qing
bdbea6ac40
- Replace legacy MsgClient (low-level TCP frames) with RpcClient (high-level
RPC) to match dbv2's RpcServer interface; the old MsgClient-based version
was incompatible with the current RPC routing protocol
- Apply all hardening fixes from the service copies:
- Outer try/except in _flush_loop to prevent any exception from killing
the background thread
- _safe_json() helper for unserializable extra fields (fallback to str/repr)
- Timestamp generated at push() (enqueue time) instead of _send() time
- Event-based flush() synchronization instead of unreliable sleep(0.6)
- Queue maxsize=10000 with drop-oldest policy to prevent unbounded memory
- put_nowait with Full handling ensures push() never blocks business threads
- RpcClient construction wrapped in try/except
- Add explicit service_name parameter example for all 4 services in comments
- This is the template file referenced by db/README.md and copied by new
services; keeping it in sync prevents propagating old bugs
256 lines
10 KiB
Python
256 lines
10 KiB
Python
"""
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统一日志客户端 SDK — 各服务复制即用（模板）。
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设计要点：
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- 通过 pymsg RpcClient（高层 RPC 封装）调用 dbv2 execute 路由，逐条 INSERT 到 Logs 表
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- 异步非阻塞：内存队列 + 后台线程批量推送，不拖慢业务
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- fail-safe：db 服务不可用时静默丢弃，绝不影响业务；后台线程任何异常都不会崩溃
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- 缓冲批量：队列满 50 条或超时 2 秒时自动 flush
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- 时间戳：日志入队时即记录 ts，反映事件真实发生时间
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复制到目标服务目录后，按需修改底部全局单例的 service_name 即可：
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from log_client import logs
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logs.info("dnfs", "节点新增成功 id=42")
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logs.error("dnfs", "数据库连接失败", extra={"errno": 2002})
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logs.push("gateway", "WARNING", "登录失败次数超限",
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trace_id="req-abc", extra={"ip": "1.2.3.4"})
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"""
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import json
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import os as _os
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import sys as _sys
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import threading
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import queue
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import time
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import atexit
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from datetime import datetime, timezone
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_sys.path.insert(0, _os.path.join(_os.path.dirname(__file__), ".."))
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from pymsg import RpcClient, RpcError # noqa: E402
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# ── 配置 ──────────────────────────────────────────────────────────────
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_DBV2_ADDR = _os.environ.get('DB_HOST', '127.0.0.1')
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_DBV2_PORT = int(_os.environ.get('DB_PORT', '8005'))
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_BATCH_SIZE = 50 # 队列满 50 条时 flush
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_FLUSH_INTERVAL = 2.0 # 超时 2 秒强制 flush
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_TIMEOUT = 5 # socket 超时（秒）
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_QUEUE_MAXSIZE = 10000 # 队列上限，防止后台线程异常时内存无限增长；满则丢弃最旧条目
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def _safe_json(obj):
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"""安全序列化 extra 字段，不可序列化对象转为 repr 字符串，保证不抛异常。"""
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try:
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return json.dumps(obj, ensure_ascii=False, default=str)
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except Exception:
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return repr(obj)
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def _now_iso():
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"""生成当前 UTC 时间 ISO 字符串（在入队时调用，保证时间戳准确）。"""
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return datetime.now(timezone.utc).isoformat()
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class LogClient:
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"""异步批量日志推送客户端。
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通过 RpcClient（pymsg 高层 RPC 封装）逐条 INSERT 到 dbv2 的 Logs 表。
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service_name 用于在 dbv2 连接中标识来源，各服务复制时自行修改。
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"""
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def __init__(self, service_name="example",
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batch_size=_BATCH_SIZE,
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flush_interval=_FLUSH_INTERVAL):
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self._service_name = service_name
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self._batch_size = batch_size
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self._flush_interval = flush_interval
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self._queue = queue.Queue(maxsize=_QUEUE_MAXSIZE)
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self._stop = threading.Event()
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self._flush_signal = threading.Event()
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self._flush_done = threading.Event()
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self._thread = threading.Thread(target=self._flush_loop,
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daemon=True, name='log-client')
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self._thread.start()
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atexit.register(self._shutdown)
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# ── 公开接口 ────────────────────────────────────────────────────────
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def push(self, service, level, message, trace_id=None, extra=None):
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"""推送一条日志（非阻塞，立即返回）。
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队列满时静默丢弃最旧条目再放入新条目，保证不阻塞业务线程、不导致 OOM。
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"""
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entry = {
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'ts': _now_iso(), # 入队时即生成时间戳，反映真实事件时间
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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,
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}
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try:
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self._queue.put_nowait(entry)
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except queue.Full:
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# 队列满：丢弃最旧的一条，再放入新条目（drop-oldest 策略）
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try:
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self._queue.get_nowait()
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except queue.Empty:
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pass
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try:
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self._queue.put_nowait(entry)
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except queue.Full:
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pass # 极端竞争下仍失败则静默丢弃
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def debug(self, service, message, **kw):
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self.push(service, 'DEBUG', message, **kw)
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def info(self, service, message, **kw):
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self.push(service, 'INFO', message, **kw)
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def warning(self, service, message, **kw):
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self.push(service, 'WARNING', message, **kw)
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def error(self, service, message, **kw):
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self.push(service, 'ERROR', message, **kw)
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def critical(self, service, message, **kw):
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self.push(service, 'CRITICAL', message, **kw)
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def flush(self):
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"""手动 flush 队列中剩余的日志（含后台线程持有的局部 batch）。"""
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self._flush_done.clear()
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self._flush_signal.set() # 通知后台线程立即 flush 其局部 batch
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# 等待后台线程完成 flush（最多等待 flush_interval + 2 秒余量）
