You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
183 lines
4.1 KiB
183 lines
4.1 KiB
/*
|
|
|
|
Classical-inheritance-style service declarations.
|
|
Services can be started, then stopped, then optionally restarted.
|
|
Users can override the OnStart/OnStop methods.
|
|
By default, these methods are guaranteed to be called at most once.
|
|
A call to Reset will panic, unless OnReset is overwritten, allowing OnStart/OnStop to be called again.
|
|
Caller must ensure that Start() and Stop() are not called concurrently.
|
|
It is ok to call Stop() without calling Start() first.
|
|
Services cannot be re-started unless OnReset is overwritten to allow it.
|
|
|
|
Typical usage:
|
|
|
|
type FooService struct {
|
|
BaseService
|
|
// private fields
|
|
}
|
|
|
|
func NewFooService() *FooService {
|
|
fs := &FooService{
|
|
// init
|
|
}
|
|
fs.BaseService = *NewBaseService(log, "FooService", fs)
|
|
return fs
|
|
}
|
|
|
|
func (fs *FooService) OnStart() error {
|
|
fs.BaseService.OnStart() // Always call the overridden method.
|
|
// initialize private fields
|
|
// start subroutines, etc.
|
|
}
|
|
|
|
func (fs *FooService) OnStop() error {
|
|
fs.BaseService.OnStop() // Always call the overridden method.
|
|
// close/destroy private fields
|
|
// stop subroutines, etc.
|
|
}
|
|
|
|
*/
|
|
package common
|
|
|
|
import (
|
|
"sync/atomic"
|
|
|
|
"github.com/tendermint/log15"
|
|
)
|
|
|
|
type Service interface {
|
|
Start() (bool, error)
|
|
OnStart() error
|
|
|
|
Stop() bool
|
|
OnStop()
|
|
|
|
Reset() (bool, error)
|
|
OnReset() error
|
|
|
|
IsRunning() bool
|
|
|
|
String() string
|
|
}
|
|
|
|
type BaseService struct {
|
|
log log15.Logger
|
|
name string
|
|
started uint32 // atomic
|
|
stopped uint32 // atomic
|
|
Quit chan struct{}
|
|
|
|
// The "subclass" of BaseService
|
|
impl Service
|
|
}
|
|
|
|
func NewBaseService(log log15.Logger, name string, impl Service) *BaseService {
|
|
return &BaseService{
|
|
log: log,
|
|
name: name,
|
|
Quit: make(chan struct{}),
|
|
impl: impl,
|
|
}
|
|
}
|
|
|
|
// Implements Servce
|
|
func (bs *BaseService) Start() (bool, error) {
|
|
if atomic.CompareAndSwapUint32(&bs.started, 0, 1) {
|
|
if atomic.LoadUint32(&bs.stopped) == 1 {
|
|
if bs.log != nil {
|
|
bs.log.Warn(Fmt("Not starting %v -- already stopped", bs.name), "impl", bs.impl)
|
|
}
|
|
return false, nil
|
|
} else {
|
|
if bs.log != nil {
|
|
bs.log.Info(Fmt("Starting %v", bs.name), "impl", bs.impl)
|
|
}
|
|
}
|
|
err := bs.impl.OnStart()
|
|
return true, err
|
|
} else {
|
|
if bs.log != nil {
|
|
bs.log.Debug(Fmt("Not starting %v -- already started", bs.name), "impl", bs.impl)
|
|
}
|
|
return false, nil
|
|
}
|
|
}
|
|
|
|
// Implements Service
|
|
// NOTE: Do not put anything in here,
|
|
// that way users don't need to call BaseService.OnStart()
|
|
func (bs *BaseService) OnStart() error { return nil }
|
|
|
|
// Implements Service
|
|
func (bs *BaseService) Stop() bool {
|
|
if atomic.CompareAndSwapUint32(&bs.stopped, 0, 1) {
|
|
if bs.log != nil {
|
|
bs.log.Info(Fmt("Stopping %v", bs.name), "impl", bs.impl)
|
|
}
|
|
bs.impl.OnStop()
|
|
close(bs.Quit)
|
|
return true
|
|
} else {
|
|
if bs.log != nil {
|
|
bs.log.Debug(Fmt("Stopping %v (ignoring: already stopped)", bs.name), "impl", bs.impl)
|
|
}
|
|
return false
|
|
}
|
|
}
|
|
|
|
// Implements Service
|
|
// NOTE: Do not put anything in here,
|
|
// that way users don't need to call BaseService.OnStop()
|
|
func (bs *BaseService) OnStop() {}
|
|
|
|
// Implements Service
|
|
func (bs *BaseService) Reset() (bool, error) {
|
|
if atomic.CompareAndSwapUint32(&bs.stopped, 1, 0) {
|
|
// whether or not we've started, we can reset
|
|
atomic.CompareAndSwapUint32(&bs.started, 1, 0)
|
|
|
|
return true, bs.impl.OnReset()
|
|
} else {
|
|
if bs.log != nil {
|
|
bs.log.Debug(Fmt("Can't reset %v. Not stopped", bs.name), "impl", bs.impl)
|
|
}
|
|
return false, nil
|
|
}
|
|
// never happens
|
|
return false, nil
|
|
}
|
|
|
|
// Implements Service
|
|
func (bs *BaseService) OnReset() error {
|
|
PanicSanity("The service cannot be reset")
|
|
return nil
|
|
}
|
|
|
|
// Implements Service
|
|
func (bs *BaseService) IsRunning() bool {
|
|
return atomic.LoadUint32(&bs.started) == 1 && atomic.LoadUint32(&bs.stopped) == 0
|
|
}
|
|
|
|
func (bs *QuitService) Wait() {
|
|
<-bs.Quit
|
|
}
|
|
|
|
// Implements Servce
|
|
func (bs *BaseService) String() string {
|
|
return bs.name
|
|
}
|
|
|
|
//----------------------------------------
|
|
|
|
type QuitService struct {
|
|
BaseService
|
|
}
|
|
|
|
func NewQuitService(log log15.Logger, name string, impl Service) *QuitService {
|
|
if log != nil {
|
|
log.Warn("QuitService is deprecated, use BaseService instead")
|
|
}
|
|
return &QuitService{
|
|
BaseService: *NewBaseService(log, name, impl),
|
|
}
|
|
}
|