64 lines
1.7 KiB
Go
64 lines
1.7 KiB
Go
package common
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import "sync/atomic"
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// BaseService represents a service that can be started then stopped,
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// but cannot be restarted.
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// .Start() calls the onStart callback function, and .Stop() calls onStop.
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// It is meant to be embedded into service structs.
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// The user must ensure that Start() and Stop() are not called concurrently.
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// It is ok to call Stop() without calling Start() first -- the onStop
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// callback will be called, and the service will never start.
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type BaseService struct {
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name string
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service interface{} // for log statements.
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started uint32 // atomic
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stopped uint32 // atomic
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onStart func()
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onStop func()
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}
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func NewBaseService(name string, service interface{}, onStart, onStop func()) *BaseService {
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return &BaseService{
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name: name,
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service: service,
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onStart: onStart,
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onStop: onStop,
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}
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}
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func (bs *BaseService) Start() bool {
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if atomic.CompareAndSwapUint32(&bs.started, 0, 1) {
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if atomic.LoadUint32(&bs.stopped) == 1 {
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log.Warn(Fmt("Not starting %v -- already stopped", bs.name), "service", bs.service)
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return false
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} else {
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log.Notice(Fmt("Starting %v", bs.name), "service", bs.service)
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}
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if bs.onStart != nil {
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bs.onStart()
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}
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return true
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} else {
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log.Info(Fmt("Not starting %v -- already started", bs.name), "service", bs.service)
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return false
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}
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}
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func (bs *BaseService) Stop() bool {
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if atomic.CompareAndSwapUint32(&bs.stopped, 0, 1) {
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log.Notice(Fmt("Stopping %v", bs.name), "service", bs.service)
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if bs.onStop != nil {
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bs.onStop()
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}
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return true
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} else {
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log.Notice(Fmt("Not stopping %v", bs.name), "service", bs.service)
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return false
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}
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}
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func (bs *BaseService) IsRunning() bool {
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return atomic.LoadUint32(&bs.started) == 1 && atomic.LoadUint32(&bs.stopped) == 0
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}
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