Custom Go Errors Examples

custom_errors.go

package main

import (
	"errors"
	"fmt"
	"time"
)

type HostError struct {
	message   string
	host      string
	timestamp time.Time
}

func (e *HostError) Error() string {
	return e.message
}

func (e *HostError) GetHost() time.Time {
	return e.timestamp
}

type ExecutionError struct {
	message   string
	function  string
	timestamp time.Time
}

func (e *ExecutionError) Error() string {
	return e.message
}

func (e *ExecutionError) GetHost() time.Time {
	return e.timestamp
}

func main() {

	errs := []interface{}{
		HostError{"Host error.", "host01.local", time.Now()},
		ExecutionError{"Function could not successfully execute.", "build()", time.Now()},
		errors.New("Generic error"),
	}

	for _, e := range errs {
		if v, ok := e.(HostError); ok {
			fmt.Println("Error: ", v.Error())
			fmt.Println("  -> This error is of type HostError")
		} else if v, ok := e.(ExecutionError); ok {
			fmt.Println("Error: ", v.Error())
			fmt.Println("  -> This error is of type ExecutionError")
		} else {
			fmt.Println("Error: ", v.Error())
			fmt.Println("  -> This error is generic")
		}
	}

}