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Merge pull request #632 from rjnagal/docker

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Readability changes for events.
This commit is contained in:
Victor Marmol 2015-04-06 08:08:49 -07:00
commit ec3fd88a39
2 changed files with 73 additions and 83 deletions
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152
events/handler.go
View File

@ -25,64 +25,28 @@ import (
info "github.com/google/cadvisor/info/v1"
)
// EventManager is implemented by Events. It provides two ways to monitor
// events and one way to add events
type EventManager interface {
// Watch checks if events fed to it by the caller of AddEvent satisfy the
// request and if so sends the event back to the caller on outChannel
WatchEvents(request *Request) (*EventChannel, error)
// GetEvents() returns a slice of all events detected that have passed
// the *Request object parameters to the caller
GetEvents(request *Request) (EventSlice, error)
// AddEvent allows the caller to add an event to an EventManager
// object
AddEvent(e *info.Event) error
// Removes a watch instance from the EventManager's watchers map
StopWatch(watch_id int)
}
// Events holds a slice of *Event objects with a potential field
// that caps the number of events held. It is an implementation of the
// EventManager interface
type events struct {
// eventlist holds the complete set of events found over an
// EventManager events instantiation.
eventlist EventSlice
// the slice of watch pointers allows the EventManager access to channels
// linked to different calls of WatchEvents. When new events are found that
// satisfy the request of a given watch object in watchers, the event
// is sent over the channel to that caller of WatchEvents
watchers map[int]*watch
// lock that blocks eventlist from being accessed until a writer releases it
eventsLock sync.RWMutex
// lock that blocks watchers from being accessed until a writer releases it
watcherLock sync.RWMutex
// receives notices when a watch event ends and needs to be removed from
// the watchers list
lastId int
}
// initialized by a call to WatchEvents(), a watch struct will then be added
// to the events slice of *watch objects. When AddEvent() finds an event that
// satisfies the request parameter of a watch object in events.watchers,
// it will send that event out over the watch object's channel. The caller that
// called WatchEvents will receive the event over the channel provided to
// WatchEvents
type watch struct {
// request specifies all the parameters that events sent through the
// channel must satisfy. Specified by the creator of the watch object
request *Request
// a channel created by the caller through which events satisfying the
// request are sent to the caller
eventChannel *EventChannel
// unique identifier of a watch that is used as a key in events' watchers
// map
id int
}
// typedef of a slice of Event pointers
type EventSlice []*info.Event
// functions necessary to implement the sort interface on the Events struct
func (e EventSlice) Len() int {
return len(e)
}
func (e EventSlice) Swap(i, j int) {
e[i], e[j] = e[j], e[i]
}
func (e EventSlice) Less(i, j int) bool {
return e[i].Timestamp.Before(e[j].Timestamp)
}
type EventChannel struct {
// Watch ID. Can be used by the caller to request cancellation of watch events.
watchId int
// Channel on which the caller can receive watch events.
channel chan *info.Event
}
// Request holds a set of parameters by which Event objects may be screened.
// The caller may want events that occurred within a specific timeframe
// or of a certain type, which may be specified in the *Request object
@ -97,7 +61,7 @@ type Request struct {
// EventType is a map that specifies the type(s) of events wanted
EventType map[info.EventType]bool
// allows the caller to put a limit on how many
// events they receive. If there are more events than MaxEventsReturned
// events to receive. If there are more events than MaxEventsReturned
// then the most chronologically recent events in the time period
// specified are returned. Must be >= 1
MaxEventsReturned int
@ -108,9 +72,50 @@ type Request struct {
IncludeSubcontainers bool
}
type EventChannel struct {
watchId int
channel chan *info.Event
// EventManager is implemented by Events. It provides two ways to monitor
// events and one way to add events
type EventManager interface {
// WatchEvents() allows a caller to register for receiving events based on the specified request.
// On successful registration, an EventChannel object is returned.
WatchEvents(request *Request) (*EventChannel, error)
