如何解决带有aiocache和Redis的FastAPI无法设置database.backends.postgres.Record对象
我正在尝试使用aiocache库在端点上实现Redis。 我使用aiocache进行的第一个测试是使用@cache的,没有指示任何其他服务,并且一切正常。但是当我尝试使用Redis时,我看到此错误(端点仍返回请求)
ERROR: Couldn't set [<databases.backends.postgres.Record object at 0x7fb9f01d86a0>,<databases.backends.postgres.Record object at 0x7fb9f01d88b0>,<databases.backends.postgres.Record object at 0x7fb9f01d8a60>] in key app.api.authorget_authors()[],unexpected error
Traceback (most recent call last):
File "/usr/local/lib/python3.8/site-packages/aiocache/decorators.py",line 144,in set_in_cache
await self.cache.set(key,value,ttl=self.ttl)
File "/usr/local/lib/python3.8/site-packages/aiocache/base.py",line 61,in _enabled
return await func(*args,**kwargs)
File "/usr/local/lib/python3.8/site-packages/aiocache/base.py",line 45,in _timeout
return await asyncio.wait_for(func(self,*args,**kwargs),timeout)
File "/usr/local/lib/python3.8/asyncio/tasks.py",line 483,in wait_for
return fut.result()
File "/usr/local/lib/python3.8/site-packages/aiocache/base.py",line 75,in _plugins
ret = await func(self,line 265,in set
ns_key,dumps(value),ttl=self._get_ttl(ttl),_cas_token=_cas_token,_conn=_conn
File "/usr/local/lib/python3.8/site-packages/aiocache/serializers/serializers.py",line 140,in dumps
return json.dumps(value)
TypeError: <databases.backends.postgres.Record object at 0x7fb9f01d8a60> is not JSON serializable
方法是:
@authors.get("/",response_model=List[AuthorOut])
@cached(
ttl=100,cache=Cache.REDIS,endpoint="X.X.X.X",#my local ip
serializer=JsonSerializer(),port=6379,namespace="main",#key="key",)
async def get_authors():
return await db_manager.get_all_authors()
整个环境基于docker,2个容器,1个FastApi,1个PostgreSQL和1个Redis。
看来端点返回的对象存在问题,所以我问你如何将这样一个复杂的对象传递给Redis?
按照aiochace文档,我尝试了所有存在的序列化器,但没有成功。
我的docker-compose
version: '3.7'
services:
book_service:
build: ./book-service
command: uvicorn app.main:app --reload --host 0.0.0.0 --port 8000
volumes:
- ./book-service/:/app/
ports:
- 8001:8000
environment:
- DATABASE_URI=postgresql://book_db_username:book_db_password@book_db/book_db_dev
- AUTHOR_SERVICE_HOST_URL=http://author_service:8000/api/v1/authors/
depends_on:
- book_db
book_db:
image: postgres:12.1-alpine
volumes:
- postgres_data_book:/var/lib/postgresql/data/
environment:
- POSTGRES_USER=book_db_username
- POSTGRES_PASSWORD=book_db_password
- POSTGRES_DB=book_db_dev
author_service:
build: ./author-service
command: uvicorn app.main:app --reload --host 0.0.0.0 --port 8000
volumes:
- ./author-service/:/app/
ports:
- 8002:8000
environment:
- DATABASE_URI=postgresql://author_db_username:author_db_password@author_db/author_db_dev
depends_on:
- author_db
author_db:
image: postgres:12.1-alpine
volumes:
- postgres_data_author:/var/lib/postgres/data
environment:
- POSTGRES_USER=author_db_username
- POSTGRES_PASSWORD=author_db_password
- POSTGRES_DB=author_db_dev
nginx:
image: nginx:latest
ports:
- "8080:8080"
volumes:
- ./nginx_config.conf:/etc/nginx/conf.d/default.conf
depends_on:
- author_service
- book_service
redis:
image: redis:3.2-alpine
volumes:
# - redis_data:/data
- ./redis.conf:/usr/local/etc/redis/redis.conf
command: redis-server /usr/local/etc/redis/redis.conf
ports:
- 6379:6379
networks:
node_net:
ipv4_address: 172.28.1.4
networks:
node_net:
ipam:
driver: default
config:
- subnet: 172.28.0.0/16
volumes:
postgres_data_book:
postgres_data_author:
redis_data:
解决方法
错误说明了一切
TypeError: <databases.backends.postgres.Record object at 0x7fb9f01d8a60> is not JSON serializable
错误在于您正在以JSON序列化对象以缓存无法在JSON中序列化的对象。
我曾经遇到过类似的问题,但是发现fastAPI的编码器支持Record
对象,而其他的则不支持。您可以返回通过此类编码器序列化的对象,也可以在redis缓存参数中将其设置为编码器。参见https://fastapi.tiangolo.com/tutorial/encoder/#using-the-jsonable_encoder。
我没有测试以下代码,但足以让我明白我的意思。
from fastapi.encoders import jsonable_encoder
@authors.get("/",response_model=List[AuthorOut])
@cached(
ttl=100,cache=Cache.REDIS,endpoint="X.X.X.X",#my local ip
serializer=JsonSerializer(),port=6379,namespace="main",#key="key",)
async def get_authors():
return jsonable_encoder(await db_manager.get_all_authors())
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