Initial commit

vendor/github.com/hyperhq/hypercli/daemon/events/events.go

@@ -0,0 +1,126 @@
+package events
+
+import (
+	"sync"
+	"time"
+
+	"github.com/hyperhq/hypercli/pkg/pubsub"
+	eventtypes "github.com/docker/engine-api/types/events"
+)
+
+const (
+	eventsLimit = 64
+	bufferSize  = 1024
+)
+
+// Events is pubsub channel for events generated by the engine.
+type Events struct {
+	mu     sync.Mutex
+	events []eventtypes.Message
+	pub    *pubsub.Publisher
+}
+
+// New returns new *Events instance
+func New() *Events {
+	return &Events{
+		events: make([]eventtypes.Message, 0, eventsLimit),
+		pub:    pubsub.NewPublisher(100*time.Millisecond, bufferSize),
+	}
+}
+
+// Subscribe adds new listener to events, returns slice of 64 stored
+// last events, a channel in which you can expect new events (in form
+// of interface{}, so you need type assertion), and a function to call
+// to stop the stream of events.
+func (e *Events) Subscribe() ([]eventtypes.Message, chan interface{}, func()) {
+	e.mu.Lock()
+	current := make([]eventtypes.Message, len(e.events))
+	copy(current, e.events)
+	l := e.pub.Subscribe()
+	e.mu.Unlock()
+
+	cancel := func() {
+		e.Evict(l)
+	}
+	return current, l, cancel
+}
+
+// SubscribeTopic adds new listener to events, returns slice of 64 stored
+// last events, a channel in which you can expect new events (in form
+// of interface{}, so you need type assertion).
+func (e *Events) SubscribeTopic(since, sinceNano int64, ef *Filter) ([]eventtypes.Message, chan interface{}) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	var buffered []eventtypes.Message
+	topic := func(m interface{}) bool {
+		return ef.Include(m.(eventtypes.Message))
+	}
+
+	if since != -1 {
+		for i := len(e.events) - 1; i >= 0; i-- {
+			ev := e.events[i]
+			if ev.Time < since || ((ev.Time == since) && (ev.TimeNano < sinceNano)) {
+				break
+			}
+			if ef.filter.Len() == 0 || topic(ev) {
+				buffered = append([]eventtypes.Message{ev}, buffered...)
+			}
+		}
+	}
+
+	var ch chan interface{}
+	if ef.filter.Len() > 0 {
+		ch = e.pub.SubscribeTopic(topic)
+	} else {
+		// Subscribe to all events if there are no filters
+		ch = e.pub.Subscribe()
+	}
+
+	return buffered, ch
+}
+
+// Evict evicts listener from pubsub
+func (e *Events) Evict(l chan interface{}) {
+	e.pub.Evict(l)
+}
+
+// Log broadcasts event to listeners. Each listener has 100 millisecond for
+// receiving event or it will be skipped.
+func (e *Events) Log(action, eventType string, actor eventtypes.Actor) {
+	now := time.Now().UTC()
+	jm := eventtypes.Message{
+		Action:   action,
+		Type:     eventType,
+		Actor:    actor,
+		Time:     now.Unix(),
+		TimeNano: now.UnixNano(),
+	}
+
+	// fill deprecated fields for container and images
+	switch eventType {
+	case eventtypes.ContainerEventType:
+		jm.ID = actor.ID
+		jm.Status = action
+		jm.From = actor.Attributes["image"]
+	case eventtypes.ImageEventType:
+		jm.ID = actor.ID
+		jm.Status = action
+	}
+
+	e.mu.Lock()
+	if len(e.events) == cap(e.events) {
+		// discard oldest event
+		copy(e.events, e.events[1:])
+		e.events[len(e.events)-1] = jm
+	} else {
+		e.events = append(e.events, jm)
+	}
+	e.mu.Unlock()
+	e.pub.Publish(jm)
+}
+
+// SubscribersCount returns number of event listeners
+func (e *Events) SubscribersCount() int {
+	return e.pub.Len()
+}