refactor(egress): extract request policy stages

bot_bottle/gateway/egress/addon.py

@@ -33,11 +33,12 @@ from bot_bottle.gateway.egress.dlp import (
 )
 from bot_bottle.gateway.egress.matching import (
     decide,
-    decide_git_fetch,
-    is_git_fetch_request,
-    is_git_push_request,
     match_route,
 )
+from bot_bottle.gateway.egress.request_pipeline import (
+    evaluate_route_policy,
+    git_block_reason,
+)
 from bot_bottle.gateway.egress.schema import route_to_yaml_dict
 from bot_bottle.gateway.egress.types import (
     LOG_BLOCKS,
@@ -435,21 +436,12 @@ class EgressAddon:
         request_path: str, query: str,
     ) -> bool:
         """Apply the HTTPS Git push/fetch boundary before general routing."""
-        if is_git_push_request(request_path, query):
-            self._block(
-                flow,
-                "egress: git push over HTTPS is not supported; "
-                "use the bottle.git SSH path (gitleaks-scanned by "
-                "git-gate's pre-receive hook).",
-                ctx=self._req_ctx(flow),
-            )
-            return False
-        if not is_git_fetch_request(request_path, query):
+        reason = git_block_reason(
+            config.routes, flow.request.pretty_host, request_path, query,
+        )
+        if not reason:
             return True
-        git_decision = decide_git_fetch(config.routes, flow.request.pretty_host)
-        if git_decision.action != "block":
-            return True
-        self._block(flow, git_decision.reason, ctx=self._req_ctx(flow))
+        self._block(flow, reason, ctx=self._req_ctx(flow))
         return False
 
     def _apply_route_policy(
@@ -461,30 +453,26 @@ class EgressAddon:
         # are caught above; the route may inject gateway-owned auth below.
         # Routes with preserve_auth=True pass the header through as-is so the
         # agent's own credentials (e.g. registry bearer tokens) reach the upstream.
-        if route is None or not route.preserve_auth:
+        result = evaluate_route_policy(
+            config,
+            route,
+            host=flow.request.pretty_host,
+            request_path=request_path,
+            method=flow.request.method,
+            headers=dict(flow.request.headers),
+            env=env,
+        )
+        if result.strip_authorization:
             flow.request.headers.pop("authorization", None)
 
-        # Build headers mapping for match evaluation
-        req_headers = {k.lower(): v for k, v in flow.request.headers.items()}
-
-        decision = decide(
-            config.routes,
-            flow.request.pretty_host,
-            request_path,
-            env,
-            request_method=flow.request.method,
-            request_headers=req_headers,
-            deny_reason=config.deny_reason,
-        )
-
-        if decision.action == "block":
-            self._block(flow, decision.reason, ctx=self._req_ctx(flow))
+        if result.block_reason:
+            self._block(flow, result.block_reason, ctx=self._req_ctx(flow))
             return
 
-        if decision.inject_authorization is not None:
-            flow.request.headers["authorization"] = decision.inject_authorization
+        if result.inject_authorization is not None:
+            flow.request.headers["authorization"] = result.inject_authorization
 
-        if config.log >= LOG_FULL:
+        if result.log_request:
             self._log_request(flow, env)
 
     def _block_dlp(self, flow: http.HTTPFlow, result: ScanResult) -> None:

