fix(gateway): bound stdlib HTTP request work

bot_bottle/gateway/bounded_http.py

@@ -0,0 +1,109 @@
+"""Shared resource boundaries for gateway stdlib HTTP services."""
+
+from __future__ import annotations
+
+import http.server
+import socket
+import threading
+import time
+from dataclasses import dataclass
+from typing import Any, Protocol
+
+
+class Readable(Protocol):
+    def read(self, size: int = -1, /) -> bytes: ...
+
+
+@dataclass(frozen=True)
+class BodyReadError(Exception):
+    status: int
+    message: str
+
+
+def read_declared_body(
+    stream: Readable,
+    connection: socket.socket,
+    raw_length: str | None,
+    *,
+    maximum: int,
+    timeout_seconds: float,
+    require_length: bool,
+) -> bytes:
+    """Validate and read exactly one declared body under a read deadline."""
+    if raw_length is None:
+        if require_length:
+            raise BodyReadError(411, "Content-Length required")
+        raw_length = "0"
+    try:
+        length = int(raw_length)
+    except ValueError as exc:
+        raise BodyReadError(400, "invalid Content-Length") from exc
+    if length < 0:
+        raise BodyReadError(400, "invalid Content-Length")
+    if length > maximum:
+        raise BodyReadError(413, "request body too large")
+    previous_timeout = connection.gettimeout()
+    deadline = time.monotonic() + timeout_seconds
+    chunks: list[bytes] = []
+    remaining = length
+    try:
+        while remaining:
+            timeout = deadline - time.monotonic()
+            if timeout <= 0:
+                raise BodyReadError(408, "request body read timed out")
+            connection.settimeout(timeout)
+            chunk = stream.read(min(remaining, 64 * 1024))
+            if not chunk:
+                raise BodyReadError(400, "incomplete request body")
+            chunks.append(chunk)
+            remaining -= len(chunk)
+    except TimeoutError as exc:
+        raise BodyReadError(408, "request body read timed out") from exc
+    finally:
+        connection.settimeout(previous_timeout)
+    return b"".join(chunks)
+
+
+class BoundedThreadingHTTPServer(http.server.ThreadingHTTPServer):
+    """ThreadingHTTPServer with a hard cap on in-flight request threads."""
+
+    daemon_threads = True
+
+    def __init__(  # pylint: disable=consider-using-with
+        self, *args, max_workers: int = 32, **kwargs,  # type: ignore[no-untyped-def]
+    ):
+        if max_workers < 1:
+            raise ValueError("max_workers must be positive")
+        self._request_slots = threading.BoundedSemaphore(max_workers)
+        super().__init__(*args, **kwargs)
+
+    def process_request(
+        self, request: Any, client_address: Any,
+    ) -> None:
+        if not self._request_slots.acquire(  # pylint: disable=consider-using-with
+            blocking=False,
+        ):
+            try:
+                request.sendall(
+                    b"HTTP/1.1 503 Service Unavailable\r\n"
+                    b"Content-Length: 0\r\nConnection: close\r\n\r\n"
+                )
+            finally:
+                self.shutdown_request(request)
+            return
+        try:
+            super().process_request(request, client_address)
+        except BaseException:
+            self._request_slots.release()
+            raise
+
+    def process_request_thread(
+        self, request: Any, client_address: Any,
+    ) -> None:
+        try:
+            super().process_request_thread(request, client_address)
+        finally:
+            self._request_slots.release()
+
+
+__all__ = ["BodyReadError", "BoundedThreadingHTTPServer", "read_declared_body"]

bot_bottle/gateway/git_gate/http_backend.py

@@ -22,11 +22,16 @@ import os
 import subprocess
 import sys
 import typing
-from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
+from http.server import BaseHTTPRequestHandler
 from pathlib import Path
 from urllib.parse import urlsplit
 
 from bot_bottle.constants import GIT_GATE_TIMEOUT_SECS, IDENTITY_HEADER
+from bot_bottle.gateway.bounded_http import (
+    BodyReadError,
+    BoundedThreadingHTTPServer,
+    read_declared_body,
+)
 from bot_bottle.gateway.policy_resolver import PolicyResolveError, PolicyResolver
 