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self._flush_done.wait(timeout=self._flush_interval + 2.0)
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# 主线程排空队列中剩余条目
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self._drain_queue_to_db()
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def _drain_queue_to_db(self):
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"""排空主线程可见的队列中剩余条目，直接发送到 db。"""
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batch = []
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while True:
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try:
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batch.append(self._queue.get_nowait())
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if len(batch) >= self._batch_size:
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self._send(batch)
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batch = []
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except queue.Empty:
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break
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if batch:
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self._send(batch)
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# ── 内部实现 ────────────────────────────────────────────────────────
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def _flush_loop(self):
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"""后台线程：积攒到 batch_size 或超时 flush_interval 时发送。
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外层捕获所有异常，保证后台线程在任何情况下（网络故障、序列化错误等）
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都不会死亡，避免日志队列无限增长导致 OOM。
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"""
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batch = []
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last_flush = time.monotonic()
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while not self._stop.is_set():
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try:
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timeout = self._flush_interval - (time.monotonic() - last_flush)
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chk_timeout = max(0.1, min(timeout, 0.5))
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try:
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item = self._queue.get(timeout=chk_timeout)
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batch.append(item)
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while len(batch) < self._batch_size:
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try:
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batch.append(self._queue.get_nowait())
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except queue.Empty:
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break
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except queue.Empty:
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pass
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should_flush = (
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len(batch) >= self._batch_size or
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self._flush_signal.is_set() or
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(batch and time.monotonic() - last_flush >= self._flush_interval)
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)
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if should_flush and batch:
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try:
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self._send(batch)
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except Exception as e:
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# _send 内部已有细粒度异常处理，此处是最终安全网
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print(f"[log_client] _send 异常（已捕获，线程继续运行）: {e}",
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file=_sys.stderr)
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batch = []
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last_flush = time.monotonic()
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if self._flush_signal.is_set():
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self._flush_signal.clear()
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self._flush_done.set()
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except Exception as e:
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# 最外层安全网：任何意外异常都不应杀死日志线程
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print(f"[log_client] _flush_loop 异常（已捕获，线程继续运行）: {e}",
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file=_sys.stderr)
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time.sleep(0.5) # 防止异常风暴导致 CPU 满载
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# 退出前 flush 剩余
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if batch:
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try:
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self._send(batch)
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except Exception as e:
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print(f"[log_client] 退出时 flush 异常: {e}", file=_sys.stderr)
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self._flush_done.set()
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def _send(self, batch):
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"""通过 pymsg RpcClient（execute 路由）批量发送到 dbv2 Logs 表。
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整个 batch 复用一个 TCP 连接；网络错误时放弃本批剩余条目（fail-safe），
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不抛异常给调用方。
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"""
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try:
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client = RpcClient(_DBV2_ADDR, _DBV2_PORT, self._service_name + "-log")
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except Exception as e:
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print(f"[log_client] 创建 RpcClient 失败: {e}", file=_sys.stderr)
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return
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for entry in batch:
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extra_val = entry.get("extra")
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try:
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extra_json = _safe_json(extra_val) if extra_val is not None else None
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except Exception:
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extra_json = None
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payload = {
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"action": "insert",
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"table": "Logs",
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"values": {
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"ts": entry.get("ts", _now_iso()),
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"service": entry.get("service"),
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"level": entry.get("level"),
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"message": entry.get("message"),
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"trace_id": entry.get("trace_id"),
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"extra": extra_json,
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},
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}
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try:
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client.call("execute", payload, timeout=_TIMEOUT)
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except RpcError as e:
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# 业务错误（如表结构不符）：打印后继续下一条
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print(f"[log_client] INSERT 失败: {e}", file=_sys.stderr)
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except Exception as e:
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# 网络错误：db 不可用，放弃本批剩余（fail-safe）
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print(f"[log_client] 发送失败: {e}", file=_sys.stderr)
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break
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def _shutdown(self):
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"""进程退出时 flush 剩余日志。"""
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self._stop.set()
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self.flush()
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# ── 全局单例 ──────────────────────────────────────────────────────────
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# 各服务复制时，把 "example" 改为自己的服务名即可。
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# 例如 dnfs/log_client.py → logs = LogClient(service_name="dnfs")
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# 例如 smtp/log_client.py → logs = LogClient(service_name="smtp")
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# 例如 static/log_client.py → logs = LogClient(service_name="static")
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# 例如 confs/log_client.py → logs = LogClient(service_name="confs")
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logs = LogClient(service_name="example")
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