Add user-specific rate limits with admin API management #440

msaroufim · 2026-02-08T08:44:37Z

Introduces per-user submission rate limiting (hourly and daily caps)
configurable via the admin API. Users without an override are unrestricted.

New migration: leaderboard.user_rate_limits table
DB methods: get/set/delete user rate limits + submission rate checking
Admin endpoints: GET/PUT/DELETE /admin/rate-limits/{user_id}
Both submission endpoints check user rate limits (return 429 if exceeded)
Tests for DB methods and all API endpoints

https://claude.ai/code/session_01LiSWKfcKe4riGZwMYdubiJ

Introduces per-user submission rate limiting (hourly and daily caps) configurable via the admin API. Users without an override are unrestricted. - New migration: leaderboard.user_rate_limits table - DB methods: get/set/delete user rate limits + submission rate checking - Admin endpoints: GET/PUT/DELETE /admin/rate-limits/{user_id} - Both submission endpoints check user rate limits (return 429 if exceeded) - Tests for DB methods and all API endpoints https://claude.ai/code/session_01LiSWKfcKe4riGZwMYdubiJ

https://claude.ai/code/session_01LiSWKfcKe4riGZwMYdubiJ

github-actions · 2026-02-08T08:45:34Z

Coverage report

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File	Statements	Missing	Coverage	Coverage (new stmts)	Lines missing
src/libkernelbot
leaderboard_db.py					1340
utils.py
Project Total

_{This report was generated by python-coverage-comment-action}

Copilot

Pull request overview

Adds per-user submission rate limiting (hourly/daily) with admin-managed overrides via new DB table + admin API endpoints, and enforces these limits on submission endpoints.

Changes:

Added leaderboard.user_rate_limits table + DB CRUD/check helpers for per-user submission caps.
Enforced rate-limit checks in both submission endpoints (429 on exceeded limits).
Added admin endpoints and tests for listing/getting/setting/deleting user rate limits.

Reviewed changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
`tests/test_leaderboard_db.py`	Adds DB-level tests for rate limit CRUD and enforcement behavior.
`tests/test_admin_api.py`	Adds admin API tests for rate limit management endpoints.
`tests/conftest.py`	Ensures new table is truncated between tests.
`src/migrations/20260208_01_RkLmN-add-user-rate-limits.py`	Introduces the `user_rate_limits` table.
`src/libkernelbot/leaderboard_db.py`	Implements rate limit CRUD plus submission-rate checking logic.
`src/kernelbot/api/main.py`	Enforces per-user rate limits on submission endpoints and adds admin endpoints.

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Copilot · 2026-02-08T08:46:29Z

src/kernelbot/api/main.py

+    if max_per_hour is not None and (not isinstance(max_per_hour, int) or max_per_hour < 0):
+        raise HTTPException(status_code=400, detail="max_submissions_per_hour must be a non-negative integer")
+
+    if max_per_day is not None and (not isinstance(max_per_day, int) or max_per_day < 0):


isinstance(x, int) also accepts booleans (True/False), which would silently become limits of 1/0. Use a stricter check (e.g., type(x) is int) to ensure only real integers are accepted.

Suggested change

if max_per_hour is not None and (not isinstance(max_per_hour, int) or max_per_hour < 0):

raise HTTPException(status_code=400, detail="max_submissions_per_hour must be a non-negative integer")

if max_per_day is not None and (not isinstance(max_per_day, int) or max_per_day < 0):

if max_per_hour is not None and (type(max_per_hour) is not int or max_per_hour < 0):

raise HTTPException(status_code=400, detail="max_submissions_per_hour must be a non-negative integer")

if max_per_day is not None and (type(max_per_day) is not int or max_per_day < 0):

Copilot · 2026-02-08T08:46:30Z

src/kernelbot/api/main.py

+async def set_user_rate_limit(
+    user_id: str,
+    payload: dict,
+    _: Annotated[None, Depends(require_admin)],
+    db_context=Depends(get_db),
+) -> dict:


Using an untyped payload: dict loses FastAPI schema/validation and makes the API contract ambiguous. Prefer a Pydantic model (optional max_submissions_per_hour, max_submissions_per_day, note) so invalid types are rejected consistently and the OpenAPI docs reflect the request body.

