vendor: bump docker/go-metrics v0.0.1:

full diff: 4ea375f775...v0.0.1

- docker/go-metrics#15 Add functions that instruments http handler using promhttp
- docker/go-metrics#20 Rename LICENSE.code → LICENSE
- docker/go-metrics#22 Support Go Modules

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor/github.com/docker/go-metrics/README.md

@@ -68,6 +68,18 @@ If you need to use a unit but it is not defined in the package please open a PR
 
 Package documentation can be found [here](https://godoc.org/github.com/docker/go-metrics).
 
+## HTTP Metrics
+
+To instrument a http handler, you can wrap the code like this:
+
+```go
+namespace := metrics.NewNamespace("docker_distribution", "http", metrics.Labels{"handler": "your_http_handler_name"})
+httpMetrics := namespace.NewDefaultHttpMetrics()
+metrics.Register(namespace)
+instrumentedHandler = metrics.InstrumentHandler(httpMetrics, unInstrumentedHandler)
+```
+Note: The `handler` label must be provided when a new namespace is created.
+
 ## Additional Metrics
 
 Additional metrics are also defined here that are not available in the prometheus client.

vendor/github.com/docker/go-metrics/go.mod

@@ -0,0 +1,5 @@
+module github.com/docker/go-metrics
+
+go 1.11
+
+require github.com/prometheus/client_golang v1.1.0

vendor/github.com/docker/go-metrics/handler.go

@@ -4,10 +4,71 @@ import (
 	"net/http"
 
 	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+// HTTPHandlerOpts describes a set of configurable options of http metrics
+type HTTPHandlerOpts struct {
+	DurationBuckets     []float64
+	RequestSizeBuckets  []float64
+	ResponseSizeBuckets []float64
+}
+
+const (
+	InstrumentHandlerResponseSize = iota
+	InstrumentHandlerRequestSize
+	InstrumentHandlerDuration
+	InstrumentHandlerCounter
+	InstrumentHandlerInFlight
+)
+
+type HTTPMetric struct {
+	prometheus.Collector
+	handlerType int
+}
+
+var (
+	defaultDurationBuckets     = []float64{.005, .01, .025, .05, .1, .25, .5, 1, 2.5, 5, 10, 25, 60}
+	defaultRequestSizeBuckets  = prometheus.ExponentialBuckets(1024, 2, 22) //1K to 4G
+	defaultResponseSizeBuckets = defaultRequestSizeBuckets
 )
 
 // Handler returns the global http.Handler that provides the prometheus
-// metrics format on GET requests
+// metrics format on GET requests. This handler is no longer instrumented.
 func Handler() http.Handler {
-	return prometheus.Handler()
+	return promhttp.Handler()
+}
+
+func InstrumentHandler(metrics []*HTTPMetric, handler http.Handler) http.HandlerFunc {
+	return InstrumentHandlerFunc(metrics, handler.ServeHTTP)
+}
+
+func InstrumentHandlerFunc(metrics []*HTTPMetric, handlerFunc http.HandlerFunc) http.HandlerFunc {
+	var handler http.Handler
+	handler = http.HandlerFunc(handlerFunc)
+	for _, metric := range metrics {
+		switch metric.handlerType {
+		case InstrumentHandlerResponseSize:
+			if collector, ok := metric.Collector.(prometheus.ObserverVec); ok {
+				handler = promhttp.InstrumentHandlerResponseSize(collector, handler)
+			}
+		case InstrumentHandlerRequestSize:
+			if collector, ok := metric.Collector.(prometheus.ObserverVec); ok {
+				handler = promhttp.InstrumentHandlerRequestSize(collector, handler)
+			}
+		case InstrumentHandlerDuration:
+			if collector, ok := metric.Collector.(prometheus.ObserverVec); ok {
+				handler = promhttp.InstrumentHandlerDuration(collector, handler)
+			}
+		case InstrumentHandlerCounter:
+			if collector, ok := metric.Collector.(*prometheus.CounterVec); ok {
+				handler = promhttp.InstrumentHandlerCounter(collector, handler)
+			}
+		case InstrumentHandlerInFlight:
+			if collector, ok := metric.Collector.(prometheus.Gauge); ok {
+				handler = promhttp.InstrumentHandlerInFlight(collector, handler)
+			}
+		}
+	}
+	return handler.ServeHTTP
 }