 
@@ -77,6 +82,8 @@ def resolve_sandbox_root(
 
 # Bound memory use while still allowing ordinary git push packfiles.
 MAX_BODY_BYTES = 100 * 1024 * 1024
+REQUEST_BODY_TIMEOUT_SECONDS = 30.0
+MAX_REQUEST_WORKERS = 16
 
 
 class GitHttpHandler(BaseHTTPRequestHandler):
@@ -184,19 +191,18 @@ class GitHttpHandler(BaseHTTPRequestHandler):
             value = self.headers.get(header)
             if value:
                 env[variable] = value
-        raw_length = self.headers.get("content-length", "0") or "0"
         try:
-            length = int(raw_length)
-        except ValueError:
-            self.send_error(400, "Bad Content-Length")
+            body = read_declared_body(
+                self.rfile,
+                self.connection,
+                self.headers.get("content-length"),
+                maximum=MAX_BODY_BYTES,
+                timeout_seconds=REQUEST_BODY_TIMEOUT_SECONDS,
+                require_length=False,
+            )
+        except BodyReadError as exc:
+            self.send_error(exc.status, exc.message)
             return
-        if length < 0:
-            self.send_error(400, "Negative Content-Length")
-            return
-        if length > MAX_BODY_BYTES:
-            self.send_error(413, "Request body too large")
-            return
-        body = self.rfile.read(length) if length else b""
         proc = subprocess.run(
             ["git", "http-backend"],
             input=body,
@@ -273,7 +279,9 @@ def main() -> int:
             "(no single-tenant flat-root fallback)\n"
         )
         return 1
-    server = ThreadingHTTPServer(("0.0.0.0", port), GitHttpHandler)
+    server = BoundedThreadingHTTPServer(
+        ("0.0.0.0", port), GitHttpHandler, max_workers=MAX_REQUEST_WORKERS,
+    )
     # Resolve each request's sandbox namespace by source IP against the
     # orchestrator control plane.
     server.policy_resolver = PolicyResolver(orch_url)  # type: ignore[attr-defined]

bot_bottle/gateway/supervisor/mcp_dispatch.py

@@ -6,9 +6,8 @@ import json
 from dataclasses import dataclass
 from typing import Callable, Protocol
 
-from bot_bottle.gateway.egress.context import resolve_client_context
-from bot_bottle.gateway.egress.schema import route_to_yaml_dict
-from bot_bottle.gateway.policy_resolver import PolicyResolver
+from bot_bottle.gateway.egress.schema import load_config, route_to_yaml_dict
+from bot_bottle.gateway.policy_resolver import PolicyResolveError, PolicyResolver
 from bot_bottle.supervisor import types as _sv
 
 
@@ -24,6 +23,10 @@ class MethodNotFoundError(Exception):
     """Raised when a JSON-RPC method has no MCP handler."""
 
 
+class RouteResolutionError(Exception):
+    """The caller's live route table could not be resolved authoritatively."""
+
+
 Handler = Callable[[dict[str, object]], object]
 
 
@@ -60,10 +63,19 @@ def resolved_routes_payload(
     source_ip: str,
     identity_token: str,
 ) -> dict[str, object]:
-    """Render the calling bottle's routes, failing closed to an empty list."""
-    config, _slug, _tokens = resolve_client_context(
-        resolver, source_ip, identity_token,
-    )
+    """Render an authoritatively resolved route table for the calling bottle."""
+    try:
+        policy, bottle_id, _tokens = resolver.resolve_policy_and_bottle_id(
+            source_ip, identity_token,
+        )
+    except PolicyResolveError as exc:
+        raise RouteResolutionError("orchestrator unavailable") from exc
+    if not bottle_id:
+        raise RouteResolutionError("request source is not attributed to a bottle")
+    try:
+        config = load_config(policy or "")
+    except ValueError as exc:
+        raise RouteResolutionError("resolved policy is invalid") from exc
     body = json.dumps(
         {"routes": [route_to_yaml_dict(route) for route in config.routes]},
         indent=2,
@@ -74,6 +86,7 @@ def resolved_routes_payload(
 __all__ = [
     "Handlers",
     "MethodNotFoundError",
+    "RouteResolutionError",
     "dispatch",
     "resolved_routes_payload",
 ]

