6

I'm working in Amazon's Cloud9.

ec2-user:~/environment/flask_init $ python -V
Python 2.7.14
ec2-user:~/environment/flask_init $ virtualenv -p python3 venv
Running virtualenv with interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in /home/ec2-user/environment/flask_init/venv/bin/python3
Also creating executable in /home/ec2-user/environment/flask_init/venv/bin/python
Installing setuptools, pip, wheel...done.
ec2-user:~/environment/flask_init $ source venv/bin/activate
(venv) ec2-user:~/environment/flask_init $ python -V
Python 2.7.14

Why is the virtual environment not using Python 3?

Please note that this question is not a duplicate of this one. The issue was specifically to do with the way the Cloud 9 environment sets up Python alias.

Improve this question
7
  • 1
    could you try giving the full path to python3 while creating virtualenv like virtualenv -p path/to/python3 venv Commented Oct 20, 2018 at 6:19
  • Still doesn't work when I create using the link /usr/bin/python3 Commented Oct 20, 2018 at 14:29
  • @RubyNoob Could you please try creating the venv again with -v flag and paste the logs into the question? Commented Oct 20, 2018 at 15:04
  • Everything looks okay in your output, could you try executing python3 -v and if the output is Python 3.x then try running python3 -m virtualenv venv Commented Oct 20, 2018 at 15:20
  • @Dluzak Stack Overflow says there's too much code in the edit when I enter the logs, so I pasted it here: (pastebin.com/dSzuM73a) Commented Oct 20, 2018 at 15:23

4 Answers 4

Reset to default
4

I tried your flow on my machine and everything works as expected.

dluzak@Karol-PC:/tmp$ python -V
Python 2.7.12
dluzak@Karol-PC:/tmp$ virtualenv -p python3 venv
Already using interpreter /usr/bin/python3
Using base prefix '/usr'
New python executable in /tmp/venv/bin/python3
Also creating executable in /tmp/venv/bin/python
Installing setuptools, pkg_resources, pip, wheel...done.
dluzak@Karol-PC:/tmp$ source venv/bin/activate
(venv) dluzak@Karol-PC:/tmp$ python -V
Python 3.5.2
(venv) dluzak@Karol-PC:/tmp$

Nonetheless I personally use virtualenv as module when creating venv with python 3: python3 -m virtualenv venv. Maybe this would work.

You provided very little details. Have you installed virtualenv for both Python 2 and 3? Are you sure Python 3 interpreter works fine?

Edit:

After investigation in comments we found out that the problem was in bash settings configured by Amazon. It seams that Amazon configures bash (probably in ~/.bashrc) to replace python calls with an alias. To fix this a call unalias python before enabling venv is needed. It is described in Amazon docs

Improve this answer
Sign up to request clarification or add additional context in comments.

12 Comments

thanks for the suggestions. Python 3 interpreter runs and shows v3.6.5. python3 -m pip install virtualenv gives me Requirement already satisfied: virtualenv in /usr/local/lib/python3.6/site-packages. I tried your module approach but the virtual environment is still running Python 2.
It's almost as though the virtual environment isn't running, because when I am in it and run python3 it opens the python3 interpreter. So it seems to have two pythons and is using python3 by default, just like the host environment without the virtual environment running.
@RubyNoob I don't quite understand your second comment. So after activating virtualenv, when calling python3 you are getting python3, that is: exactly what you wanted? If in doubt if it is the host or virtualenv one you can call which python3
Python3 is definitely the virtual environment's version: ~/environment/flask_init/venv/bin/python3 - but I want this virtual environment to use python 3 by default, and right now it's using python 2.7 by default. I didn't want Python 2 at all in this venv.
@RubyNoob venv/bin/python should be symlink pointing to the venv/bin/python3. Could you check if thats the case? The easiest way would be to call ls -alF ~/environment/flask_init/venv/bin.
|
1

When I was using virtualenv earlier today, I had the same problem that my env was not using the right version of python.

Instead of activating my environment like this:

source activate

I found that activating it like this actually worked:

source ./activate

Hope this is helpful!

Improve this answer

Comments

1

Here is how i create virtualenv on Cloud9

Python 3.4

$ sudo pip install virtualenv
$ virtualenv -p /usr/bin/python3.4 venv
$ source venv/bin/activate

Python 3.6

$ sudo apt update
$ sudo apt install python3.6-venv
$ python3.6 -mvenv venv
$ source venv/bin/activate
Improve this answer

Comments

0

I have encountered a similar issue. In my case did not work because I moved the virtual env folder (but the same thing happens when you rename it).

You can understand which version of python (and thus which module will import) is using by typing 

$ which python

If it write something like:

/usr/bin/python

Then it means your virtual env is not being activated.
To solve this issue, instead of creating a new virtual environment, you can simply edit the script activation file in your env:

$ nano venv/bin/activate

And edit the following line with your absolute path of your virtual environment:

VIRTUAL_ENV="/YOUR_ABSOLUT/PATH_TO/venv"

Hope it helps :)

Improve this answer

Comments

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.