Copilot · 2026-02-08T08:46:30Z

src/libkernelbot/leaderboard_db.py

+            self.cursor.execute(
+                """
+                INSERT INTO leaderboard.user_rate_limits
+                    (user_id, max_submissions_per_hour, max_submissions_per_day, note)
+                VALUES (%s, %s, %s, %s)
+                ON CONFLICT (user_id) DO UPDATE SET
+                    max_submissions_per_hour = EXCLUDED.max_submissions_per_hour,
+                    max_submissions_per_day = EXCLUDED.max_submissions_per_day,
+                    note = EXCLUDED.note,
+                    updated_at = NOW()
+                RETURNING user_id, max_submissions_per_hour, max_submissions_per_day,
+                          note, created_at, updated_at
+                """,
+                (user_id, max_submissions_per_hour, max_submissions_per_day, note),
+            )


This insert is subject to the FK constraint (user_rate_limits.user_id → user_info.id). If an admin tries to set a limit for a non-existent user, Postgres will raise an integrity error that currently becomes a generic KernelBotError (likely surfacing as a 500). Catch integrity violations and return a domain-specific error so the API can respond with a clear 400/404.

Copilot · 2026-02-08T08:46:30Z

src/migrations/20260208_01_RkLmN-add-user-rate-limits.py

+        CREATE TABLE leaderboard.user_rate_limits (
+            user_id TEXT PRIMARY KEY REFERENCES leaderboard.user_info(id),
+            max_submissions_per_hour INTEGER,
+            max_submissions_per_day INTEGER,
+            note TEXT,
+            created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW(),
+            updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()
+        );


The schema allows negative limits, which would invert enforcement semantics and can slip in via non-API callers. Add CHECK constraints to enforce max_submissions_per_hour >= 0 / max_submissions_per_day >= 0 (while still allowing NULL).

Copilot · 2026-02-08T08:46:31Z

src/libkernelbot/leaderboard_db.py

+            self.cursor.execute(
+                """
+                SELECT
+                    COUNT(*) FILTER (WHERE submission_time > NOW() - INTERVAL '1 hour') AS hourly_count,
+                    COUNT(*) FILTER (WHERE submission_time > NOW() - INTERVAL '1 day') AS daily_count
+                FROM leaderboard.submission
+                WHERE user_id = %s
+                """,
+                (user_id,),
+            )


This query runs on every submission for rate-limited users and will become expensive as leaderboard.submission grows unless it can use an index efficiently. Consider adding an index like (user_id, submission_time) (or confirm an existing one) to keep the hourly/daily counts fast.

Copilot · 2026-02-08T08:46:31Z

src/kernelbot/api/main.py

+    with db_context as db:
+        rate_check = db.check_user_submission_rate(user_info["user_id"])
+    if not rate_check["allowed"]:
+        raise HTTPException(status_code=429, detail=f"Rate limit exceeded. {rate_check['retry_after']}")


For 429 responses, it’s best practice to include a Retry-After header (seconds or HTTP date). Since retry_after is currently a human string, consider also returning a machine-readable duration and setting HTTPException(..., headers={'Retry-After': ...}).

Suggested change

raise HTTPException(status_code=429, detail=f"Rate limit exceeded. {rate_check['retry_after']}")

retry_after_header = str(rate_check.get("retry_after_seconds", rate_check["retry_after"]))

raise HTTPException(

status_code=429,

detail=f"Rate limit exceeded. {rate_check['retry_after']}",

headers={"Retry-After": retry_after_header},

)

Copilot · 2026-02-08T08:46:31Z

tests/test_admin_api.py

+    def test_set_user_rate_limit(self, test_client, mock_backend):
+        """PUT /admin/rate-limits/{user_id} sets rate limit."""
+        self._setup_db_mock(mock_backend)
+        mock_backend.db.set_user_rate_limit = MagicMock(return_value={
+            "user_id": "123", "max_submissions_per_hour": 5, "max_submissions_per_day": 20,
+            "note": "restricted", "created_at": None, "updated_at": None,
+        })


Given the FK constraint in the migration, setting a rate limit for a non-existent user_id is an important error path. Add an admin API test that PUT /admin/rate-limits/{user_id} returns a clear 400/404 when the user doesn’t exist (once the handler is updated to translate the DB integrity error).

claude added 2 commits February 8, 2026 08:43

Add *.egg-info/ to .gitignore

cf49a7a

https://claude.ai/code/session_01LiSWKfcKe4riGZwMYdubiJ

Copilot AI review requested due to automatic review settings February 8, 2026 08:44

Copilot AI reviewed Feb 8, 2026

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