json2go - convert json to go code

This module converts a json blob to go code. The generated code includes both a struct definition and an instance for the input json.

Reading from stdin is supported, as well as reading from input files, making it suitable for use with go generate.

quick start - generate code from stdin

Try the following example to generate code from stdin:

cat <<EOF | go run .
{
  "name": "bob",
  "age": 28
}
EOF

The generated go source will be written to the console, including both the struct definition and an instance.

how to use as a go generator

Be sure to check out the example app

To use this module with go generate, use a directive like the following in your go source:

//go:generate go run github.com/christopherriley/json2go -in config.json -out config.go -struct Config -var config

step 1 - create json file

Create a simple json file to start with, for example

config.json

{
  "name": "bob",
  "age": 28
}

step 2 - create a go main

Create a go program that will consume the json file. include the go generate directive.

main.go

package main

import "fmt"

//go:generate go run github.com/christopherriley/json2go -in config.json -out config.go -struct Config -var config

func main() {
	// note the instance variable name matches the -var flag to the generate directive, above
	fmt.Println("name: ", config.name)
	fmt.Println("age: ", config.age)
}

step 3 - generate the code

In order for the app to run, the go code will need to be generated from the json

go generate

You can examine the generated source

cat config.go

// this file was generated from config.json
// do not modify

package main

type Config struct {
    age int
    name string
}

var config Config = Config{
    age: 28,
    name: "bob",
}

step 4 - run the app

go run main.go config.go

You should see the following output:

name: bob
age: 28

unsupported features

json/javascript has support for mixed arrays. go can achieve the same thing using []any, but defeats the purpose of this project. therefore json arrays with mixed types are not supported.