package cli
import (
"fmt"
"io"
"os"
"strings"
)
// OsExiter is the function used when the app exits. If not set defaults to os.Exit.
var OsExiter = os.Exit
// ErrWriter is used to write errors to the user. This can be anything
// implementing the io.Writer interface and defaults to os.Stderr.
var ErrWriter io.Writer = os.Stderr
// MultiError is an error that wraps multiple errors.
type MultiError struct {
Errors []error
}
// NewMultiError creates a new MultiError. Pass in one or more errors.
func NewMultiError(err ...error) MultiError {
return MultiError{Errors: err}
}
// Error implements the error interface.
func (m MultiError) Error() string {
errs := make([]string, len(m.Errors))
for i, err := range m.Errors {
errs[i] = err.Error()
}
return strings.Join(errs, "\n")
}
type ErrorFormatter interface {
Format(s fmt.State, verb rune)
}
// ExitCoder is the interface checked by `App` and `Command` for a custom exit
// code
type ExitCoder interface {
error
ExitCode() int
}
// ExitError fulfills both the builtin `error` interface and `ExitCoder`
type ExitError struct {
exitCode int
message interface{}
}
// NewExitError makes a new *ExitError
func NewExitError(message interface{}, exitCode int) *ExitError {
return &ExitError{
exitCode: exitCode,
message: message,
}
}
// Error returns the string message, fulfilling the interface required by
// `error`
func (ee *ExitError) Error() string {
return fmt.Sprintf("%v", ee.message)
}
// ExitCode returns the exit code, fulfilling the interface required by
// `ExitCoder`
func (ee *ExitError) ExitCode() int {
return ee.exitCode
}
// HandleExitCoder checks if the error fulfills the ExitCoder interface, and if
// so prints the error to stderr (if it is non-empty) and calls OsExiter with the
// given exit code. If the given error is a MultiError, then this func is
// called on all members of the Errors slice and calls OsExiter with the last exit code.
func HandleExitCoder(err error) {
if err == nil {
return
}
if exitErr, ok := err.(ExitCoder); ok {
if err.Error() != "" {
if _, ok := exitErr.(ErrorFormatter); ok {
fmt.Fprintf(ErrWriter, "%+v\n", err)
} else {
fmt.Fprintln(ErrWriter, err)
}
}
OsExiter(exitErr.ExitCode())
return
}
if multiErr, ok := err.(MultiError); ok {
code := handleMultiError(multiErr)
OsExiter(code)
return
}
}
func handleMultiError(multiErr MultiError) int {
code := 1
for _, merr := range multiErr.Errors {
if multiErr2, ok := merr.(MultiError); ok {
code = handleMultiError(multiErr2)
} else {
fmt.Fprintln(ErrWriter, merr)
if exitErr, ok := merr.(ExitCoder); ok {
code = exitErr.ExitCode()
}
}
}
return code
}
