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Python
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connect() stages albedo's python bundle on the target, boots the same kernelover one long-lived ssh connection, and answers its host-route calls againstthis session's daemon, so session tools (work, skills, cells) keep runningwhere the daemon runs while machine tools (bash, files) run on the target.Both kernels load the same content-hashed bundle, so a tool's remote shapematches its local one and results cross as real objects.
Every call is one reference: the reply inlines the value when it can cross andkeeps the object live over there otherwise, so methods can be called on theremote object either way. If the kernel cannot boot, the connection degradesto command mode -- only rem.bash() -- and says so at connect."""from __future__ import annotations
import asyncioimport base64import hashlibimport importlibimport ioimport jsonimport osimport shleximport structimport tarfileimport tempfileimport uuidfrom pathlib import Pathfrom typing import Any
from albedo_api import PythonApi, ReadyList
CONNECT_TIMEOUT = 15 # seconds before an unreachable target gives upHANDSHAKE_TIMEOUT = 30 # seconds for the remote kernel to say readySTAGE_TIMEOUT = 120 # seconds to move the bundle over one ssh streamINVOKE_TIMEOUT = 3600 # anti-wedge bound; the cell deadline is the real limitCOMMAND_TIMEOUT = 120 # degraded-mode command defaultMAX_FRAME = 8 * 1024 * 1024 # control-frame ceiling, as in the kernelSTDERR_TAIL = 65536 # bytes of ssh diagnostics kept for failures
loop: asyncio.AbstractEventLoophost_call: AnyHostErrorType: type[Exception]capture_factory: Anysend_frame: Anysession_modules: list[str] = []_fallback_live: set[str] = set() # degraded-mode jobs still running over ssh
def _report_live() -> None: """Tell the local supervisor how many remote jobs are still live.
Releasing the kernel would kill every ssh client and with them the remote kernels, so the idle sweep keeps a kernel alive while remote work runs. """ try: live = len(_fallback_live) + sum(len(c._live) for c in connections) send_frame({"type": "jobs", "live": live}) except Exception: pass # no channel or shutdown; the supervisor keeps the last count
configured: dict[str, str | None] = {}connections: list["RemoteConnection"] = []
_UNSET = object() # a value result that has not settled yet
class RemoteError(RuntimeError): """A remote operation failed; the message names what happened."""
class RemoteBootError(RemoteError): """The remote kernel could not start; the connection degrades to commands."""
class RemoteLost(RemoteError): """The ssh channel is gone; every reference it held is invalid."""
class RemoteTimeout(RemoteError): """A remote call did not answer; an interrupt was sent."""
class RemoteCancelled(RemoteError): """The wait was cancelled; the remote effect may continue."""
class RemoteExecutionError(RemoteError): """A remote tool call raised; its traceback crossed the connection."""
def __init__(self, ename: str, evalue: str, traceback: list[str]): lines = "\n".join(traceback[-4:]) super().__init__(f"{ename}: {evalue}" + (f"\n{lines}" if lines else "")) self.ename = ename self.evalue = evalue self.traceback = tuple(traceback)
def parse_target(arg: str) -> dict[str, str | None]: """Split `user@host[:/path]`; a colon not followed by a path stays in the host.""" head, separator, tail = arg.partition(":") remote_cwd = tail if separator and tail.startswith("/") else None return {"host": arg if remote_cwd is None else head, "remote_cwd": remote_cwd}
def _settings() -> dict[str, str]: """The `remote` section of extensions.json, falling back to `ssh`; errors raise.""" home = os.environ.get("ALBEDO_HOME") or os.path.expanduser("~/.albedo") try: with open(os.path.join(home, "extensions.json"), "rb") as handle: sections = json.load(handle) except FileNotFoundError: return {} if not isinstance(sections, dict): raise RemoteError("extensions.json must hold an object") section = sections.get("remote", sections.get("ssh")) if section is None: return {} if not isinstance(section, dict): raise RemoteError("extensions.json remote section must be an object") keys = ("host", "remoteCwd", "python") return {key: section[key] for key in keys if key in section}
def resolve(host: str | None = None, remote_cwd: str | None = None, python: str | None = None) -> dict[str, str | None]: """The target a connection runs against, or a misuse error naming every source.""" if host is None and configured: target = dict(configured) else: if host is None: host = os.environ.get("ALBEDO_SSH") or _settings().get("host") if host is None: raise RemoteError( "no remote target: pass host=, call remote.configure(), set $ALBEDO_SSH, " 'or add a "remote" section to extensions.json') target = parse_target(host) if target["remote_cwd"] is None: target["remote_cwd"] = _settings().get("remoteCwd") if remote_cwd is not None: target["remote_cwd"] = remote_cwd if python is None: python = _settings().get("python") target["python"] = python return target
def ssh_base() -> list[str]: """The ssh argv prefix: one multiplexed control connection per target.
