spanner-rows-to-struct.go

package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"strconv"
)

type Migration struct {
	Id        int64
	Migration string
	Created   string
}
type Migrations struct {
	Migrations []Migration
}

type DTO struct {
	Data [][]string `json:"rows"`
}

func read_json() []byte {
	// read file
	data, err := ioutil.ReadFile("./data.json")
	if err != nil {
		fmt.Print(err)
	}
	return data
}

func (d DTO) UnmarshalJson(b []byte) error {
	if err := json.Unmarshal(b, &d); err != nil {
		return err
	}
	return nil
}

func (m *Migrations) populateMigrations(dto DTO) {
	var err error
	var migration Migration
	for i := 0; i < len(dto.Data); i++ {
		migration.Id, err = strconv.ParseInt(dto.Data[i][0], 10, 64)
		if err != nil {
			log.Fatal(err)
		}
		migration.Migration = dto.Data[i][1]
		migration.Created = dto.Data[i][2]
		m.Migrations = append(m.Migrations, migration)
	}
}

func main() {
	var dto DTO
	if err := json.Unmarshal(read_json(), &dto); err != nil {
		log.Fatal(err)
	}
	var m Migrations

	m.populateMigrations(dto)
	for _, v := range m.Migrations {
		fmt.Println(v.Id)
		fmt.Println(v.Migration)
		fmt.Println(v.Created)
	}
}