traefik/pkg/middlewares/metrics/metrics.go

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package metrics
import (
"context"
"net/http"
"strconv"
"strings"
"time"
"unicode/utf8"
"github.com/containous/alice"
gokitmetrics "github.com/go-kit/kit/metrics"
"github.com/traefik/traefik/v2/pkg/log"
"github.com/traefik/traefik/v2/pkg/metrics"
"github.com/traefik/traefik/v2/pkg/middlewares"
"github.com/traefik/traefik/v2/pkg/middlewares/retry"
traefiktls "github.com/traefik/traefik/v2/pkg/tls"
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)
const (
protoHTTP = "http"
protoSSE = "sse"
protoWebsocket = "websocket"
typeName = "Metrics"
nameEntrypoint = "metrics-entrypoint"
nameService = "metrics-service"
)
type metricsMiddleware struct {
next http.Handler
reqsCounter gokitmetrics.Counter
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reqsTLSCounter gokitmetrics.Counter
reqDurationHistogram metrics.ScalableHistogram
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openConnsGauge gokitmetrics.Gauge
baseLabels []string
}
// NewEntryPointMiddleware creates a new metrics middleware for an Entrypoint.
func NewEntryPointMiddleware(ctx context.Context, next http.Handler, registry metrics.Registry, entryPointName string) http.Handler {
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log.FromContext(middlewares.GetLoggerCtx(ctx, nameEntrypoint, typeName)).Debug("Creating middleware")
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return &metricsMiddleware{
next: next,
reqsCounter: registry.EntryPointReqsCounter(),
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reqsTLSCounter: registry.EntryPointReqsTLSCounter(),
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reqDurationHistogram: registry.EntryPointReqDurationHistogram(),
openConnsGauge: registry.EntryPointOpenConnsGauge(),
baseLabels: []string{"entrypoint", entryPointName},
}
}
// NewServiceMiddleware creates a new metrics middleware for a Service.
func NewServiceMiddleware(ctx context.Context, next http.Handler, registry metrics.Registry, serviceName string) http.Handler {
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log.FromContext(middlewares.GetLoggerCtx(ctx, nameService, typeName)).Debug("Creating middleware")
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return &metricsMiddleware{
next: next,
reqsCounter: registry.ServiceReqsCounter(),
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reqsTLSCounter: registry.ServiceReqsTLSCounter(),
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reqDurationHistogram: registry.ServiceReqDurationHistogram(),
openConnsGauge: registry.ServiceOpenConnsGauge(),
baseLabels: []string{"service", serviceName},
}
}
// WrapEntryPointHandler Wraps metrics entrypoint to alice.Constructor.
func WrapEntryPointHandler(ctx context.Context, registry metrics.Registry, entryPointName string) alice.Constructor {
return func(next http.Handler) (http.Handler, error) {
return NewEntryPointMiddleware(ctx, next, registry, entryPointName), nil
}
}
// WrapServiceHandler Wraps metrics service to alice.Constructor.
func WrapServiceHandler(ctx context.Context, registry metrics.Registry, serviceName string) alice.Constructor {
return func(next http.Handler) (http.Handler, error) {
return NewServiceMiddleware(ctx, next, registry, serviceName), nil
}
}
func (m *metricsMiddleware) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
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var labels []string
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labels = append(labels, m.baseLabels...)
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labels = append(labels, "method", getMethod(req), "protocol", getRequestProtocol(req))
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m.openConnsGauge.With(labels...).Add(1)
defer m.openConnsGauge.With(labels...).Add(-1)
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// TLS metrics
if req.TLS != nil {
var tlsLabels []string
tlsLabels = append(tlsLabels, m.baseLabels...)
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tlsLabels = append(tlsLabels, "tls_version", traefiktls.GetVersion(req.TLS), "tls_cipher", traefiktls.GetCipherName(req.TLS))
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m.reqsTLSCounter.With(tlsLabels...).Add(1)
}
recorder := newResponseRecorder(rw)
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start := time.Now()
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m.next.ServeHTTP(recorder, req)
labels = append(labels, "code", strconv.Itoa(recorder.getCode()))
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histograms := m.reqDurationHistogram.With(labels...)
histograms.ObserveFromStart(start)
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m.reqsCounter.With(labels...).Add(1)
}
func getRequestProtocol(req *http.Request) string {
switch {
case isWebsocketRequest(req):
return protoWebsocket
case isSSERequest(req):
return protoSSE
default:
return protoHTTP
}
}
// isWebsocketRequest determines if the specified HTTP request is a websocket handshake request.
func isWebsocketRequest(req *http.Request) bool {
return containsHeader(req, "Connection", "upgrade") && containsHeader(req, "Upgrade", "websocket")
}
// isSSERequest determines if the specified HTTP request is a request for an event subscription.
func isSSERequest(req *http.Request) bool {
return containsHeader(req, "Accept", "text/event-stream")
}
func containsHeader(req *http.Request, name, value string) bool {
items := strings.Split(req.Header.Get(name), ",")
for _, item := range items {
if value == strings.ToLower(strings.TrimSpace(item)) {
return true
}
}
return false
}
func getMethod(r *http.Request) string {
if !utf8.ValidString(r.Method) {
log.Warnf("Invalid HTTP method encoding: %s", r.Method)
return "NON_UTF8_HTTP_METHOD"
}
return r.Method
}
type retryMetrics interface {
ServiceRetriesCounter() gokitmetrics.Counter
}
// NewRetryListener instantiates a MetricsRetryListener with the given retryMetrics.
func NewRetryListener(retryMetrics retryMetrics, serviceName string) retry.Listener {
return &RetryListener{retryMetrics: retryMetrics, serviceName: serviceName}
}
// RetryListener is an implementation of the RetryListener interface to
// record RequestMetrics about retry attempts.
type RetryListener struct {
retryMetrics retryMetrics
serviceName string
}
// Retried tracks the retry in the RequestMetrics implementation.
func (m *RetryListener) Retried(req *http.Request, attempt int) {
m.retryMetrics.ServiceRetriesCounter().With("service", m.serviceName).Add(1)
}