Examples

To validate a JSON model file, use the ‘model’ subcommand:

osvalidate model mymodel.json

Or, to check that a CSV sheet satisfies the requirements of an existing model, use the ‘data’ subcommand:

osvalidate data --model mymodel.json BigData.csv

Both commands will emit error messages whenever they find an inconsistency but otherwise try to continue the validation. Note, however, that a valid model file is required to run the data validator.

Upgrading the Format

The model schema changes from time to time, so a migration option is provided so that existing files can be upgraded:

osvalidate migrate old.json >new.json

This will attempt to execute pending migrations and set an appropriate model version.

Schema / Format

The JSON model format is described in further detail in the documentation.

You can generate a bare mapping from a JSON model file using:

osvalidate mapping mymodel.json

If you don’t have a JSON model file, you can generate one from a CSV file as follows:

osvalidate mapgen data.csv

You will need to edit the result of this to add information (like textual explanations of the fields) can’t be programmatically inferred from the contents of the CSV file.

Installation

Installation is as a conventional Python tool:

virtualenv pyenv

. pyenv/bin/activate

python setup.py install

Developer notes

Each new version of osvalidate needs to be published in a few steps:

• Update the version in setup.py to a new release of the form YYYY-MM-DD.SS with the last two digits signifying a serial number for the day.

• Commit and push the new release to the GitHub repository.

• Upload a source distribution to pypi (python setup.py sdist upload).

• Update the required version of osvalidate in the main openspending app.

How to write a migration - Migrations of model formats are simple functions, usually named mYYYY_MM_DD_purpose and stored in the migrations module. They must both accept and return a model file and be registered in openspending.validation.model.migration:MIGRATIONS with an increasing version stamp (i.e. the current date). The version stamp of the latest executed migration will automatically be saved to the model and used as a minimum for the next run.

In general, migrations should make as few assumptions about the input they receive as possible and execute idempotently. Migrations cannot change the dataset section of the model.

Contact

• E-Mail: info@openspending.org

• Issues: https://github.com/openspending/openspending/issues