fix(log_client): update example_log_client template to use RpcClient

- 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
This commit is contained in:
qing committed 2026-08-01 03:26:19 +08:00
1 parent 3be9e78335
commit bdbea6ac40
1 file changed
+135 -64
+135 -64
View File
@@ -1,13 +1,14 @@
"""
统一日志客户端 SDK — 各服务复制即用。
统一日志客户端 SDK — 各服务复制即用(模板)。
设计要点:
- 通过 pymsg TCP 调用 dbv2 execute 路由,逐条 INSERT 到 Logs 表
- 通过 pymsg RpcClient(高层 RPC 封装)调用 dbv2 execute 路由,逐条 INSERT 到 Logs 表
- 异步非阻塞:内存队列 + 后台线程批量推送,不拖慢业务
- fail-safe:db 服务不可用时静默丢弃,绝不影响业务
- 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
- 缓冲批量:队列满 50 条或超时 2 秒时自动 flush
- 时间戳:日志入队时即记录 ts,反映事件真实发生时间
复制到目标服务目录后,按需修改 service_name 即可::
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:
from log_client import logs
@@ -27,22 +28,36 @@ import atexit
from datetime import datetime, timezone
_sys.path.insert(0, _os.path.join(_os.path.dirname(__file__), ".."))
from pymsg import MsgClient # noqa: E402
from pymsg import RpcClient, RpcError # noqa: E402
# ── 配置 ──────────────────────────────────────────────────────────────
_DBV2_ADDR = '127.0.0.1'
_DBV2_PORT = 8005
_DBV2_ADDR = _os.environ.get('DB_HOST', '127.0.0.1')
_DBV2_PORT = int(_os.environ.get('DB_PORT', '8005'))
_BATCH_SIZE = 50 # 队列满 50 条时 flush
_FLUSH_INTERVAL = 2.0 # 超时 2 秒强制 flush
_TIMEOUT = 5 # socket 超时(秒)
_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
def _safe_json(obj):
"""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。"""
try:
return json.dumps(obj, ensure_ascii=False, default=str)
except Exception:
return repr(obj)
def _now_iso():
"""生成当前 UTC 时间 ISO 字符串(在入队时调用,保证时间戳准确)。"""
return datetime.now(timezone.utc).isoformat()
class LogClient:
"""异步批量日志推送客户端。
通过 MsgClient(pymsg TCP 协议)逐条 INSERT 到 dbv2 的 Logs 表。
通过 RpcClient(pymsg 高层 RPC 封装)逐条 INSERT 到 dbv2 的 Logs 表。
service_name 用于在 dbv2 连接中标识来源,各服务复制时自行修改。
"""
@@ -52,9 +67,10 @@ class LogClient:
self._service_name = service_name
self._batch_size = batch_size
self._flush_interval = flush_interval
self._queue = queue.Queue()
self._queue = queue.Queue(maxsize=_QUEUE_MAXSIZE)
self._stop = threading.Event()
self._flush_signal = threading.Event()
self._flush_done = threading.Event()
self._thread = threading.Thread(target=self._flush_loop,
daemon=True, name='log-client')
self._thread.start()
@@ -63,14 +79,30 @@ class LogClient:
# ── 公开接口 ────────────────────────────────────────────────────────
def push(self, service, level, message, trace_id=None, extra=None):
"""推送一条日志(非阻塞,立即返回)。"""
self._queue.put({
"""推送一条日志(非阻塞,立即返回)。
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。
"""
entry = {
'ts': _now_iso(), # 入队时即生成时间戳,反映真实事件时间
'service': service,
'level': level,
'message': message,
'trace_id': trace_id,
'extra': extra,
})
}
try:
self._queue.put_nowait(entry)
except queue.Full:
# 队列满:丢弃最旧的一条,再放入新条目(drop-oldest 策略)
try:
self._queue.get_nowait()
except queue.Empty:
pass
try:
self._queue.put_nowait(entry)
except queue.Full:
pass # 极端竞争下仍失败则静默丢弃
def debug(self, service, message, **kw):
self.push(service, 'DEBUG', message, **kw)
@@ -89,8 +121,15 @@ class LogClient:
def flush(self):
"""手动 flush 队列中剩余的日志(含后台线程持有的局部 batch)。"""
self._flush_done.clear()
self._flush_signal.set() # 通知后台线程立即 flush 其局部 batch
time.sleep(0.6) # 等待后台线程响应
# 等待后台线程完成 flush(最多等待 flush_interval + 2 秒余量)
self._flush_done.wait(timeout=self._flush_interval + 2.0)
# 主线程排空队列中剩余条目
self._drain_queue_to_db()
def _drain_queue_to_db(self):
"""排空主线程可见的队列中剩余条目,直接发送到 db。"""
batch = []
while True:
try:
@@ -102,73 +141,103 @@ class LogClient:
break
if batch:
self._send(batch)
self._flush_signal.clear()
# ── 内部实现 ────────────────────────────────────────────────────────
def _flush_loop(self):
"""后台线程:积攒到 batch_size 或超时 flush_interval 时发送。"""
"""后台线程:积攒到 batch_size 或超时 flush_interval 时发送。
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)
都不会死亡,避免日志队列无限增长导致 OOM。
"""
batch = []
last_flush = time.monotonic()
