hermes-agent/tui_gateway/synthetic_turn.py
brooklyn! 7d27a31ce7
feat(dashboard): isolate turns in compute host (#65895)
Add the flag-gated compute-host supervisor, delta/control protocol, PPID orphan guard, inline fail-open path, synthetic GIL-heavy turn seam, and AC-4 certify harness.

Verified on current origin/main: 343 focused tests pass; Ruff and diff checks pass; 360s AC-4 run with six heavy lanes passes at 6.11ms serving p99 with zero stalls and valid load.

Co-authored-by: Kyzcreig <9063726+Kyzcreig@users.noreply.github.com>
2026-07-16 15:24:03 -04:00

231 lines
9.8 KiB
Python

"""Synthetic GIL-heavy turn driver for the AC-4 isolation certify harness.
Mechanism B (the class ``docs/desktop/2026-07-04-dashboard-process-isolation-PRD.md``
targets) is interpreter-wide GIL starvation: concurrent heavy agent turns run
compute in threads of the SERVING process, and CPython's single GIL lets those
threads starve the event loop that flushes WebSocket frames for MINUTES. A
2026-07-04 ``sample`` showed the loop thread parked in ``take_gil`` while worker
threads burned the interpreter — NOT blocked on I/O.
To certify the fix (AC-4) without spending real tokens on 6 concurrent 100K+
context model calls, the harness needs a turn driver that reproduces THAT
regime: sustained pure-Python CPU that holds the GIL for the turn's duration.
A network/sleep stub is WRONG here — it would release the GIL during I/O and
never reproduce ``take_gil`` contention, so a dry-run green off it is a fake
green (the spec says so explicitly).
This module is a **test seam**: it is dead unless ``HERMES_ISO_CERTIFY_SYNTH_TURN``
is set. When armed, ``tui_gateway.server._make_agent`` returns a
:class:`SyntheticHeavyAgent` instead of a real ``AIAgent``. Because both the
in-process ``_pool`` path (isolation OFF) and the compute-host child path
(isolation ON) build their agent through ``_make_agent``, the SAME synthetic
turn exercises whichever dispatch path is under test — the isolation boundary
is the only variable between an OFF run and an ON run.
The per-turn intensity (wall duration, CPU chunk size, streamed-delta cadence,
token accounting) is carried in the prompt text as a small JSON spec so the
harness has full control and the server seam stays dumb. Any prompt that is not
a JSON object falls back to env / built-in defaults.
"""
from __future__ import annotations
import json
import os
import threading
import time
from typing import Any, Callable, Optional
def synth_turn_armed() -> bool:
"""True when the synthetic-turn test seam is armed via env."""
return os.environ.get("HERMES_ISO_CERTIFY_SYNTH_TURN") == "1"
def _env_float(name: str, default: float) -> float:
try:
return float(os.environ.get(name, "") or default)
except (TypeError, ValueError):
return default
def _env_int(name: str, default: int) -> int:
try:
return int(os.environ.get(name, "") or default)
except (TypeError, ValueError):
return default
class SyntheticHeavyAgent:
"""An AIAgent-shaped object whose turn is a GIL-holding CPU burn.
Presents only the surface ``tui_gateway.server``'s turn path and status
helpers read: ``run_conversation``/``interrupt``/``clear_interrupt`` plus a
handful of ``model``/``provider``/``session_*`` attributes consumed by
``_get_usage`` and ``_session_info``. It never opens a socket or spawns a
subprocess, so the only work it does is the deterministic Python loop below —
exactly the ``take_gil`` regime under test.
"""
def __init__(self, session_id: str, *, model: str = "synthetic-heavy") -> None:
self.session_id = session_id
self.model = model
self.provider = "synthetic"
self.api_mode = "chat_completions"
self.base_url = ""
self.api_key = ""
self.platform = ""
self.tools: list[Any] = []
self.reasoning_config: dict | None = None
self.service_tier: str | None = None
self.context_compressor = None
self._config_context_length = 200_000
self._cached_system_prompt = ""
# Cumulative session counters (read by _get_usage → status bar).
self.session_input_tokens = 0
self.session_output_tokens = 0
self.session_prompt_tokens = 0
self.session_completion_tokens = 0
self.session_reasoning_tokens = 0
self.session_total_tokens = 0
self.session_api_calls = 0
self.history: list[dict[str, str]] = []
self._interrupt = threading.Event()
# ── interrupt contract (mirrors AIAgent) ───────────────────────────
def clear_interrupt(self) -> None:
self._interrupt.clear()
def interrupt(self) -> None:
self._interrupt.set()
