move common metrics-related funcs to internal package

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

2 files changed, 4 insertions, 58 deletions

diff --git a/modules/caddyhttp/metrics.go b/modules/caddyhttp/metrics.go
index f2023cf..458c22a 100644
--- a/modules/caddyhttp/metrics.go
+++ b/modules/caddyhttp/metrics.go
@@ -3,10 +3,10 @@ package caddyhttp
 import (
 	"context"
 	"net/http"
-	"strconv"
 	"sync"
 	"time"
 
+	"github.com/caddyserver/caddy/v2/internal/metrics"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 )
@@ -108,7 +108,7 @@ func newMetricsInstrumentedHandler(handler string, mh MiddlewareHandler) *metric
 func (h *metricsInstrumentedHandler) ServeHTTP(w http.ResponseWriter, r *http.Request, next Handler) error {
 	server := serverNameFromContext(r.Context())
 	labels := prometheus.Labels{"server": server, "handler": h.handler}
-	method := sanitizeMethod(r.Method)
+	method := metrics.SanitizeMethod(r.Method)
 	// the "code" value is set later, but initialized here to eliminate the possibility
 	// of a panic
 	statusLabels := prometheus.Labels{"server": server, "handler": h.handler, "method": method, "code": ""}
@@ -123,7 +123,7 @@ func (h *metricsInstrumentedHandler) ServeHTTP(w http.ResponseWriter, r *http.Re
 	// being called when the headers are written.
 	// Effectively the same behaviour as promhttp.InstrumentHandlerTimeToWriteHeader.
 	writeHeaderRecorder := ShouldBufferFunc(func(status int, header http.Header) bool {
-		statusLabels["code"] = sanitizeCode(status)
+		statusLabels["code"] = metrics.SanitizeCode(status)
 		ttfb := time.Since(start).Seconds()
 		httpMetrics.responseDuration.With(statusLabels).Observe(ttfb)
 		return false
@@ -142,7 +142,7 @@ func (h *metricsInstrumentedHandler) ServeHTTP(w http.ResponseWriter, r *http.Re
 	if statusLabels["code"] == "" {
 		// we still sanitize it, even though it's likely to be 0. A 200 is
 		// returned on fallthrough so we want to reflect that.
-		statusLabels["code"] = sanitizeCode(wrec.Status())
+		statusLabels["code"] = metrics.SanitizeCode(wrec.Status())
 	}
 
 	httpMetrics.requestDuration.With(statusLabels).Observe(dur)
@@ -152,37 +152,6 @@ func (h *metricsInstrumentedHandler) ServeHTTP(w http.ResponseWriter, r *http.Re
 	return nil
 }
 
-func sanitizeCode(code int) string {
-	if code == 0 {
-		return "200"
-	}
-	return strconv.Itoa(code)
-}
-
-// Only support the list of "regular" HTTP methods, see
-// https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods
-var methodMap = map[string]string{
-	"GET": http.MethodGet, "get": http.MethodGet,
-	"HEAD": http.MethodHead, "head": http.MethodHead,
-	"PUT": http.MethodPut, "put": http.MethodPut,
-	"POST": http.MethodPost, "post": http.MethodPost,
-	"DELETE": http.MethodDelete, "delete": http.MethodDelete,
-	"CONNECT": http.MethodConnect, "connect": http.MethodConnect,
-	"OPTIONS": http.MethodOptions, "options": http.MethodOptions,
-	"TRACE": http.MethodTrace, "trace": http.MethodTrace,
-	"PATCH": http.MethodPatch, "patch": http.MethodPatch,
-}
-
-// sanitizeMethod sanitizes the method for use as a metric label. This helps
-// prevent high cardinality on the method label. The name is always upper case.
-func sanitizeMethod(m string) string {
-	if m, ok := methodMap[m]; ok {
-		return m
-	}
-
-	return "OTHER"
-}
-
 // taken from https://github.com/prometheus/client_golang/blob/6007b2b5cae01203111de55f753e76d8dac1f529/prometheus/promhttp/instrument_server.go#L298
 func computeApproximateRequestSize(r *http.Request) int {
 	s := 0
diff --git a/modules/caddyhttp/metrics_test.go b/modules/caddyhttp/metrics_test.go
index 95f6d9b..6311935 100644
--- a/modules/caddyhttp/metrics_test.go
+++ b/modules/caddyhttp/metrics_test.go
@@ -5,7 +5,6 @@ import (
 	"errors"
 	"net/http"
 	"net/http/httptest"
-	"strings"
 	"testing"
 
 	"github.com/prometheus/client_golang/prometheus/testutil"
@@ -83,25 +82,3 @@ type middlewareHandlerFunc func(http.ResponseWriter, *http.Request, Handler) err
 func (f middlewareHandlerFunc) ServeHTTP(w http.ResponseWriter, r *http.Request, h Handler) error {
 	return f(w, r, h)
 }
-
-func TestSanitizeMethod(t *testing.T) {
-	tests := []struct {
-		method   string
-		expected string
-	}{
-		{method: "get", expected: "GET"},
-		{method: "POST", expected: "POST"},
-		{method: "OPTIONS", expected: "OPTIONS"},
-		{method: "connect", expected: "CONNECT"},
-		{method: "trace", expected: "TRACE"},
-		{method: "UNKNOWN", expected: "OTHER"},
-		{method: strings.Repeat("ohno", 9999), expected: "OTHER"},
-	}
-
-	for _, d := range tests {
-		actual := sanitizeMethod(d.method)
-		if actual != d.expected {
-			t.Errorf("Not same: expected %#v, but got %#v", d.expected, actual)
-		}
-	}
-}