bot_bottle/gateway/supervisor/server.py

@@ -51,19 +51,24 @@ from __future__ import annotations
 import http.server
 import json
 import os
-import socketserver
 import sys
 import time
 import typing
 from dataclasses import dataclass
 
 from bot_bottle.constants import IDENTITY_HEADER
+from bot_bottle.gateway.bounded_http import (
+    BodyReadError,
+    BoundedThreadingHTTPServer,
+    read_declared_body,
+)
 from bot_bottle.gateway.egress.schema import load_config
 from bot_bottle.gateway.egress.types import LOG_OFF
 from bot_bottle.gateway.policy_resolver import PolicyResolveError, PolicyResolver
 from bot_bottle.gateway.supervisor.mcp_dispatch import (
     Handlers as DispatchHandlers,
     MethodNotFoundError,
+    RouteResolutionError,
     dispatch,
     resolved_routes_payload,
 )
@@ -570,6 +575,8 @@ def format_unknown_proposal_text(proposal_id: str) -> str:
 # Max request body the server accepts. 1 MB is well above any realistic
 # routes.yaml proposal.
 MAX_BODY_BYTES = 1 * 1024 * 1024
+REQUEST_BODY_TIMEOUT_SECONDS = 10.0
+MAX_REQUEST_WORKERS = 32
 
 
 class MCPHandler(http.server.BaseHTTPRequestHandler):
@@ -592,19 +599,18 @@ class MCPHandler(http.server.BaseHTTPRequestHandler):
         self._write_text(405, "use POST for MCP requests\n")
 
     def do_POST(self) -> None:
-        length_header = self.headers.get("Content-Length")
-        if length_header is None:
-            self._write_text(411, "Content-Length required\n")
-            return
         try:
-            length = int(length_header)
-        except ValueError:
-            self._write_text(400, "invalid Content-Length\n")
+            body = read_declared_body(
+                self.rfile,
+                self.connection,
+                self.headers.get("Content-Length"),
+                maximum=MAX_BODY_BYTES,
+                timeout_seconds=REQUEST_BODY_TIMEOUT_SECONDS,
+                require_length=True,
+            )
+        except BodyReadError as exc:
+            self._write_text(exc.status, exc.message + "\n")
             return
-        if length < 0 or length > MAX_BODY_BYTES:
-            self._write_text(413, "request body too large\n")
-            return
-        body = self.rfile.read(length)
 
         try:
             req = parse_jsonrpc(body)
@@ -660,20 +666,25 @@ class MCPHandler(http.server.BaseHTTPRequestHandler):
                 identity_token=self._identity_token(),
             )
 
-        return dispatch(
-            req,
-            DispatchHandlers(
-                initialize=handle_initialize,
-                tools_list=handle_tools_list,
-                list_routes=lambda _params: resolved_routes_payload(
+        def list_routes(_params: dict[str, object]) -> object:
+            try:
+                return resolved_routes_payload(
                     self._resolver_or_fail(),
                     self.client_address[0],
                     self._identity_token(),
-                ),
-                check_proposal=check,
-                propose=propose,
-            ),
-        )
+                )
+            except RouteResolutionError as exc:
+                raise _RpcInternalError(
+                    f"could not resolve live egress routes: {exc}"
+                ) from exc
+
+        return dispatch(req, DispatchHandlers(
+            initialize=handle_initialize,
+            tools_list=handle_tools_list,
+            list_routes=list_routes,
+            check_proposal=check,
+            propose=propose,
+        ))
 
     def _identity_token(self) -> str:
         """The agent's per-bottle identity token from the request header (the
@@ -711,7 +722,7 @@ class MCPHandler(http.server.BaseHTTPRequestHandler):
             self.wfile.write(encoded)
 
 
-class MCPServer(socketserver.ThreadingMixIn, http.server.HTTPServer):
+class MCPServer(BoundedThreadingHTTPServer):
     allow_reuse_address = True
     daemon_threads = True
     config: ServerConfig = ServerConfig()
@@ -720,6 +731,9 @@ class MCPServer(socketserver.ThreadingMixIn, http.server.HTTPServer):
     # closed per request (see `_resolver_or_fail`).
     policy_resolver: "PolicyResolver | None" = None
 
