OpenFisca Core

OpenFisca is a versatile microsimulation free software. Check the online documentation for more details.

This package contains the core features of OpenFisca, which are meant to be used by country packages such as OpenFisca-France. Bootstrapping your own country package should not take more than 5 minutes: check our country package template.

Environment

OpenFisca runs on Python 3.7. More recent versions should work, but are not tested.

OpenFisca also relies strongly on NumPy. Last four minor versions should work, but only latest/stable is tested.

Installation

If you're developing your own country package, you don't need to explicitly install OpenFisca-Core. It just needs to appear in your package dependencies.

If you want to contribute to OpenFisca-Core itself, welcome! To install it locally in development mode run the following commands:

git clone https://github.com/openfisca/openfisca-core.git
cd openfisca-core
python3 -m venv .venv
source .venv/bin/activate
pip install -U pip
pip install --editable .[dev] --use-deprecated=legacy-resolver

Testing

To run the entire test suite:

make test

To run all the tests defined on a test file:

pytest tests/core/test_parameters.py

To run a single test:

pytest tests/core/test_parameters.py -k test_parameter_for_period

Types

This repository relies on MyPy for optional dynamic & static type checking.

As NumPy introduced the typing module in 1.20.0, to ensure type hints do not break the code at runtime, we run the checker against the last four minor NumPy versions.

Type checking is already run with make test. To run the type checker alone:

make check-types

Style

This repository adheres to a certain coding style, and we invite you to follow it for your contributions to be integrated promptly.

Style checking is already run with make test. To run the style checker alone:

make check-style

To automatically style-format your code changes:

make format-style

To automatically style-format your code changes each time you commit:

touch .git/hooks/pre-commit
chmod +x .git/hooks/pre-commit

tee -a .git/hooks/pre-commit << END
#!/bin/sh
#
# Automatically format your code before committing.
exec make format-style
END

Documentation

Yet however OpenFisca does not follow a common convention for docstrings, our current toolchain allows to check whether documentation builds correctly and to update it automatically with each contribution to this repository.

In the meantime, please take a look at our contributing guidelines for some general tips on how to document your contributions, and at our official documentation's repository to in case you want to know how to build it by yourself —and improve it!

To verify that the documentation still builds correctly

You can run:

make test-doc

If it doesn't, or if the doc is already broken.

Here's how you can fix it:

1. Clone the documentation, if not yet done:

make test-doc-checkout

2. Install the documentation's dependencies, if not yet done:

make test-doc-install

3. Create a branch, both in core and in the doc, to correct the problems:

git checkout -b fix-doc
sh -c "cd doc && git checkout -b `git branch --show-current`"

4. Fix the offending problems —they could be in core, in the doc, or in both.

You can test-drive your fixes by checking that each change works as expected:

make test-doc-build branch=`git branch --show-current`

5. Commit at each step, so you don't accidentally lose your progress:

git add -A && git commit -m "Fix outdated argument for Entity"
sh -c "cd doc && git add -A && git commit -m \"Fix outdated argument for Entity\""

6. Once you're done, push your changes and cleanup:

git push origin `git branch --show-current`
sh -c "cd doc && git push origin `git branch --show-current`"
rm -rf doc

7. Finally, open a pull request both in core and in the doc.

Continuous integration will automatically try to build the documentation from the same branch in both core and the doc (in our example "fix-doc") so we can integrate first our changes to Core, and then our changes to the doc.

If no changes were needed to the doc, then your changes to core will be verified against the production version of the doc.

If your changes concern only the doc, please take a look at the doc's README.

That's it! 🙌

Serving the API

OpenFisca-Core provides a Web-API. It is by default served on the 5000 port.

To run it with the mock country package openfisca_country_template and another port value such as 2000, run:

openfisca serve --country-package openfisca_country_template --port 2000

To read more about the openfisca serve command, check out its documentation.

By default, the Web API uses 3 workers to avoid this issue. Without it, AJAX requests from Chrome sometimes take more than 20s to process. You can change the number of workers by specifying a --workers k option.

You can test that the API is running by executing the command:

curl http://localhost:2000/parameters

For more information about endpoints and input formatting, see the official documentation.

Tracker

The OpenFisca Web API comes with an optional tracker which allows you to measure the usage of the API.

Tracker installation

The tracker is not installed by default. To install it, run:

pip install openfisca_core[tracker] --use-deprecated=legacy-resolver # Or `pip install --editable ".[tracker]"` for an editable installation

Tracker configuration

The tracker is activated when these two options are set:

• --tracker-url: An URL ending with piwik.php. It defines the Piwik instance that will receive the tracking information. To use the main OpenFisca Piwik instance, use https://stats.data.gouv.fr/piwik.php.
• --tracker-idsite: An integer. It defines the identifier of the tracked site on your Piwik instance. To use the main OpenFisca piwik instance, use 4.
• --tracker-token: A string. It defines the Piwik API Authentification token to differentiate API calls based on the user IP. Otherwise, all API calls will seem to come from your server. The Piwik API Authentification token can be found in your Piwik interface, when you are logged.

For instance, to run the Web API with the mock country package openfisca_country_template and the tracker activated, run:

openfisca serve --country-package openfisca_country_template --port 5000 --tracker-url https://stats.data.gouv.fr/piwik.php --tracker-idsite 4 --tracker-token $TRACKER_TOKEN