Go custom error handling example

main.go

package main

import (
	"errors"
	"fmt"
)

var MyCustomError *ErrCustom

type ErrCustom struct{}

func (e *ErrCustom) Error() string {
	return "CustomError occurred"
}

func (e *ErrCustom) Is(target error) bool {
	if _, ok := target.(*ErrCustom); ok {
		return true
	}
	return false
}

func main() {
	err := process()
	if errors.Is(err, MyCustomError) {
		fmt.Println("Error is of type MyCustomError")
	}
}

func process() error {
	e := &ErrCustom{}
	return fmt.Errorf("Wrapped error:%w", e)
}