tegwick
2bd2d19a98
Assistant: codex Assistant-Model: gpt-5.6-sol Assistant-Session: 01a05e2e-805b-7042-a750-71f473bceea2
114 lines
4.3 KiB
Python
114 lines
4.3 KiB
Python
"""Fail-closed PEP client and sequencing harness for GH-DEC-2026-003."""
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from __future__ import annotations
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import json
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from pathlib import Path
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from typing import Any, Callable
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from urllib.error import HTTPError, URLError
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from urllib.parse import quote
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from urllib.request import Request, urlopen
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class ApprovalProtocolError(RuntimeError):
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pass
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class ApprovalHTTPClient:
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def __init__(
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self,
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base_url: str,
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token_file: str | Path,
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*,
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timeout_seconds: float = 3,
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opener: Callable[..., Any] = urlopen,
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) -> None:
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self.base_url = base_url.rstrip("/")
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self.token_file = Path(token_file)
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self.timeout_seconds = timeout_seconds
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self.opener = opener
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def _request(
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self, method: str, path: str, body: dict[str, Any] | None = None
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) -> dict[str, Any]:
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token = self.token_file.read_text(encoding="utf-8").strip()
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if not token or any(ch.isspace() for ch in token):
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raise ApprovalProtocolError("approval credential is unavailable")
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encoded = None if body is None else json.dumps(body).encode("utf-8")
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request = Request(
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self.base_url + path,
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data=encoded,
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method=method,
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headers={
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"Authorization": f"Bearer {token}",
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"Content-Type": "application/json",
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},
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)
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try:
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response = self.opener(request, timeout=self.timeout_seconds)
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status = int(response.getcode())
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raw = response.read(256 * 1024 + 1)
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response.close()
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except (HTTPError, URLError, OSError) as exc:
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raise ApprovalProtocolError(type(exc).__name__) from exc
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if status != 200 or len(raw) > 256 * 1024:
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raise ApprovalProtocolError(f"approval endpoint returned status {status}")
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try:
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result = json.loads(raw)
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except (UnicodeDecodeError, json.JSONDecodeError) as exc:
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raise ApprovalProtocolError("approval endpoint returned invalid JSON") from exc
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if not isinstance(result, dict):
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raise ApprovalProtocolError("approval endpoint returned invalid payload")
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return result
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def claim(self, approval_id: str) -> dict[str, Any]:
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encoded_id = quote(approval_id, safe="")
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return self._request("GET", f"/v1/approvals/{encoded_id}/claim")
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def consume(
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self, approval_id: str, request_digest: str, decision_id: str
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) -> dict[str, Any]:
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encoded_id = quote(approval_id, safe="")
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return self._request(
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"POST",
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f"/v1/approvals/{encoded_id}/consume",
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{"request_digest": request_digest, "decision_id": decision_id},
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)
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class ProtectedActionHarness:
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"""Sequence a supplied PDP decision and dry-run/protected callback.
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The decision callback owns authorization. This class only enforces that a
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fresh approval claim precedes it and a successful CAS consume precedes the
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side effect.
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"""
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def __init__(self, client: ApprovalHTTPClient) -> None:
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self.client = client
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def execute(
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self,
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approval_id: str,
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request_digest: str,
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decide: Callable[[dict[str, Any]], dict[str, Any]],
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side_effect: Callable[[], Any],
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) -> Any:
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claim = self.client.claim(approval_id)
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if claim.get("valid_now") is not True or claim.get("consumed") is not False:
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raise ApprovalProtocolError("approval claim is not valid for use")
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decision = decide(claim)
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if decision.get("effect") != "ALLOW":
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raise ApprovalProtocolError("authorization decision did not allow")
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decision_id = decision.get("decision_id")
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if not isinstance(decision_id, str) or not decision_id:
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raise ApprovalProtocolError("authorization decision lacks decision_id")
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if decision.get("request_digest") != request_digest:
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raise ApprovalProtocolError("authorization decision digest does not match")
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consumed = self.client.consume(approval_id, request_digest, decision_id)
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if (
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consumed.get("status") != "consumed"
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or consumed.get("request_digest") != request_digest
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):
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raise ApprovalProtocolError("approval consumption was not confirmed")
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return side_effect()
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