drivel

drivel is a command-line tool written in Rust for inferring a schema from an example JSON (or JSON lines) file, outputting it in human-readable or JSON Schema format, and generating synthetic data (the drivel in question) based on the inferred schema.

Features

• Schema Inference: drivel can analyze JSON input and infer its schema, including data types, array lengths, and object structures.
• JSON Schema Output: Export inferred schemas in standard JSON Schema format (draft 2020-12) for integration with other tools and validation workflows.
• Data Generation: Based on the inferred schema, drivel can generate synthetic data that adheres to the inferred structure.
• Easy to integrate: drivel reads JSON input from stdin and writes its output to stdout, allowing for easy integration into pipelines and workflows.

Installation

Binaries and a shell-based installer are available for each release.

To install the drivel executable through Cargo, ensure you have the Rust toolchain installed and run:

cargo install drivel

To add drivel as a dependency to your project, e.g., to use the schema inference engine, run:

cargo add drivel

Usage

Infer a schema from JSON input, and generate synthetic data based on the inferred schema.

Usage: drivel [OPTIONS] <COMMAND>

Commands:
  describe  Describe the inferred schema for the input data
  produce   Produce synthetic data adhering to the inferred schema
  help      Print this message or the help of the given subcommand(s)

Options:
      --infer-enum                     Infer that some string fields are enums based on the number of unique values seen
      --enum-max-uniq <ENUM_MAX_UNIQ>  The maximum ratio of unique values to total values for a field to be considered an enum. Default = 0.1
      --enum-min-n <ENUM_MIN_N>        The minimum number of strings to consider when inferring enums. Default = 1
  -h, --help                           Print help
  -V, --version                        Print version

Examples

Consider a JSON file input.json:

{
  "name": "John Doe",
  "id": "0e3a99a5-0201-4444-9ab1-8343fac56233",
  "age": 30,
  "is_student": false,
  "grades": [85, 90, 78],
  "address": {
    "city": "New York",
    "zip_code": "10001"
  }
}

Running drivel in 'describe' mode:

cat input.json | drivel describe

Or output JSON Schema format:

cat input.json | drivel describe --json-schema

Output:

{
  "age": int (30),
  "address": {
    "city": string (8),
    "zip_code": string (5)
  },
  "is_student": boolean,
  "grades": [
    int (78-90)
  ] (3),
  "name": string (8),
  "id": string (uuid)
}

Running drivel in 'produce' mode:

cat input.json | drivel produce -n 3

Output:

[
  {
    "address": {
      "city": "o oowrYN",
      "zip_code": "01110"
    },
    "age": 30,
    "grades": [83, 88, 88],
    "is_student": true,
    "name": "nJ heo D",
    "id": "9e0a7687-800d-404b-835f-e7d803b60380"
  },
  {
    "address": {
      "city": "oro wwNN",
      "zip_code": "11000"
    },
    "age": 30,
    "grades": [83, 88, 89],
    "is_student": false,
    "name": "oeoooeeh",
    "id": "c6884c6b-4f6a-4788-a048-e749ec30793d"
  },
  {
    "address": {
      "city": "orww ok ",
      "zip_code": "00010"
    },
    "age": 30,
    "grades": [85, 90, 86],
    "is_student": false,
    "name": "ehnDoJDo",
    "id": "71884608-2760-4853-8c12-e11149c642cd"
  }
]

Contributing

We welcome contributions from anyone interested in improving or extending drivel! Whether you have ideas for new features, bug fixes, or improvements to the documentation, feel free to open an issue or submit a pull request.

License

This project is licensed under the MIT License - see the LICENSE file for details.