CODEWITHSUNDEEP
pythoninstallationpip
d0c_s4vage
d0c_s4vage

Reputation: 4077

Cannot import dynamically installed python module

I am dynamically installing code during the runtime of a script by directly importing the pip module and installing a requirements.txt:

import pip
import site
import sys

# since I'm installing with --user, packages should be installed here,
# so make sure it's on the path
sys.path.insert(0, site.USER_SITE)

pip.main(["install", "--user", "package1"])
import package1

The package installs without error, but import package1 fails. If I quit the script and run it again without doing the install (since it's already been installed), it works just fine.

I've also double checked that the site.USER_SITE is where package1 was installed. Everything is on sys.path, but I still can't import it.

Upvotes: 2

Views: 2706

Answers (1)

d0c_s4vage
d0c_s4vage

Reputation: 4077

Well, this was a fast turnaround. I've been trying to figure this one out for a few days and finally came up with my answer a few minutes after asking on here.

If a path that does not yet exist is added to sys.path, it doesn't seem like it will ever be checked again when importing modules, even if it exists at a later point (or at least in python 2.7).

In my testing, site.USER_SITE didn't exist when I added it to sys.path. If I first made sure that that directory exists, then everything works how you would think it should:

import os
import pip
import site
import sys

# this makes it work
if not os.path.exists(site.USER_SITE):
    os.makedirs(site.USER_SITE)

# since I'm installing with --user, packages should be installed here,
# so make sure it's on the path
sys.path.insert(0, site.USER_SITE)

pip.main(["install", "--user", "package1"])
import package1

Upvotes: 4

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