Home » Python » Renaming a virtualenv folder without breaking it

Renaming a virtualenv folder without breaking it

Posted by: admin November 1, 2017 Leave a comment

Questions:

I’ve created folder and initialized a virtualenv instance in it.

$ mkdir myproject
$ cd myproject
$ virtualenv env

When I run (env)$ pip freeze, it shows the installed packages as it should.

Now I want to rename myproject/ to project/.

$ mv myproject/ project/

However, now when I run

$ . env/bin/activate
(env)$ pip freeze

it says pip is not installed. How do I rename the project folder without breaking the environment?

Answers:

You need to adjust your install to use relative paths. virtualenv provides for this with the --relocatable option. From the docs:

Normally environments are tied to a
specific path. That means that you
cannot move an environment around or
copy it to another computer. You can
fix up an environment to make it
relocatable with the command:

$ virtualenv –relocatable ENV

NOTE: ENV is the name of the virtual environment and you must run this from outside the ENV directory.

This will make some of the files
created by setuptools or distribute
use relative paths, and will change
all the scripts to use
activate_this.py instead of using the
location of the Python interpreter to
select the environment.

Note: you must run this after you’ve
installed any packages into the
environment. If you make an
environment relocatable, then install
a new package, you must run virtualenv
–relocatable again.

Questions:
Answers:

What I believe is that "knowing why" matters more than "knowing how". So, here is another approach to fix this.

When you run:

$ . env/bin/activate

it actually execute the following commands:

( I test this in /tmp )

VIRTUAL_ENV="/tmp/myproject/env"
export VIRTUAL_ENV

However, you have just renamed myproject to project, so that command failed to execute.
That is why it says pip is not installed, because neither you have installed pip in the system global environment nor your virtualenv pip is sourced correctly.

If you want to fix this manually, that is the way:

  1. modify /tmp/project/env/bin/activate with yout favoriate editor like Vim, usually in
    Line 42

    VIRTUAL_ENV='/tmp/myproject/env' => VIRTUAL_ENV='/tmp/project/env'

  2. modify /tmp/project/env/bin/pip in Line 1

    #!/tmp/myproject/env/bin/python => #!/tmp/project/env/bin/python

After that, activate your virtual environment env again, and you will see your pip has come back again.

Questions:
Answers:

NOTE: As @jb. points out, this solution only applies to easily (re)created virtualenvs. If an environment takes several hours to install this solution is not recommended


Virtualenvs are great because they are easy to make and switch around; they keep you from getting locked into a single configuration. If you know the project requirements, or can get them, Make a new virtualenv:

  • Create a requirements.txt file

    (env)$ pip freeze > requirements.txt

    • If you can’t create the requirements.txt file, check env/lib/pythonX.X/site-packages before removing the original env.
  • Delete the existing (env)

    deactivate && rm -rf env

  • Create a new virtualenv, activate it, and install requirements

    virtualenv env && . env/bin/activate && pip install -r requirements.txt


Alternatively, use virtualenvwrapper to make things a little easier as all virtualenvs are kept in a centralized location

$(old-venv) pip freeze > temp-reqs.txt
$(old-venv) deactivate
$ mkvirtualenv new-venv
$(new-venv) pip install -r temp-reqs.txt
$(new-venv) rmvirtualenv old-venv

Questions:
Answers:

I always install virtualenvwrapper to help out. From the shell prompt:

pip install virtualenvwrapper

There is a way documented in the virtualenvwrapper documents – cpvirtualenv
This is what you do. Make sure you are out of your environment and back to the shell prompt. Type in this with the names required:

cpvirtualenv oldenv newenv

And then, if necessary:

rmvirtualenv oldenv

To go to your newenv:

workon newenv

Questions:
Answers:

You can fix your issue by following these steps:

  1. rename your directory
  2. rerun this: $ virtualenv ..\path\renamed_directory
  3. virtualenv will correct the directory associations while leaving your packages in place
  4. $ scripts/activate
  5. $ pip freeze to verify your packages are in place
  6. An important caveat, if you have any static path dependencies in script files in your virtualenv directory, you will have to manually change those.
Questions:
Answers:

Yet another way to do it that worked for me many times without problems is virtualenv-clone:

pip install virtualenv-clone
virtualenv-clone old-dir/env new-dir/env

Questions:
Answers:

virtualenv --relocatable ENV is not a desirable solution. I assume most people want the ability to rename a virtualenv without any long-term side effects.

So I’ve created a simple tool to do just that. The project page for virtualenv-mv outlines it in a bit more detail, but essentially you can use virtualenv-mv just like you’d use a simple implementation of mv (without any options).

For example:

virtualenv-mv myproject project

Please note however that I just hacked this up. It could break under unusual circumstances (e.g. symlinked virtualenvs) so please be careful (back up what you can’t afford to lose) and let me know if you encounter any problems.