JSON Schema for FireWorks

This package provides a JSON schema for the FireWorks package.

Why should I use JSON schema?

The input for FireWorks is often provided in JSON or YAML formats and generated by third-party software that is unaware of the valid data types in FireWorks. Latent mismatches of data types may produce run-time errors, such as missing keywords or wrong data types, that are more difficult to handle than a validation of the initial input.

The fireworks_schema package provides a formal human- and machine-readable description of the data types used in classes in FireWorks. Additionally, a function is provided that checks the validity of JSON and YAML inputs immediately before deserialization.

Installing fireworks_schema

The recommended way to install this package into your virtual environment is using pip (in any folder):

python -m pip install fireworks-schema

Alternatively you can download a release from the GitHub repository, unpack the archive, change into the folder containing setup.py and run:

python setup.py install

After the installation you can run the tests, for example using the nose package:

nosetests fireworks_schema.tests

Using fireworks_schema to validate input for FireWorks

There are two ways to perform JSON schema validation:

• Call the schema validator explicitly
• Activate automatic schema validation

Call the schema validator explicitly

This is the case when you use Python but read JSON/YAML serialized objects provided externally. In the following example, a serialized workflow object is loaded from a YAML file and validated against the Workflow schema:

  import yaml
  import fireworks_schema
  from fireworks import Workflow

  with open('empty_fws.yaml', 'rt') as yf:
      dct = yaml.safe_load(yf)
  fireworks_schema.validate(dct, 'Workflow')
  wf = Workflow.from_dict(dct)

Activate automatic schema validation

To activate automatic schema validation you must specify:

  JSON_SCHEMA_VALIDATE: true

in your FWConfig file. For more details about managing your FWConfig file see the FW Config tutorial.

The default value of JSON_SCHEMA_VALIDATE is false.

If automatic validation is turned on, i.e. JSON_SCHEMA_VALIDATE is true, then validation is performed only for the classes specified in the list JSON_SCHEMA_VALIDATE_LIST, whenever an object of these classes is loaded from file. There is no default for JSON_SCHEMA_VALIDATE_LIST and therefore you must set JSON_SCHEMA_VALIDATE_LIST in your FWConfig file. For example, to turn on automatic validation for serialized Firework and Workflow objects these two lines must be added to the FWConfig file:

  JSON_SCHEMA_VALIDATE: true
  JSON_SCHEMA_VALIDATE_LIST: [Firework, Workflow]