Convert from JSON to Golang struct definition in Python

json2gostruct.py

#!/usr/bin/env python
import sys
import os
import json

def usage():
    print("Usage: json2gostruct.py struct_name")
    os.exit(0)

def indent(nest):
    return "\t" * nest

def guess_list_type(lst, name, nest):
    if len(lst) == 0:
        return "string"

    first_type = type(lst[0])
    if first_type == dict:
        return encode(lst[0], name, nest)
    elif first_type == list:
        return "[]" . guess_array_type(lst[0], name, nest)
    elif first_type == str:
        return "string"
    elif first_type == float:
        return "float64"
    elif first_type == int:
        return "int"
    else:
        print("Unknown type: '{}'".format(first_type))
        exit(1)

def encode_element(obj, name, nest):
    ret = []
    for (k, v) in obj.items():
        v_type = type(v)
        if v_type == dict:
            elm_type = encode(v, name, nest)
        elif v_type == list:
            elm_type = "[]" + guess_list_type(v, name, nest)
        elif v_type == int:
            elm_type = "int"
        elif v_type == float:
            elm_type = "float64"
        else:
            elm_type = "string"

        field_decl = "{}{} {} `json:{}`".format(indent(nest), k.capitalize(), elm_type, k)
        ret.append(field_decl)

    return ret


def encode(obj, name, nest):
    lines = []
    if nest == 0:
        lines.append("type {} struct {{".format(name))
    else:
        lines.append("struct {")

    for line in encode_element(obj, name, nest+1):
        lines.append(line)

    if nest == 0:
        lines.append("}\n")
    else:
        lines.append(indent(nest) + "}")

    return "\n".join(lines)


if __name__ == '__main__':
    if len(sys.argv) == 1:
        print("Missing struct name")
        usage()

    struct_name = sys.argv[1]

    obj = json.loads(sys.stdin.read())
    struct_def = encode(obj, struct_name, 0)
    print(struct_def)