Move signature.go and related tests to the model package.

The LabelsToSignature function is now used outside of the prometheus
package, too. Leaving it in the prometheuos package is misleading
design and will lead to circulat import chains soon.

Change-Id: If1ca442d4023b33b138cf79fee68e82ff2a355be

model/signature.go

@@ -4,13 +4,11 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package prometheus
+package model
 
 import (
 	"hash/fnv"
 	"sort"
-
-	"github.com/prometheus/client_golang/model"
 )
 
 // cache the signature of an empty label set.
@@ -23,18 +21,18 @@ func LabelsToSignature(labels map[string]string) uint64 {
 		return emptyLabelSignature
 	}
 
-	names := make(model.LabelNames, 0, len(labels))
+	names := make([]string, 0, len(labels))
 	for name := range labels {
-		names = append(names, model.LabelName(name))
+		names = append(names, name)
 	}
 
-	sort.Sort(names)
+	sort.Strings(names)
 
 	hasher := fnv.New64a()
 
 	for _, name := range names {
 		hasher.Write([]byte(name))
-		hasher.Write([]byte(labels[string(name)]))
+		hasher.Write([]byte(labels[name]))
 	}
 
 	return hasher.Sum64()
@@ -42,22 +40,22 @@ func LabelsToSignature(labels map[string]string) uint64 {
 
 // LabelValuesToSignature provides a way of building a unique signature
 // (i.e., fingerprint) for a given set of label's values.
-func labelValuesToSignature(labels map[string]string) uint64 {
+func LabelValuesToSignature(labels map[string]string) uint64 {
 	if len(labels) == 0 {
 		return emptyLabelSignature
 	}
 
-	names := make(model.LabelNames, 0, len(labels))
+	names := make([]string, 0, len(labels))
 	for name := range labels {
-		names = append(names, model.LabelName(name))
+		names = append(names, name)
 	}
 
-	sort.Sort(names)
+	sort.Strings(names)
 
 	hasher := fnv.New64a()
 
 	for _, name := range names {
-		hasher.Write([]byte(labels[string(name)]))
+		hasher.Write([]byte(labels[name]))
 	}
 
 	return hasher.Sum64()

model/signature_test.go

@@ -4,14 +4,16 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-package prometheus
+package model
 
 import (
 	"runtime"
 	"testing"
+
+	"github.com/prometheus/client_golang/test"
 )
 
-func testLabelsToSignature(t tester) {
+func testLabelsToSignature(t test.Tester) {
 	var scenarios = []struct {
 		in  map[string]string
 		out uint64
@@ -66,7 +68,7 @@ func BenchmarkLabelToSignature(b *testing.B) {
 
 func benchmarkLabelValuesToSignature(b *testing.B, l map[string]string, e uint64) {
 	for i := 0; i < b.N; i++ {
-		if a := labelValuesToSignature(l); a != e {
+		if a := LabelValuesToSignature(l); a != e {
 			b.Fatalf("expected signature of %d for %s, got %d", e, l, a)
 		}
 	}

prometheus/counter.go

@@ -14,6 +14,8 @@ import (
 	dto "github.com/prometheus/client_model/go"
 
 	"code.google.com/p/goprotobuf/proto"
+
+	"github.com/prometheus/client_golang/model"
 )
 
 // TODO(matt): Refactor to de-duplicate behaviors.
@@ -49,7 +51,7 @@ func (metric *counter) Set(labels map[string]string, value float64) float64 {
 		labels = blankLabelsSingleton
 	}
 
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 
 	metric.mutex.Lock()
 	defer metric.mutex.Unlock()
@@ -67,7 +69,7 @@ func (metric *counter) Set(labels map[string]string, value float64) float64 {
 }
 
 func (metric *counter) Reset(labels map[string]string) {
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 
 	metric.mutex.Lock()
 	defer metric.mutex.Unlock()
@@ -100,7 +102,7 @@ func (metric *counter) IncrementBy(labels map[string]string, value float64) floa
 		labels = blankLabelsSingleton
 	}
 
