Create a hash package and move fnv hashing

Signed-off-by: Kyle Eckhart <[email protected]>

Author: kgeckhart

collectors/monitoring_metrics.go

@@ -21,6 +21,7 @@ import (
 
 	"sort"
 
+	"github.com/prometheus-community/stackdriver_exporter/hash"
 	"github.com/prometheus-community/stackdriver_exporter/utils"
 )
 
@@ -196,13 +197,13 @@ func (t *timeSeriesMetrics) newConstMetric(fqName string, reportTime time.Time,
 }
 
 func hashLabelKeys(labelKeys []string) uint64 {
-	dh := HashNew()
+	dh := hash.New()
 	sortedKeys := make([]string, len(labelKeys))
 	copy(sortedKeys, labelKeys)
 	sort.Strings(sortedKeys)
 	for _, key := range sortedKeys {
-		dh = HashAdd(dh, key)
-		dh = hashAddByte(dh, separatorByte)
+		dh = hash.Add(dh, key)
+		dh = hash.AddByte(dh, hash.SeparatorByte)
 	}
 	return dh
 }

delta/counter.go

@@ -25,6 +25,7 @@ import (
 	"google.golang.org/api/monitoring/v3"
 
 	"github.com/prometheus-community/stackdriver_exporter/collectors"
+	"github.com/prometheus-community/stackdriver_exporter/hash"
 )
 
 type MetricEntry struct {
@@ -95,8 +96,8 @@ func toCounterKey(c *collectors.ConstMetric) uint64 {
 		keyParts = append(keyParts, fmt.Sprintf("%s:%s", k, labels[k]))
 	}
 	hashText := fmt.Sprintf("%s|%s", c.FqName, strings.Join(keyParts, "|"))
-	h := collectors.HashNew()
-	h = collectors.HashAdd(h, hashText)
+	h := hash.New()
+	h = hash.Add(h, hashText)
 
 	return h
 }

delta/histogram.go

@@ -25,6 +25,7 @@ import (
 	"google.golang.org/api/monitoring/v3"
 
 	"github.com/prometheus-community/stackdriver_exporter/collectors"
+	"github.com/prometheus-community/stackdriver_exporter/hash"
 )
 
 type HistogramEntry struct {
@@ -94,8 +95,8 @@ func toHistogramKey(hist *collectors.HistogramMetric) uint64 {
 		keyParts = append(keyParts, fmt.Sprintf("%s:%s", k, labels[k]))
 	}
 	hashText := fmt.Sprintf("%s|%s", hist.FqName, strings.Join(keyParts, "|"))
-	h := collectors.HashNew()
-	h = collectors.HashAdd(h, hashText)
+	h := hash.New()
+	h = hash.Add(h, hashText)
 
 	return h
 }

collectors/fnv.go renamed to hash/fnv.go

@@ -11,9 +11,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package collectors
+package hash
 
-const separatorByte = 255
+const SeparatorByte = 255
 
 // https://github.com/prometheus/client_golang/blob/master/prometheus/fnv.go
 // Inline and byte-free variant of hash/fnv's fnv64a.
@@ -23,22 +23,22 @@ const (
 	prime64  = 1099511628211
 )
 
-// HashNew initializies a new fnv64a hash value.
-func HashNew() uint64 {
+// New initializies a new fnv64a hash value.
+func New() uint64 {
 	return offset64
 }
 
-// HashAdd adds a string to a fnv64a hash value, returning the updated hash.
-func HashAdd(h uint64, s string) uint64 {
+// Add adds a string to a fnv64a hash value, returning the updated hash.
+func Add(h uint64, s string) uint64 {
 	for i := 0; i < len(s); i++ {
 		h ^= uint64(s[i])
 		h *= prime64
 	}
 	return h
 }
 
-// hashAddByte adds a byte to a fnv64a hash value, returning the updated hash.
-func hashAddByte(h uint64, b byte) uint64 {
+// AddByte adds a byte to a fnv64a hash value, returning the updated hash.
+func AddByte(h uint64, b byte) uint64 {
 	h ^= uint64(b)
 	h *= prime64
 	return h