Add goreport card and remove warnings where feasible

README.md

@@ -1,6 +1,7 @@
 # Prometheus Go client library
 
 [![Build Status](https://travis-ci.org/prometheus/client_golang.svg?branch=master)](https://travis-ci.org/prometheus/client_golang)
+[![Go Report Card](https://goreportcard.com/badge/github.com/prometheus/client_golang)](https://goreportcard.com/report/github.com/prometheus/client_golang)
 
 This is the [Go](http://golang.org) client library for
 [Prometheus](http://prometheus.io). It has two separate parts, one for

api/prometheus/api.go

@@ -42,10 +42,11 @@ const (
 	epSeries      = "/series"
 )
 
+// ErrorType models the different API error types.
 type ErrorType string
 
+// Possible values for ErrorType.
 const (
-	// The different API error types.
 	ErrBadData     ErrorType = "bad_data"
 	ErrTimeout               = "timeout"
 	ErrCanceled              = "canceled"
@@ -70,6 +71,7 @@ type CancelableTransport interface {
 	CancelRequest(req *http.Request)
 }
 
+// DefaultTransport is used if no Transport is set in Config.
 var DefaultTransport CancelableTransport = &http.Transport{
 	Proxy: http.ProxyFromEnvironment,
 	Dial: (&net.Dialer{
@@ -96,6 +98,7 @@ func (cfg *Config) transport() CancelableTransport {
 	return cfg.Transport
 }
 
+// Client is the interface for an API client.
 type Client interface {
 	url(ep string, args map[string]string) *url.URL
 	do(context.Context, *http.Request) (*http.Response, []byte, error)

api/prometheus/api_test.go

@@ -352,19 +352,19 @@ func TestAPIs(t *testing.T) {
 
 	client := &apiTestClient{T: t}
 
-	queryApi := &httpQueryAPI{
+	queryAPI := &httpQueryAPI{
 		client: client,
 	}
 
 	doQuery := func(q string, ts time.Time) func() (interface{}, error) {
 		return func() (interface{}, error) {
-			return queryApi.Query(context.Background(), q, ts)
+			return queryAPI.Query(context.Background(), q, ts)
 		}
 	}
 
 	doQueryRange := func(q string, rng Range) func() (interface{}, error) {
 		return func() (interface{}, error) {
-			return queryApi.QueryRange(context.Background(), q, rng)
+			return queryAPI.QueryRange(context.Background(), q, rng)
 		}
 	}
 

prometheus/desc.go

@@ -78,7 +78,7 @@ type Desc struct {
 	// Help string. Each Desc with the same fqName must have the same
 	// dimHash.
 	dimHash uint64
-	// err is an error that occured during construction. It is reported on
+	// err is an error that occurred during construction. It is reported on
 	// registration time.
 	err error
 }

prometheus/examples_test.go

@@ -113,7 +113,7 @@ func ExampleCounter() {
 	pushComplete := make(chan struct{})
 	// TODO: Start a goroutine that performs repository pushes and reports
 	// each completion via the channel.
-	for _ = range pushComplete {
+	for range pushComplete {
 		pushCounter.Inc()
 	}
 	// Output:
@@ -169,8 +169,8 @@ func ExampleInstrumentHandler() {
 
 func ExampleLabelPairSorter() {
 	labelPairs := []*dto.LabelPair{
-		&dto.LabelPair{Name: proto.String("status"), Value: proto.String("404")},
+		{Name: proto.String("status"), Value: proto.String("404")},
-		&dto.LabelPair{Name: proto.String("method"), Value: proto.String("get")},
+		{Name: proto.String("method"), Value: proto.String("get")},
 	}
 
 	sort.Sort(prometheus.LabelPairSorter(labelPairs))
@@ -640,6 +640,7 @@ func ExampleAlreadyRegisteredError() {
 			panic(err)
 		}
 	}
+	reqCounter.Inc()
 }
 
 func ExampleGatherers() {

prometheus/expvar_collector_test.go

@@ -24,7 +24,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 )
 
-func ExampleExpvarCollector() {
+func ExampleNewExpvarCollector() {
 	expvarCollector := prometheus.NewExpvarCollector(map[string]*prometheus.Desc{
 		"memstats": prometheus.NewDesc(
 			"expvar_memstats",

prometheus/push/examples_test.go

@@ -24,7 +24,7 @@ import (
 func ExampleCollectors() {
 	completionTime := prometheus.NewGauge(prometheus.GaugeOpts{
 		Name: "db_backup_last_completion_timestamp_seconds",
-		Help: "The timestamp of the last succesful completion of a DB backup.",
+		Help: "The timestamp of the last successful completion of a DB backup.",
 	})
 	completionTime.Set(float64(time.Now().Unix()))
 	if err := push.Collectors(
@@ -36,12 +36,12 @@ func ExampleCollectors() {
 	}
 }
 
-func ExampleRegistry() {
+func ExampleFromGatherer() {
 	registry := prometheus.NewRegistry()
 
 	completionTime := prometheus.NewGauge(prometheus.GaugeOpts{
 		Name: "db_backup_last_completion_timestamp_seconds",
-		Help: "The timestamp of the last succesful completion of a DB backup.",
+		Help: "The timestamp of the last successful completion of a DB backup.",
 	})
 	registry.MustRegister(completionTime)
 

prometheus/registry.go

@@ -447,7 +447,7 @@ func (r *Registry) Gather() ([]*dto.MetricFamily, error) {
 
 	// Drain metricChan in case of premature return.
 	defer func() {
-		for _ = range metricChan {
+		for range metricChan {
 		}
 	}()
 
@@ -683,7 +683,7 @@ func (s metricSorter) Less(i, j int) bool {
 	return s[i].GetTimestampMs() < s[j].GetTimestampMs()
 }
 
-// normalizeMetricFamilies returns a MetricFamily slice whith empty
+// normalizeMetricFamilies returns a MetricFamily slice with empty
 // MetricFamilies pruned and the remaining MetricFamilies sorted by name within
 // the slice, with the contained Metrics sorted within each MetricFamily.
 func normalizeMetricFamilies(metricFamiliesByName map[string]*dto.MetricFamily) []*dto.MetricFamily {

prometheus/summary_test.go

@@ -305,7 +305,7 @@ func TestSummaryDecay(t *testing.T) {
 	m := &dto.Metric{}
 	i := 0
 	tick := time.NewTicker(time.Millisecond)
-	for _ = range tick.C {
+	for range tick.C {
 		i++
 		sum.Observe(float64(i))
 		if i%10 == 0 {

prometheus/vec_test.go

@@ -241,8 +241,8 @@ func TestCounterVecEndToEndWithCollision(t *testing.T) {
 
 func BenchmarkMetricVecWithLabelValuesBasic(b *testing.B) {
 	benchmarkMetricVecWithLabelValues(b, map[string][]string{
-		"l1": []string{"onevalue"},
+		"l1": {"onevalue"},
-		"l2": []string{"twovalue"},
+		"l2": {"twovalue"},
 	})
 }