go-json-schema-generator

Generate JSON Schema out of Golang schema

Usage

First install the package

go get -u github.com/urakozz/go-json-schema-generator

Then create your generator file (see Example folder)

package main

import (
	"fmt"
	"github.com/urakozz/go-json-schema-generator"
)

type Domain struct {
	Data string `json:"data"`
}

func main(){
	fmt.Println(generator.Generate(&Domain{}))
}

Supported tags

required:"true" - field will be marked as required
description:"description" - description will be added

On string fields:

minLength:"5" - Set the minimum length of the value
maxLength:"5" - Set the maximum length of the value
enum:"apple|banana|pear" - Limit the available values to a defined set, separated by vertical bars
const:"I need to be there" - Require the field to have a specific value.

On numeric types (strings and floats)

min:"-4.141592" - Set a minimum value
max:"123456789" - Set a maximum value
exclusiveMin:"0" - Values must be strictly greater than this value
exclusiveMax:"11" - Values must be strictly smaller than this value
const:"42" - Property must have exactly this value.

Expected behaviour

If struct field is pointer to the primitive type, then schema will allow this typa and null. E.g.:

type Domain struct {
	NullableData *string `json:"nullableData"`
}

Output

{
    "$schema": "http://json-schema.org/schema#",
    "type": "object",
    "properties": {
        "nullableData": {
            "anyOf": [
                {
                    "type": "string"
                },
                {
                    "type": "null"
                }
            ]
        }
    }
}