Check If My Application Runs In Development/editable Mode

My Python application can be install the normal way, or in development/editable mode with pip, like this: virtualenv my_app source my_app/bin/activate pip install -e my_app How ca

Solution 1:

Using code from pip we can determine this:

import pip
import pkg_resources

# I've done `pip install -e .` for a git repo I'm working in inside# a virtualenv
distributions = {v.key: v for v in pkg_resources.working_set}
# >>> distribution# pre-commit 0.9.3 (/home/asottile/workspace/pre-commit)
distribution = distributions['pre-commit']

# Below is approximately how `pip freeze` works, see the end of# the answer for a simpler approach, still using pip# Turn into a pip FrozenRequirement (I'm using pip 9.0.1, it may# be different for your version)# I've passed an empty list for the second argument (dependency_links)# I don't think it's necessary?
frozen_requirement = pip.FrozenRequirement.from_dist(distribution, [])

# Query whether the requirement is installed editably:print(frozen_requirement.editable)

The magic of this comes from a little function inside pip (pip.utils):

defdist_is_editable(dist):
    """Is distribution an editable install?"""for path_item in sys.path:
        egg_link = os.path.join(path_item, dist.project_name + '.egg-link')
        if os.path.isfile(egg_link):
            returnTruereturnFalse

The dist in this is a pkg_resources distribution (as we acquired above). You of course can use the dist_is_editable function directly instead of going through FrozenRequirement:

# With `distribution` as above:from pip.utils import dist_is_editable
print(dist_is_editable(distribution))  # True in my case ;)

Solution 2:

The top solution needs updating for a more recent version of pip, where the FrozenRequirement class is no longer accessible in pip's namespace.

I used this workaround in the relevant lines.

from pip._internal.operations.freeze importFrozenRequirementfrozen_requirement= FrozenRequirement.from_dist(distribution)

Solution 3:

I am not sure if there's a reliable way to determine this. In fact, I would advise you against testing paths like that because you might run into into different special cases on various operating systems or environments.

There are a few alternatives I recommend instead:

1) If this is a command-line utility, I'd recommend to allow loading of a custom configuration file configurable via a command-line flag:

from argparse import ArgumentParser
import sys
import json

parser = ArgumentParser(description='...')
parser.add_argument('-c', '--config', default='config.json')

defmain(argv):
    args = parser.parse_args(argv)
    print('loading config file:', args.config)
    withopen(args.config, 'r') as config:
        config = json.loads(config.read())
    print('loaded config', config) 
    # TODO do something with the configif __name__ == '__main__':
    main(sys.argv[1:])

Run with: python3 test1.py -c config-dev.json

2) If this is not a CLI app, you can achieve a similar thing by using an environment variable:

import os
import json

os.environ.get('CONFIG', 'config.json')

def main():
    config_file = os.environ.get('CONFIG', 'config.json')
    print('loading config file:', config_file)
    with open(config_file, 'r') as config:
        config = json.loads(config.read())
    print('loaded config', config) 
    # TODO do something with the configif __name__ == '__main__':
    main()

Run with: CONFIG=config-dev.json python3 test2.py, or:

export CONFIG=config-dev.json
python3 test2.py

You could also make a shell script to help with set your dev environment, let's call it customenv:

sourceenv/bin/activate
export CONFIG=config-dev.json

And then you could use this file to activate the dev environment:

source customenv

3) If you really wish to have a special case in your code for the development environment, you could specify this via an environment variable too:

import os
is_dev_mode = 'MY_APP_DEV'inos.environ andos.environ['MY_APP_DEV'] == '1'if is_dev_mode:
    print('dev mode!')

Run with MY_APP_DEV=1 python3 test3.py, or:

export MY_APP_DEV=1
python3 -m test3.py

4) For more customization:

import os
app_mode = os.environ.get('MY_APP_MODE', 'prod')
print(app_mode)