dy-pkg/examples/errors/main.go

package main

import (
	"fmt"
	"net/http"

	"gogs.tyduyong.com/duyong/dy-pkg/errors"
)

const (
	ErrDatabase = iota + 100000
	ErrEncodingFailed
)

func init() {
	errors.RegisterCode(ErrDatabase, http.StatusInternalServerError, "数据错误", "")
	errors.RegisterCode(ErrEncodingFailed, http.StatusInternalServerError, "绑定错误", "")
}

func main() {
	if err := bindUser(); err != nil {
		// %s: Returns the user-safe error string mapped to the error code or the error message if none is specified.
		fmt.Println("====================> %s <====================")
		fmt.Printf("%s\n\n", err)

		// %v: Alias for %s.
		fmt.Println("====================> %v <====================")
		fmt.Printf("%v\n\n", err)
		//
		// %-v: Output caller details, useful for troubleshooting.
		fmt.Println("====================> %-v <====================")
		fmt.Printf("%-v\n\n", err)
		//
		// %+v: Output full error stack details, useful for debugging.
		fmt.Println("====================> %+v <====================")
		fmt.Printf("%+v\n\n", err)
		//
		// %#-v: Output caller details, useful for troubleshooting with JSON formatted output.
		fmt.Println("====================> %#-v <====================")
		fmt.Printf("%#-v\n\n", err)
		//
		// %#+v: Output full error stack details, useful for debugging with JSON formatted output.
		fmt.Println("====================> %#+v <====================")
		fmt.Printf("%#+v\n\n", err)
		//
		// do some business process based on the error type
		if errors.IsCode(err, ErrEncodingFailed) {
			fmt.Println("this is a ErrEncodingFailed error")
		}
		//
		if errors.IsCode(err, ErrDatabase) {
			fmt.Println("this is a ErrDatabase error")
		}

		// we can also find the cause error
		fmt.Println(errors.Cause(err))
	}
}

func bindUser() error {
	if err := getUser(); err != nil {
		// Step3: Wrap the error with a new error message and a new error code if needed.
		return errors.WrapC(err, ErrEncodingFailed, "encoding user 'Lingfei Kong' failed.")
	}

	return nil
}

func getUser() error {
	if err := queryDatabase(); err != nil {
		// Step2: Wrap the error with a new error message.
		return errors.Wrap(err, "get user failed.")
	}

	return nil
}

func queryDatabase() error {
	// Step1. Create error with specified error code.
	return errors.WithCode(ErrDatabase, "user 'Lingfei Kong' not found.")
}