Small fix.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
prometheus · Aug 2, 2022 · 094f97f · 094f97f
1 parent da8f44d
commit 094f97f
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Showing 2 changed files with 11 additions and 6 deletions.
diff --git a/prometheus/promhttp/instrument_server.go b/prometheus/promhttp/instrument_server.go
@@ -79,7 +79,7 @@ func InstrumentHandlerInFlight(g prometheus.Gauge, next http.Handler) http.Handl
 // Note that this method is only guaranteed to never observe negative durations
 // if used with Go1.9+.
 func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler, opts ...Option) http.HandlerFunc {
-	mwOpts := &option{getExemplarFn: func(ctx context.Context) map[string]string { return nil }}
+	mwOpts := &option{getExemplarFn: func(ctx context.Context) prometheus.Labels { return nil }}
 	for _, o := range opts {
 		o(mwOpts)
 	}
@@ -130,7 +130,7 @@ func InstrumentHandlerDuration(obs prometheus.ObserverVec, next http.Handler, op
 //
 // See the example for InstrumentHandlerDuration for example usage.
 func InstrumentHandlerCounter(counter *prometheus.CounterVec, next http.Handler, opts ...Option) http.HandlerFunc {
-	mwOpts := &option{getExemplarFn: func(ctx context.Context) map[string]string { return nil }}
+	mwOpts := &option{getExemplarFn: func(ctx context.Context) prometheus.Labels { return nil }}
 	for _, o := range opts {
 		o(mwOpts)
 	}

diff --git a/prometheus/promhttp/option.go b/prometheus/promhttp/option.go
@@ -13,14 +13,18 @@
 
 package promhttp
 
-import "context"
+import (
+	"context"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
 
 // Option are used to configure a middleware or round tripper.
 type Option func(*option)
 
 type option struct {
 	extraMethods  []string
-	getExemplarFn func(ctx context.Context) map[string]string
+	getExemplarFn func(ctx context.Context) prometheus.Labels
 }
 
 // WithExtraMethods adds additional HTTP methods to the list of allowed methods.
@@ -34,8 +38,9 @@ func WithExtraMethods(methods ...string) Option {
 }
 
 // WithExemplarFromRequestContext adds allows to put a hook to all counter and histogram metrics.
-// If the hook function returns non-nil map representing key values, exemplars will be added for that request.
-func WithExemplarFromRequestContext(getExemplarFn func(ctx context.Context) map[string]string) Option {
+// If the hook function returns non-nil labels, exemplars will be added for that request, otherwise metric will get instrumented
+// without exemplar.
+func WithExemplarFromRequestContext(getExemplarFn func(ctx context.Context) prometheus.Labels) Option {
 	return func(o *option) {
 		o.getExemplarFn = getExemplarFn
 	}