// GetEvents() returns all detected events based on the filters specified in request.
GetEvents(request *Request) (EventSlice, error)
// AddEvent allows the caller to add an event to an EventManager
// object
AddEvent(e *info.Event) error
// Cancels a previously requested watch event.
StopWatch(watch_id int)
}
// events provides an implementation for the EventManager interface.
type events struct {
// eventList holds the complete set of events found over an
// EventManager events instantiation.
eventList EventSlice
// map of registered watchers keyed by watch id.
watchers map[int]*watch
// lock guarding the eventList.
eventsLock sync.RWMutex
// lock guarding watchers.
watcherLock sync.RWMutex
// last allocated watch id.
lastId int
}
// initialized by a call to WatchEvents(), a watch struct will then be added
// to the events slice of *watch objects. When AddEvent() finds an event that
// satisfies the request parameter of a watch object in events.watchers,
// it will send that event out over the watch object's channel. The caller that
// called WatchEvents will receive the event over the channel provided to
// WatchEvents
type watch struct {
// request parameters passed in by the caller of WatchEvents()
request *Request
// a channel used to send event back to the caller.
eventChannel *EventChannel
// unique identifier of a watch that is used as a key in events' watchers
// map
id int
}
func NewEventChannel(watchId int) *EventChannel {
@ -123,7 +128,7 @@ func NewEventChannel(watchId int) *EventChannel {
// returns a pointer to an initialized Events object
func NewEventManager() *events {
return &events{
eventlist: make(EventSlice, 0),
eventList: make(EventSlice, 0),
watchers: make(map[int]*watch),
}
}
@ -153,21 +158,6 @@ func (self *EventChannel) GetWatchId() int {
return self.watchId
}
// function necessary to implement the sort interface on the Events struct
func (e EventSlice) Len() int {
return len(e)
}
// function necessary to implement the sort interface on the Events struct
func (e EventSlice) Swap(i, j int) {
e[i], e[j] = e[j], e[i]
}
// function necessary to implement the sort interface on the Events struct
func (e EventSlice) Less(i, j int) bool {
return e[i].Timestamp.Before(e[j].Timestamp)
}
// sorts and returns up to the last MaxEventsReturned chronological elements
func getMaxEventsReturned(request *Request, eSlice EventSlice) EventSlice {
sort.Sort(eSlice)
@ -213,7 +203,7 @@ func checkIfEventSatisfiesRequest(request *Request, event *info.Event) bool {
return true
}
// method of Events object that screens Event objects found in the eventlist
// method of Events object that screens Event objects found in the eventList
// attribute and if they fit the parameters passed by the Request object,
// adds it to a slice of *Event objects that is returned. If both MaxEventsReturned
// and StartTime/EndTime are specified in the request object, then only
@ -222,7 +212,7 @@ func (self *events) GetEvents(request *Request) (EventSlice, error) {
returnEventList := EventSlice{}
self.eventsLock.RLock()
defer self.eventsLock.RUnlock()
for _, e := range self.eventlist {
for _, e := range self.eventList {
if checkIfEventSatisfiesRequest(request, e) {
returnEventList = append(returnEventList, e)
}
@ -251,11 +241,11 @@ func (self *events) WatchEvents(request *Request) (*EventChannel, error) {
return returnEventChannel, nil
}
// helper function to update the event manager's eventlist
// helper function to update the event manager's eventList
func (self *events) updateEventList(e *info.Event) {
self.eventsLock.Lock()
defer self.eventsLock.Unlock()
self.eventlist = append(self.eventlist, e)
self.eventList = append(self.eventList, e)
}
func (self *events) findValidWatchers(e *info.Event) []*watch {
@ -270,7 +260,7 @@ func (self *events) findValidWatchers(e *info.Event) []*watch {
}
// method of Events object that adds the argument Event object to the
// eventlist. It also feeds the event to a set of watch channels
// eventList. It also feeds the event to a set of watch channels
// held by the manager if it satisfies the request keys of the channels
func (self *events) AddEvent(e *info.Event) error {
self.updateEventList(e)

4
events/handler_test.go
View File

@ -139,8 +139,8 @@ func TestAddEventAddsEventsToEventManager(t *testing.T) {
myEventHolder.AddEvent(fakeEvent)
checkNumberOfEvents(t, 1, myEventHolder.eventlist.Len())
ensureProperEventReturned(t, fakeEvent, myEventHolder.eventlist[0])
checkNumberOfEvents(t, 1, myEventHolder.eventList.Len())
ensureProperEventReturned(t, fakeEvent, myEventHolder.eventList[0])
}
func TestGetEventsForOneEvent(t *testing.T) {