364 lines
14 KiB
Python
364 lines
14 KiB
Python
"""
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dbv2 — 基于 pymsg 协议(MsgServer)的数据库服务。
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替代 Flask HTTP 接口,通过 TCP 长度前缀帧收发 JSON。
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协议:每条消息为完整 JSON,新增 ``_route`` 字段对应原 HTTP 路由路径。
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请求示例::
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{
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"_route": "execute",
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"action": "select",
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"table": "Users",
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"where": {"age": {"gt": 20}},
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"order_by": [{"column": "id", "desc": true}],
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"limit": 10
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}
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支持的路由::
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execute → 通用 CRUD(select / insert / update / delete)
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"""
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import json
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import os
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import time
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import traceback
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from datetime import datetime, timezone, timedelta
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from sqlalchemy import (
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create_engine, MetaData, Table,
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select, insert, update, delete, func, and_,
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)
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from sqlalchemy.exc import SQLAlchemyError
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# pymsg 导入
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import sys as _sys
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_sys.path.insert(0, os.path.join(os.path.dirname(__file__), ".."))
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from pymsg import MsgServer # noqa: E402
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# ── 数据库配置 ──────────────────────────────────────────────────────────
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DATABASE_URL = os.environ.get("DATABASE_URL", "sqlite:///database.db")
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# ── 日志模块常量 ────────────────────────────────────────────────────────
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MAX_MESSAGE_LEN = 8192 # message 上限 8KB
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MAX_EXTRA_LEN = 4096 # extra 上限 4KB
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DEFAULT_RETENTION_DAYS = 30
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DEFAULT_MAX_RECORDS = 1_000_000
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DEFAULT_CLEANUP_INTERVAL = 3600 # 秒
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# ═══════════════════════════════════════════════════════════════════════
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# DBServer — 主服务类
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# ═══════════════════════════════════════════════════════════════════════
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class DBServer:
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"""基于 pymsg 的数据库服务,通过 TCP 长连接收发 JSON。"""
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def __init__(self, addr="127.0.0.1", port=8005):
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self.addr = addr
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self.port = port
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self.engine = create_engine(DATABASE_URL)
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self.metadata = MetaData()
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self._server = MsgServer(addr, port)
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# 日志表缓存(避免重复反射)
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self._logs_table_cache = {}
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# 路由表
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self._routes = {
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"execute": self._handle_execute,
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}
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# ── 启动 / 停止 ──────────────────────────────────────────────────
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def start(self) -> None:
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"""启动服务(阻塞当前线程)。"""
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print(f"[dbv2] 监听 tcp://{self.addr}:{self.port}")
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self._ensure_logs_table() # 确保 Logs 表已建好(外部 MsgClient 写日志前)
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self._start_cleanup_thread()
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self._server.start(self._dispatch)
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def stop(self) -> None:
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"""从另一线程停止服务。"""
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self._server.stop()
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# ── 消息调度 -------------------------------------------------------
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def _dispatch(self, sock, addr, text):
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"""解析 JSON 中的 _route,分发给对应的 handler,并回复结果。"""
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try:
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req = json.loads(text)
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except json.JSONDecodeError as e:
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self._reply(sock, False, error=f"JSON 解析失败: {e}")
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return
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route = req.pop("_route", "")
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handler = self._routes.get(route)
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if handler is None:
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self._reply(sock, False, error=f"未知路由: {route}")
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return
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try:
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result = handler(req, sock=sock)
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self._reply(sock, True, data=result)
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except Exception as e:
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traceback.print_exc()
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self._reply(sock, False, error=str(e))
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def _reply(self, sock, success, data=None, error=None):
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resp = {"success": success}
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if data is not None:
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resp["data"] = data
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if error is not None:
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resp["error"] = error
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self._server.reply(sock, json.dumps(resp, ensure_ascii=False, default=str))
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# ── 表反射 ---------------------------------------------------------
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def _get_table(self, table_name):
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if table_name not in self.metadata.tables:
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Table(table_name, self.metadata, autoload_with=self.engine)
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return self.metadata.tables[table_name]
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def _build_where(self, table, conditions):
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if not conditions:
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return None
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clauses = []
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for col, val in conditions.items():
