Reorganize instrument code

lib/instrument/dummy.go

@@ -2,13 +2,10 @@
 
 package instrument
 
-import "time"
-
 type dummyInst struct{}
 
 func Init() Instrument {
 	return &dummyInst{}
 }
 
-func (i dummyInst) Visit(section string, id string, search string, fmt string)     {}
-func (i dummyInst) Duration(section string, search string, duration time.Duration) {}
+func (i dummyInst) Request(req RequestData) {}

lib/instrument/instrument.go

@@ -2,7 +2,14 @@ package instrument
 
 import "time"
 
-type Instrument interface {
-	Visit(section string, id string, search string, fmt string)
-	Duration(section string, search string, duration time.Duration)
+type RequestData struct {
+	Section  string
+	ID       string
+	Search   string
+	Fmt      string
+	Duration time.Duration
+}
+
+type Instrument interface {
+	Request(req RequestData)
 }

lib/instrument/prometheus.go

@@ -3,8 +3,6 @@
 package instrument
 
 import (
-	"time"
-
 	log "github.com/cihub/seelog"
 
 	"net/http"
@@ -37,7 +35,7 @@ func Init() Instrument {
 			Name: "trantor_request_duration_seconds",
 			Help: "Duration of the request in seconds.",
 		},
-		[]string{"section", "search"},
+		[]string{"section"},
 	)
 
 	prometheus.MustRegister(visits)
@@ -57,10 +55,7 @@ func promHandle() {
 	log.Error(server.ListenAndServe())
 }
 
-func (in promInst) Visit(section string, id string, search string, fmt string) {
-	in.visits.WithLabelValues(section, id, search, fmt).Inc()
-}
-
-func (in promInst) Duration(section string, search string, duration time.Duration) {
-	in.reqDur.WithLabelValues(section, search).Observe(duration.Seconds())
+func (in promInst) Request(req RequestData) {
+	in.visits.WithLabelValues(req.Section, req.ID, req.Search, req.Fmt).Inc()
+	in.reqDur.WithLabelValues(req.Section).Observe(req.Duration.Seconds())
 }

lib/stats.go

@@ -119,8 +119,13 @@ func (sg StatsGatherer) worker() {
 			section = pattern[1]
 		}
 
-		sg.instrument.Visit(section, id, search, fmt)
-		sg.instrument.Duration(section, search, req.duration)
+		sg.instrument.Request(instrument.RequestData{
+			Section: section,
+			ID: id,
+			Search: search,
+			Fmt: fmt,
+			Duration: req.duration
+		})
 		switch section {
 		case "download":
 			err = sg.db.IncDownloads(id)