HW4 done

.gitignore

@@ -132,3 +132,6 @@ dmypy.json
 
 # macOS
 .DS_Store
+
+shop.db
+test.db

Dockerfile

@@ -0,0 +1,22 @@
+# syntax=docker/dockerfile:1
+FROM python:3.11-slim AS base
+
+ENV PYTHONDONTWRITEBYTECODE=1 \
+PYTHONUNBUFFERED=1
+
+
+WORKDIR /app
+
+
+COPY hw2/hw/requirements.txt ./requirements.txt
+RUN pip install --no-cache-dir -r requirements.txt
+
+
+COPY hw2/hw ./hw
+
+ENV PYTHONPATH=/app/hw
+
+
+EXPOSE 8000
+
+CMD ["uvicorn", "shop_api.main:app", "--host", "0.0.0.0", "--port", "8000"]

docker-compose.yml

@@ -0,0 +1,76 @@
+version: "3.9"
+
+services:
+  app:
+    build: .
+    container_name: shop_api
+    ports:
+      - "8000:8000"
+    environment:
+      - PYTHONPATH=/app/hw
+      - DATABASE_URL=postgresql+psycopg://shop:shop@db:5432/shopdb
+    depends_on:
+      - db
+    networks:
+      - monitor-net
+
+  db:
+    image: postgres:16
+    container_name: postgres
+    environment:
+      - POSTGRES_DB=shopdb
+      - POSTGRES_USER=shop
+      - POSTGRES_PASSWORD=shop
+    ports:
+      - "5432:5432"    
+    volumes:
+      - pgdata:/var/lib/postgresql/data
+    networks:
+      - monitor-net
+
+  adminer:
+    image: adminer
+    container_name: adminer
+    ports:
+      - "8080:8080"
+    depends_on:
+      - db
+    networks:
+      - monitor-net
+
+  prometheus:
+    image: prom/prometheus:latest
+    container_name: prometheus
+    volumes:
+      - ./prometheus.yml:/etc/prometheus/prometheus.yml:ro
+      - prom-data:/prometheus
+    ports:
+      - "9090:9090"
+    networks:
+      - monitor-net
+    depends_on:
+      - app
+
+  grafana:
+    image: grafana/grafana:latest
+    container_name: grafana
+    ports:
+      - "3000:3000"
+    volumes:
+      - grafana-data:/var/lib/grafana
+    environment:
+      - GF_SECURITY_ADMIN_USER=admin
+      - GF_SECURITY_ADMIN_PASSWORD=admin
+    networks:
+      - monitor-net
+    depends_on:
+      - prometheus
+
+volumes:
+  prom-data:
+  grafana-data:
+  pgdata:
+
+networks:
+  monitor-net:
+    driver: bridge

hw1/app.py

@@ -1,4 +1,7 @@
 from typing import Any, Awaitable, Callable
+import json
+from math import prod
+from urllib.parse import parse_qs
 
