distribution/notifications/metrics.go
Stephen J Day d2d46fca41 Move notifications package to distribution
Since the notifications package is now decoupled from storage, we are moving it
to the root package.

Signed-off-by: Stephen J Day <stephen.day@docker.com>
2015-02-12 14:40:35 -08:00

152 lines
4 KiB
Go

package notifications
import (
"expvar"
"fmt"
"net/http"
"sync"
)
// EndpointMetrics track various actions taken by the endpoint, typically by
// number of events. The goal of this to export it via expvar but we may find
// some other future solution to be better.
type EndpointMetrics struct {
Pending int // events pending in queue
Events int // total events incoming
Successes int // total events written successfully
Failures int // total events failed
Errors int // total events errored
Statuses map[string]int // status code histogram, per call event
}
// safeMetrics guards the metrics implementation with a lock and provides a
// safe update function.
type safeMetrics struct {
EndpointMetrics
sync.Mutex // protects statuses map
}
// newSafeMetrics returns safeMetrics with map allocated.
func newSafeMetrics() *safeMetrics {
var sm safeMetrics
sm.Statuses = make(map[string]int)
return &sm
}
// httpStatusListener returns the listener for the http sink that updates the
// relevent counters.
func (sm *safeMetrics) httpStatusListener() httpStatusListener {
return &endpointMetricsHTTPStatusListener{
safeMetrics: sm,
}
}
// eventQueueListener returns a listener that maintains queue related counters.
func (sm *safeMetrics) eventQueueListener() eventQueueListener {
return &endpointMetricsEventQueueListener{
safeMetrics: sm,
}
}
// endpointMetricsHTTPStatusListener increments counters related to http sinks
// for the relevent events.
type endpointMetricsHTTPStatusListener struct {
*safeMetrics
}
var _ httpStatusListener = &endpointMetricsHTTPStatusListener{}
func (emsl *endpointMetricsHTTPStatusListener) success(status int, events ...Event) {
emsl.safeMetrics.Lock()
defer emsl.safeMetrics.Unlock()
emsl.Statuses[fmt.Sprintf("%d %s", status, http.StatusText(status))] += len(events)
emsl.Successes += len(events)
}
func (emsl *endpointMetricsHTTPStatusListener) failure(status int, events ...Event) {
emsl.safeMetrics.Lock()
defer emsl.safeMetrics.Unlock()
emsl.Statuses[fmt.Sprintf("%d %s", status, http.StatusText(status))] += len(events)
emsl.Failures += len(events)
}
func (emsl *endpointMetricsHTTPStatusListener) err(err error, events ...Event) {
emsl.safeMetrics.Lock()
defer emsl.safeMetrics.Unlock()
emsl.Errors += len(events)
}
// endpointMetricsEventQueueListener maintains the incoming events counter and
// the queues pending count.
type endpointMetricsEventQueueListener struct {
*safeMetrics
}
func (eqc *endpointMetricsEventQueueListener) ingress(events ...Event) {
eqc.Lock()
defer eqc.Unlock()
eqc.Events += len(events)
eqc.Pending += len(events)
}
func (eqc *endpointMetricsEventQueueListener) egress(events ...Event) {
eqc.Lock()
defer eqc.Unlock()
eqc.Pending -= len(events)
}
// endpoints is global registry of endpoints used to report metrics to expvar
var endpoints struct {
registered []*Endpoint
mu sync.Mutex
}
// register places the endpoint into expvar so that stats are tracked.
func register(e *Endpoint) {
endpoints.mu.Lock()
defer endpoints.mu.Unlock()
endpoints.registered = append(endpoints.registered, e)
}
func init() {
// NOTE(stevvooe): Setup registry metrics structure to report to expvar.
// Ideally, we do more metrics through logging but we need some nice
// realtime metrics for queue state for now.
registry := expvar.Get("registry")
if registry == nil {
registry = expvar.NewMap("registry")
}
var notifications expvar.Map
notifications.Init()
notifications.Set("endpoints", expvar.Func(func() interface{} {
endpoints.mu.Lock()
defer endpoints.mu.Unlock()
var names []interface{}
for _, v := range endpoints.registered {
var epjson struct {
Name string `json:"name"`
URL string `json:"url"`
EndpointConfig
Metrics EndpointMetrics
}
epjson.Name = v.Name()
epjson.URL = v.URL()
epjson.EndpointConfig = v.EndpointConfig
v.ReadMetrics(&epjson.Metrics)
names = append(names, epjson)
}
return names
}))
registry.(*expvar.Map).Set("notifications", &notifications)
}