I have a deployment of FastAPI 0.81.0 + uvicorn 0.18.3 using Python 3.10.1 on AWS Fargate with a load balancer. The server runs (as expected) indefinitely in my local Docker, however on AWS the application always shuts down after 1-2 minutes.
This is the uvicorn invocation in Docker:
CMD ["uvicorn", "--host", "0.0.0.0", "--port", "8000", "--log-level", "trace", "app.main:app"]
My FastAPI application looks like this:
from fastapi import FastAPI
from fastapi.middleware.cors import CORSMiddleware
app = FastAPI()
app = FastAPI()
origins = [
"*"
]
app.add_middleware(
CORSMiddleware,
allow_origins=origins,
allow_credentials=True,
allow_methods=["*"],
allow_headers=["*"],
)
@app.get("/")
async def root():
return {"Hello": "World"}
My guess is that it has something to do with the Load Balancer, since RAM usage of my Fargate service is not too high:
The usual suspect seems to be health checks via TCP instead of HTTP, however AFAIK the health checks are already via HTTP per default in the Fargate task definition or the EC2 target group, respectively.
Here are the logs of my Fargate Task:
2022-09-22 18:43:46 INFO: Finished server process [1]
2022-09-22 18:43:46 INFO: Waiting for application shutdown.
2022-09-22 18:43:46 TRACE: ASGI [1] Receive {'type': 'lifespan.shutdown'}
2022-09-22 18:43:46 TRACE: ASGI [1] Send {'type': 'lifespan.shutdown.complete'}
2022-09-22 18:43:46 TRACE: ASGI [1] Completed
2022-09-22 18:43:46 INFO: Application shutdown complete.
2022-09-22 18:43:45 INFO: Shutting down
2022-09-22 18:43:39 TRACE: 172.31.21.3:16662 - ASGI [7] Send {'type': 'http.response.body', 'body': '<17 bytes>'}
2022-09-22 18:43:39 TRACE: 172.31.21.3:16662 - ASGI [7] Completed
2022-09-22 18:43:39 TRACE: 172.31.21.3:16662 - HTTP connection lost
2022-09-22 18:43:39 INFO: 172.31.21.3:16662 - "GET / HTTP/1.1" 200 OK
2022-09-22 18:43:39 TRACE: 172.31.21.3:16662 - HTTP connection made
2022-09-22 18:43:39 TRACE: 172.31.21.3:16662 - ASGI [7] Started scope={'type': 'http', 'asgi': {'version': '3.0', 'spec_version': '2.3'}, 'http_version': '1.1', 'server': ('172.31.30.157', 8000), 'client': ('172.31.21.3', 16662), 'scheme': 'http', 'method': 'GET', 'root_path': '', 'path': '/', 'raw_path': b'/', 'query_string': b'', 'headers': '<...>'}
2022-09-22 18:43:39 TRACE: 172.31.21.3:16662 - ASGI [7] Send {'type': 'http.response.start', 'status': 200, 'headers': '<...>'}
2022-09-22 18:43:39 INFO: 172.31.47.71:3856 - "GET / HTTP/1.1" 200 OK
2022-09-22 18:43:39 TRACE: 172.31.47.71:3856 - ASGI [6] Send {'type': 'http.response.body', 'body': '<17 bytes>'}
2022-09-22 18:43:39 TRACE: 172.31.47.71:3856 - ASGI [6] Completed
2022-09-22 18:43:39 TRACE: 172.31.47.71:3856 - HTTP connection lost
2022-09-22 18:43:39 TRACE: 172.31.47.71:3856 - HTTP connection made
2022-09-22 18:43:39 TRACE: 172.31.47.71:3856 - ASGI [6] Started scope={'type': 'http', 'asgi': {'version': '3.0', 'spec_version': '2.3'}, 'http_version': '1.1', 'server': ('172.31.30.157', 8000), 'client': ('172.31.47.71', 3856), 'scheme': 'http', 'method': 'GET', 'root_path': '', 'path': '/', 'raw_path': b'/', 'query_string': b'', 'headers': '<...>'}
2022-09-22 18:43:39 TRACE: 172.31.47.71:3856 - ASGI [6] Send {'type': 'http.response.start', 'status': 200, 'headers': '<...>'}
2022-09-22 18:43:09 TRACE: 172.31.21.3:39448 - ASGI [5] Completed
2022-09-22 18:43:09 TRACE: 172.31.21.3:39448 - HTTP connection lost
2022-09-22 18:43:09 TRACE: 172.31.21.3:39448 - ASGI [5] Send {'type': 'http.response.body', 'body': '<17 bytes>'}
2022-09-22 18:43:09 TRACE: 172.31.21.3:39448 - HTTP connection made
