hermes-agent/acp_adapter/entry.py
Teknium a33e890644
fix(acp): silence 'Background task failed' noise on liveness-probe requests (#12855)
Clients like acp-bridge send periodic bare `ping` JSON-RPC requests as a
liveness probe. The acp router correctly returns JSON-RPC -32601 to the
caller, which those clients already handle as 'agent alive'. But the
supervisor task that ran the request then surfaces the raised RequestError
via `logging.exception('Background task failed', ...)`, dumping a full
traceback to stderr on every probe interval.

Install a logging filter on the stderr handler that suppresses
'Background task failed' records only when the exception is an acp
RequestError(-32601) for one of {ping, health, healthcheck}. Real
method_not_found for any other method, other exception classes, other log
messages, and -32601 logged under a different message all pass through
untouched.

The protocol response is unchanged — the client still receives a standard
-32601 'Method not found' error back. Only the server-side stderr noise is
silenced.

Closes #12529
2026-04-20 00:10:27 -07:00

126 lines
4.2 KiB
Python

"""CLI entry point for the hermes-agent ACP adapter.
Loads environment variables from ``~/.hermes/.env``, configures logging
to write to stderr (so stdout is reserved for ACP JSON-RPC transport),
and starts the ACP agent server.
Usage::
python -m acp_adapter.entry
# or
hermes acp
# or
hermes-acp
"""
import asyncio
import logging
import sys
from pathlib import Path
from hermes_constants import get_hermes_home
# Methods clients send as periodic liveness probes. They are not part of the
# ACP schema, so the acp router correctly returns JSON-RPC -32601 to the
# caller — but the supervisor task that dispatches the request then surfaces
# the raised RequestError via ``logging.exception("Background task failed")``,
# which dumps a traceback to stderr every probe interval. Clients like
# acp-bridge already treat the -32601 response as "agent alive", so the
# traceback is pure noise. We keep the protocol response intact and only
# silence the stderr noise for this specific benign case.
_BENIGN_PROBE_METHODS = frozenset({"ping", "health", "healthcheck"})
class _BenignProbeMethodFilter(logging.Filter):
"""Suppress acp 'Background task failed' tracebacks caused by unknown
liveness-probe methods (e.g. ``ping``) while leaving every other
background-task error — including method_not_found for any non-probe
method — visible in stderr.
"""
def filter(self, record: logging.LogRecord) -> bool:
if record.getMessage() != "Background task failed":
return True
exc_info = record.exc_info
if not exc_info:
return True
exc = exc_info[1]
# Imported lazily so this module stays importable when the optional
# ``agent-client-protocol`` dependency is not installed.
try:
from acp.exceptions import RequestError
except ImportError:
return True
if not isinstance(exc, RequestError):
return True
if getattr(exc, "code", None) != -32601:
return True
data = getattr(exc, "data", None)
method = data.get("method") if isinstance(data, dict) else None
return method not in _BENIGN_PROBE_METHODS
def _setup_logging() -> None:
"""Route all logging to stderr so stdout stays clean for ACP stdio."""
handler = logging.StreamHandler(sys.stderr)
handler.setFormatter(
logging.Formatter(
"%(asctime)s [%(levelname)s] %(name)s: %(message)s",
datefmt="%Y-%m-%d %H:%M:%S",
)
)
handler.addFilter(_BenignProbeMethodFilter())
root = logging.getLogger()
root.handlers.clear()
root.addHandler(handler)
root.setLevel(logging.INFO)
# Quiet down noisy libraries
logging.getLogger("httpx").setLevel(logging.WARNING)
logging.getLogger("httpcore").setLevel(logging.WARNING)
logging.getLogger("openai").setLevel(logging.WARNING)
def _load_env() -> None:
"""Load .env from HERMES_HOME (default ``~/.hermes``)."""
from hermes_cli.env_loader import load_hermes_dotenv
hermes_home = get_hermes_home()
loaded = load_hermes_dotenv(hermes_home=hermes_home)
if loaded:
for env_file in loaded:
logging.getLogger(__name__).info("Loaded env from %s", env_file)
else:
logging.getLogger(__name__).info(
"No .env found at %s, using system env", hermes_home / ".env"
)
def main() -> None:
"""Entry point: load env, configure logging, run the ACP agent."""
_setup_logging()
_load_env()
logger = logging.getLogger(__name__)
logger.info("Starting hermes-agent ACP adapter")
# Ensure the project root is on sys.path so ``from run_agent import AIAgent`` works
project_root = str(Path(__file__).resolve().parent.parent)
if project_root not in sys.path:
sys.path.insert(0, project_root)
import acp
from .server import HermesACPAgent
agent = HermesACPAgent()
try:
asyncio.run(acp.run_agent(agent, use_unstable_protocol=True))
except KeyboardInterrupt:
logger.info("Shutting down (KeyboardInterrupt)")
except Exception:
logger.exception("ACP agent crashed")
sys.exit(1)
if __name__ == "__main__":
main()