Control sockets live under /tmp when it fits, else the temp dir: unix socket paths are capped (~104 bytes on macOS) and %C hashes to 40 more, so neither ALBEDO_HOME nor macOS's deep $TMPDIR may be on the path. """ control = os.path.join("/tmp", "albedo-ssh-cm") if len(control) + 42 > 104: control = os.path.join(tempfile.gettempdir(), "albedo-ssh-cm") os.makedirs(control, exist_ok=True) return ["ssh", "-o", "BatchMode=yes", "-o", "ConnectTimeout=10", "-o", "StrictHostKeyChecking=accept-new", "-o", "ControlMaster=auto", "-o", f"ControlPath={control}/%C", "-o", "ControlPersist=600"]
async def ssh_run(target: str, script: str, *, timeout: float, stdin: bytes | None = None) -> tuple[int | None, bytes, str]: """One command over the control connection; its exit code is data.""" process = await asyncio.create_subprocess_exec( *ssh_base(), target, script, stdin=asyncio.subprocess.PIPE if stdin is not None else asyncio.subprocess.DEVNULL, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE) try: stdout, stderr = await asyncio.wait_for(process.communicate(stdin), timeout) except asyncio.TimeoutError: process.kill() raise RemoteTimeout(f"ssh command did not finish in {timeout:g}s: {script}") from None return process.returncode, stdout, stderr.decode(errors="replace")
_BUNDLE: dict[str, str] = {}
def bundle() -> dict[str, str]: """Content hash of the packaged python tree, so both sides run the same code.""" if not _BUNDLE: root = Path(__file__).resolve().parents[1] digest = hashlib.sha256() for path in sorted(root.rglob("*.py")): digest.update(str(path.relative_to(root)).encode()) digest.update(path.read_bytes()) _BUNDLE["id"] = digest.hexdigest() _BUNDLE["root"] = str(root) _BUNDLE["remote"] = f"~/.albedo-remote/{digest.hexdigest()[:16]}" return _BUNDLE
async def stage(target: str) -> None: """Move the bundle over one ssh stream: candidate dir, then tar into it.""" remote = bundle()["remote"] archive = io.BytesIO() with tarfile.open(fileobj=archive, mode="w") as tar: tar.add(bundle()["root"], arcname=".") script = f"mkdir -p {shlex.quote(remote)} && tar -C {shlex.quote(remote)} -xf -" code, _, stderr = await ssh_run(target, script, timeout=STAGE_TIMEOUT, stdin=archive.getvalue()) if code != 0: raise RemoteBootError(f"staging failed ({code}): {stderr.strip()[:500]}")
def _load_class(marker: str) -> type: """The class a wire marker names; both bundles are identical, so it exists.""" module, _, qualified = marker.rpartition(".") obj: Any = importlib.import_module(module) for part in qualified.split("."): obj = getattr(obj, part) return obj
def wire_decode(value: Any) -> Any: """Rebuild real objects from wire values, so remote results read like local ones.""" if isinstance(value, dict): if set(value) == {"__bytes__"} and isinstance(value.get("__bytes__"), str): try: return base64.b64decode(value["__bytes__"], validate=True) except ValueError as error: raise RemoteError("invalid remote byte encoding") from error if set(value) == {"__class__", "fields"} and isinstance(value.get("__class__"), str): try: return _load_class(value["__class__"])( **{key: wire_decode(item) for key, item in value["fields"].items()}) except Exception: return {key: wire_decode(item) for key, item in value["fields"].items()} if set(value) == {"__record__", "fields"} and isinstance(value.get("__record__"), str): fields = {key: wire_decode(item) for key, item in value["fields"].items()} try: return _load_class(value["__record__"])(fields) except Exception: return fields if set(value) == {"__list__", "items"} and isinstance(value.get("__list__"), str): items = [wire_decode(item) for item in value["items"]] try: return _load_class(value["__list__"])(items) except Exception: return items return {key: wire_decode(item) for key, item in value.items()} if isinstance(value, list): return [wire_decode(item) for item in value] return value
def _revive(value: Any) -> Any: """Pickle hook target: a reference with a crossed value saves as its value.""" return value
class RemoteRef: """One remote reference: pending, live, or settled into its value.
