labels

This directory contains all the predefined data label definitions used for classification. The label metadata is specified in the labels.yaml file, and the classification rules are defined in individual Rego files for each label.

To add a new predefined label, add its metadata to labels.yaml (following the file's instructions), as well as a corresponding classification rule Rego file.

Classification Rule Rego Files

Each label has a corresponding Rego file that defines the classification rule for that label. The Rego file should be named after the label, with the .rego extension. For example, the classification rule for the label first_name should be defined in a file named first_name.rego.

The package for the rule should be named classifier_<label>, where <label> is the name of the label in lowercase. For example, the package for the classification rule for the label first_name should be named classifier_first_name.

Rules should also have tests defined in a file named <label>_test.rego.

All Rego files (including tests) should be linted using regal to ensure they are formatted correctly, e.g.

$ regal lint /path/to/label.rego

Input and Output

The input data for a classification rule is a JSON object containing the data to be classified. This often represents a database table sample, for example. The key names in the input data object correspond to the column names in the database table, and the values are the sampled data in the table. For example, input data representing a data sample from a database table called users might look like this:

{
  "first_name": "John",
  "last_name": "Doe",
  "email": "john.doe@example.com"
}

Each rule must define an output variable named output, which must an object of the form:

{
  "key": boolean
}

where key is each key from the input data, and boolean is a boolean value indicating whether the key is classified as the label or not. For example, the output object for the first_name label using the example input data above would look like this:

{
  "first_name": true,
  "last_name": false,
  "email": false
}

See this example on the Rego Playground.

Please see the existing classification rules and their tests for examples of how to write classification rules.