DockerCLI/command/system/events_utils.go

67 lines
1.5 KiB
Go

package system
import (
"encoding/json"
"io"
"sync"
"github.com/Sirupsen/logrus"
eventtypes "github.com/docker/docker/api/types/events"
)
// EventHandler is abstract interface for user to customize
// own handle functions of each type of events
type EventHandler interface {
Handle(action string, h func(eventtypes.Message))
Watch(c <-chan eventtypes.Message)
}
// InitEventHandler initializes and returns an EventHandler
func InitEventHandler() EventHandler {
return &eventHandler{handlers: make(map[string]func(eventtypes.Message))}
}
type eventHandler struct {
handlers map[string]func(eventtypes.Message)
mu sync.Mutex
}
func (w *eventHandler) Handle(action string, h func(eventtypes.Message)) {
w.mu.Lock()
w.handlers[action] = h
w.mu.Unlock()
}
// Watch ranges over the passed in event chan and processes the events based on the
// handlers created for a given action.
// To stop watching, close the event chan.
func (w *eventHandler) Watch(c <-chan eventtypes.Message) {
for e := range c {
w.mu.Lock()
h, exists := w.handlers[e.Action]
w.mu.Unlock()
if !exists {
continue
}
logrus.Debugf("event handler: received event: %v", e)
go h(e)
}
}
// DecodeEvents decodes event from input stream
func DecodeEvents(input io.Reader, ep eventProcessor) error {
dec := json.NewDecoder(input)
for {
var event eventtypes.Message
err := dec.Decode(&event)
if err != nil && err == io.EOF {
break
}
if procErr := ep(event, err); procErr != nil {
return procErr
}
}
return nil
}