refactor: add default values to the configuration

Author: buraksezer

Diff for: consistent.go

@@ -21,9 +21,9 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.
 
-// Package consistent provides a consistent hashing function with bounded loads.
-// For more information about the underlying algorithm, please take a look at
-// https://research.googleblog.com/2017/04/consistent-hashing-with-bounded-loads.html
+// Package consistent provides a consistent hashing function with bounded loads. This implementation also adds
+// partitioning logic on top of the original algorithm. For more information about the underlying algorithm,
+// please take a look at https://research.googleblog.com/2017/04/consistent-hashing-with-bounded-loads.html
 //
 // Example Use:
 //
@@ -65,15 +65,16 @@ import (
 	"sync"
 )
 
-var (
-	// ErrInsufficientMemberCount represents an error which means there are not enough members to complete the task.
-	ErrInsufficientMemberCount = errors.New("insufficient member count")
-
-	// ErrMemberNotFound represents an error which means requested member could not be found in consistent hash ring.
-	ErrMemberNotFound = errors.New("member could not be found in ring")
+const (
+	DefaultPartitionCount    int     = 271
+	DefaultReplicationFactor int     = 20
+	DefaultLoad              float64 = 1.25
 )
 
-// Hasher is responsible for generating unsigned, 64 bit hash of provided byte slice.
+// ErrInsufficientMemberCount represents an error which means there are not enough members to complete the task.
+var ErrInsufficientMemberCount = errors.New("insufficient member count")
+
+// Hasher is responsible for generating unsigned, 64-bit hash of provided byte slice.
 // Hasher should minimize collisions (generating same hash for different byte slice)
 // and while performance is also important fast functions are preferable (i.e.
 // you can use FarmHash family).
@@ -88,7 +89,7 @@ type Member interface {
 
 // Config represents a structure to control consistent package.
 type Config struct {
-	// Hasher is responsible for generating unsigned, 64 bit hash of provided byte slice.
+	// Hasher is responsible for generating unsigned, 64-bit hash of provided byte slice.
 	Hasher Hasher
 
 	// Keys are distributed among partitions. Prime numbers are good to
@@ -120,16 +121,26 @@ type Consistent struct {
 
 // New creates and returns a new Consistent object.
 func New(members []Member, config Config) *Consistent {
+	if config.Hasher == nil {
+		panic("Hasher cannot be nil")
+	}
+	if config.PartitionCount == 0 {
+		config.PartitionCount = DefaultPartitionCount
+	}
+	if config.ReplicationFactor == 0 {
+		config.ReplicationFactor = DefaultReplicationFactor
+	}
+	if config.Load == 0 {
+		config.Load = DefaultLoad
+	}
+
 	c := &Consistent{
 		config:         config,
 		members:        make(map[string]*Member),
 		partitionCount: uint64(config.PartitionCount),
 		ring:           make(map[uint64]*Member),
 	}
-	if config.Hasher == nil {
-		panic("Hasher cannot be nil")
-	}
-	// TODO: Check configuration here
+
 	c.hasher = config.Hasher
 	for _, member := range members {
 		c.add(member)

Diff for: consistent_test.go

@@ -1,4 +1,4 @@
-// Copyright (c) 2018-2021 Burak Sezer
+// Copyright (c) 2018-2022 Burak Sezer
 // All rights reserved.
 //
 // This code is licensed under the MIT License.
@@ -76,7 +76,7 @@ func TestConsistentAdd(t *testing.T) {
 }
 
 func TestConsistentRemove(t *testing.T) {
-	members := []Member{}
+	var members []Member
 	for i := 0; i < 8; i++ {
 		member := testMember(fmt.Sprintf("node%d.olric", i))
 		members = append(members, member)
@@ -144,7 +144,7 @@ func TestConsistentLocateKey(t *testing.T) {
 }
 
 func TestConsistentInsufficientMemberCount(t *testing.T) {
-	members := []Member{}
+	var members []Member
 	for i := 0; i < 8; i++ {
 		member := testMember(fmt.Sprintf("node%d.olric", i))
 		members = append(members, member)
@@ -159,7 +159,7 @@ func TestConsistentInsufficientMemberCount(t *testing.T) {
 }
 
 func TestConsistentClosestMembers(t *testing.T) {
-	members := []Member{}
+	var members []Member
 	for i := 0; i < 8; i++ {
 		member := testMember(fmt.Sprintf("node%d.olric", i))
 		members = append(members, member)
@@ -215,6 +215,6 @@ func BenchmarkGetClosestN(b *testing.B) {
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
 		key := []byte("key" + strconv.Itoa(i))
-		c.GetClosestN(key, 3)
+		_, _ = c.GetClosestN(key, 3)
 	}
 }