A call returns this immediately -- the invoke is already in flight, no round trip blocks the call -- and the reference settles on first await. Methods called before the reply lands target the pending call, so `rem.bash(cmd)` behaves like local bash: the handle exists now, `await` waits for the object, and mirrored job state answers tail() and poll() locally, with no round trip. A result whose value crossed reads and iterates like that value; its local methods run locally, and attributes that only exist remotely are remote calls. """
def __init__(self, connection: "RemoteConnection", handle: str | None = None, value: Any = None, task: "asyncio.Task[Any] | None" = None, call_id: str | None = None, label: str = "") -> None: self._connection = connection self._handle = handle self._value = value self._task = task self._call_id = call_id self._label = label self._settled: Any = _UNSET self._withdrawn: bool = False
# --- mirrored job state: sync, like the local handle ---
def tail(self, n: int = 4000) -> str: """The recent output of the remote job this reference holds.""" state = self._mirror() data = str(state.get("tail", "")) if state else "" return data[-max(1, min(n, 16384)):]
def poll(self) -> int | None: """The remote job's exit status so far, from the mirrored stream.""" state = self._mirror() return state.get("exit_code") if state else None
@property def exit_code(self) -> int | None: """The remote job's exit status; the mirror keeps it current.""" return self.poll()
@property def returncode(self) -> int | None: """`exit_code` under subprocess's name; both spellings answer.""" return self.poll()
@property def timed_out(self) -> bool: """Whether the remote job lost its deadline.""" state = self._mirror() return bool(state.get("timed_out")) if state else False
@property def duration(self) -> float | None: """The remote job's wall seconds, known once it ended.""" state = self._mirror() return state.get("duration") if state else None
@property def id(self) -> str | None: """The remote job's id, for output.read on the remote side.""" state = self._mirror() return state.get("job") if state else None
def _mirror(self) -> dict[str, Any] | None: if self._handle is None: return None state = self._connection._mirrors.get(self._handle) # A finished job read through its mirror is consumed on the remote side # too, or its kernel would keep retrying a wake this read satisfies. if (state is not None and state.get("exit_code") is not None and not self._withdrawn): self._withdrawn = True try: _ = loop.create_task(self._connection.mark_read(self._handle)) except RuntimeError: pass # the loop is closing; the notice dies with the kernel return state
# --- the value surface: identical output to the local tool ---
def __repr__(self) -> str: if self._value is not None: return repr(self._value) if self._handle is not None: return f"<remote reference {self._handle[:8]} on {self._connection.host}>" return f"<pending remote {self._label or 'call'}; await it>"
__str__ = __repr__
def _wanted(self) -> Any: if self._value is None and self._handle is None: raise TypeError( f"the remote {self._label or 'result'} is still pending; await it first") if self._value is None: raise TypeError("a live remote reference is not a value; await it or call its methods") return self._value
def __iter__(self): return iter(self._wanted())
def __len__(self) -> int: return len(self._wanted())
def __getitem__(self, key: Any) -> Any: return self._wanted()[key]
def __contains__(self, key: Any) -> bool: return key in self._wanted()
def __eq__(self, other: object) -> bool: return self._value == other if self._value is not None else self is other
def __dir__(self) -> list[str]: return sorted(set(dir(type(self))) | (set(dir(self._value)) if self._value is not None else set()))
def __reduce__(self): if self._value is None: raise TypeError("a live remote reference cannot be saved; await or release it first") return _revive, (self._value,)
# --- the remote surface ---
def __getattr__(self, name: str) -> Any: if name.startswith("_"): raise AttributeError(name) if self._value is not None and hasattr(self._value, name): return getattr(self._value, name) if self._connection.closed: raise RemoteLost(f"the connection for reference {self._label or '?'} is closed") if self._handle is not None: return _RemoteCall(self._connection, self._handle, name) return _RemoteCall(self._connection, None, name, pending=self._call_id, label=f"{self._label}.{name}" if self._label else name)
def __await__(self): return self._settle().__await__()
async def _settle(self) -> Any: """Resolve the in-flight call; awaiting a live object awaits the object.""" if self._task is not None: task, self._task = self._task, None result = await task if result is not self: self._settled = result return result if self._settled is not _UNSET: return self._settled if self._handle is not None and self._value is None: await self._connection.invoke(handle=self._handle, wait=True) return self
async def release(self) -> None: """Drop the live reference; the object itself is the remote plugin's to keep.""" if self._task is not None: self._task.cancel() self._task = None return if self._handle is not None: self._connection._refs.pop(self._handle, None) await self._connection.invoke_release(self._handle) self._value = None
class _RemoteCall: """A method of the remote namespace, of one live reference, or of a pending call."""