vendor/github.com/docker/go-metrics/namespace.go

@@ -179,3 +179,137 @@ func makeName(name string, unit Unit) string {
 
 	return fmt.Sprintf("%s_%s", name, unit)
 }
+
+func (n *Namespace) NewDefaultHttpMetrics(handlerName string) []*HTTPMetric {
+	return n.NewHttpMetricsWithOpts(handlerName, HTTPHandlerOpts{
+		DurationBuckets:     defaultDurationBuckets,
+		RequestSizeBuckets:  defaultResponseSizeBuckets,
+		ResponseSizeBuckets: defaultResponseSizeBuckets,
+	})
+}
+
+func (n *Namespace) NewHttpMetrics(handlerName string, durationBuckets, requestSizeBuckets, responseSizeBuckets []float64) []*HTTPMetric {
+	return n.NewHttpMetricsWithOpts(handlerName, HTTPHandlerOpts{
+		DurationBuckets:     durationBuckets,
+		RequestSizeBuckets:  requestSizeBuckets,
+		ResponseSizeBuckets: responseSizeBuckets,
+	})
+}
+
+func (n *Namespace) NewHttpMetricsWithOpts(handlerName string, opts HTTPHandlerOpts) []*HTTPMetric {
+	var httpMetrics []*HTTPMetric
+	inFlightMetric := n.NewInFlightGaugeMetric(handlerName)
+	requestTotalMetric := n.NewRequestTotalMetric(handlerName)
+	requestDurationMetric := n.NewRequestDurationMetric(handlerName, opts.DurationBuckets)
+	requestSizeMetric := n.NewRequestSizeMetric(handlerName, opts.RequestSizeBuckets)
+	responseSizeMetric := n.NewResponseSizeMetric(handlerName, opts.ResponseSizeBuckets)
+	httpMetrics = append(httpMetrics, inFlightMetric, requestDurationMetric, requestTotalMetric, requestSizeMetric, responseSizeMetric)
+	return httpMetrics
+}
+
+func (n *Namespace) NewInFlightGaugeMetric(handlerName string) *HTTPMetric {
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	metric := prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace:   n.name,
+		Subsystem:   n.subsystem,
+		Name:        "in_flight_requests",
+		Help:        "The in-flight HTTP requests",
+		ConstLabels: prometheus.Labels(labels),
+	})
+	httpMetric := &HTTPMetric{
+		Collector:   metric,
+		handlerType: InstrumentHandlerInFlight,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}
+
+func (n *Namespace) NewRequestTotalMetric(handlerName string) *HTTPMetric {
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	metric := prometheus.NewCounterVec(
+		prometheus.CounterOpts{
+			Namespace:   n.name,
+			Subsystem:   n.subsystem,
+			Name:        "requests_total",
+			Help:        "Total number of HTTP requests made.",
+			ConstLabels: prometheus.Labels(labels),
+		},
+		[]string{"code", "method"},
+	)
+	httpMetric := &HTTPMetric{
+		Collector:   metric,
+		handlerType: InstrumentHandlerCounter,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}
+func (n *Namespace) NewRequestDurationMetric(handlerName string, buckets []float64) *HTTPMetric {
+	if len(buckets) == 0 {
+		panic("DurationBuckets must be provided")
+	}
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	opts := prometheus.HistogramOpts{
+		Namespace:   n.name,
+		Subsystem:   n.subsystem,
+		Name:        "request_duration_seconds",
+		Help:        "The HTTP request latencies in seconds.",
+		Buckets:     buckets,
+		ConstLabels: prometheus.Labels(labels),
+	}
+	metric := prometheus.NewHistogramVec(opts, []string{"method"})
+	httpMetric := &HTTPMetric{
+		Collector:   metric,
+		handlerType: InstrumentHandlerDuration,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}
+
+func (n *Namespace) NewRequestSizeMetric(handlerName string, buckets []float64) *HTTPMetric {
+	if len(buckets) == 0 {
+		panic("RequestSizeBuckets must be provided")
+	}
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	opts := prometheus.HistogramOpts{
+		Namespace:   n.name,
+		Subsystem:   n.subsystem,
+		Name:        "request_size_bytes",
+		Help:        "The HTTP request sizes in bytes.",
+		Buckets:     buckets,
+		ConstLabels: prometheus.Labels(labels),
+	}
+	metric := prometheus.NewHistogramVec(opts, []string{})
+	httpMetric := &HTTPMetric{
+		Collector:   metric,
+		handlerType: InstrumentHandlerRequestSize,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}
+
+func (n *Namespace) NewResponseSizeMetric(handlerName string, buckets []float64) *HTTPMetric {
+	if len(buckets) == 0 {
+		panic("ResponseSizeBuckets must be provided")
+	}
+	labels := prometheus.Labels(n.labels)
+	labels["handler"] = handlerName
+	opts := prometheus.HistogramOpts{
+		Namespace:   n.name,
+		Subsystem:   n.subsystem,
+		Name:        "response_size_bytes",
+		Help:        "The HTTP response sizes in bytes.",
+		Buckets:     buckets,
+		ConstLabels: prometheus.Labels(labels),
+	}
+	metrics := prometheus.NewHistogramVec(opts, []string{})
+	httpMetric := &HTTPMetric{
+		Collector:   metrics,
+		handlerType: InstrumentHandlerResponseSize,
+	}
+	n.Add(httpMetric)
+	return httpMetric
+}