syncthing/lib/svcutil/svcutil.go

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// Copyright (C) 2016 The Syncthing Authors.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.
package svcutil
import (
"context"
"errors"
"fmt"
"time"
"github.com/syncthing/syncthing/lib/logger"
"github.com/syncthing/syncthing/lib/sync"
"github.com/thejerf/suture/v4"
)
const ServiceTimeout = 10 * time.Second
type FatalErr struct {
Err error
Status ExitStatus
}
// AsFatalErr wraps the given error creating a FatalErr. If the given error
// already is of type FatalErr, it is not wrapped again.
func AsFatalErr(err error, status ExitStatus) *FatalErr {
var ferr *FatalErr
if errors.As(err, &ferr) {
return ferr
}
return &FatalErr{
Err: err,
Status: status,
}
}
func (e *FatalErr) Error() string {
return e.Err.Error()
}
func (e *FatalErr) Unwrap() error {
return e.Err
}
func (e *FatalErr) Is(target error) bool {
return target == suture.ErrTerminateSupervisorTree
}
// NoRestartErr wraps the given error err (which may be nil) to make sure that
// `errors.Is(err, suture.ErrDoNotRestart) == true`.
func NoRestartErr(err error) error {
if err == nil {
return suture.ErrDoNotRestart
}
return &noRestartErr{err}
}
type noRestartErr struct {
err error
}
func (e *noRestartErr) Error() string {
return e.err.Error()
}
func (e *noRestartErr) Unwrap() error {
return e.err
}
func (e *noRestartErr) Is(target error) bool {
return target == suture.ErrDoNotRestart
}
type ExitStatus int
const (
ExitSuccess ExitStatus = 0
ExitError ExitStatus = 1
ExitNoUpgradeAvailable ExitStatus = 2
ExitRestart ExitStatus = 3
ExitUpgrade ExitStatus = 4
)
func (s ExitStatus) AsInt() int {
return int(s)
}
type ServiceWithError interface {
suture.Service
fmt.Stringer
Error() error
}
// AsService wraps the given function to implement suture.Service. In addition
// it keeps track of the returned error and allows querying that error.
func AsService(fn func(ctx context.Context) error, creator string) ServiceWithError {
return &service{
creator: creator,
serve: fn,
mut: sync.NewMutex(),
}
}
type service struct {
creator string
serve func(ctx context.Context) error
err error
mut sync.Mutex
}
func (s *service) Serve(ctx context.Context) error {
s.mut.Lock()
s.err = nil
s.mut.Unlock()
err := s.serve(ctx)
s.mut.Lock()
s.err = err
s.mut.Unlock()
return err
}
func (s *service) Error() error {
s.mut.Lock()
defer s.mut.Unlock()
return s.err
}
func (s *service) String() string {
return fmt.Sprintf("Service@%p created by %v", s, s.creator)
}
type doneService func()
func (fn doneService) Serve(ctx context.Context) error {
<-ctx.Done()
fn()
return nil
}
// OnSupervisorDone calls fn when sup is done.
func OnSupervisorDone(sup *suture.Supervisor, fn func()) {
sup.Add(doneService(fn))
}
func SpecWithDebugLogger(l logger.Logger) suture.Spec {
return spec(func(e suture.Event) { l.Debugln(e) })
}
func SpecWithInfoLogger(l logger.Logger) suture.Spec {
return spec(func(e suture.Event) { l.Infoln(e) })
}
func spec(eventHook suture.EventHook) suture.Spec {
return suture.Spec{
EventHook: eventHook,
Timeout: ServiceTimeout,
PassThroughPanics: true,
DontPropagateTermination: false,
}
}