while not self._stop.is_set():
timeout = self._flush_interval - (time.monotonic() - last_flush)
chk_timeout = max(0.0, min(timeout, 0.5))
try:
item = self._queue.get(timeout=chk_timeout)
batch.append(item)
while len(batch) < self._batch_size:
try:
batch.append(self._queue.get_nowait())
except queue.Empty:
break
except queue.Empty:
pass
timeout = self._flush_interval - (time.monotonic() - last_flush)
chk_timeout = max(0.1, min(timeout, 0.5))
try:
item = self._queue.get(timeout=chk_timeout)
batch.append(item)
while len(batch) < self._batch_size:
try:
batch.append(self._queue.get_nowait())
except queue.Empty:
break
except queue.Empty:
pass
should_flush = (
len(batch) >= self._batch_size or
self._flush_signal.is_set() or
(batch and time.monotonic() - last_flush >= self._flush_interval)
)
if should_flush and batch:
self._send(batch)
batch = []
last_flush = time.monotonic()
should_flush = (
len(batch) >= self._batch_size or
self._flush_signal.is_set() or
(batch and time.monotonic() - last_flush >= self._flush_interval)
)
if should_flush and batch:
try:
self._send(batch)
except Exception as e:
# _send 内部已有细粒度异常处理,此处是最终安全网
print(f"[log_client] _send 异常(已捕获,线程继续运行): {e}",
file=_sys.stderr)
batch = []
last_flush = time.monotonic()
if self._flush_signal.is_set():
self._flush_signal.clear()
self._flush_done.set()
except Exception as e:
# 最外层安全网:任何意外异常都不应杀死日志线程
print(f"[log_client] _flush_loop 异常(已捕获,线程继续运行): {e}",
file=_sys.stderr)
time.sleep(0.5) # 防止异常风暴导致 CPU 满载
# 退出前 flush 剩余
if batch:
self._send(batch)
try:
self._send(batch)
except Exception as e:
print(f"[log_client] 退出时 flush 异常: {e}", file=_sys.stderr)
self._flush_done.set()
def _send(self, batch):
"""通过 pymsg 使用 execute 路由逐条 INSERT 到 dbv2 Logs 表。"""
now = datetime.now(timezone.utc).isoformat()
"""通过 pymsg RpcClient(execute 路由)批量发送到 dbv2 Logs 表。
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),
不抛异常给调用方。
"""
try:
client = MsgClient(_DBV2_ADDR, _DBV2_PORT, self._service_name + "-log")
for entry in batch:
extra_val = entry.get("extra")
payload = {
"_route": "execute",
"action": "insert",
"table": "Logs",
"values": {
"ts": now,
"service": entry.get("service"),
"level": entry.get("level"),
"message": entry.get("message"),
"trace_id": entry.get("trace_id"),
"extra": json.dumps(extra_val, ensure_ascii=False)
if extra_val is not None else None,
},
}
resp = client.call(json.dumps(payload), timeout=_TIMEOUT)
resp_obj = json.loads(resp)
if not resp_obj.get("success"):
import sys
print(f"[log_client] INSERT 失败: {resp_obj.get('error')}",
file=sys.stderr)
client = RpcClient(_DBV2_ADDR, _DBV2_PORT, self._service_name + "-log")
except Exception as e:
import sys
print(f"[log_client] 发送失败: {e}", file=sys.stderr)
print(f"[log_client] 创建 RpcClient 失败: {e}", file=_sys.stderr)
return
for entry in batch:
extra_val = entry.get("extra")
try:
extra_json = _safe_json(extra_val) if extra_val is not None else None
except Exception:
extra_json = None
payload = {
"action": "insert",
"table": "Logs",
"values": {
"ts": entry.get("ts", _now_iso()),
"service": entry.get("service"),
"level": entry.get("level"),
"message": entry.get("message"),
"trace_id": entry.get("trace_id"),
"extra": extra_json,
},
}
try:
client.call("execute", payload, timeout=_TIMEOUT)
except RpcError as e:
# 业务错误(如表结构不符):打印后继续下一条
print(f"[log_client] INSERT 失败: {e}", file=_sys.stderr)
except Exception as e:
# 网络错误:db 不可用,放弃本批剩余(fail-safe)
print(f"[log_client] 发送失败: {e}", file=_sys.stderr)
break
def _shutdown(self):
"""进程退出时 flush 剩余日志。"""
@@ -180,5 +249,7 @@ class LogClient:
# 各服务复制时,把 "example" 改为自己的服务名即可。
# 例如 dnfs/log_client.py → logs = LogClient(service_name="dnfs")
# 例如 smtp/log_client.py → logs = LogClient(service_name="smtp")
# 例如 static/log_client.py → logs = LogClient(service_name="static")
# 例如 confs/log_client.py → logs = LogClient(service_name="confs")
logs = LogClient()
logs = LogClient(service_name="example")