change config prefix to namespace (#10)

metrics/prometheus/config.go

@@ -3,8 +3,8 @@ package prometheus
 import "github.com/prometheus/client_golang/prometheus"
 
 type Config struct {
-	// Prefix is the prefix that will be set on the metrics, by default it will be empty.
-	Prefix string
+	// Namespace is the prefix that will be set on the metrics, by default it will be empty.
+	Namespace string
 	// DurationBuckets are the buckets used by Prometheus for the HTTP request duration metrics,
 	// by default uses Prometheus default buckets (from 5ms to 10s).
 	DurationBuckets []float64

metrics/prometheus/recorder.go

@@ -45,21 +45,21 @@ func NewRecorder(config Config) *Recorder {
 
 	return &Recorder{
 		httpRequestDurHistogram: prometheus.NewHistogramVec(prometheus.HistogramOpts{
-			Namespace: config.Prefix,
+			Namespace: config.Namespace,
 			Subsystem: "http",
 			Name:      "request_duration_seconds",
 			Help:      "The latency of the HTTP requests (in seconds).",
 			Buckets:   config.DurationBuckets,
 		}, []string{config.IdentifierLabel, config.MethodLabel, config.StatusCodeLabel}),
 		httpResponseSizeHistogram: prometheus.NewHistogramVec(prometheus.HistogramOpts{
-			Namespace: config.Prefix,
+			Namespace: config.Namespace,
 			Subsystem: "http",
 			Name:      "response_size_bytes",
 			Help:      "The size of the HTTP responses (in bytes).",
 			Buckets:   config.SizeBuckets,
 		}, []string{config.IdentifierLabel, config.MethodLabel, config.StatusCodeLabel}),
 		httpRequestsInflight: prometheus.NewGaugeVec(prometheus.GaugeOpts{
-			Namespace: config.Prefix,
+			Namespace: config.Namespace,
 			Subsystem: "http",
 			Name:      "requests_inflight",
 			Help:      "The number of inflight requests being handled at the same time.",