Files
hermes-agent/agent/subagent_lifecycle.py

459 lines
18 KiB
Python

"""Public, plugin-safe lifecycle API for delegated Hermes subagents.
Exposes immutable contracts, not ``AIAgent`` objects; plugins obtain it via
``PluginContext.subagent_lifecycle``.
"""
from __future__ import annotations
import contextvars
import dataclasses
import enum
import hashlib
import hmac
import json
import math
import secrets
import threading
import time
from contextlib import contextmanager
from concurrent.futures import Future, TimeoutError
from typing import Any, Callable, Mapping, Optional
from agent.interrupt_compat import request_hard_interrupt
PUBLIC_CONTRACT_VERSION = 1
_MAX_GOAL_CHARS = 16_000
_MAX_CONTEXT_CHARS = 32_000
_MAX_METADATA_BYTES = 8_192
_MAX_RESULT_CHARS = 32_000
_TERMINAL_RETENTION_SECONDS = 3_600
class SubagentLifecycleError(ValueError):
"""A request cannot be safely accepted by the public lifecycle API."""
class SubagentState(str, enum.Enum):
PENDING = "PENDING"
STARTING = "STARTING"
RUNNING = "RUNNING"
SUCCEEDED = "SUCCEEDED"
FAILED = "FAILED"
INTERRUPTED = "INTERRUPTED"
CANCEL_REQUESTED = "CANCEL_REQUESTED"
CANCELLED = "CANCELLED"
UNKNOWN = "UNKNOWN"
@dataclasses.dataclass(frozen=True)
class SubagentLaunchRequest:
goal: str
context: Optional[str] = None
role: str = "leaf"
model: Optional[str] = None
allowed_toolsets: Optional[tuple[str, ...]] = None
blocked_tools: tuple[str, ...] = ()
working_directory: Optional[str] = None
parent_session_id: Optional[str] = None
correlation_id: Optional[str] = None
metadata: Mapping[str, Any] = dataclasses.field(default_factory=dict)
timeout_seconds: Optional[float] = None
@dataclasses.dataclass(frozen=True)
class SubagentHandle:
contract_version: int
subagent_id: str
parent_session_id: Optional[str]
correlation_id: Optional[str]
created_at: float
provider: Optional[str]
model: Optional[str]
role: str
depth: int
capability: str
def to_dict(self) -> dict[str, Any]:
return dataclasses.asdict(self)
@classmethod
def from_dict(cls, value: Mapping[str, Any]) -> "SubagentHandle":
try:
return cls(**dict(value))
except (TypeError, ValueError) as exc:
raise SubagentLifecycleError("Malformed subagent handle.") from exc
@dataclasses.dataclass(frozen=True)
class SubagentStatus:
handle: SubagentHandle
state: SubagentState
updated_at: float
diagnostic: Optional[str] = None
@dataclasses.dataclass(frozen=True)
class SubagentTerminalState:
handle: SubagentHandle
state: SubagentState
completed: bool
timed_out: bool = False
diagnostic: Optional[str] = None
@dataclasses.dataclass(frozen=True)
class SubagentCancelResult:
accepted: bool
already_terminal: bool = False
unknown_handle: bool = False
unsupported: bool = False
state: SubagentState = SubagentState.UNKNOWN
@dataclasses.dataclass(frozen=True)
class SubagentResult:
handle: SubagentHandle
terminal_state: SubagentState
ready: bool
summary: Optional[str] = None
structured_payload: Optional[Mapping[str, Any]] = None
started_at: Optional[float] = None
completed_at: Optional[float] = None
error_classification: Optional[str] = None
error_message: Optional[str] = None
usage_metadata: Mapping[str, Any] = dataclasses.field(default_factory=dict)
tool_execution_summary: Mapping[str, Any] = dataclasses.field(default_factory=dict)
result_hash: Optional[str] = None
@dataclasses.dataclass(frozen=True)
class SubagentReconnectResult:
connected: bool
state: SubagentState
diagnostic: Optional[str] = None
@dataclasses.dataclass
class _Record:
handle: SubagentHandle
state: SubagentState
updated_at: float
agent: Any = None
future: Optional[Future] = None
started_at: Optional[float] = None
completed_at: Optional[float] = None
result: Optional[SubagentResult] = None
@dataclasses.dataclass
class _Registry:
"""Thread-safe terminal-retention registry; never returns live records."""