2022-09-22 18:43:09 TRACE: 172.31.21.3:39448 - ASGI [5] Started scope={'type': 'http', 'asgi': {'version': '3.0', 'spec_version': '2.3'}, 'http_version': '1.1', 'server': ('172.31.30.157', 8000), 'client': ('172.31.21.3', 39448), 'scheme': 'http', 'method': 'GET', 'root_path': '', 'path': '/', 'raw_path': b'/', 'query_string': b'', 'headers': '<...>'}
2022-09-22 18:43:09 TRACE: 172.31.21.3:39448 - ASGI [5] Send {'type': 'http.response.start', 'status': 200, 'headers': '<...>'}
2022-09-22 18:43:09 INFO: 172.31.21.3:39448 - "GET / HTTP/1.1" 200 OK
2022-09-22 18:43:09 TRACE: 172.31.47.71:50778 - ASGI [4] Completed
2022-09-22 18:43:09 TRACE: 172.31.47.71:50778 - HTTP connection lost
2022-09-22 18:43:09 TRACE: 172.31.47.71:50778 - ASGI [4] Send {'type': 'http.response.start', 'status': 200, 'headers': '<...>'}
2022-09-22 18:43:09 INFO: 172.31.47.71:50778 - "GET / HTTP/1.1" 200 OK
2022-09-22 18:43:09 TRACE: 172.31.47.71:50778 - ASGI [4] Send {'type': 'http.response.body', 'body': '<17 bytes>'}
2022-09-22 18:43:09 TRACE: 172.31.47.71:50778 - HTTP connection made
2022-09-22 18:43:09 TRACE: 172.31.47.71:50778 - ASGI [4] Started scope={'type': 'http', 'asgi': {'version': '3.0', 'spec_version': '2.3'}, 'http_version': '1.1', 'server': ('172.31.30.157', 8000), 'client': ('172.31.47.71', 50778), 'scheme': 'http', 'method': 'GET', 'root_path': '', 'path': '/', 'raw_path': b'/', 'query_string': b'', 'headers': '<...>'}
2022-09-22 18:42:39 INFO: 172.31.47.71:55984 - "GET / HTTP/1.1" 200 OK
2022-09-22 18:42:39 TRACE: 172.31.47.71:55984 - ASGI [3] Send {'type': 'http.response.start', 'status': 200, 'headers': '<...>'}
2022-09-22 18:42:39 TRACE: 172.31.47.71:55984 - ASGI [3] Send {'type': 'http.response.body', 'body': '<17 bytes>'}
2022-09-22 18:42:39 TRACE: 172.31.47.71:55984 - ASGI [3] Completed
2022-09-22 18:42:39 TRACE: 172.31.47.71:55984 - HTTP connection lost
2022-09-22 18:42:39 TRACE: 172.31.21.3:59240 - HTTP connection lost
2022-09-22 18:42:39 TRACE: 172.31.47.71:55984 - ASGI [3] Started scope={'type': 'http', 'asgi': {'version': '3.0', 'spec_version': '2.3'}, 'http_version': '1.1', 'server': ('172.31.30.157', 8000), 'client': ('172.31.47.71', 55984), 'scheme': 'http', 'method': 'GET', 'root_path': '', 'path': '/', 'raw_path': b'/', 'query_string': b'', 'headers': '<...>'}
2022-09-22 18:42:39 TRACE: 172.31.21.3:59240 - ASGI [2] Completed
2022-09-22 18:42:39 TRACE: 172.31.47.71:55984 - HTTP connection made
2022-09-22 18:42:39 INFO: 172.31.21.3:59240 - "GET / HTTP/1.1" 200 OK
2022-09-22 18:42:39 TRACE: 172.31.21.3:59240 - ASGI [2] Send {'type': 'http.response.body', 'body': '<17 bytes>'}
2022-09-22 18:42:39 TRACE: 172.31.21.3:59240 - ASGI [2] Started scope={'type': 'http', 'asgi': {'version': '3.0', 'spec_version': '2.3'}, 'http_version': '1.1', 'server': ('172.31.30.157', 8000), 'client': ('172.31.21.3', 59240), 'scheme': 'http', 'method': 'GET', 'root_path': '', 'path': '/', 'raw_path': b'/', 'query_string': b'', 'headers': '<...>'}
2022-09-22 18:42:39 TRACE: 172.31.21.3:59240 - ASGI [2] Send {'type': 'http.response.start', 'status': 200, 'headers': '<...>'}
2022-09-22 18:42:39 TRACE: 172.31.21.3:59240 - HTTP connection made
2022-09-22 18:42:30 INFO: Uvicorn running on http://0.0.0.0:8000 (Press CTRL+C to quit)
2022-09-22 18:42:30 INFO: Waiting for application startup.
2022-09-22 18:42:30 TRACE: ASGI [1] Started scope={'type': 'lifespan', 'asgi': {'version': '3.0', 'spec_version': '2.0'}}
2022-09-22 18:42:30 TRACE: ASGI [1] Receive {'type': 'lifespan.startup'}
2022-09-22 18:42:30 TRACE: ASGI [1] Send {'type': 'lifespan.startup.complete'}
2022-09-22 18:42:30 INFO: Application startup complete.
2022-09-22 18:42:30 INFO: Started server process [1]
Any suggestions on how to solve this problem? Thanks!