def __init__(self, connection: "RemoteConnection", handle: str | None, name: str, pending: str | None = None, label: str | None = None) -> None: self._connection = connection self._handle = handle self._name = name self._pending = pending self._label = label or name
def __call__(self, *args: Any, **kwargs: Any) -> RemoteRef: """Start the call now; the reference it produces settles on first await.""" return self._connection.start(self, args, kwargs)
def __await__(self): """Awaiting an uncalled method runs it with no arguments, like a property.""" return self().__await__()
def __getattr__(self, name: str) -> Any: if name.startswith("_"): raise AttributeError(name) return _RemoteCall(self._connection, self._handle, f"{self._name}.{name}", pending=self._pending)
def __repr__(self) -> str: where = self._handle[:8] if self._handle else (self._pending[:8] if self._pending else "namespace") return f"<remote call {self._name} on {where}>"
class RemoteConnection: """One ssh channel owning one remote kernel, or degraded to plain commands."""
def __init__(self, target: dict[str, str | None]) -> None: self.target = target self._process: asyncio.subprocess.Process | None = None self._stdin = None self._stdout = None self._write_lock = asyncio.Lock() self._pending: dict[str, asyncio.Future[dict[str, Any]]] = {} self._refs: dict[str, RemoteRef] = {} self._mirrors: dict[str, dict[str, Any]] = {} self._handshake: asyncio.Future[dict[str, Any]] | None = None self._live: set[str] = set() self._stderr_tail = bytearray() self._reader: asyncio.Task[None] | None = None self._drain: asyncio.Task[None] | None = None self.closed = False self.degraded: RemoteBootError | None = None
# --- boot ---
async def boot(self, modules: list[str] | None = None, timeout: float = HANDSHAKE_TIMEOUT) -> None: """Stage, spawn, and wait for ready; a failure raises RemoteBootError.""" remote_root = bundle()["remote"] script_path = f"{remote_root}/albedo_kernel.py" code, _, _ = await ssh_run(self.host, f"test -f {shlex.quote(script_path)}", timeout=CONNECT_TIMEOUT) if code != 0: await stage(self.host) python = self.target.get("python") or "python3" # The stamp reaches the remote kernel's plugins, so a finished remote # job's wake notice names the machine it ran on. script = f"ALBEDO_REMOTE_TARGET={shlex.quote(self.host)} exec " \ + f"{shlex.quote(python)} -u {shlex.quote(script_path)}" \ + " " + shlex.quote(json.dumps(modules if modules is not None else default_modules())) if self.target.get("remote_cwd"): script = f"cd {shlex.quote(self.target['remote_cwd'])} && {script}" self._handshake = loop.create_future() self._process = await asyncio.create_subprocess_exec( *ssh_base(), self.host, script, stdin=asyncio.subprocess.PIPE, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE) self._stdin, self._stdout = self._process.stdin, self._process.stdout self._drain = loop.create_task(self._drain_stderr()) self._reader = loop.create_task(self._read_frames()) try: frame = await asyncio.wait_for(asyncio.shield(self._handshake), timeout) except asyncio.TimeoutError: raise RemoteBootError( f"kernel did not say ready in {timeout:g}s") from None if frame.get("type") != "ready": raise RemoteBootError(str(frame.get("message", "invalid kernel handshake"))) self._handshake = None
async def _drain_stderr(self) -> None: """Keep a bounded tail of ssh diagnostics; a banner must not wedge the pipe.""" assert self._process is not None and self._process.stderr is not None while True: chunk = await self._process.stderr.read(4096) if not chunk: return self._stderr_tail.extend(chunk) del self._stderr_tail[:-STDERR_TAIL]
# --- frames ---
async def _read_frames(self) -> None: try: while True: assert self._stdout is not None header = await self._stdout.readexactly(4) size = struct.unpack(">I", header)[0] if size > MAX_FRAME: raise RemoteLost("remote control frame exceeds the ceiling") frame = json.loads(await self._stdout.readexactly(size)) self._dispatch(frame) except asyncio.CancelledError: raise except (asyncio.IncompleteReadError, ConnectionResetError, OSError, ValueError): self._lost()
def _dispatch(self, frame: dict[str, Any]) -> None: kind = frame.get("type") if kind in ("invoked", "introspected"): future = self._pending.get(frame.get("id")) if future is not None and not future.done(): future.set_result(frame) elif kind in ("ready", "startup_error"): if self._handshake is not None and not self._handshake.done(): self._handshake.set_result(frame) elif kind == "call": _ = loop.create_task(self._relay(frame)) elif kind == "mirror" and isinstance(frame.get("handle"), str): self._mirrors[frame["handle"]] = frame elif kind == "job_start" and isinstance(frame.get("id"), str): self._live.add(frame["id"]) _report_live() elif kind == "job" and isinstance(frame.get("id"), str): self._live.discard(frame["id"]) _report_live() # trace, done, cleanup describe remote cells; those are addressed # through references, not events on this side.