lock: threading.RLock = dataclasses.field(default_factory=threading.RLock)
records: dict[str, _Record] = dataclasses.field(default_factory=dict)
correlations: dict[tuple[Optional[str], str], str] = dataclasses.field(default_factory=dict)
_REGISTRY = _Registry()
# Daemon pool: a wedged/abandoned child must never block interpreter exit.
from tools.daemon_pool import DaemonThreadPoolExecutor as _DaemonExecutor
_EXECUTOR = _DaemonExecutor(max_workers=8, thread_name_prefix="hermes-lifecycle")
_SECRET = secrets.token_bytes(32)
_ACTIVE_PARENT_AGENT: contextvars.ContextVar[Any] = contextvars.ContextVar(
"hermes_subagent_lifecycle_parent", default=None
)
@contextmanager
def bind_subagent_parent(parent_agent: Any):
"""Bind the host-owned parent for the current agent turn."""
token = _ACTIVE_PARENT_AGENT.set(parent_agent)
try:
yield
finally:
_ACTIVE_PARENT_AGENT.reset(token)
def get_active_subagent_parent() -> Any:
"""Return the parent bound to this execution context, if any."""
return _ACTIVE_PARENT_AGENT.get()
def _opt_str(value: Any) -> bool:
return value is None or isinstance(value, str)
def _session_id_of(agent: Any) -> Optional[str]:
return str(getattr(agent, "session_id", "") or "") or None
def _finite_number(value: Any) -> bool:
return not isinstance(value, bool) and isinstance(value, (int, float)) and math.isfinite(value)
# Per-field shape check applied to a (possibly deserialized) handle before trusting it.
_HANDLE_FIELD_CHECKS: tuple[tuple[str, Callable[[Any], bool]], ...] = (
("contract_version", lambda v: type(v) is int and v == PUBLIC_CONTRACT_VERSION),
("subagent_id", lambda v: isinstance(v, str) and bool(v)),
("parent_session_id", _opt_str),
("correlation_id", _opt_str),
("created_at", _finite_number),
("provider", _opt_str),
("model", _opt_str),
("role", lambda v: isinstance(v, str)),
("depth", lambda v: type(v) is int),
("capability", lambda v: isinstance(v, str)),
)
# Launch-request fields the public contract deliberately rejects: (predicate, error).
_UNSUPPORTED_REQUEST_FIELDS: tuple[tuple[Callable[[SubagentLaunchRequest], bool], str], ...] = (
(lambda r: r.timeout_seconds is not None,
"Per-launch timeout is not supported; configure delegation timeout explicitly."),
(lambda r: r.working_directory is not None,
"working_directory is not supported because Hermes delegates use isolated task environments."),
(lambda r: bool(r.blocked_tools),
"Per-tool blocking is not supported; use allowed_toolsets. Hermes always blocks unsafe child tools."),
)
def _handle_is_well_formed(handle: Any) -> bool:
return isinstance(handle, SubagentHandle) and all(
check(getattr(handle, field)) for field, check in _HANDLE_FIELD_CHECKS
)
class SubagentLifecycleService:
"""Stable public service returned by :attr:`PluginContext.subagent_lifecycle`. Children run
in-process only; completed results stay until process exit, and ``reconnect`` reports that a
serialized handle cannot reconnect after a restart instead of launching work again."""
def __init__(self, parent_agent_resolver: Callable[[], Any]) -> None:
self._parent_agent_resolver = parent_agent_resolver
def launch(self, request: SubagentLaunchRequest) -> SubagentHandle:
parent = self._parent_agent_resolver()
if parent is None:
raise SubagentLifecycleError("No active Hermes parent session is available.")
self._validate_request(request, parent)
parent_session_id = _session_id_of(parent)
if request.parent_session_id and request.parent_session_id != parent_session_id:
raise SubagentLifecycleError("parent_session_id does not match the active session.")
correlation_key = (parent_session_id, request.correlation_id or "")
with _REGISTRY.lock:
self._cleanup_locked()
if request.correlation_id and correlation_key in _REGISTRY.correlations:
raise SubagentLifecycleError("Duplicate correlation_id for this parent session.")
