⚡️ Use Redis to cache REST responses

backend/backend/settings.py

@@ -1,4 +1,6 @@
-from pydantic import BaseModel, BaseSettings, Field, SecretStr
+from typing import Any
+
+from pydantic import BaseModel, BaseSettings, Field, root_validator, SecretStr
 
 
 class HttpSettings(BaseModel):
@@ -7,14 +9,43 @@ class HttpSettings(BaseModel):
     cert: str | None = None
 
 
+def check_user_password(cls, values: dict[str, Any]) -> dict[str, Any]:
+    user = values.get("user")
+    password = values.get("password")
+
+    if user is not None and password is None:
+        raise ValueError("user is set, password shall be set too.")
+
+    if password is not None and user is None:
+        raise ValueError("password is set, user shall be set too.")
+
+    return values
+
+
 class DatabaseSettings(BaseModel):
     name: str = "carrramba-encore-rate"
     host: str = "127.0.0.1"
     port: int = 5432
     driver: str = "postgresql+psycopg"
-    user: str = "cer"
+    user: str | None = None
     password: SecretStr | None = None
 
+    _user_password_validation = root_validator(allow_reuse=True)(check_user_password)
+
+
+class CacheSettings(BaseModel):
+    enable: bool = False
+    host: str = "127.0.0.1"
+    port: int = 6379
+    user: str | None = None
+    password: SecretStr | None = None
+
+    _user_password_validation = root_validator(allow_reuse=True)(check_user_password)
+
+
+class TracingSettings(BaseModel):
+    enable: bool = False
+
 
 class Settings(BaseSettings):
     app_name: str
@@ -24,3 +55,5 @@ class Settings(BaseSettings):
 
     http: HttpSettings = HttpSettings()
     db: DatabaseSettings = DatabaseSettings()
+    cache: CacheSettings = CacheSettings()
+    tracing: TracingSettings = TracingSettings()

backend/dependencies.py

@@ -1,10 +1,12 @@
 from os import environ
 
+from fastapi_cache.backends.redis import RedisBackend
+from redis import asyncio as aioredis
 from yaml import safe_load
 
 from backend.db import db
 from backend.idfm_interface import IdfmInterface
-from backend.settings import Settings
+from backend.settings import CacheSettings, Settings
 
 
 CONFIG_PATH = environ.get("CONFIG_PATH", "./config.sample.yaml")
@@ -20,3 +22,17 @@ def load_settings(path: str) -> Settings:
 settings = load_settings(CONFIG_PATH)
 
 idfm_interface = IdfmInterface(settings.idfm_api_key.get_secret_value(), db)
+
+
+def init_redis_backend(settings: CacheSettings) -> RedisBackend:
+    login = f"{settings.user}:{settings.password}@" if settings.user is not None else ""
+
+    url = f"redis://{login}{settings.host}:{settings.port}"
+
+    redis_connections_pool = aioredis.from_url(
+        url, encoding="utf8", decode_responses=True
+    )
+    return RedisBackend(redis_connections_pool)
+
+
+redis_backend = init_redis_backend(settings.cache)

backend/main.py

@@ -5,6 +5,7 @@ from contextlib import asynccontextmanager
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.staticfiles import StaticFiles
+from fastapi_cache import FastAPICache
 from opentelemetry import trace
 from opentelemetry.exporter.otlp.proto.http.trace_exporter import OTLPSpanExporter
 from opentelemetry.instrumentation.fastapi import FastAPIInstrumentor
@@ -13,12 +14,14 @@ from opentelemetry.sdk.trace import TracerProvider
 from opentelemetry.sdk.trace.export import BatchSpanProcessor
 
 from backend.db import db
-from dependencies import idfm_interface, settings
+from dependencies import idfm_interface, redis_backend, settings
 from routers import line, stop
 
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
+    FastAPICache.init(redis_backend, prefix="api", enable=settings.cache.enable)
+
     await db.connect(settings.db, settings.clear_static_data)
     if settings.clear_static_data:
         await idfm_interface.startup()
@@ -44,20 +47,29 @@ app.include_router(line.router)
 app.include_router(stop.router)
 
