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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 interface {
error
Errors() []error
}
// newMultiError creates a new MultiError. Pass in one or more errors.
func newMultiError(err ...error) MultiError {
ret := multiError(err)
return &ret
}
type multiError []error
// Error implements the error interface.
func (m *multiError) Error() string {
errs := make([]string, len(*m))
for i, err := range *m {
errs[i] = err.Error()
}
return strings.Join(errs, "\n")
}
// Errors returns a copy of the errors slice
func (m *multiError) Errors() []error {
errs := make([]error, len(*m))
copy(errs, *m)
return errs
}
type requiredFlagsErr interface {
error
}
type errRequiredFlags struct {
missingFlags []string
}
func (e *errRequiredFlags) Error() string {
if len(e.missingFlags) == 1 {
return fmt.Sprintf("Required flag %q not set", e.missingFlags[0])
}
joinedMissingFlags := strings.Join(e.missingFlags, ", ")
return fmt.Sprintf("Required flags %q not set", joinedMissingFlags)
}
type mutuallyExclusiveGroup struct {
flag1Name string
flag2Name string
}
func (e *mutuallyExclusiveGroup) Error() string {
return fmt.Sprintf("option %s cannot be set along with option %s", e.flag1Name, e.flag2Name)
}
type mutuallyExclusiveGroupRequiredFlag struct {
flags *MutuallyExclusiveFlags
}
func (e *mutuallyExclusiveGroupRequiredFlag) Error() string {
var missingFlags []string
for _, grpf := range e.flags.Flags {
var grpString []string
for _, f := range grpf {
grpString = append(grpString, f.Names()...)
}
missingFlags = append(missingFlags, strings.Join(grpString, " "))
}
return fmt.Sprintf("one of these flags needs to be provided: %s", strings.Join(missingFlags, ", "))
}
// ErrorFormatter is the interface that will suitably format the error output
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
}
type exitError struct {
exitCode int
err error
}
// Exit wraps a message and exit code into an error, which by default is
// handled with a call to os.Exit during default error handling.
//
// This is the simplest way to trigger a non-zero exit code for an App without
// having to call os.Exit manually. During testing, this behavior can be avoided
// by overriding the ExitErrHandler function on an App or the package-global
// OsExiter function.
func Exit(message interface{}, exitCode int) ExitCoder {
var err error
switch e := message.(type) {
case ErrorFormatter:
err = fmt.Errorf("%+v", message)
case error:
err = e
default:
err = fmt.Errorf("%+v", message)
}
return &exitError{
err: err,
exitCode: exitCode,
}
}
func (ee *exitError) Error() string {
return ee.err.Error()
}
func (ee *exitError) ExitCode() int {
return ee.exitCode
}
// HandleExitCoder handles errors implementing ExitCoder by printing their
// message and calling OsExiter with the given exit code.
//
// If the given error instead implements MultiError, each error will be checked
// for the ExitCoder interface, and OsExiter will be called with the last exit
// code found, or exit code 1 if no ExitCoder is found.
//
// This function is the default error-handling behavior for an App.
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 if merr != nil {
fmt.Fprintln(ErrWriter, merr)
if exitErr, ok := merr.(ExitCoder); ok {
code = exitErr.ExitCode()
}
}
}
return code
}
|
