional[tuple]:
             row = cur.fetchone()
             return row
     finally:
-        POOL.putconn(conn)
+        pool.putconn(conn)
 
 
 def ensure_user_table() -> None:
@@ -248,6 +261,8 @@ def static_files(filename: str) -> Response:
 @app.get("/healthz")
 def healthz() -> Response:
     try:
+        if not db_configured():
+            return jsonify({"ok": False, "error": "db_not_configured"}), 500
         row = db_one("select 1 as ok")
         if not row:
             return jsonify({"ok": False}), 500
@@ -259,6 +274,8 @@ def healthz() -> Response:
 @app.post("/api/auth/sync")
 def api_auth_sync() -> Response:
     try:
+        if not db_configured():
+            return jsonify({"ok": False, "error": "db_not_configured"}), 500
         ensure_user_table()
         id_token = bearer_token()
         if not id_token:
@@ -318,6 +335,8 @@ def api_auth_sync() -> Response:
 @app.post("/api/auth/logout")
 def api_auth_logout() -> Response:
     try:
+        if not db_configured():
+            return jsonify({"ok": False, "error": "db_not_configured"}), 500
         ensure_user_table()
         id_token = bearer_token()
         if not id_token:
@@ -364,6 +383,8 @@ def api_config_auth_get() -> Response:
                 }
             )
 
+        if not db_configured():
+            return jsonify({"ok": False, "error": "not_set"}), 404
         ensure_config_table()
         row = db_one(f"select value, updated_at from public.{CONFIG_TABLE} where key = %s", ("auth",))
         if not row:
@@ -384,6 +405,8 @@ def api_config_auth_get() -> Response:
 @app.post("/api/config/auth")
 def api_config_auth_post() -> Response:
     try:
+        if not db_configured():
+            return jsonify({"ok": False, "error": "db_not_configured"}), 500
         ensure_config_table()
         if not CONFIG_TOKEN:
             return jsonify({"ok": False, "error": "config_token_not_set"}), 403