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column = table.columns[col]
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if isinstance(val, dict):
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if "eq" in val:
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clauses.append(column == val["eq"])
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if "ne" in val:
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clauses.append(column != val["ne"])
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if "gt" in val:
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clauses.append(column > val["gt"])
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if "lt" in val:
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clauses.append(column < val["lt"])
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if "ge" in val:
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clauses.append(column >= val["ge"])
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if "le" in val:
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clauses.append(column <= val["le"])
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if "like" in val:
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clauses.append(column.like(val["like"]))
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if "in" in val:
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clauses.append(column.in_(val["in"]))
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else:
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clauses.append(column == val)
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return and_(*clauses)
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# ═══════════════════════════════════════════════════════════════════
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# 路由处理 — execute
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# ═══════════════════════════════════════════════════════════════════
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def _handle_execute(self, data, **kw):
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action = data.get("action", "select")
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table_name = data.get("table")
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if not table_name:
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raise ValueError("缺少 table 字段")
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try:
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table = self._get_table(table_name)
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except Exception as e:
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raise ValueError(f"表加载失败: {e}")
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with self.engine.connect() as conn:
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if action == "select":
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return self._do_select(conn, table, data)
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elif action == "insert":
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return self._do_insert(conn, table, data)
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elif action == "update":
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return self._do_update(conn, table, data)
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elif action == "delete":
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return self._do_delete(conn, table, data)
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else:
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raise ValueError(f"不支持的操作: {action}")
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def _do_select(self, conn, table, data):
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columns = data.get("columns")
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if columns:
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cols = [table.columns[c] for c in columns]
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else:
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cols = [table]
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stmt = select(*cols)
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where_cond = self._build_where(table, data.get("where"))
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if where_cond is not None:
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stmt = stmt.where(where_cond)
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order_by = data.get("order_by")
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if order_by:
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for item in order_by:
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col = table.columns[item["column"]]
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stmt = stmt.order_by(col.desc() if item.get("desc") else col.asc())
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limit = data.get("limit")
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if limit is not None:
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stmt = stmt.limit(limit)
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offset = data.get("offset")
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if offset is not None:
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stmt = stmt.offset(offset)
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res = conn.execute(stmt)
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return [dict(row._mapping) for row in res.fetchall()]
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def _do_insert(self, conn, table, data):
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values = data.get("values", {})
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stmt = insert(table).values(**values)
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res = conn.execute(stmt)
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conn.commit()
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return [{"lastrowid": res.lastrowid}] if hasattr(res, "lastrowid") else []
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def _do_update(self, conn, table, data):
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values = data.get("values", {})
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where_cond = self._build_where(table, data.get("where"))
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stmt = update(table).values(**values)
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if where_cond is not None:
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stmt = stmt.where(where_cond)
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res = conn.execute(stmt)
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conn.commit()
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return [{"rowcount": res.rowcount}]
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def _do_delete(self, conn, table, data):
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where_cond = self._build_where(table, data.get("where"))
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stmt = delete(table)
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if where_cond is not None:
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stmt = stmt.where(where_cond)
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res = conn.execute(stmt)
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conn.commit()
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return [{"rowcount": res.rowcount}]
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# ═══════════════════════════════════════════════════════════════════
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# 日志表管理 + 后台清理
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# ═══════════════════════════════════════════════════════════════════
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# ── 日志表管理 ────────────────────────────────────────────────────
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def _ensure_logs_table(self):
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if "Logs" in self._logs_table_cache:
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return self._logs_table_cache["Logs"]
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with self.engine.connect() as conn:
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conn.exec_driver_sql("""
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CREATE TABLE IF NOT EXISTS Logs (
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id INTEGER PRIMARY KEY AUTOINCREMENT,
