Elpy install not working seems to not find flake8

[fjs2097]

Hi there, I am a newbie to elpy and emacs. I am trying to install elpy so I can code some Python in Emacs and after going through the install guidelines defined by Elpy, it does not seem to work (no auto-fill, or syntax error checking etc...). I ran the elpy-config function and got the following

_**Virtualenv........: None RPC Python........: 2.7.10 (/usr/bin/python) Interactive Python: python (/usr/bin/python) Emacs.............: 24.5.1 Elpy..............: 1.12.0 Jedi..............: 0.9.0 Rope..............: 0.10.3 Importmagic.......: 0.1.7 Autopep8..........: 1.2.2 Yapf..............: 0.7.1 Syntax checker....: Not found (flake8)

You have not activated a virtual env. While Elpy supports this, it is often a good idea to work inside a virtual env. You can use M-x pyvenv-activate or M-x pyvenv-workon to activate a virtual env.

The directory ~/.local/bin/ is not in your PATH. As there is no active virtualenv, installing Python packages locally will place executables in that directory, so Emacs won't find them. If you are missing some commands, do add this directory to your PATH.

The configured syntax checker could not be found. Elpy uses this program to provide syntax checks of your programs, so you might want to install one. Elpy by default uses flake8.

[run] python -m pip install --user flake8**_

I made sure that flake8 was indeed installed (uninstalled and reinstalled it using pip and directly from the elpy-config window) but the message does not change. I also made sure to add the ~/.local/bin/ folder to my Path by writing (add-to-list 'load-path "~/.local/bin/") in my init file, but the " The directory ~/.local/bin/ is not in your PATH" error is still there.

Can you please help?

thanks so much

[jorgenschaefer]

Hello, and thanks for the question! There are multiple ones, so let's address each in turn :-)

it does not seem to work (no auto-fill, or syntax error checking etc...).

Can you confirm Elpy mode is active at all? E.g. is there an Elpy string in the mode line? Does C-c C-o work?

If so, what does M-TAB and C-c C-d do?

I also made sure to add the ~/.local/bin/ folder to my Path by writing (add-to-list 'load-path "~/.local/bin/")

All the syntax check problems are because of a misunderstanding here. load-path is where Emacs tries to find Emacs Lisp files. Elpy needs the flake8 program in the system PATH. You probably want to add ~/.local/bin to PATH in your shell, or, depending on what environment (OS, desktop, etc.) you run Emacs in, you can try and add it to exec-path instead of load-path. Verify it works by using C-c C-v.

Does this help?

[fjs2097]

Thank you for your quick answer! The 'exec-path' solved the syntax error checking issue. I tried a bunch of things after sending my questions yesterday, hence there had been some improvement ( Python||elpy was showing in the mode line and the autofill seemed to be working fine, M-Tab included) but the error checking was still not working, as highlighted byt the following error occuring when I pressed C-C C-v :

-- mode: compilation; default-directory: "~/Documents/" -- Compilation started at Wed May 11 10:22:57

flake8 /home/fj/Documents/firstproject.py /bin/bash: flake8: command not found

Compilation exited abnormally with code 127 at Wed May 11 10:22:57

The interesting thing though is that even before I fixed the exec-path thing, flake8 was functional after activating a virtual environment, not sure why. As a follow up question, if ok, would you mind telling me the advantages of working in a virtual environment vs not?

Thanks you so much for all your answers and quick turnaround.

[jorgenschaefer]

The interesting thing though is that even before I fixed the exec-path thing, flake8 was functional after activating a virtual environment, not sure why.

That would indicate that flake8 was installed in that virtualenv :-)

would you mind telling me the advantages of working in a virtual environment vs not?

A virtualenv means you can install dependencies of your project in one spot, and have an isolated environment with exactly the dependencies of your project in the versions required by your project. If you work on another project, you can use a different virtualenv for that.

http://docs.python-guide.org/en/latest/dev/virtualenvs/ has some basic info on that.

[fjs2097]

actually, it was working earlier, but after doing a package-refresh-contents and installing flycheck and autopep8, I now get the following error when doing C-c C-v :

/bin/bash: flake8: command not found
Compilation exited abnormally with code 127 at Wed May 11 13:07:33

not sure what happened in between...

[jorgenschaefer]

You have to make sure that flake8 is in your PATH – it's a bit tricky to figure out why it isn't remotely.

[fjs2097]

Yes, flake8 is in .local/bin, which I added to the path earlier using the 'exec-path' as you suggested. C-c C-v was working fine until I installed flycheck and autopep and now it is giving me this error again, as if it was looking for in /bin/bash folder (which does not exist)? M-x elpy config now say that flake8 is installed and gives me no error message on the .local/bin folder (see below)

/bin/bash: flake8: command not found
Compilation exited abnormally with code 127 at Wed May 11 13:07:33

Elpy Configuration

Virtualenv........: None
RPC Python........: 2.7.10 (/usr/bin/python)
Interactive Python: python (/usr/bin/python)
Emacs.............: 24.5.1
Elpy..............: 1.12.0
Jedi..............: 0.9.0
Rope..............: 0.10.3
Importmagic.......: 0.1.7
Autopep8..........: 1.2.2
Yapf..............: 0.8.0
Syntax checker....: flake8 (/home/fj/.local/bin/flake8)

You have not activated a virtual env. While Elpy supports this, it is
often a good idea to work inside a virtual env. You can use M-x
pyvenv-activate or M-x pyvenv-workon to activate a virtual env.

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[jorgenschaefer]

Elpy uses /bin/bash to run the command you specify for syntax checks. /bin/bash can not find flake8. You will have to make sure that /bin/bash can find flake8. As I said, exec-path will be a bit limited (it only affects Emacs), you really want to add $HOME/.local/bin to PATH.

[thomas-louvigne]

I got the same problem because i use zsh.... I find a work around in adding that in my .emacs (setenv "PATH" (concat (getenv "PATH") ":/home/tlu/.local/bin")) (setq exec-path (append exec-path '("/home/tlu/.local/bin")))

I still have the problem for virtualenv. If you have idea...

[jorgenschaefer]

I do not use zsh so can not help you with that tool.

[monbru]

You can set the flake8 executable in the elpy configuration group Like this [-]-\ Group Elpy . . . `--- # Option Elpy Syntax Check Command Select option and put the path to flake8 executable.

Hide Elpy Syntax Check Command: /home/{user}/.local/bin/flake8 [Or other Path] I think this can solve your issue.

[plpxsk]

To add why the solution works:

In my case, the flake8 string (path) was simply flake8 which works in a default (global) non-virtual environment

But that command fails when you do not have flake8 in the activated virtual environment

Changing the string (path) to an explicit location like /my/bin/directory/flake8 fixes this issue.

Good reference from doc: https://elpy.readthedocs.io/en/latest/concepts.html