def _has_stream_consumers(self) -> bool: # defensive; not used by our loop
return True
def close(self) -> None:
"""No-op teardown (session lifecycle calls agent.close() on some paths)."""
self._interrupt.set()
# ── spec parsing ───────────────────────────────────────────────────
@staticmethod
def _parse_spec(message: Any) -> dict[str, Any]:
spec: dict[str, Any] = {}
if isinstance(message, str):
text = message.strip()
if text.startswith("{"):
try:
parsed = json.loads(text)
if isinstance(parsed, dict):
spec = parsed
except (ValueError, TypeError):
spec = {}
return {
# Primary control: wall-clock seconds of GIL-holding compute.
"duration_s": float(spec.get("duration_s", _env_float("HERMES_ISO_CERTIFY_DURATION_S", 8.0))),
# Pure-Python integer ops per interrupt-check chunk. Small enough
# that an interrupt is honored within a few ms; large enough that
# the loop stays hot on the GIL between checks.
"chunk": int(spec.get("chunk", _env_int("HERMES_ISO_CERTIFY_CHUNK", 20_000))),
# Streamed-delta cadence (seconds). Each delta is a loop wakeup that
# marshals a frame across the transport — the serving-path pressure.
"delta_interval_s": float(spec.get("delta_interval_s", _env_float("HERMES_ISO_CERTIFY_DELTA_S", 0.05))),
# Notional output tokens attributed per streamed delta (drives the
# 100K+-token "heavy turn" proxy in usage/metadata).
"tokens_per_delta": int(spec.get("tokens_per_delta", _env_int("HERMES_ISO_CERTIFY_TPD", 512))),
# Optional per-chunk sleep to model a lighter/mixed regime (0 = pure
# burn). --dry-run uses a short duration, NOT a sleep, so the smoke
# path still exercises the real dispatch seam.
"sleep_s": float(spec.get("sleep_s", 0.0)),
}
# ── the turn ───────────────────────────────────────────────────────
def run_conversation(
self,
message: Any,
*,
conversation_history: Optional[list[dict[str, str]]] = None,
stream_callback: Optional[Callable[[str], None]] = None,
task_id: Optional[str] = None,
**_kwargs: Any,
) -> dict[str, Any]:
spec = self._parse_spec(message)
duration = max(0.0, spec["duration_s"])
chunk = max(1, spec["chunk"])
interval = max(0.001, spec["delta_interval_s"])
tokens_per_delta = max(0, spec["tokens_per_delta"])
sleep_s = max(0.0, spec["sleep_s"])
base_history = list(conversation_history if conversation_history is not None else self.history)
start = time.monotonic()
last_delta = start
acc = 0
deltas = 0
interrupted = False
while True:
if self._interrupt.is_set():
interrupted = True
break
now = time.monotonic()
if now - start >= duration:
break
# GIL-holding pure-Python work. A tight integer loop runs one
# bytecode step per iteration and NEVER releases the GIL — this is
# the exact interpreter contention that starves the serving loop.
for _ in range(chunk):
acc = (acc * 1_000_003 + 12_345) & 0xFFFFFFFFFFFFFFFF
if sleep_s:
time.sleep(sleep_s)
if now - last_delta >= interval:
deltas += 1
self.session_output_tokens += tokens_per_delta
self.session_completion_tokens += tokens_per_delta
self.session_total_tokens += tokens_per_delta
if stream_callback is not None:
stream_callback(f"synthtok-{deltas:05d} ")
last_delta = now
self.session_api_calls += 1
# Fold the checksum into the reply so the loop is not dead-code-eliminated
# and the turn produces a deterministic, inspectable result.
final = (
f"[synthetic heavy turn] deltas={deltas} "
f"out_tokens={self.session_output_tokens} "
f"interrupted={interrupted} checksum={acc & 0xFFFF:04x}"
)
messages = [
*base_history,
{"role": "user", "content": str(message)[:200]},
{"role": "assistant", "content": final},
]
self.history = messages
return {
"final_response": final,
"messages": messages,
"interrupted": interrupted,
"error": None,
"last_reasoning": None,
}
def maybe_build_synthetic_agent(session_id: str, model_override: Any = None) -> SyntheticHeavyAgent | None:
"""Return a :class:`SyntheticHeavyAgent` when the seam is armed, else ``None``.
``model_override`` (dict or str) only influences the reported ``model`` label
so status frames look plausible; it never changes the compute.
"""
if not synth_turn_armed():
return None
model = "synthetic-heavy"
if isinstance(model_override, dict) and model_override.get("model"):
model = str(model_override["model"])
elif isinstance(model_override, str) and model_override:
model = model_override
return SyntheticHeavyAgent(session_id, model=model)
__all__ = [
"SyntheticHeavyAgent",
"maybe_build_synthetic_agent",
"synth_turn_armed",
]