json-schema-to-avro

Converts JSON Schema definitions into Avro Schema definitions.

Install

yarn add @inaiat/jsonschema-avro
yarn add @types/json-schema --dev

Consume

import {convert} from '@inaiat/jsonschema-avro'
import type { JSONSchema7 } from 'json-schema'

const inJson: JSONSchema7 = {
  $id: 'http://your-domain.com/schemas/your-schema.json',
  description: 'Example description',
  type: 'object',
  properties: {
    first_name: { type: 'string' },
    address: {
      type: 'object',
      properties: {
        street_address: { type: 'string' },
      },
    },
  },
}

const avro = convert(inJson)

Cli

• create a configuration file json-schema-avro.mts with the following content:

import type { Config } from '@inaiat/jsonschema-avro'
import { myDto } from './src/mymodel/myjsonschema.js'

const config: Config = {
  outDir: 'dist/avro-schemas',
  models: {
    user: {
      jsonSchema: myDto,
    },
  },
}

export default config

• finally add the generate script to your package.json and run it

  {
    // package.json
    "scripts": {
      "generate-avro-models": "jsonschema-avro generate",
      "postbuild": "yarn generate-avro-models" // If you want always generate models at build phase
    }
  }
  

• Typebox. We can use some library that generates json schema and use directly on jsonSchema field.

// src/user-dto.ts
import type { Static} from '@sinclair/typebox'
import { Type } from '@sinclair/typebox'

export const userDtoSchema = Type.Object({
  id: Type.Optional(Type.String({ maxLength: 22 })),
  name: Type.String({ maxLength: 100, minLength: 10 }),
  phone: Type.String({ maxLength: 20, minLength: 8 }),
}, { $id: 'userDto' })

import type { Config } from '@inaiat/jsonschema-avro'
import { userDtoSchema } from './src/usr-dto.js'

//json-schema-avro.mts
const config: Config = {
  outDir: 'dist/avro-schemas',
  models: {
    user: {
      jsonSchema: userDtoSchema,
    },
  },
}

export default config

Configuration

Json Schema to Avro requires a configuration file written in TypeScript, to ensure the models have applied the decorators accordingly to read the required metadata.

The models record in the config is mandatory. Each entry requires jsonSchema - a reference to the TypeScript json schema (@types/json-schema). The name file is defined by entry name.

Additionally, an output directory outDir can be declared as seen above. If it is not specified, the generated schemas will be generate on folder 'avro-schemas' on root.

Locating config not in root

By default, Json Schema to Avro will check the current working directory for the file json-schema-avro.mts. If your config is located in a different folder, pass it to the program using the flag --config <path> or -c <path>.

Test

npm test

ESM Only

This package only supports to be directly imported in a ESM context.

For informations on how to use it in a CommonJS context, please check this page.

TODO

• Handle anyOf and allOf.