How can I install Python packages using pip according to the requirements.txt file from a local directory?

python

pip-installation

requirements-txt

package-management

byAnton Shumikhin·Sep 10, 2024

Run the command:

pip install -r requirements.txt

in the folder with your requirements.txt to bulk install the packages listed. This assumes you've activated a virtual environment if necessary, and pip is operational.

To install packagess from a local directory, especially when required for offline or private packages deployment, you will have to use:

pip install -r requirements.txt --no-index --find-links file:///path_to_local_packages

In this case, --no-index signals pip to ignore package indices (like PyPI), and --find-links points towards the local directories containing your packages.

Smooth sailing with local directories

When installing right from local directories, ensure that:

Your requirements.txt wrap-up is fresh as cucumber with the right package versions.
The 'yellow brick road' or path to local packages is paved straight with the file:// prefix.
You've got the required OS jazz bands or development libraries installed if you're jazzing up from source (e.g., libtiff5-dev for TIFF support).

Handling multiple 'Mission Impossibles'

For mega-projects with several requirements files (such as dev.txt, test.txt), you can just repeat the -r flag:

pip install -r requirements_dev.txt -r requirements_test.txt

This neat trick allows for layered installations, managing different scenarios or branches of your project is a breeze now!

Upgrading your gadget inventory

Desire to upgrade all existing packages while doing a requirements.txt install? Just use:

pip install -U -r requirements.txt

The -U or --upgrade flag ensures all the latest versions from requirements.txt are catered for, overwriting any 'old timers'.

Troubleshooting 'Why won't this work' instances

Issues that usually pop up with installations are:

Missing or outdated pip itself. Double-check you've got the latest version of pip with pip install --upgrade pip, straight from the Pip-horse's mouth!
Compilation fiascos due to missing system libraries. Patch it up by installing the right OS-specific dev packages.
Incorrect GPS coordinates in find-links. Re-examine the map, as in, directory structure, and check the paths!

It works! Or does it?

Post installation, you need to verify.

Examine your 'site-packages' directory, the default residence of pip installs.
Run script rehearsals in a Python shell to check the script is stage ready.
Have a mock enactment of your project to ensure all dependencies are team players.

Pip: Your multifaceted tool

Understanding pip is like knowing where the cheese is in a maze. Type:

pip install --help

And unveil more awesome options such as:

Specifying a private parking spot for downloads with --cache-dir.
Installing in editable mode with -e for local package development. It's like giving your package a 'Home-Alone' experience!
Controlling verbosity for debugging. More verbosity can sometimes result in enlightening moments!