feat(orchestrator+egress): slice 8 — multi-tenant egress via the resolver (#352)

The egress addon now selects each request's Config by the calling bottle's
source IP, so one shared sidecar serves every bottle. Opt-in and fail-closed;
single-tenant behaviour is unchanged.

Orchestrator side (source-IP-primary attribution, per the PRD invariant):
  * registry: `by_source_ip` (the single active bottle at a source IP —
    network-layer attribution); `attribute` now composes it + the token.
  * service: `resolve(source_ip, token="")` — with a token, strict
    attribution; without, source IP alone.
  * control_plane: `POST /resolve`'s identity_token is now OPTIONAL (absent
    → source-IP-only); split cleanly from the token-required `/attribute`.
  * policy_resolver: `resolve` token now optional.

Egress side:
  * egress_addon_core: `resolve_client_config(resolver, client_ip, token)` —
    fetches + parses the client's Config, **fail-closed**: unattributed, a
    resolver error, or an unparseable policy all yield deny-all (no routes).
    Host-testable; `PolicyResolverLike` Protocol keeps it import-free.
  * egress_addon: consolidated mode when `BOT_BOTTLE_ORCHESTRATOR_URL` is
    set → `_active_config(flow)` resolves per client IP (reads + strips the
    `x-bot-bottle-identity` header); `request()` uses it. Unset → the static
    routes file, exactly as before. `PolicyResolver` added to the bundle.

Security note: source-IP-only resolution is safe where the IP is unspoofable
(Firecracker /31 + nft) AND the control plane is reachable only by the
trusted sidecar; the identity token, when the agent injects it, strengthens
it on weaker backends.

Scope note: the egress data plane is now multi-tenant. Remaining to be fully
live: the network topology routing every bottle's proxy to the one shared
sidecar, git-gate multitenancy, and agent-side identity-token injection.

Tests: registry by_source_ip; orchestrator resolve (with/without token);
control-plane /resolve token-optional; resolver token-optional;
resolve_client_config fail-closed matrix. All 182 egress tests still pass
(single-tenant unchanged). Full suite green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WBMWTEtQdJ4W5UrWuLHCck

bot_bottle/egress_addon.py

@@ -32,6 +32,7 @@ from egress_addon_core import (  # type: ignore[import-not-found]  # pylint: dis
     is_git_push_request,
     load_config,
     match_route,
+    resolve_client_config,
     outbound_scan_headers,
     route_to_yaml_dict,
     scan_inbound,
@@ -51,11 +52,26 @@ try:
 except ImportError:  # pragma: no cover - host-side path
     from bot_bottle import supervise as _sv  # type: ignore[import-not-found]
 
+try:
+    from policy_resolver import PolicyResolver  # type: ignore[import-not-found]
+except ImportError:  # pragma: no cover - host-side path
+    from bot_bottle.policy_resolver import PolicyResolver
+
 
 DEFAULT_ROUTES_PATH = "/etc/egress/routes.yaml"
 
 INTROSPECT_HOST = "_egress.local"
 
+# Consolidated (multi-tenant) mode: when this points at the per-host
+# orchestrator's control plane, the addon resolves each client's Config by
+# source IP per request instead of using a single static routes file. Unset
+# → legacy per-bottle single-tenant mode (unchanged).
+ORCHESTRATOR_URL_ENV = "BOT_BOTTLE_ORCHESTRATOR_URL"
+
+# App-layer identity token (defense-in-depth over the source-IP invariant);
+# the agent injects it, the addon strips it so it never leaks upstream.
+IDENTITY_HEADER = "x-bot-bottle-identity"
+
 # Seconds the egress proxy holds a token-blocked request open waiting for the
 # operator's supervisor decision (PRD 0062), overridable via env.
 DEFAULT_TOKEN_ALLOW_TIMEOUT_SECONDS = 300.0
@@ -72,9 +88,17 @@ _TOKEN_ALLOW_JUSTIFICATION = (
 
 
 class EgressAddon:
+    # Class default so addons built via __new__ (e.g. in tests) default to
+    # single-tenant; __init__ sets the instance attribute for real runs.
+    _resolver: "PolicyResolver | None" = None
+
     def __init__(self) -> None:
         self.routes_path = os.environ.get("EGRESS_ROUTES", DEFAULT_ROUTES_PATH)
         self.config: Config = Config(routes=())
+        # Consolidated mode: resolve per-client Config from the orchestrator.
+        # Absent → single-tenant (static routes file); behaviour unchanged.
+        orch_url = os.environ.get(ORCHESTRATOR_URL_ENV, "").strip()
+        self._resolver = PolicyResolver(orch_url) if orch_url else None
         # Tokens the operator has approved this session (PRD 0062). In-memory
         # only — a restart re-prompts. Mutated only from the asyncio loop that
         # runs the addon hooks, so no lock is needed.
@@ -194,6 +218,20 @@ class EgressAddon:
             + "\n"
         )
 
+    def _active_config(self, flow: http.HTTPFlow) -> Config:
+        """The Config to apply to this request. Single-tenant → the static
+        `self.config`. Consolidated → the calling bottle's Config, resolved
+        by source IP (fail-closed to deny-all if unattributed). The identity
+        token, if the agent injected one, is read then stripped so it never
+        leaks upstream."""
+        if self._resolver is None:
+            return self.config
+        conn = flow.client_conn
+        client_ip = conn.peername[0] if conn and conn.peername else ""
+        token = flow.request.headers.get(IDENTITY_HEADER, "")
+        flow.request.headers.pop(IDENTITY_HEADER, None)
+        return resolve_client_config(self._resolver, client_ip, token)
+
     async def request(self, flow: http.HTTPFlow) -> None:
         request_path, _, query = flow.request.path.partition("?")
 
@@ -201,10 +239,12 @@ class EgressAddon:
             self._serve_introspection(flow, request_path)
             return
 
+        config = self._active_config(flow)
+
         # DLP outbound scan BEFORE stripping auth — catches tokens the
         # agent tried to smuggle in any header, path, query param, or body.
         # Hostname is included to catch DNS-tunnelling exfiltration attempts.
-        route = match_route(self.config.routes, flow.request.pretty_host)
+        route = match_route(config.routes, flow.request.pretty_host)
         if route is not None:
             if not await self._handle_outbound_dlp(flow, route):
                 return
@@ -224,7 +264,7 @@ class EgressAddon:
 
         if is_git_fetch_request(request_path, query):
             git_decision = decide_git_fetch(
-                self.config.routes, flow.request.pretty_host,
+                config.routes, flow.request.pretty_host,
             )
             if git_decision.action == "block":
                 self._block(
@@ -242,7 +282,7 @@ class EgressAddon:
         req_headers = {k.lower(): v for k, v in flow.request.headers.items()}
 
         decision = decide(
-            self.config.routes,
+            config.routes,
             flow.request.pretty_host,
             request_path,
             os.environ,
@@ -257,7 +297,7 @@ class EgressAddon:
         if decision.inject_authorization is not None:
             flow.request.headers["authorization"] = decision.inject_authorization
 
-        if self.config.log >= LOG_FULL:
+        if config.log >= LOG_FULL:
             self._log_request(flow)
 
     def _block_dlp(self, flow: http.HTTPFlow, result: ScanResult) -> None: