diff --git a/service.go b/service.go index f17371336..6a274a798 100644 --- a/service.go +++ b/service.go @@ -1,42 +1,3 @@ -/* - -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 ( @@ -60,6 +21,48 @@ type Service interface { String() string } +/* +Classical-inheritance-style service declarations. Services can be started, then +stopped, then optionally restarted. + +Users can override the OnStart/OnStop methods. In the absence of errors, these +methods are guaranteed to be called at most once. If OnStart returns an error, +service won't be marked as started, so the user can call Start again. + +A call to Reset will panic, unless OnReset is overwritten, allowing +OnStart/OnStop to be called again. + +The caller must ensure that Start and Stop are not called concurrently. + +It is ok to call Stop without calling Start first. + +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. + } +*/ type BaseService struct { log log15.Logger name string @@ -94,6 +97,11 @@ func (bs *BaseService) Start() (bool, error) { } } err := bs.impl.OnStart() + if err != nil { + // revert flag + atomic.StoreUint32(&bs.started, 0) + return false, err + } return true, err } else { if bs.log != nil {