sorry, is anyone else having trouble launching sub...
# ask-communityr
Riya Sinha
11/08/2025, 7:33 PMsorry, is anyone else having trouble launching subflows when running on prefect managed infrastructure / prefect cloud? i have an hourly flow that launches some subflows, and that used to work, but for the past 12 hours the prefect python api is giving an http read error when trying to launch the subflows eg:
Copy code
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/flow_engine.py", line 1079, in create_flow_run
return await client.create_flow_run(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/client/orchestration/_flow_runs/client.py", line 568, in create_flow_run
response = await self.request("POST", "/flow_runs/", json=flow_run_create_json)Riya Sinha
11/08/2025, 7:34 PM Copy code
Traceback: Traceback (most recent call last):
File "/usr/local/lib/python3.12/site-packages/httpx/_transports/default.py", line 101, in map_httpcore_exceptions
yield
File "/usr/local/lib/python3.12/site-packages/httpx/_transports/default.py", line 394, in handle_async_request
resp = await self._pool.handle_async_request(req)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/connection_pool.py", line 256, in handle_async_request
raise exc from None
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/connection_pool.py", line 236, in handle_async_request
response = await connection.handle_async_request(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/connection.py", line 103, in handle_async_request
return await self._connection.handle_async_request(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/http11.py", line 136, in handle_async_request
raise exc
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/http11.py", line 106, in handle_async_request
) = await self._receive_response_headers(**kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/http11.py", line 177, in _receive_response_headers
event = await self._receive_event(timeout=timeout)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/http11.py", line 217, in _receive_event
data = await self._network_stream.read(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_backends/anyio.py", line 32, in read
with map_exceptions(exc_map):
^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/contextlib.py", line 158, in __exit__
self.gen.throw(value)
File "/usr/local/lib/python3.12/site-packages/httpcore/_exceptions.py", line 14, in map_exceptions
raise to_exc(exc) from exc
httpcore.ReadError
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/opt/prefect/chrombpnet-registry-proj/app/workflows/submit.py", line 387, in process_job_by_type
result = await variant_scoring_submit_flow(scoring_input, temp_table_id, chromosomes)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/flow_engine.py", line 1391, in run_flow_async
async with engine.start():
^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/contextlib.py", line 210, in __aenter__
return await anext(self.gen)
^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/flow_engine.py", line 1309, in start
async with self.initialize_run():
^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/contextlib.py", line 210, in __aenter__
return await anext(self.gen)
^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/flow_engine.py", line 1234, in initialize_run
self.flow_run = await self.create_flow_run(self.client)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/flow_engine.py", line 1079, in create_flow_run
return await client.create_flow_run(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/client/orchestration/_flow_runs/client.py", line 568, in create_flow_run
response = await self.request("POST", "/flow_runs/", json=flow_run_create_json)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/client/orchestration/base.py", line 53, in request
return await self._client.send(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/client/base.py", line 330, in send
response = await self._send_with_retry(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/client/base.py", line 250, in _send_with_retry
response = await send(request, *send_args, **send_kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_client.py", line 1629, in send
response = await self._send_handling_auth(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_client.py", line 1657, in _send_handling_auth
response = await self._send_handling_redirects(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_client.py", line 1694, in _send_handling_redirects
response = await self._send_single_request(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_client.py", line 1730, in _send_single_request
response = await transport.handle_async_request(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_transports/default.py", line 393, in handle_async_request
with map_httpcore_exceptions():
^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/contextlib.py", line 158, in __exit__
self.gen.throw(value)
File "/usr/local/lib/python3.12/site-packages/httpx/_transports/default.py", line 118, in map_httpcore_exceptions
raise mapped_exc(message) from exc
httpx.ReadError
Traceback (most recent call last):
File "/usr/local/lib/python3.12/site-packages/httpx/_transports/default.py", line 101, in map_httpcore_exceptions
yield
File "/usr/local/lib/python3.12/site-packages/httpx/_transports/default.py", line 394, in handle_async_request
resp = await self._pool.handle_async_request(req)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/connection_pool.py", line 256, in handle_async_request
raise exc from None
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/connection_pool.py", line 236, in handle_async_request
response = await connection.handle_async_request(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/connection.py", line 103, in handle_async_request
return await self._connection.handle_async_request(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/http11.py", line 136, in handle_async_request
raise exc
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/http11.py", line 106, in handle_async_request
) = await self._receive_response_headers(**kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/http11.py", line 177, in _receive_response_headers
event = await self._receive_event(timeout=timeout)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_async/http11.py", line 217, in _receive_event
data = await self._network_stream.read(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpcore/_backends/anyio.py", line 32, in read
with map_exceptions(exc_map):
^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/contextlib.py", line 158, in __exit__
self.gen.throw(value)
File "/usr/local/lib/python3.12/site-packages/httpcore/_exceptions.py", line 14, in map_exceptions
raise to_exc(exc) from exc
httpcore.ReadError
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "/opt/prefect/chrombpnet-registry-proj/app/workflows/submit.py", line 387, in process_job_by_type
result = await variant_scoring_submit_flow(scoring_input, temp_table_id, chromosomes)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/flow_engine.py", line 1391, in run_flow_async
async with engine.start():
^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/contextlib.py", line 210, in __aenter__
return await anext(self.gen)
^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/flow_engine.py", line 1309, in start
async with self.initialize_run():
^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/contextlib.py", line 210, in __aenter__
return await anext(self.gen)
^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/flow_engine.py", line 1234, in initialize_run
self.flow_run = await self.create_flow_run(self.client)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/flow_engine.py", line 1079, in create_flow_run
return await client.create_flow_run(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/client/orchestration/_flow_runs/client.py", line 568, in create_flow_run
response = await self.request("POST", "/flow_runs/", json=flow_run_create_json)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/client/orchestration/base.py", line 53, in request
return await self._client.send(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/client/base.py", line 330, in send
response = await self._send_with_retry(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/prefect/client/base.py", line 250, in _send_with_retry
response = await send(request, *send_args, **send_kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_client.py", line 1629, in send
response = await self._send_handling_auth(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_client.py", line 1657, in _send_handling_auth
response = await self._send_handling_redirects(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_client.py", line 1694, in _send_handling_redirects
response = await self._send_single_request(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_client.py", line 1730, in _send_single_request
response = await transport.handle_async_request(request)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/httpx/_transports/default.py", line 393, in handle_async_request
with map_httpcore_exceptions():
^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/contextlib.py", line 158, in __exit__
self.gen.throw(value)
File "/usr/local/lib/python3.12/site-packages/httpx/_transports/default.py", line 118, in map_httpcore_exceptions
raise mapped_exc(message) from exc
httpx.ReadErrorn
Nate
11/09/2025, 1:09 AMhi @Riya Sinha are you still encountering this? there was a scheduled maintenance window today about an hour before you posted this
or the past 12 hoursover the past 12 hours, have you been seeing the same error that you posted above? if so, please DM your account ID and workspace ID (the url of a resource in your workspace will do)
r
Riya Sinha
11/09/2025, 1:11 AMjust dm’d, thank you!
10 Views