Implement WP-0011 hub service, CLI, and deployment artifacts

Add FederationHubAPI spec, hub registration schema, FastAPI hub with SQLite
persistence, reuse-surface hub CLI client, Dockerfile, and hub tests. Activate
workplan; T05 deploy and T06 ops docs remain open pending railiance01 cutover.

reuse_surface/hub/app.py

@@ -0,0 +1,143 @@
+from __future__ import annotations
+
+import os
+from pathlib import Path
+from typing import Any
+
+import yaml
+from fastapi import Depends, FastAPI, Header, HTTPException, Query, Request
+from fastapi.responses import JSONResponse, Response
+
+from reuse_surface.hub.compose import compose_from_store, DEFAULT_DOMAIN
+from reuse_surface.hub.store import HubStore
+
+HUB_VERSION = "0.1.0"
+
+
+def _db_path() -> Path:
+    return Path(os.environ.get("REUSE_SURFACE_HUB_DB", "/data/hub.db"))
+
+
+def _cache_dir() -> Path:
+    return Path(os.environ.get("REUSE_SURFACE_HUB_CACHE_DIR", "/data/cache"))
+
+
+def _write_token() -> str:
+    return os.environ.get("REUSE_SURFACE_HUB_TOKEN", "")
+
+
+def _store() -> HubStore:
+    return HubStore(_db_path())
+
+
+def _http_error(status: int, error: str, message: str) -> HTTPException:
+    return HTTPException(
+        status_code=status,
+        detail={"error": error, "message": message, "details": []},
+    )
+
+
+def _require_auth(authorization: str | None = Header(default=None)) -> None:
+    write_token = _write_token()
+    if not write_token:
+        raise _http_error(
+            503, "misconfigured", "REUSE_SURFACE_HUB_TOKEN is not configured"
+        )
+    if not authorization or not authorization.startswith("Bearer "):
+        raise _http_error(401, "unauthorized", "Bearer token required")
+    token = authorization.removeprefix("Bearer ").strip()
+    if token != write_token:
+        raise _http_error(401, "unauthorized", "Invalid token")
+
+
+def create_app() -> FastAPI:
+    app = FastAPI(title="reuse-surface federation hub", version=HUB_VERSION)
+    store = _store()
+
+    @app.get("/health")
+    def health() -> dict[str, str]:
+        return {"status": "ok", "service": "reuse-surface-hub", "version": HUB_VERSION}
+
+    @app.get("/v1/repos")
+    def list_repos() -> dict[str, Any]:
+        repos = store.list_repos()
+        return {"count": len(repos), "repos": repos}
+
+    @app.post("/v1/repos", status_code=201, dependencies=[Depends(_require_auth)])
+    async def register_repo(request: Request) -> dict[str, Any]:
+        payload = await request.json()
+        try:
+            return store.create_repo(payload)
+        except FileExistsError as exc:
+            raise _http_error(409, "conflict", str(exc)) from exc
+        except ValueError as exc:
+            raise _http_error(400, "validation_error", str(exc)) from exc
+
+    @app.get("/v1/repos/{repo}")
+    def get_repo(repo: str) -> dict[str, Any]:
+        registration = store.get_repo(repo)
+        if registration is None:
+            raise _http_error(404, "not_found", f"repo not found: {repo}")
+        return registration
+
+    @app.patch("/v1/repos/{repo}", dependencies=[Depends(_require_auth)])
+    async def update_repo(repo: str, request: Request) -> dict[str, Any]:
+        payload = await request.json()
+        try:
+            return store.update_repo(repo, payload)
+        except KeyError as exc:
+            raise _http_error(404, "not_found", str(exc)) from exc
+        except ValueError as exc:
+            raise _http_error(400, "validation_error", str(exc)) from exc
+
+    @app.delete("/v1/repos/{repo}", status_code=204, dependencies=[Depends(_require_auth)])
+    def delete_repo(repo: str) -> Response:
+        if not store.delete_repo(repo):
+            raise _http_error(404, "not_found", f"repo not found: {repo}")
+        return Response(status_code=204)
+
+    def _federated_response(
+        refresh: bool,
+        accept: str | None,
+        format_param: str,
+    ) -> Response:
+        try:
+            federated, warnings = compose_from_store(
+                store, refresh=refresh, cache_dir=_cache_dir(), domain=DEFAULT_DOMAIN
+            )
+        except FileNotFoundError as exc:
+            raise _http_error(502, "compose_error", str(exc)) from exc
+
+        use_yaml = format_param == "yaml" or (accept and "yaml" in accept.lower())
+        headers: dict[str, str] = {}
+        if warnings:
+            headers["X-Federation-Warnings"] = "; ".join(warnings)
+        if use_yaml:
+            body = yaml.safe_dump(federated, sort_keys=False)
+            return Response(content=body, media_type="application/yaml", headers=headers)
+        return JSONResponse(content=federated, headers=headers)
+
+    @app.get("/v1/federated", response_model=None)
+    def get_federated(
+        request: Request,
+        refresh: bool = Query(default=False),
+        format: str = Query(default="json"),
+    ) -> Response:
+        return _federated_response(refresh, request.headers.get("accept"), format)
+
+    @app.post("/v1/federated/compose", response_model=None, dependencies=[Depends(_require_auth)])
+    def compose_federated(
+        request: Request,
+        format: str = Query(default="json"),
+    ) -> Response:
+        return _federated_response(True, request.headers.get("accept"), format)
+
+    return app
+
+
+def main() -> None:
+    import uvicorn
+
+    host = os.environ.get("REUSE_SURFACE_HUB_HOST", "0.0.0.0")
+    port = int(os.environ.get("REUSE_SURFACE_HUB_PORT", "8000"))
+    uvicorn.run(create_app(), host=host, port=port, reload=False)