+    def __init__(self, *args, **kwargs):  # type: ignore[no-untyped-def]
+        super().__init__(*args, max_workers=MAX_REQUEST_WORKERS, **kwargs)
+
 
 # --- Entry point -----------------------------------------------------------
 

tests/unit/test_gateway_bounded_http.py

@@ -0,0 +1,79 @@
+"""Unit tests for shared gateway stdlib HTTP resource boundaries."""
+# pylint: disable=protected-access
+
+from __future__ import annotations
+
+import io
+import socket
+import unittest
+
+from bot_bottle.gateway.bounded_http import (
+    BodyReadError,
+    BoundedThreadingHTTPServer,
+    read_declared_body,
+)
+
+
+class _Handler:
+    pass
+
+
+class _TimeoutStream:
+    def read(self, _size: int = -1, /) -> bytes:
+        raise TimeoutError
+
+
+class TestDeclaredBody(unittest.TestCase):
+    def setUp(self) -> None:
+        self.left, self.right = socket.socketpair()
+
+    def tearDown(self) -> None:
+        self.left.close()
+        self.right.close()
+
+    def test_rejects_incomplete_body(self) -> None:
+        with self.assertRaisesRegex(BodyReadError, "incomplete"):
+            read_declared_body(
+                io.BytesIO(b"short"),
+                self.left,
+                "10",
+                maximum=100,
+                timeout_seconds=1,
+                require_length=True,
+            )
+
+    def test_maps_read_timeout(self) -> None:
+        with self.assertRaises(BodyReadError) as caught:
+            read_declared_body(
+                _TimeoutStream(),
+                self.left,
+                "1",
+                maximum=100,
+                timeout_seconds=1,
+                require_length=True,
+            )
+        self.assertEqual(408, caught.exception.status)
+
+
+class TestBoundedServer(unittest.TestCase):
+    def test_saturated_server_rejects_without_spawning_thread(self) -> None:
+        client, peer = socket.socketpair()
+        with BoundedThreadingHTTPServer(
+            ("127.0.0.1", 0), _Handler, max_workers=1,  # type: ignore[arg-type]
+        ) as server:
+            with client, peer:
+                # Directly reserve the only slot to model an in-flight handler.
+                self.assertTrue(
+                    server._request_slots.acquire(  # pylint: disable=consider-using-with
+                        blocking=False,
+                    ),
+                )
+                try:
+                    server.process_request(client, ("127.0.0.1", 1))
+                    self.assertIn(b"503 Service Unavailable", peer.recv(1024))
+                finally:
+                    server._request_slots.release()
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/unit/test_supervise_server.py

@@ -717,18 +717,26 @@ class TestResolvedRoutesPayload(unittest.TestCase):
         hosts = {r["host"] for r in data["routes"]}
         self.assertEqual({"api.anthropic.com", "www.google.com"}, hosts)
 
-    def test_orchestrator_error_fails_closed_to_empty(self) -> None:
-        # resolve_client_context swallows resolver errors → deny-all (empty),
-        # never another bottle's routes.
+    def test_orchestrator_error_is_not_reported_as_empty_policy(self) -> None:
+        with self.assertRaises(supervise_server.RouteResolutionError):
+            resolved_routes_payload(
+                typing.cast(
+                    supervise_server.PolicyResolver,
+                    _FakeSuperviseResolver(raises=True),
+                ),
+                _SRC,
+                _TOK,
+            )
+
+    def test_authoritative_empty_policy_remains_successful(self) -> None:
         payload = resolved_routes_payload(
             typing.cast(
                 supervise_server.PolicyResolver,
-                _FakeSuperviseResolver(raises=True),
+                _FakeSuperviseResolver(bottle_id="b1", policy="routes: []\n"),
             ),
             _SRC,
             _TOK,
         )
-        assert payload is not None
         data = json.loads(payload["content"][0]["text"])  # type: ignore[index]
         self.assertEqual([], data["routes"])