async def _relay(self, frame: dict[str, Any]) -> None: """Answer one remote host-route call against this session's daemon.""" try: value = await host_call(frame["method"], frame["args"]) reply: dict[str, Any] = {"ok": True, "value": value} except HostErrorType as error: reply = {"ok": False, "code": getattr(error, "code", "host"), "message": str(getattr(error, "message", error))} except Exception as error: # the daemon's answer must always be a reply reply = {"ok": False, "code": "host", "message": f"{type(error).__name__}: {error}"} await self._send({"type": "reply", "id": frame["id"], "value": reply})
async def _send(self, frame: dict[str, Any]) -> None: if self.closed or self._stdin is None: raise RemoteLost(f"the connection to {self.host} is closed") data = json.dumps(frame).encode() if len(data) > MAX_FRAME: raise RemoteError( f"remote call payload is {len(data)} bytes, over the {MAX_FRAME}-byte ceiling") async with self._write_lock: self._stdin.write(struct.pack(">I", len(data)) + data) await self._stdin.drain()
def _lost(self) -> None: """The channel died: every pending call and reference learns it once.""" if self._handshake is not None and not self._handshake.done(): self._handshake.set_exception(RemoteBootError( "the ssh channel closed at startup: " + bytes(self._stderr_tail).decode(errors="replace").strip()[:500])) for future in self._pending.values(): if not future.done(): future.set_exception(RemoteLost(f"the connection to {self.host} was lost")) self.closed = True
# --- calls ---
def start(self, call: "_RemoteCall", args: tuple[Any, ...], kwargs: dict[str, Any]) -> RemoteRef: """Fire one call and return its reference immediately; it settles on await.""" call_id = uuid.uuid4().hex reference = RemoteRef(self, call_id=call_id, label=call._label) reference._task = loop.create_task(self.invoke( name=call._name, handle=call._handle, pending=call._pending, args=args, kwargs=kwargs, call_id=call_id, placeholder=reference)) return reference
async def invoke(self, name: str = "", *, handle: str | None = None, pending: str | None = None, args: tuple[Any, ...] = (), kwargs: dict[str, Any] | None = None, wait: bool = False, timeout: float = INVOKE_TIMEOUT, call_id: str | None = None, placeholder: RemoteRef | None = None) -> Any: """One remote call; the answer is a value, or a reference to the live object.
A `pending` target names an earlier call whose result this one uses, so method calls raced ahead of their own reply still resolve in order. The `placeholder` is the reference the caller already holds; a handle reply adopts into it rather than minting a second object. """ if self.degraded is not None: raise RemoteError( f"degraded to ssh command mode ({self.degraded}); only rem.bash() is available") call_id = call_id or uuid.uuid4().hex frame: dict[str, Any] = {"type": "invoke", "id": call_id, "args": [_encode_arg(item) for item in args], "kwargs": {key: _encode_arg(item) for key, item in (kwargs or {}).items()}} if name: frame["name"] = name if handle is not None: frame["target"] = {"handle": handle} elif pending is not None: frame["target"] = {"pending": pending} if wait: frame["await"] = True future: asyncio.Future[dict[str, Any]] = loop.create_future() self._pending[call_id] = future await self._send(frame) try: reply = await asyncio.wait_for(future, timeout) except asyncio.TimeoutError: await self._interrupt(call_id) raise RemoteTimeout( f"remote call {name or ('await ' + str(handle))!r} did not answer " f"in {timeout:g}s; an interrupt was sent") from None except asyncio.CancelledError: await self._interrupt(call_id) raise finally: self._pending.pop(call_id, None) return self._result(reply, placeholder)
def _result(self, reply: dict[str, Any], placeholder: RemoteRef | None = None) -> Any: """One reply into a value or a reference, or the error it names.""" if reply.get("ok") is not True: error = reply.get("error") or {} if reply.get("cancelled"): raise RemoteCancelled(str(error.get("evalue", "cancelled remotely"))) raise RemoteExecutionError(str(error.get("ename", "RemoteError")), str(error.get("evalue", "")), [str(line) for line in error.get("traceback", [])]) if "handle" in reply: handle = str(reply["handle"]) state = reply.get("state") if state is not None: self._mirrors[handle] = state value = wire_decode(reply["value"]) if "value" in reply else None reference = placeholder if placeholder is not None else self._refs.get(handle) if reference is None: reference = RemoteRef(self, handle, value) else: reference._handle = handle reference._value = value self._refs[handle] = reference return reference return wire_decode(reply.get("value"))
async def _interrupt(self, call_id: str) -> None: """Best-effort: tell the remote kernel this wait is over.""" try: await self._send({"type": "interrupt", "id": call_id}) except Exception: pass # the channel is already gone; the caller has that error
async def invoke_release(self, handle: str) -> None: """Drop a live reference; no reply waits for it.""" self._refs.pop(handle, None) await self._send({"type": "release", "handle": handle})
async def mark_read(self, handle: str) -> None: """Tell the remote object its result was read, retiring its wake.