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 
 	metric.mutex.Lock()
 	defer metric.mutex.Unlock()
@@ -126,7 +128,7 @@ func (metric *counter) DecrementBy(labels map[string]string, value float64) floa
 		labels = blankLabelsSingleton
 	}
 
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 
 	metric.mutex.Lock()
 	defer metric.mutex.Unlock()

prometheus/gauge.go

@@ -14,6 +14,8 @@ import (
 	"code.google.com/p/goprotobuf/proto"
 
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/model"
 )
 
 // A gauge metric merely provides an instantaneous representation of a scalar
@@ -55,7 +57,7 @@ func (metric *gauge) Set(labels map[string]string, value float64) float64 {
 		labels = blankLabelsSingleton
 	}
 
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 
 	metric.mutex.Lock()
 	defer metric.mutex.Unlock()
@@ -73,7 +75,7 @@ func (metric *gauge) Set(labels map[string]string, value float64) float64 {
 }
 
 func (metric *gauge) Reset(labels map[string]string) {
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 
 	metric.mutex.Lock()
 	defer metric.mutex.Unlock()

prometheus/histogram.go

@@ -18,6 +18,8 @@ import (
 	dto "github.com/prometheus/client_model/go"
 
 	"code.google.com/p/goprotobuf/proto"
+
+	"github.com/prometheus/client_golang/model"
 )
 
 // This generates count-buckets of equal size distributed along the open
@@ -101,7 +103,7 @@ func (h *histogram) Add(labels map[string]string, value float64) {
 		labels = blankLabelsSingleton
 	}
 
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 	var histogram *histogramVector = nil
 
 	h.mutex.Lock()
@@ -298,7 +300,7 @@ func (h *histogram) Purge() {
 }
 
 func (h *histogram) Reset(labels map[string]string) {
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 
 	h.mutex.Lock()
 	defer h.mutex.Unlock()

prometheus/registry.go

@@ -158,7 +158,7 @@ func (r *registry) isValidCandidate(name string, baseLabels map[string]string) (
 	}
 
 	baseLabels[string(model.MetricNameLabel)] = name
-	signature = LabelsToSignature(baseLabels)
+	signature = model.LabelsToSignature(baseLabels)
 
 	if _, contains := r.signatureContainers[signature]; contains {
 		err = fmt.Errorf("metric named %s with baseLabels %s is already registered", name, baseLabels)

prometheus/untyped.go

@@ -14,6 +14,8 @@ import (
 	"code.google.com/p/goprotobuf/proto"
 
 	dto "github.com/prometheus/client_model/go"
+
+	"github.com/prometheus/client_golang/model"
 )
 
 // An Untyped metric represents scalar values without any type implications
@@ -56,7 +58,7 @@ func (metric *untyped) Set(labels map[string]string, value float64) float64 {
 		labels = blankLabelsSingleton
 	}
 
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 
 	metric.mutex.Lock()
 	defer metric.mutex.Unlock()
@@ -74,7 +76,7 @@ func (metric *untyped) Set(labels map[string]string, value float64) float64 {
 }
 
 func (metric *untyped) Reset(labels map[string]string) {
-	signature := labelValuesToSignature(labels)
+	signature := model.LabelValuesToSignature(labels)
 
 	metric.mutex.Lock()
 	defer metric.mutex.Unlock()

text/parse.go

@@ -26,7 +26,6 @@ import (
 
 	"code.google.com/p/goprotobuf/proto"
 	"github.com/prometheus/client_golang/model"
-	"github.com/prometheus/client_golang/prometheus"
 )
 
 // A stateFn is a function that represents a state in a state machine. By
@@ -332,7 +331,7 @@ func (p *Parser) readingValue() stateFn {
 	// infamous special case of a summary, we can finally find out
 	// if the metric already exists.
 	if p.currentMF.GetType() == dto.MetricType_SUMMARY {
-		signature := prometheus.LabelsToSignature(p.currentLabels)
+		signature := model.LabelsToSignature(p.currentLabels)
 		if summary := p.summaries[signature]; summary != nil {
 			p.currentMetric = summary
 		} else {