uvicorn error on AWS EC2 with uvicorn + fastapi

Question

I have a server running locally. When I run it on AWS EC2 and send a request from outside on port 8000, I get the following error:

$ uvicorn sql_app.main:app --host="0.0.0.0" --port=8000
INFO:     Started server process [9806]
INFO:     Waiting for application startup.
INFO:     Application startup complete.
INFO:     Uvicorn running on http://0.0.0.0:8000 (Press CTRL+C to quit)
WARNING:  Invalid HTTP request received.
Traceback (most recent call last):
  File "/home/ec2-user/.local/lib/python3.7/site-packages/uvicorn/protocols/http/h11_impl.py", line 170, in handle_events
    event = self.conn.next_event()
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_connection.py", line 443, in next_event
    exc._reraise_as_remote_protocol_error()
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_util.py", line 76, in _reraise_as_remote_protocol_error
    raise self
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_connection.py", line 425, in next_event
    event = self._extract_next_receive_event()
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_connection.py", line 367, in _extract_next_receive_event
    event = self._reader(self._receive_buffer)
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_readers.py", line 73, in maybe_read_from_IDLE_client
    request_line_re, lines[0], "illegal request line: {!r}", lines[0]
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_util.py", line 88, in validate
    raise LocalProtocolError(msg)
h11._util.RemoteProtocolError: illegal request line: bytearray(b'\x16\x03\x01\x02\x00\x01\x00\x01\xfc\x03\x03\x91\xa5\xe2Y\xf0\xa1\xdd\x1d+\x08\x1c\r\x15X\x1d@\x1e/\xb1N\x00\xb5\xe5\xec\xf3F\x1fm\x03\xa1{> \xa80\xb4\x14\x1aUs\xaa\xcd\xc3<s\xcd\xd1\x17\xdf3\x0e\xdbh\xd1c\x88}\x8c\x1f\xa5\x15\x9aa\x14I\x00 ')
WARNING:  Invalid HTTP request received.
Traceback (most recent call last):
  File "/home/ec2-user/.local/lib/python3.7/site-packages/uvicorn/protocols/http/h11_impl.py", line 170, in handle_events
    event = self.conn.next_event()
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_connection.py", line 443, in next_event
    exc._reraise_as_remote_protocol_error()
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_util.py", line 76, in _reraise_as_remote_protocol_error
    raise self
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_connection.py", line 425, in next_event
    event = self._extract_next_receive_event()
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_connection.py", line 367, in _extract_next_receive_event
    event = self._reader(self._receive_buffer)
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_readers.py", line 68, in maybe_read_from_IDLE_client
    raise LocalProtocolError("illegal request line")
h11._util.RemoteProtocolError: illegal request line
WARNING:  Invalid HTTP request received.
Traceback (most recent call last):
  File "/home/ec2-user/.local/lib/python3.7/site-packages/uvicorn/protocols/http/h11_impl.py", line 170, in handle_events
    event = self.conn.next_event()
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_connection.py", line 443, in next_event
    exc._reraise_as_remote_protocol_error()
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_util.py", line 76, in _reraise_as_remote_protocol_error
    raise self
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_connection.py", line 425, in next_event
    event = self._extract_next_receive_event()
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_connection.py", line 367, in _extract_next_receive_event
    event = self._reader(self._receive_buffer)
  File "/home/ec2-user/.local/lib/python3.7/site-packages/h11/_readers.py", line 68, in maybe_read_from_IDLE_client
    raise LocalProtocolError("illegal request line")
h11._util.RemoteProtocolError: illegal request line
WARNING:  Invalid HTTP request received.

It would be very nice if you could tell me how to do it on port 80.

Answer 1

I was getting the same arcane WARNING: Invalid HTTP request received. error with an unhelpful stack trace. I tried all of the environment variable tweaks recommended and none worked (see FastAPI issue #680, uvicorn issue #441).

My issue was that when I was calling my FastAPI microservice I was using https when my microservice did not have HTTPS support. I changed the url from https to http and it started working as expected.

Note that if your service requires HTTPS support you can add HTTPS support as Ilgizar Murzakov suggests.

Answer 2

Had the same issue. Disabling http2 on application load balancer helped me.