A local mirror read never crosses the channel on its own, so this one round trip (a poll, which the job counts as a read) is the only way a finished remote job learns the model already has its output. """ try: await self.invoke(handle=handle, name="poll", timeout=30) except Exception: pass # the channel is gone; the notice fails its own way
async def tools(self) -> dict[str, Any]: """What the remote namespace holds, and the live references it kept.""" if self.degraded is not None: return {"names": ["bash"], "handles": [], "degraded": str(self.degraded)} call_id = uuid.uuid4().hex future: asyncio.Future[dict[str, Any]] = loop.create_future() self._pending[call_id] = future await self._send({"type": "introspect", "id": call_id}) try: frame = await asyncio.wait_for(future, CONNECT_TIMEOUT) finally: self._pending.pop(call_id, None) return {"names": frame.get("names", []), "handles": frame.get("handles", [])}
# --- ssh conveniences, both modes ---
async def read(self, path: str, *, timeout: float = COMMAND_TIMEOUT) -> str: """A remote file's text over the control connection, not the kernel.""" remote = _remote_path(self, path) code, stdout, stderr = await ssh_run( self.host, f"cat {shlex.quote(remote)}", timeout=timeout) if code != 0: raise RemoteError(f"SSH failed ({code}): {stderr.strip()}") return stdout.decode(errors="replace")
async def write(self, path: str, content: str, *, timeout: float = COMMAND_TIMEOUT) -> None: """Replace a remote file; bytes travel base64, never as shell text.""" remote = _remote_path(self, path) encoded = base64.b64encode(content.encode()).decode() code, _, stderr = await ssh_run( self.host, f"printf %s {shlex.quote(encoded)} | base64 -d > {shlex.quote(remote)}", timeout=timeout) if code != 0: raise RemoteError(f"SSH failed ({code}): {stderr.strip()}")
# --- degraded mode ---
@property def bash(self) -> Any: """rem.bash: the remote binding in kernel mode, command mode otherwise.""" if self.degraded is None: if self.closed: raise RemoteLost(f"the connection to {self.host} is closed") return _RemoteCall(self, None, "bash")
def run(command: str, *, timeout: float = 300) -> FallbackJob: if not isinstance(command, str) or not 0 < timeout <= 3600: raise ValueError("command must be text; 0 < timeout <= 3600 required") return FallbackJob(self, command, timeout)
return run
# --- surface ---
def __getattr__(self, name: str) -> Any: if name.startswith("_"): raise AttributeError(name) if self.degraded is not None: raise AttributeError( f"{name!r} is unavailable: this connection is degraded to ssh command " f"mode ({self.degraded}); only rem.bash(), rem.read, and rem.write work") if self.closed: raise RemoteLost(f"the connection to {self.host} is closed") return _RemoteCall(self, None, name)
def __repr__(self) -> str: state = "degraded" if self.degraded is not None else ("closed" if self.closed else "kernel") return f"<remote {self.host} ({state})>"
async def close(self) -> None: """End the kernel and its channel: shutdown frame, then the signal ladder.""" if self.closed and self._process is None: return if self._process is not None and self._process.returncode is None: try: await self._send({"type": "shutdown"}) except Exception: pass try: await asyncio.wait_for(self._process.wait(), 1.0) except asyncio.TimeoutError: self._process.terminate() try: await asyncio.wait_for(self._process.wait(), 1.0) except asyncio.TimeoutError: self._process.kill() self.closed = True self._live.clear() _report_live() for future in self._pending.values(): if not future.done(): future.set_exception(RemoteLost(f"the connection to {self.host} closed")) self._pending.clear() for task in (self._reader, self._drain): if task is not None: task.cancel() if self in connections: connections.remove(self)
async def __aenter__(self) -> "RemoteConnection": return self
async def __aexit__(self, *_: Any) -> None: await self.close()
@property def host(self) -> str: return str(self.target["host"])
