CODEWITHSUNDEEP
pythongoogle-app-engineflaskpip
klenwell
klenwell

Reputation: 7148

With Google's Flask skeleton for Python App Engine, how can install additional libraries with Pip?

To install dependences, the appengine-python-flask-skeleton docs advise running this command:

pip install -r requirements.txt -t lib

That works simply enough.

Now say I want to add the Requests package.

Ideally I just add it to the requirements.txt file:

# This requirements file lists all third-party dependencies for this project.
#
# Run 'pip install -r requirements.txt -t lib/' to install these dependencies
# in `lib/` subdirectory.
#
# Note: The `lib` directory is added to `sys.path` by `appengine_config.py`.
Flask==0.10
requests

And then re-run the command:

pip install -r requirements.txt -t lib

However, as this Github issue for pip notes, pip is not idempotent with the -T option recommended by Google here. The existing flask packages will be re-added and this will lead to the following error when running the devapp

ImportError: cannot import name exceptions

How can I best work around this problem?

Upvotes: 0

Views: 210

Answers (2)

Jeffrey Godwyll
Jeffrey Godwyll

Reputation: 3893

Like said, updating pip solves the issue for many, but for what it's worth I think you can get around all of this if the use of virtualenv is an option. Symlink /path/to/virtualenv's/sitepackages/ to lib/ and just always keep an up to date requirements.txt file. There are no duplication of packages this way and one won't have to manually install dependencies. See also https://stackoverflow.com/a/30447848/2295256

Upvotes: 1

klenwell
klenwell

Reputation: 7148

Upgrading to the latest version of pip solved my problem (that issue had been closed):

pip install -U pip

Otherwise, as noted in that thread, you can always just wipe out your lib directory and reinstall from scratch. One note of warning: if you manually added additional packages to the lib directory not tracked in requirements.txt, they would be lost and have to be re-installed manually.

Upvotes: 0

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