bot_bottle/gateway/egress/request_pipeline.py

@@ -0,0 +1,92 @@
+"""Framework-neutral request policy stages for the egress adapter.
+
+The mitmproxy addon owns flow mutation and response construction. This module
+owns the ordered Git and route-policy decisions so those rules remain directly
+testable without a live proxy flow.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import Mapping, Sequence
+
+from .matching import (
+    decide,
+    decide_git_fetch,
+    is_git_fetch_request,
+    is_git_push_request,
+)
+from .types import LOG_FULL, Config, Route
+
+GIT_PUSH_BLOCK_REASON = (
+    "egress: git push over HTTPS is not supported; "
+    "use the bottle.git SSH path (gitleaks-scanned by "
+    "git-gate's pre-receive hook)."
+)
+
+
+@dataclass(frozen=True)
+class RoutePolicyResult:
+    """The flow mutations and outcome produced by general route policy."""
+
+    block_reason: str = ""
+    strip_authorization: bool = False
+    inject_authorization: str | None = None
+    log_request: bool = False
+
+
+def git_block_reason(
+    routes: Sequence[Route],
+    host: str,
+    request_path: str,
+    query: str,
+) -> str:
+    """Return the HTTPS Git policy denial, or ``""`` when allowed."""
+    if is_git_push_request(request_path, query):
+        return GIT_PUSH_BLOCK_REASON
+    if not is_git_fetch_request(request_path, query):
+        return ""
+    decision = decide_git_fetch(routes, host)
+    return decision.reason if decision.action == "block" else ""
+
+
+def evaluate_route_policy(
+    config: Config,
+    route: Route | None,
+    *,
+    host: str,
+    request_path: str,
+    method: str,
+    headers: Mapping[str, str],
+    env: Mapping[str, str],
+) -> RoutePolicyResult:
+    """Evaluate authorization stripping, matching, injection, and logging."""
+    strip_authorization = route is None or not route.preserve_auth
+    effective_headers = {
+        name.lower(): value
+        for name, value in headers.items()
+        if not (strip_authorization and name.lower() == "authorization")
+    }
+    decision = decide(
+        config.routes,
+        host,
+        request_path,
+        env,
+        request_method=method,
+        request_headers=effective_headers,
+        deny_reason=config.deny_reason,
+    )
+    return RoutePolicyResult(
+        block_reason=decision.reason if decision.action == "block" else "",
+        strip_authorization=strip_authorization,
+        inject_authorization=decision.inject_authorization,
+        log_request=config.log >= LOG_FULL,
+    )
+
+
+__all__ = [
+    "GIT_PUSH_BLOCK_REASON",
+    "RoutePolicyResult",
+    "evaluate_route_policy",
+    "git_block_reason",
+]

tests/unit/test_egress_request_pipeline.py

@@ -0,0 +1,89 @@
+"""Unit tests for framework-neutral egress request policy stages."""
+
+from __future__ import annotations
+
+import unittest
+
+from bot_bottle.gateway.egress.request_pipeline import (
+    GIT_PUSH_BLOCK_REASON,
+    evaluate_route_policy,
+    git_block_reason,
+)
+from bot_bottle.gateway.egress.types import Config, LOG_FULL, Route
+
+
+class TestGitPolicy(unittest.TestCase):
+    def test_push_is_always_blocked(self) -> None:
+        reason = git_block_reason(
+            (), "git.example.com", "/repo.git/git-receive-pack", "",
+        )
+        self.assertEqual(GIT_PUSH_BLOCK_REASON, reason)
+
+    def test_fetch_requires_route_opt_in(self) -> None:
+        path = "/repo.git/git-upload-pack"
+        blocked = git_block_reason((), "git.example.com", path, "")
+        allowed = git_block_reason(
+            (Route(host="git.example.com", git_fetch=True),),
+            "git.example.com",
+            path,
+            "",
+        )
+        self.assertTrue(blocked)
+        self.assertEqual("", allowed)
+
+    def test_non_git_request_is_not_decided_here(self) -> None:
+        self.assertEqual(
+            "",
+            git_block_reason((), "api.example.com", "/v1/messages", ""),
+        )
+
+
+class TestRoutePolicy(unittest.TestCase):
+    def test_strips_agent_auth_and_injects_gateway_auth(self) -> None:
+        route = Route(
+            host="api.example.com",
+            auth_scheme="Bearer",
+            token_env="API_TOKEN",
+        )
+        result = evaluate_route_policy(
+            Config(routes=(route,)),
+            route,
+            host="api.example.com",
+            request_path="/v1/messages",
+            method="POST",
+            headers={"Authorization": "agent-secret"},
+            env={"API_TOKEN": "gateway-secret"},
+        )
+        self.assertTrue(result.strip_authorization)
+        self.assertEqual("Bearer gateway-secret", result.inject_authorization)
+        self.assertFalse(result.block_reason)
+
+    def test_preserved_auth_participates_in_matching(self) -> None:
+        route = Route(host="registry.example.com", preserve_auth=True)
+        result = evaluate_route_policy(
+            Config(routes=(route,), log=LOG_FULL),
+            route,
+            host="registry.example.com",
+            request_path="/v2/",
+            method="GET",
+            headers={"Authorization": "Bearer agent-token"},
+            env={},
+        )
+        self.assertFalse(result.strip_authorization)
+        self.assertTrue(result.log_request)
+
+    def test_missing_route_fails_closed(self) -> None:
+        result = evaluate_route_policy(
+            Config(routes=(), deny_reason="not allowed"),
+            None,
+            host="blocked.example.com",
+            request_path="/",
+            method="GET",
+            headers={},
+            env={},
+        )
+        self.assertEqual("not allowed", result.block_reason)
+
+
+if __name__ == "__main__":
+    unittest.main()