go-chaff

A Json Schema Faker for Go 🙈.

It will genreate random data that should validate against a given schema.

[CC0 by @Iroshi_]

Documentation

Documentation for the library functions can be found here.

Installation

go get github.com/ryanolee/go-chaff@1

Usage

package main

import (
	"encoding/json"
	"fmt"

	"github.com/ryanolee/go-chaff"
)

const schema = `{"type": "number"}`

func main() {
	generator, err := chaff.ParseSchemaStringWithDefaults(schema)
	if err != nil {
		panic(err)
	}
	
	fmt.Println(generator.Metadata.Errors)
	result := generator.GenerateWithDefaults()
	if err != nil {
		panic(err)
	}

	res, err := json.Marshal(result)
	if err != nil {
		panic(err)
	}
	fmt.Println(string(res))
}

CLI

There is also a cli tool available for this package that can be installed from the releases section.

CLI too for generating random JSON data matching given JSON schema
Usage: go-chaff [flags]
  -allow-insecure
        Allow fetching remote $ref documents over insecure HTTP connections.
  -allow-outside-cwd
        Allow fetching $ref documents from file system paths outside the current working directory.
  -allowed-hosts string
        Comma separated list of allowed hosts to fetch remote $ref documents from over HTTP(S). If empty http and https resolution will fail.
  -allowed-paths string
        Comma separated list of allowed file system paths to fetch $ref documents from.
  -bypass-cyclic-reference-check
        Bypass cyclic reference check when generating schemas with cyclic $ref references.
  -cutoff-generation-steps int
        Maximum number of generation steps to perform before aborting generation entirely and returning what was generated. (default 2000)
  -file string
        Specify a file path to read the JSON Schema from
  -format
        Format JSON output.
  -help
        Print out help.
  -maximum-generation-steps int
        Maximum number of generation steps to perform before reducing the effort put into the generation process to a bare minimum. (default 1000)
  -maximum-if-attempts int
        Maximum number of attempts to satisfy 'if' conditions when generating data. (default 100)
  -maximum-oneof-attempts int
        Maximum number of attempts to satisfy 'oneOf' conditions when generating data. (default 100)
  -maximum-reference-depth int
        Maximum depth of $ref references to resolve at once when generating data. (default 10)
  -output string
        Specify file path to write generated output to.
  -verbose
        Print out detailed error information.
  -version
        Print out cli version information.

You can also pipe into STDIN for the cli

echo '{"type": "string", "format": "ipv4"}' | go-chaff
"217.2.244.95"

Current support:

• Strings: (Including pattern through regen and formats through go faker), minLength, maxLength
• Number / Integer: multipleOf, min, max, exclusiveMin, exclusiveMax
• Constant types: enum, const, null
• References: $ref, $defs, definitions, $id
• Object: properties, patternProperties, additionalProperties, minProperties, maxProperties, required
• Array: items, minItems, maxItems, contains, minContains, maxContains, prefixItems, additionalItems, unevaluatedItems, uniqueItems (Limited support)
• Combination types anyOf / oneOf / allOf
• Support for if / then / else
• Support for not combinator (excluding anyOf, oneOf / allOf and if/then/else)
• Multi document resolution for $ref over http(s) or file schemes.

Credits / Dependencies

• Regen (@zach-klippenstein and @AnatolyRugalev)
• Faker
• Schema Store
• jsonschema from @kaptinlin for test validation
• jsonschema from @santhosh-tekuri for internal schema constrain validation
• Original idea, inspiration and technical support json-schema-faker

What is left to do?

• Better test coverage (Property based and unit of various generators)
• Handle many edge cases where this package might not generate schema compliant results
• Overcome the limitations of the current oneOf, anyOf and allOf keywords implementation.