def _encode_arg(value: Any) -> Any: """References pass as references; everything else must already be wire data.""" if isinstance(value, RemoteRef): if value._connection.closed: raise RemoteLost("cannot pass a reference from a closed connection") if value._handle is not None: return {"__ref__": value._handle} if value._task is not None: return {"pending": value._call_id} if value._settled is not _UNSET: return _encode_arg(value._settled) raise RemoteError("cannot pass an unusable remote reference") if isinstance(value, (str, int, float, bool)) or value is None: return value if isinstance(value, (bytes, bytearray)): return {"__bytes__": base64.b64encode(bytes(value)).decode("ascii")} if isinstance(value, list): return [_encode_arg(item) for item in value] if isinstance(value, dict) and type(value) is dict: return {key: _encode_arg(item) for key, item in value.items()} try: json.dumps(value) return value except (TypeError, ValueError) as error: raise RemoteError( f"cannot pass {type(value).__name__} to a remote call: only wire data " "and remote references cross") from error
def _remote_path(connection: RemoteConnection, path: str) -> str: """The remote spelling of a workspace path; anything else passes through.""" remote_cwd = connection.target.get("remote_cwd") if remote_cwd and path.startswith(str(Path.cwd())): return str(Path(remote_cwd) / Path(path).relative_to(Path.cwd())) return path
class FallbackJob: """One command over the control connection when no kernel could boot.
The same shape as a bash job: await it, tail() it, stop() it. Killing the ssh client cannot stop the remote side, so a deadline reports timed_out and says the remote effect is unknown rather than ended. """
def __init__(self, connection: RemoteConnection, command: str, timeout: float) -> None: self.id = uuid.uuid4().hex self.command = command self.timed_out = False self.exit_code: int | None = None self.started: float = loop.time() self.duration: float | None = None self.capture = capture_factory(self.id) self._awaited = False self._read = False self._connection = connection _fallback_live.add(self.id) _report_live() script = f"bash -c {shlex.quote(command)}" if connection.target.get("remote_cwd"): script = f"cd {shlex.quote(connection.target['remote_cwd'])} && {script}" self._task = loop.create_task(self._run(connection.host, script, timeout))
async def _run(self, host: str, script: str, timeout: float) -> "FallbackJob": process = await asyncio.create_subprocess_exec( *ssh_base(), host, script, stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.STDOUT) self._process = process copying = loop.create_task(self._copy(process.stdout)) try: self.exit_code = await asyncio.wait_for(process.wait(), timeout) except asyncio.TimeoutError: self.timed_out = True process.kill() self.exit_code = await process.wait() self.capture.write( f"\n[deadline exceeded after {timeout:g}s; the ssh client was killed; " f"the remote command may still be running]") finally: copying.cancel() self.duration = loop.time() - self.started _fallback_live.discard(self.id) _report_live() if host_call is not None and not self._awaited: _ = loop.create_task(self._announce()) return self
async def _announce(self) -> None: """Wake the session for this command, retrying while it runs.""" while not self._read and not self._awaited: try: await host_call("jobs.completed", self._notice()) return except HostErrorType as error: if getattr(error, "code", "") != "busy": self.capture.write(f"\n[completion notice not delivered: {error}\n") return except Exception: return # the kernel is going away; the result stays on the handle await asyncio.sleep(2.0)
def _notice(self) -> dict[str, object]: """The wake turn's display text, model text, and the facts behind both.""" command = self.command[:200] + ("..." if len(self.command) > 200 else "") outcome = ("timed out" if self.timed_out else f"exit_code={self.exit_code}" if self.exit_code is not None else "exit status unknown") seconds = f"{self.duration:.1f}s" if self.duration is not None else "unknown duration" display = f"bash job finished on {self._connection.host} ({outcome}, {seconds}): {command}" text = ( "<system-note>a background bash command finished with its result unread on" f" {self._connection.host} (ssh command mode): {outcome}, {seconds}," f" command: {command}." f" its handle is jobs[{self.id!r}] in python; jobs[{self.id!r}].tail() or" f" output.read({self.id!r}) reads its output." " no user sent this message; use the result if the session's work needs" " it, otherwise acknowledge briefly and stay idle.</system-note>") return {"display": display, "text": text, "id": self.id, "exit_code": self.exit_code, "timed_out": self.timed_out, "duration": self.duration, "host": self._connection.host}