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ts TEXT NOT NULL,
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service TEXT NOT NULL,
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level TEXT NOT NULL,
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message TEXT NOT NULL,
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trace_id TEXT,
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extra TEXT
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)
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""")
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conn.exec_driver_sql(
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"CREATE INDEX IF NOT EXISTS idx_logs_service_ts ON Logs(service, ts)"
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)
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conn.exec_driver_sql(
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"CREATE INDEX IF NOT EXISTS idx_logs_level_ts ON Logs(level, ts)"
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)
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conn.exec_driver_sql(
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"CREATE INDEX IF NOT EXISTS idx_logs_ts ON Logs(ts)"
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)
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conn.exec_driver_sql(
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"CREATE INDEX IF NOT EXISTS idx_logs_trace ON Logs(trace_id)"
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)
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conn.commit()
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table = Table("Logs", self.metadata, autoload_with=self.engine)
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self._logs_table_cache["Logs"] = table
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return table
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# ── 内部日志(直接写库,无 HTTP)──────────────────────────────────
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def _log_internal(self, service, level, message,
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trace_id=None, extra=None):
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try:
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table = self._ensure_logs_table()
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extra_json = json.dumps(extra, ensure_ascii=False) if extra else None
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if len(message) > MAX_MESSAGE_LEN:
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message = message[:MAX_MESSAGE_LEN]
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if extra_json and len(extra_json) > MAX_EXTRA_LEN:
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extra_json = extra_json[:MAX_EXTRA_LEN]
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with self.engine.connect() as conn:
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conn.execute(insert(table).values(
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ts=datetime.now(timezone.utc).isoformat(),
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service=service,
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level=level,
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message=message,
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trace_id=trace_id,
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extra=extra_json,
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))
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conn.commit()
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except Exception:
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pass
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# ── 后台自动清理线程 ──────────────────────────────────────────────
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def _start_cleanup_thread(self):
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def _loop():
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while True:
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time.sleep(DEFAULT_CLEANUP_INTERVAL)
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try:
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self._do_cleanup()
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except Exception:
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pass
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import threading
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t = threading.Thread(target=_loop, daemon=True, name="dbv2-cleanup")
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t.start()
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def _do_cleanup(self):
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table = self._ensure_logs_table()
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cutoff = (
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datetime.now(timezone.utc) - timedelta(days=DEFAULT_RETENTION_DAYS)
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).isoformat()
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with self.engine.connect() as conn:
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result = conn.execute(
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delete(table).where(table.columns["ts"] < cutoff)
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)
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conn.commit()
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expired_deleted = result.rowcount
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count = conn.execute(
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select(func.count()).select_from(table)
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).scalar() or 0
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trimmed = 0
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if count > DEFAULT_MAX_RECORDS:
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excess = count - DEFAULT_MAX_RECORDS
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cutoff_row = conn.execute(
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select(table.columns["ts"])
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.order_by(table.columns["ts"].asc())
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.limit(1).offset(DEFAULT_MAX_RECORDS)
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).fetchone()
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if cutoff_row:
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trim_result = conn.execute(
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delete(table).where(table.columns["ts"] < cutoff_row[0])
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)
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conn.commit()
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trimmed = trim_result.rowcount
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if expired_deleted or trimmed:
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self._log_internal(
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"db", "INFO",
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f"自动清理: 过期删除 {expired_deleted} 条, 超量裁剪 {trimmed} 条"
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)
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# ═══════════════════════════════════════════════════════════════════════
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# 入口
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# ═══════════════════════════════════════════════════════════════════════
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if __name__ == "__main__":
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import argparse
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parser = argparse.ArgumentParser(description="dbv2 — pymsg 数据库服务")
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parser.add_argument("--addr", default="127.0.0.1", help="监听地址")
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parser.add_argument("--port", type=int, default=8005, help="监听端口")
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args = parser.parse_args()
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server = DBServer(args.addr, args.port)
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try:
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server.start()
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except KeyboardInterrupt:
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server.stop()
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