83 lines
1.5 KiB
Go
83 lines
1.5 KiB
Go
package subscriptions
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import (
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"errors"
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"fmt"
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"sync"
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"time"
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)
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type SubscriptionID string
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type Subscription struct {
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mu sync.RWMutex
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id SubscriptionID
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signal *filterSignal
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quit chan struct{}
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filter filter
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started bool
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}
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func NewSubscription(namespace string, filter filter) *Subscription {
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subscriptionID := NewSubscriptionID(namespace, filter.getID())
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return &Subscription{
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id: subscriptionID,
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signal: newFilterSignal(string(subscriptionID)),
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filter: filter,
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}
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}
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func (s *Subscription) Start(checkPeriod time.Duration) error {
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s.mu.Lock()
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if s.started {
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s.mu.Unlock()
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return errors.New("subscription already started or used")
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}
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s.started = true
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s.quit = make(chan struct{})
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quit := s.quit
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s.mu.Unlock()
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ticker := time.NewTicker(checkPeriod)
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defer ticker.Stop()
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for {
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select {
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case <-ticker.C:
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filterData, err := s.filter.getChanges()
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if err != nil {
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s.signal.SendError(err)
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} else if len(filterData) > 0 {
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s.signal.SendData(filterData)
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}
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case <-quit:
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return nil
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}
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}
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}
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func (s *Subscription) Stop(uninstall bool) error {
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s.mu.Lock()
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defer s.mu.Unlock()
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if !s.started {
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return nil
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}
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select {
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case _, ok := <-s.quit:
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// handle a case of a closed channel
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if !ok {
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return nil
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}
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default:
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close(s.quit)
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}
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if !uninstall {
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return nil
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}
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return s.filter.uninstall()
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}
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func NewSubscriptionID(namespace, filterID string) SubscriptionID {
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return SubscriptionID(fmt.Sprintf("%s-%s", namespace, filterID))
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}
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