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Title
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Albert Wong

03/13/2023, 5:40 PM
I'm trying to set up a prefect server service from a virtual environment with
ExecStart=/home/ubuntu/apps/dataflows/venv/bin/prefect server start --host 0.0.0.0
Receiving the following error. Anyone ever see this and/or knows how to fix this?
File "/home/ubuntu/.pyenv/versions/3.11.2/lib/python3.11/asyncio/base_subprocess.py", line 36, in __init__
    self._start(args=args, shell=shell, stdin=stdin, stdout=stdout,
  File "/home/ubuntu/.pyenv/versions/3.11.2/lib/python3.11/asyncio/unix_events.py", line 810, in _start
    self._proc = subprocess.Popen(
                 ^^^^^^^^^^^^^^^^^
  File "/home/ubuntu/.pyenv/versions/3.11.2/lib/python3.11/subprocess.py", line 1024, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/home/ubuntu/.pyenv/versions/3.11.2/lib/python3.11/subprocess.py", line 1901, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'uvicorn'
āœ… 1
z

Zanie

03/13/2023, 5:43 PM
When you call
prefect server start
we start uvicorn in a subprocess https://github.com/PrefectHQ/prefect/blob/main/src/prefect/cli/server.py#L147-L160
Sounds like uvicorn is not available on the path
a

Albert Wong

03/13/2023, 5:44 PM
hhm, it starts fine on the command line after I start up the virtual environment. Is there some environment/variable that needs to be set?
this is what I see when I try to install the package:
(venv) ubuntu@gbi-tableau-innovation:~/apps/dataflows$ pip install uvicorn
Requirement already satisfied: uvicorn in ./venv/lib/python3.11/site-packages (0.20.0)
Requirement already satisfied: click>=7.0 in ./venv/lib/python3.11/site-packages (from uvicorn) (8.1.3)
Requirement already satisfied: h11>=0.8 in ./venv/lib/python3.11/site-packages (from uvicorn) (0.14.0)
z

Zanie

03/13/2023, 5:46 PM
It looks like you are calling `prefect `directly from the venv bin
Instead of activating the environment then calling Prefect
So nothing else from the venv will be on the path
Iā€™d take a look at the contents of
.venv/bin/activate
a

Albert Wong

03/13/2023, 5:51 PM
yeah, that's sort of the recommendation for running daemons in virtual environments based on what I've read, but makes sense and thanks for the direction. I'll see if there's something I can do on the systemd side, else just wrap the whole thing in a script that starts the virtual environment before running the server
Yup, looks like there's an Environment variable I can set in the service script:
Environment="PATH=/home/ubuntu/apps/dataflows/venv/bin:$PATH"
Working now, thanks for your help @Zanie!
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