async def _copy(self, stream: Any) -> None: while chunk := await stream.read(8192): self.capture.write(chunk.decode("utf-8", errors="replace"))
def __await__(self): self._awaited = True return asyncio.shield(self._task).__await__()
def poll(self) -> int | None: if self.exit_code is not None: self._read = True return self.exit_code
@property def returncode(self) -> int | None: """`exit_code` under subprocess's name; both spellings answer.""" return self.poll()
def tail(self, n: int = 4000) -> str: if self.exit_code is not None: self._read = True data = self.capture.tail_data return bytes(data[-max(1, min(n, 65536)):]).decode("utf-8", errors="replace")
async def stop(self) -> None: """End the ssh client; the remote command's fate is reported, not assumed.""" self._read = True # an explicit stop is its own report; no wake is owed process = getattr(self, "_process", None) if process is not None and process.returncode is None: process.terminate() try: await asyncio.wait_for(process.wait(), 2.0) except asyncio.TimeoutError: process.kill() self.capture.write("\n[stopped locally; the remote command may still be running]")
def __repr__(self) -> str: return (f"FallbackJob(id={self.id!r}, exit_code={self.exit_code!r}, " f"timed_out={self.timed_out!r}, duration={self.duration!r}, " f"bytes={self.capture.seen})")
def default_modules() -> list[str]: """The session's tool selection, minus this plugin: what boots remotely.""" return [name for name in session_modules if name != "remote"]
class Remote: """The namespace bound into the kernel as `remote`."""
@staticmethod def configure(host: str, remote_cwd: str | None = None) -> dict[str, str | None]: """Resolve `user@host[:/path]` once and keep it for later connections.""" target = parse_target(host) if remote_cwd is not None: target["remote_cwd"] = remote_cwd configured.clear() configured.update(target) return dict(target)
@staticmethod async def connect(host: str | None = None, *, remote_cwd: str | None = None, python: str | None = None, modules: list[str] | None = None, timeout: float = HANDSHAKE_TIMEOUT) -> RemoteConnection: """Boot this session's kernel on a remote host, or degrade to commands.
The target resolves per call: an explicit `host=`, then the value `remote.configure` stored, then `$ALBEDO_SSH`, then the `remote` section of extensions.json. If the host is reachable but the kernel cannot boot, the connection still returns, prints a warning, and answers only `rem.bash()`, `rem.read`, and `rem.write`. """ target = resolve(host, remote_cwd, python) code, _, stderr = await ssh_run(str(target["host"]), "true", timeout=CONNECT_TIMEOUT) if code != 0: raise RemoteError(f"ssh target {target['host']!r} is unreachable: {stderr.strip()[:300]}") if target["remote_cwd"] is None: code, stdout, _ = await ssh_run(str(target["host"]), "pwd", timeout=CONNECT_TIMEOUT) if code == 0: target["remote_cwd"] = stdout.decode(errors="replace").strip() or None connection = RemoteConnection(target) try: await connection.boot(modules, timeout) except RemoteBootError as error: connection.degraded = error if connection._process is not None: if connection._reader is not None: connection._reader.cancel() if connection._drain is not None: connection._drain.cancel() if connection._process.returncode is None: connection._process.terminate() connection._process = None connection._stdin = connection._stdout = None print(f"[remote] kernel boot failed on {target['host']}: {error}; " "degraded to ssh command mode -- only rem.bash() is available") connections.append(connection) return connection
@staticmethod def connections() -> ReadyList: """Every open connection, kernel or degraded.""" return ReadyList(connections)
@staticmethod async def close_all() -> None: """Kernel shutdown: end every connection inside the cleanup deadline.""" for connection in list(connections): await connection.close()
remote = Remote()
def setup(api: PythonApi) -> dict[str, object]: global loop, host_call, HostErrorType, capture_factory, send_frame global session_modules loop, host_call = api.loop, api.host HostErrorType, capture_factory = api.HostError, api.capture send_frame = api.send session_modules = list(api.modules) api.on_shutdown(Remote.close_all) return {"remote": remote, "RemoteError": RemoteError}