 
-FastAPIInstrumentor.instrument_app(app)
+if settings.tracing.enable:
+    FastAPIInstrumentor.instrument_app(app)
 
-trace.set_tracer_provider(
-    TracerProvider(resource=Resource.create({SERVICE_NAME: settings.app_name}))
-)
-trace.get_tracer_provider().add_span_processor(BatchSpanProcessor(OTLPSpanExporter()))
-tracer = trace.get_tracer(settings.app_name)
+    trace.set_tracer_provider(
+        TracerProvider(resource=Resource.create({SERVICE_NAME: settings.app_name}))
+    )
+    trace.get_tracer_provider().add_span_processor(
+        BatchSpanProcessor(OTLPSpanExporter())
+    )
+    tracer = trace.get_tracer(settings.app_name)
 
 
 if __name__ == "__main__":
     http_settings = settings.http
-    uvicorn.run(
-        app,
+
+    config = uvicorn.Config(
+        app=app,
         host=http_settings.host,
         port=http_settings.port,
         ssl_certfile=http_settings.cert,
+        proxy_headers=True,
     )
+
+    server = uvicorn.Server(config)
+
+    server.run()

backend/pyproject.toml

@@ -25,6 +25,7 @@ opentelemetry-instrumentation-sqlalchemy = "^0.38b0"
 sqlalchemy = "^2.0.12"
 psycopg = "^3.1.9"
 pyyaml = "^6.0"
+fastapi-cache2 = {extras = ["redis"], version = "^0.2.1"}
 
 [build-system]
 requires = ["poetry-core"]

backend/routers/line.py

@@ -1,4 +1,5 @@
 from fastapi import APIRouter, HTTPException
+from fastapi_cache.decorator import cache
 
 from backend.models import Line
 from backend.schemas import Line as LineSchema, TransportMode
@@ -8,6 +9,7 @@ router = APIRouter(prefix="/line", tags=["line"])
 
 
 @router.get("/{line_id}", response_model=LineSchema)
+@cache(namespace="line")
 async def get_line(line_id: int) -> LineSchema:
     line: Line | None = await Line.get_by_id(line_id)
 

backend/routers/stop.py

@@ -3,6 +3,7 @@ from datetime import datetime
 from typing import Sequence
 
 from fastapi import APIRouter, HTTPException
+from fastapi_cache.decorator import cache
 
 from backend.idfm_interface import (
     Destinations as IdfmDestinations,
@@ -40,6 +41,7 @@ def optional_datetime_to_ts(dt: datetime | None) -> int | None:
 
 # TODO: Add limit support
 @router.get("/")
+@cache(namespace="stop")
 async def get_stop(
     name: str = "", limit: int = 10
 ) -> Sequence[StopAreaSchema | StopSchema] | None:
@@ -83,8 +85,8 @@ async def get_stop(
     return formatted
 
 
-# TODO: Cache response for 30 secs ?
 @router.get("/{stop_id}/nextPassages")
+@cache(namespace="stop-nextPassages", expire=30)
 async def get_next_passages(stop_id: int) -> NextPassagesSchema | None:
     res = await idfm_interface.get_next_passages(stop_id)
     if res is None:
@@ -149,6 +151,7 @@ async def get_next_passages(stop_id: int) -> NextPassagesSchema | None:
 
 
 @router.get("/{stop_id}/destinations")
+@cache(namespace="stop-destinations", expire=30)
 async def get_stop_destinations(
     stop_id: int,
 ) -> IdfmDestinations | None:
@@ -158,6 +161,7 @@ async def get_stop_destinations(
 
 
 @router.get("/{stop_id}/shape")
+@cache(namespace="stop-shape")
 async def get_stop_shape(stop_id: int) -> StopShapeSchema | None:
     connection_area = None
 

docker-compose.yml

@@ -18,6 +18,12 @@ services:
       - ./backend/docker/database/docker-entrypoint-initdb.d:/docker-entrypoint-initdb.d
       - ./backend/docker/database/data:/var/lib/postgresql/data
 
+  redis:
+    image: redis:latest
+    restart: always
+    command: redis-server --loglevel warning
+    ports:
+      - "127.0.0.1:6379:6379"
 
   jaeger-agent:
     image: jaegertracing/jaeger-agent:latest