# Delegate construction stays internal so plugin code never imports
# private delegation helpers or touches the active-child registry.
from tools.delegate_tool import _build_child_preserving_parent_tools, DEFAULT_MAX_ITERATIONS
child = _build_child_preserving_parent_tools(
task_index=0,
goal=request.goal,
context=request.context,
toolsets=list(request.allowed_toolsets) if request.allowed_toolsets else None,
model=request.model,
max_iterations=DEFAULT_MAX_ITERATIONS,
task_count=1,
parent_agent=parent,
role=request.role,
)
subagent_id = str(getattr(child, "_subagent_id", "") or "")
if not subagent_id:
raise SubagentLifecycleError("Hermes failed to assign a child identity.")
created = time.time()
handle = SubagentHandle(
PUBLIC_CONTRACT_VERSION,
subagent_id,
parent_session_id,
request.correlation_id,
created,
getattr(child, "provider", None),
getattr(child, "model", None),
getattr(child, "_delegate_role", request.role),
int(getattr(child, "_delegate_depth", 1) or 1),
self._capability(subagent_id, parent_session_id, created),
)
record = _Record(handle, SubagentState.PENDING, created, agent=child)
with _REGISTRY.lock:
_REGISTRY.records[subagent_id] = record
if request.correlation_id:
_REGISTRY.correlations[correlation_key] = subagent_id
record.future = _EXECUTOR.submit(self._run, record, request.goal, parent)
return handle
def status(self, handle: SubagentHandle) -> SubagentStatus:
record = self._record(handle)
if record is None:
return SubagentStatus(handle, SubagentState.UNKNOWN, time.time(), "UNKNOWN_HANDLE")
with _REGISTRY.lock:
return SubagentStatus(record.handle, record.state, record.updated_at)
def wait(self, handle: SubagentHandle, *, timeout_seconds: Optional[float] = None) -> SubagentTerminalState:
record = self._record(handle)
if record is None:
return SubagentTerminalState(handle, SubagentState.UNKNOWN, True, diagnostic="UNKNOWN_HANDLE")
future = record.future
if future is not None:
try:
future.result(timeout=timeout_seconds)
except TimeoutError:
return SubagentTerminalState(record.handle, record.state, False, True)
except Exception:
pass
with _REGISTRY.lock:
return SubagentTerminalState(record.handle, record.state, record.result is not None)
def cancel(self, handle: SubagentHandle, *, reason: str) -> SubagentCancelResult:
record = self._record(handle)
if record is None:
return SubagentCancelResult(False, unknown_handle=True)
with _REGISTRY.lock:
if record.result is not None:
return SubagentCancelResult(False, already_terminal=True, state=record.state)
agent = record.agent
record.state = SubagentState.CANCEL_REQUESTED
record.updated_at = time.time()
unsupported = SubagentCancelResult(False, unsupported=True, state=SubagentState.CANCEL_REQUESTED)
if agent is None:
return unsupported
try:
accepted = request_hard_interrupt(
agent,
f"Lifecycle cancellation requested: {reason[:500]}",
tool_reason="subagent cancellation requested",
)
except Exception:
accepted = False
if not accepted:
return unsupported
return SubagentCancelResult(True, state=SubagentState.CANCEL_REQUESTED)
def result(self, handle: SubagentHandle) -> SubagentResult:
record = self._record(handle)
if record is None:
return SubagentResult(handle, SubagentState.UNKNOWN, False, error_classification="UNKNOWN_HANDLE")
with _REGISTRY.lock:
if record.result is not None:
return record.result
return SubagentResult(record.handle, record.state, False, error_classification="NOT_READY")
def reconnect(self, handle: SubagentHandle) -> SubagentReconnectResult:
record = self._record(handle)
if record is None:
return SubagentReconnectResult(False, SubagentState.UNKNOWN, "RECONNECT_UNAVAILABLE")
with _REGISTRY.lock:
return SubagentReconnectResult(True, record.state)
def _record(self, handle: SubagentHandle) -> Optional[_Record]:
if not _handle_is_well_formed(handle):
return None
expected = self._capability(handle.subagent_id, handle.parent_session_id, handle.created_at)
if not hmac.compare_digest(handle.capability, expected):
return None
if _session_id_of(self._parent_agent_resolver()) != handle.parent_session_id:
return None
with _REGISTRY.lock:
return _REGISTRY.records.get(handle.subagent_id)
@staticmethod
def _cleanup_locked() -> None:
"""Retain terminal snapshots for a bounded period, never live work."""