 
 async def application(
@@ -12,7 +15,116 @@ async def application(
         receive: Корутина для получения сообщений от клиента
         send: Корутина для отправки сообщений клиенту
     """
-    # TODO: Ваша реализация здесь
+
+    if scope.get("type") != "http":
+        await _send_json(send, {"detail": "unsupported scope type"}, status=422)
+        return
+
+    method = scope.get("method", "GET").upper()
+    path: str = scope.get("path", "/")
+    query = parse_qs((scope.get("query_string") or b"").decode(
+        "utf-8"), keep_blank_values=True)
+
+    if path.startswith("/fibonacci/"):
+        n_str = path[len("/fibonacci/"):].strip("/")
+        if n_str == "":
+            await _send_json(send, {"detail": "n is required"}, status=422)
+            return
+        try:
+            n = int(n_str)
+        except ValueError:
+            await _send_json(send, {"detail": "n must be an integer"}, status=422)
+            return
+        if n < 0:
+            await _send_json(send, {"detail": "n must be non-negative"}, status=400)
+            return
+
+        a, b = 0, 1
+        for _ in range(n):
+            a, b = b, a + b
+        await _send_json(send, {"result": a}, status=200)
+        return
+
+    if path == "/factorial":
+        if method != "GET":
+            await _send_json(send, {"detail": "not found"}, status=404)
+            return
+
+        raw = query.get("n", [None])[0]
+        if raw is None or raw == "":
+            await _send_json(send, {"detail": "n is required"}, status=422)
+            return
+        try:
+            n = int(raw)
+        except ValueError:
+            await _send_json(send, {"detail": "n must be an integer"}, status=422)
+            return
+        if n < 0:
+            await _send_json(send, {"detail": "n must be non-negative"}, status=400)
+            return
+
+        result = 1 if n == 0 else prod(range(1, n + 1))
+        await _send_json(send, {"result": result}, status=200)
+        return
+
+    if path == "/mean":
+        if method != "GET":
+            await _send_json(send, {"detail": "not found"}, status=404)
+            return
+
+        body_bytes = await _read_body(receive)
+        if not body_bytes:
+            await _send_json(send, {"detail": "json body required (array of numbers)"}, status=422)
+            return
+
+        try:
+            data = json.loads(body_bytes.decode("utf-8"))
+        except json.JSONDecodeError:
+            await _send_json(send, {"detail": "invalid JSON"}, status=422)
+            return
+
+        if not isinstance(data, list):
+            await _send_json(send, {"detail": "body must be a JSON array"}, status=422)
+            return
+
+        if len(data) == 0:
+            await _send_json(send, {"detail": "array must not be empty"}, status=400)
+            return
+
+        try:
+            nums = [float(x) for x in data]
+        except (TypeError, ValueError):
+            await _send_json(send, {"detail": "array must contain only numbers"}, status=422)
+            return
+
+        mean_value = sum(nums) / len(nums)
+        await _send_json(send, {"result": mean_value}, status=200)
+        return
+
+    await _send_json(send, {"detail": "not found"}, status=404)
+
+
+async def _read_body(receive: Callable[[], Awaitable[dict[str, Any]]]) -> bytes:
+    body = b""
+    more = True
+    while more:
+        message = await receive()
+        if message["type"] != "http.request":
+            break
+        body += message.get("body", b"")
+        more = message.get("more_body", False)
+    return body
+
+
+async def _send_json(send: Callable[[dict[str, Any]], Awaitable[None]], payload: dict, status: int = 200):
+    body = json.dumps(payload).encode("utf-8")
+    headers = [
+        (b"content-type", b"application/json; charset=utf-8"),
+        (b"content-length", str(len(body)).encode("ascii")),
+    ]
+    await send({"type": "http.response.start", "status": status, "headers": headers})
+    await send({"type": "http.response.body", "body": body})
+
 
 if __name__ == "__main__":
     import uvicorn

hw2/hw/requirements.txt

@@ -1,9 +1,15 @@
 # Основные зависимости для ASGI приложения
 fastapi>=0.117.1
 uvicorn>=0.24.0
+prometheus-fastapi-instrumentator>=6.1.0
 
 # Зависимости для тестирования
 pytest>=7.4.0
 pytest-asyncio>=0.21.0
 httpx>=0.27.2
 Faker>=37.8.0
+
+SQLAlchemy>=2.0
+psycopg[binary]>=3.2
+
+alembic>=1.13

hw2/hw/shop_api/HW_results/README.md

@@ -0,0 +1,52 @@
+# сценарии:
+
+docker compose exec app python -m shop_api.HW_results.tx.txn_demos nrr_rc                   # non-repeatable read на READ COMMITTED
+
+docker compose exec app python -m shop_api.HW_results.tx.txn_demos nrr_rr                   # отсутствие non-repeatable read на REPEATABLE READ
+
+docker compose exec app python -m shop_api.HW_results.tx.txn_demos phantom_rc               # phantom на READ COMMITTED
+
+docker compose exec app python -m shop_api.HW_results.tx.txn_demos phantom_rr               # отсутствие phantom на REPEATABLE READ
+
+docker compose exec app python -m shop_api.HW_results.tx.txn_demos serializable             # строгая изоляция
+
+
+nrr_rc
+
+Running scenario: nrr_rc
+[T1] first read val=100
+[T2] committed UPDATE
+[T1] second read val=101
+
+второе чтение видит новое значение —non‑repeatable read
+
+Running scenario: nrr_rr
+[T1] first read val=100
+[T2] committed UPDATE
+[T1] second read val=100
+
+ в REPEATABLE READ snapshot фиксирован, значение не меняется
+
+phantom_rc 
+
+Running scenario: phantom_rc
+[T1] first count=2
+[T2] committed INSERT
+[T1] second count=3
+
+количество строк изменилось — phantom.
+
+Running scenario: phantom_rr
+[T1] first count=2
+[T2] committed INSERT
+[T1] second count=2
+
+snapshot предотвращает появление «призрачных» строк в той же транзакции.
+
+serializable — строгая изоляция
+
+Running scenario: serializable
+[T1] bump +10 committed
+[T2] bump +20 committed
+
+за счёт блокировок операции выполняются последовательно, конфликтов нет

hw2/hw/shop_api/HW_results/tx/dirty_read.py

@@ -0,0 +1,4 @@
+print("""
+PostgreSQL не поддерживает уровень READ UNCOMMITTED. Любая попытка
+установить его сводится к READ COMMITTED, поэтому dirty read невозможен.
+""")