Go Structs and Validations Learning Project

This project is a learning resource for understanding structs and validations in Go. It provides a basic implementation of a customer management system, demonstrating the use of structs for data organization and the github.com/go-playground/validator/v10 package for data validation.

Structs

The project defines four main structs: customerId, Customer, customerName, and customerAge.

customerId is a struct that contains a single field, value, which is a globally unique identifier (GUID). This struct is not directly accessible outside the package.

Customer is a struct that represents a customer in the system. It contains three fields:

id: a customerId that represents the unique identifier of the customer.
name: a customerName that represents the name of the customer.
age: a customerAge that represents the age of the customer.

customerName and customerAge are value objects that encapsulate specific validation rules for the name and age of a customer, respectively.

Validations

The project uses the github.com/go-playground/validator/v10 package to validate Customer instances. The validation rules are as follows:

id must be present.
name cannot be empty and must be at least 5 characters long.
age must be greater than or equal to 18.

These rules are defined using struct tags, demonstrating how to use tags for validation purposes in Go.

Factory Function

The project provides a public factory function NewCustomer that creates a new Customer instance. The factory function validates the Customer instance before returning it. If the instance fails validation, the factory function returns an error. This demonstrates how to encapsulate validation logic within a function.

How to Use

To use this project, you can import the Customer struct and the NewCustomer function into your own code. Here's an example of how you can do this:

package main

import (
    "fmt"
    "github.com/josepderiu/structs"
)

func main() {
    customer, err := customer.NewCustomer("John Doe", 20)
    if err != nil {
        fmt.Println("Error creating customer:", err)
        return
    }

    fmt.Println("Created customer:", customer)
}