Un-export prometheus.LabelPairSorter

The only known external usage of it was in prometheus/pushgateway,
where it was removed by
https://github.com/prometheus/pushgateway/pull/200 .

Originally, the expectation was that users would implement the Metric
interface now and then. As we know now, neither it is happening, nor
would it make a lot of sense. (Users implement the Collector interface
instead.) By now, LabelPairSorter is essentially noise in the already
quite cluttered namespace in the prometheus package.

Signed-off-by: beorn7 <beorn@soundcloud.com>

prometheus/desc.go

@@ -156,7 +156,7 @@ func NewDesc(fqName, help string, variableLabels []string, constLabels Labels) *
 			Value: proto.String(v),
 		})
 	}
-	sort.Sort(LabelPairSorter(d.constLabelPairs))
+	sort.Sort(labelPairSorter(d.constLabelPairs))
 	return d
 }
 

prometheus/examples_test.go

@@ -19,7 +19,6 @@ import (
 	"math"
 	"net/http"
 	"runtime"
-	"sort"
 	"strings"
 	"time"
 
@@ -168,19 +167,6 @@ func ExampleInstrumentHandler() {
 	))
 }
 
-func ExampleLabelPairSorter() {
-	labelPairs := []*dto.LabelPair{
-		{Name: proto.String("status"), Value: proto.String("404")},
-		{Name: proto.String("method"), Value: proto.String("get")},
-	}
-
-	sort.Sort(prometheus.LabelPairSorter(labelPairs))
-
-	fmt.Println(labelPairs)
-	// Output:
-	// [name:"method" value:"get"  name:"status" value:"404" ]
-}
-
 func ExampleRegister() {
 	// Imagine you have a worker pool and want to count the tasks completed.
 	taskCounter := prometheus.NewCounter(prometheus.CounterOpts{

prometheus/metric.go

@@ -46,9 +46,8 @@ type Metric interface {
 	// While populating dto.Metric, it is the responsibility of the
 	// implementation to ensure validity of the Metric protobuf (like valid
 	// UTF-8 strings or syntactically valid metric and label names). It is
-	// recommended to sort labels lexicographically. (Implementers may find
+	// recommended to sort labels lexicographically. Callers of Write should
-	// LabelPairSorter useful for that.) Callers of Write should still make
+	// still make sure of sorting if they depend on it.
-	// sure of sorting if they depend on it.
 	Write(*dto.Metric) error
 	// TODO(beorn7): The original rationale of passing in a pre-allocated
 	// dto.Metric protobuf to save allocations has disappeared. The
@@ -113,20 +112,19 @@ func BuildFQName(namespace, subsystem, name string) string {
 	return name
 }
 
-// LabelPairSorter implements sort.Interface. It is used to sort a slice of
+// labelPairSorter implements sort.Interface. It is used to sort a slice of
-// dto.LabelPair pointers. This is useful for implementing the Write method of
+// dto.LabelPair pointers.
-// custom metrics.
+type labelPairSorter []*dto.LabelPair
-type LabelPairSorter []*dto.LabelPair
 
-func (s LabelPairSorter) Len() int {
+func (s labelPairSorter) Len() int {
 	return len(s)
 }
 
-func (s LabelPairSorter) Swap(i, j int) {
+func (s labelPairSorter) Swap(i, j int) {
 	s[i], s[j] = s[j], s[i]
 }
 
-func (s LabelPairSorter) Less(i, j int) bool {
+func (s labelPairSorter) Less(i, j int) bool {
 	return s[i].GetName() < s[j].GetName()
 }
 

prometheus/registry.go

@@ -819,7 +819,7 @@ func checkMetricConsistency(
 	h = hashAddByte(h, separatorByte)
 	// Make sure label pairs are sorted. We depend on it for the consistency
 	// check.
-	sort.Sort(LabelPairSorter(dtoMetric.Label))
+	sort.Sort(labelPairSorter(dtoMetric.Label))
 	for _, lp := range dtoMetric.Label {
 		h = hashAdd(h, lp.GetName())
 		h = hashAddByte(h, separatorByte)
@@ -863,7 +863,7 @@ func checkDescConsistency(
 			metricFamily.GetName(), dtoMetric, desc,
 		)
 	}
-	sort.Sort(LabelPairSorter(lpsFromDesc))
+	sort.Sort(labelPairSorter(lpsFromDesc))
 	for i, lpFromDesc := range lpsFromDesc {
 		lpFromMetric := dtoMetric.Label[i]
 		if lpFromDesc.GetName() != lpFromMetric.GetName() ||

prometheus/value.go

@@ -153,6 +153,6 @@ func makeLabelPairs(desc *Desc, labelValues []string) []*dto.LabelPair {
 		})
 	}
 	labelPairs = append(labelPairs, desc.constLabelPairs...)
-	sort.Sort(LabelPairSorter(labelPairs))
+	sort.Sort(labelPairSorter(labelPairs))
 	return labelPairs
 }