Share installed requirements between jobs - pip

Question

I have the following yml configuration file with 3 different jobs:
stages:
- build
- test
- analyze
build:
stage: build
script:
- apt-get update -qy
- apt-get install -y python3-dev python3-pip
- pip3 install -r requirements.txt
test:
stage: test
script:
- coverage run --source='.' manage.py test
cache:
paths:
- .coverage
analyze:
stage: analyze
script:
- flake8
- coverage report
In the first job I install the requirements, among which are coverage or flake8. But these tools are used in the following jobs. I have tried using 'dependencies' or 'cache', but it didn't work: only files/dirs under the project root directory can be shared, not the binaries under /user/local/bin.
I have tried to indicate another directory for pip install, but the binary is installed in /user/local/bin.
The workaround I have found is to install the dependencies in each job, but I think that this is the less optimal solution.
I think that there must be a better solution for that.
Thanks.

Answer 1

I just found a solution, at least for python3 (enough for me):
python3 has a built-in tool for managing virtual envs: venv
Using venv, we can create the virtual env in the project root dir, cache this dir, and enable our virtual env in each job.
variables:
VENV_NAME: "env"
cache:
paths:
- $VENV_NAME
first_job:
script:
- apt-get update -qy
- apt-get install -y python3-dev python3-pip python3-venv
- python3 -m venv $VENV_NAME
- source $VENV_NAME/bin/activate
- pip3 install -r requirements.txt
next_jobs:
script:
- source $VENV_NAME/bin/activate
- echo "hello world!"
PD: don't forget to exclude virtual env dir from coverage or other analysis tools