Use local random generator (#83)

Golang prior to 1.20 has a fixed seed for `math/rand.globalRand` and backup/snapshots have the same suffix in a name.

src/cinder/block_store.go

@@ -2,7 +2,6 @@ package cinder
 
 import (
 	"fmt"
-	"math/rand"
 	"os"
 	"strconv"
 
@@ -86,7 +85,7 @@ func (b *BlockStore) CreateVolumeFromSnapshot(snapshotID, volumeType, volumeAZ s
 	})
 	logWithFields.Info("BlockStore.CreateVolumeFromSnapshot called")
 
-	volumeName := fmt.Sprintf("%s.backup.%s", snapshotID, strconv.FormatUint(rand.Uint64(), 10))
+	volumeName := fmt.Sprintf("%s.backup.%s", snapshotID, strconv.FormatUint(utils.Rand.Uint64(), 10))
 	// Make sure snapshot is in ready state
 	// Possible values for snapshot state:
 	//   https://github.com/openstack/cinder/blob/master/api-ref/source/v3/volumes-v3-snapshots.inc#volume-snapshots-snapshots
@@ -168,7 +167,7 @@ func (b *BlockStore) IsVolumeReady(volumeID, volumeAZ string) (ready bool, err e
 // CreateSnapshot creates a snapshot of the specified volume, and applies any provided
 // set of tags to the snapshot.
 func (b *BlockStore) CreateSnapshot(volumeID, volumeAZ string, tags map[string]string) (string, error) {
-	snapshotName := fmt.Sprintf("%s.snap.%s", volumeID, strconv.FormatUint(rand.Uint64(), 10))
+	snapshotName := fmt.Sprintf("%s.snap.%s", volumeID, strconv.FormatUint(utils.Rand.Uint64(), 10))
 	logWithFields := b.log.WithFields(logrus.Fields{
 		"snapshotName": snapshotName,
 		"volumeID":     volumeID,

src/utils/helpers.go

@@ -1,10 +1,15 @@
 package utils
 
 import (
+	"math/rand"
 	"os"
 	"strings"
+	"time"
 )
 
+// Rand is used for a random generator exclusively for this go module
+var Rand = rand.New(rand.NewSource(time.Now().UTC().UnixNano()))
+
 // GetEnv gets value from environment variable or fallbacks to default value
 // This snippet is from https://stackoverflow.com/a/40326580/3323419
 func GetEnv(key, fallback string) string {

src/utils/helpers_test.go

@@ -2,6 +2,7 @@ package utils
 
 import (
 	"testing"
+	"time"
 )
 
 func TestReplaceAccount(t *testing.T) {
@@ -41,3 +42,23 @@ func TestReplaceAccount(t *testing.T) {
 		}
 	}
 }
+
+func TestRand(t *testing.T) {
+	Rand.Seed(time.Now().UTC().UnixNano())
+	a := Rand.Uint64()
+	Rand.Seed(time.Now().UTC().UnixNano())
+	b := Rand.Uint64()
+
+	if a == b {
+		t.Errorf("failed to verify random seed generator %v == %v", a, b)
+	}
+
+	Rand.Seed(int64(time.Now().UTC().Second()))
+	a = Rand.Uint64()
+	Rand.Seed(int64(time.Now().UTC().Second()))
+	b = Rand.Uint64()
+
+	if a != b {
+		t.Errorf("failed to verify random seed generator %v != %v", a, b)
+	}
+}