cutoff = time.time() - _TERMINAL_RETENTION_SECONDS
expired = [
sid for sid, record in _REGISTRY.records.items()
if record.result is not None and record.completed_at is not None and record.completed_at < cutoff
]
for subagent_id in expired:
handle = _REGISTRY.records.pop(subagent_id).handle
if handle.correlation_id:
_REGISTRY.correlations.pop((handle.parent_session_id, handle.correlation_id), None)
def _run(self, record: _Record, goal: str, parent: Any) -> None:
with _REGISTRY.lock:
if record.state is not SubagentState.CANCEL_REQUESTED:
record.state = SubagentState.RUNNING
record.started_at = time.time()
record.updated_at = record.started_at
try:
from tools.delegate_tool import _run_child_lifecycle
raw = _run_child_lifecycle(0, goal, record.agent, parent)
is_dict = isinstance(raw, dict)
if not is_dict:
raw = {}
status = str(raw.get("status", "error"))
if status == "interrupted":
cancelled = record.state == SubagentState.CANCEL_REQUESTED
state = SubagentState.CANCELLED if cancelled else SubagentState.INTERRUPTED
else:
state = SubagentState.SUCCEEDED if status == "completed" else SubagentState.FAILED
summary = raw.get("summary")
error = raw.get("error")
fields: dict[str, Any] = dict(
summary=str(summary)[:_MAX_RESULT_CHARS] if summary is not None else None,
error_classification=None if state == SubagentState.SUCCEEDED else status.upper(),
error_message=str(error)[:_MAX_RESULT_CHARS] if error else None,
usage_metadata={"api_calls": raw.get("api_calls", 0)} if is_dict else {},
tool_execution_summary={"duration_seconds": raw.get("duration_seconds", 0)} if is_dict else {},
)
except Exception as exc:
state = SubagentState.FAILED
fields = dict(error_classification=type(exc).__name__, error_message=str(exc)[:_MAX_RESULT_CHARS])
result = SubagentResult(
record.handle, state, True, started_at=record.started_at, completed_at=time.time(), **fields
)
payload = dataclasses.asdict(result)
payload.pop("result_hash", None)
digest = hashlib.sha256(json.dumps(payload, sort_keys=True, default=str).encode()).hexdigest()
result = dataclasses.replace(result, result_hash=digest)
with _REGISTRY.lock:
record.agent = None
record.result = result
record.state = result.terminal_state
record.completed_at = result.completed_at
record.updated_at = result.completed_at or time.time()
@staticmethod
def _capability(subagent_id: str, parent_session_id: Optional[str], created_at: float) -> str:
value = f"{subagent_id}|{parent_session_id or ''}|{created_at:.6f}".encode()
return hmac.new(_SECRET, value, hashlib.sha256).hexdigest()
@staticmethod
def _validate_request(request: SubagentLaunchRequest, parent: Any) -> None:
if (
not isinstance(request, SubagentLaunchRequest)
or not isinstance(request.goal, str)
or not request.goal.strip()
or len(request.goal) > _MAX_GOAL_CHARS
):
raise SubagentLifecycleError("goal must be a non-empty string of at most 16000 characters.")
if request.context is not None and (
not isinstance(request.context, str) or len(request.context) > _MAX_CONTEXT_CHARS
):
raise SubagentLifecycleError("context must be a string of at most 32000 characters.")
if request.role not in {"leaf", "orchestrator"}:
raise SubagentLifecycleError("role must be 'leaf' or 'orchestrator'.")
for rejected, message in _UNSUPPORTED_REQUEST_FIELDS:
if rejected(request):
raise SubagentLifecycleError(message)
try:
metadata_bytes = len(json.dumps(dict(request.metadata), sort_keys=True).encode())
except (TypeError, ValueError) as exc:
raise SubagentLifecycleError("metadata must be JSON-serializable.") from exc
if metadata_bytes > _MAX_METADATA_BYTES:
raise SubagentLifecycleError("metadata exceeds 8192 bytes.")
if request.allowed_toolsets:
from toolsets import TOOLSETS
unknown = set(request.allowed_toolsets) - set(TOOLSETS)
if unknown:
raise SubagentLifecycleError(f"Unknown toolsets: {', '.join(sorted(unknown))}.")
enabled = getattr(parent, "enabled_toolsets", None)
if enabled is not None and not set(request.allowed_toolsets).issubset(set(enabled)):
raise SubagentLifecycleError("Requested toolsets would broaden parent permissions.")