5 files changed, 128 insertions, 27 deletions
diff --git a/weed/mq/balancer/allocate.go b/weed/mq/balancer/allocate.go
new file mode 100644
index 000000000..d594c60fb
--- /dev/null
+++ b/weed/mq/balancer/allocate.go
@@ -0,0 +1,20 @@
+package balancer
+
+import (
+	cmap "github.com/orcaman/concurrent-map/v2"
+	"github.com/seaweedfs/seaweedfs/weed/pb/mq_pb"
+)
+
+func allocateTopicPartitions(brokers cmap.ConcurrentMap[string, *BrokerStats], partitionCount int) (assignments []*mq_pb.BrokerPartitionAssignment) {
+	return []*mq_pb.BrokerPartitionAssignment{
+		{
+			LeaderBroker:    "localhost:17777",
+			FollowerBrokers: []string{"localhost:17777"},
+			Partition: &mq_pb.Partition{
+				RingSize:   MaxPartitionCount,
+				RangeStart: 0,
+				RangeStop:  MaxPartitionCount,
+			},
+		},
+	}
+}
diff --git a/weed/mq/balancer/allocate_test.go b/weed/mq/balancer/allocate_test.go
new file mode 100644
index 000000000..c714788e6
--- /dev/null
+++ b/weed/mq/balancer/allocate_test.go
@@ -0,0 +1,62 @@
+package balancer
+
+import (
+	cmap "github.com/orcaman/concurrent-map/v2"
+	"github.com/seaweedfs/seaweedfs/weed/pb/mq_pb"
+	"reflect"
+	"testing"
+)
+
+func Test_allocateOneBroker(t *testing.T) {
+	brokers := cmap.New[*BrokerStats]()
+	brokers.SetIfAbsent("localhost:17777", &BrokerStats{
+		TopicPartitionCount: 0,
+		ConsumerCount:       0,
+		CpuUsagePercent:     0,
+	})
+
+	tests := []struct {
+		name            string
+		args            args
+		wantAssignments []*mq_pb.BrokerPartitionAssignment
+	}{
+		{
+			name: "test only one broker",
+			args: args{
+				brokers:        brokers,
+				partitionCount: 6,
+			},
+			wantAssignments: []*mq_pb.BrokerPartitionAssignment{
+				{
+					LeaderBroker:    "localhost:17777",
+					FollowerBrokers: []string{"localhost:17777"},
+					Partition: &mq_pb.Partition{
+						RingSize:   MaxPartitionCount,
+						RangeStart: 0,
+						RangeStop:  MaxPartitionCount,
+					},
+				},
+			},
+		},
+	}
+	testThem(t, tests)
+}
+
+type args struct {
+	brokers        cmap.ConcurrentMap[string, *BrokerStats]
+	partitionCount int
+}
+
+func testThem(t *testing.T, tests []struct {
+	name            string
+	args            args
+	wantAssignments []*mq_pb.BrokerPartitionAssignment
+}) {
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if gotAssignments := allocateTopicPartitions(tt.args.brokers, tt.args.partitionCount); !reflect.DeepEqual(gotAssignments, tt.wantAssignments) {
+				t.Errorf("allocateTopicPartitions() = %v, want %v", gotAssignments, tt.wantAssignments)
+			}
+		})
+	}
+}
diff --git a/weed/mq/balancer/balance.go b/weed/mq/balancer/balance.go
deleted file mode 100644
index 5be968399..000000000
--- a/weed/mq/balancer/balance.go
+++ /dev/null
@@ -1,26 +0,0 @@
-package balancer
-
-import "github.com/seaweedfs/seaweedfs/weed/pb/mq_pb"
-
-func (b *Balancer) LookupOrAllocateTopicPartitions(topic *mq_pb.Topic, publish bool) ([]*mq_pb.BrokerPartitionAssignment, error) {
-	// TODO lock the topic
-
-	// find the topic partitions on the filer
-	// if the topic is not found
-	//   if the request is_for_publish
-	//     create the topic
-	//   if the request is_for_subscribe
-	//     return error not found
-	// t := topic.FromPbTopic(request.Topic)
-	return []*mq_pb.BrokerPartitionAssignment{
-		{
-			LeaderBroker:    "localhost:17777",
-			FollowerBrokers: []string{"localhost:17777"},
-			Partition: &mq_pb.Partition{
-				RingSize:   MaxPartitionCount,
-				RangeStart: 0,
-				RangeStop:  MaxPartitionCount,
-			},
-		},
-	}, nil
-}
diff --git a/weed/mq/balancer/balancer.go b/weed/mq/balancer/balancer.go
index 1aa47831e..837dc0ce3 100644
--- a/weed/mq/balancer/balancer.go
+++ b/weed/mq/balancer/balancer.go
@@ -7,7 +7,7 @@ import (
 )
 
 const (
-	MaxPartitionCount = 1024
+	MaxPartitionCount = 8 * 9 * 5 * 7 //2520
 )
 
 type Balancer struct {
@@ -36,6 +36,7 @@ func (bs *BrokerStats) UpdateStats(stats *mq_pb.BrokerStats) {
 				RangeStop:  topicPartitionStats.Partition.RangeStop,
 			},
 			ConsumerCount: topicPartitionStats.ConsumerCount,
+			IsLeader:      topicPartitionStats.IsLeader,
 		}
 		consumerCount += topicPartitionStats.ConsumerCount
 		key := tps.TopicPartition.String()
@@ -60,6 +61,7 @@ type TopicPartition struct {
 type TopicPartitionStats struct {
 	TopicPartition
 	ConsumerCount int32
+	IsLeader      bool
 }
 
 func NewBalancer() *Balancer {
diff --git a/weed/mq/balancer/lookup.go b/weed/mq/balancer/lookup.go
new file mode 100644
index 000000000..55ed3e95d
--- /dev/null
+++ b/weed/mq/balancer/lookup.go
@@ -0,0 +1,43 @@
+package balancer
+
+import (
+	"github.com/seaweedfs/seaweedfs/weed/pb/mq_pb"
+)
+
+func (b *Balancer) LookupOrAllocateTopicPartitions(topic *mq_pb.Topic, publish bool) (assignments []*mq_pb.BrokerPartitionAssignment, err error) {
+	// find existing topic partition assignments
+	for brokerStatsItem := range b.Brokers.IterBuffered() {
+		broker, brokerStats := brokerStatsItem.Key, brokerStatsItem.Val
+		for topicPartitionStatsItem := range brokerStats.Stats.IterBuffered() {
+			topicPartitionStat := topicPartitionStatsItem.Val
+			if topicPartitionStat.TopicPartition.Namespace == topic.Namespace &&
+				topicPartitionStat.TopicPartition.Topic == topic.Name {
+				assignment := &mq_pb.BrokerPartitionAssignment{
+					Partition: &mq_pb.Partition{
+						RingSize:   MaxPartitionCount,
+						RangeStart: topicPartitionStat.RangeStart,
+						RangeStop:  topicPartitionStat.RangeStop,
+					},
+				}
+				if topicPartitionStat.IsLeader {
+					assignment.LeaderBroker = broker
+				} else {
+					assignment.FollowerBrokers = append(assignment.FollowerBrokers, broker)
+				}
+				assignments = append(assignments, assignment)
+			}
+		}
+	}
+	if len(assignments) > 0 {
+		return assignments, nil
+	}
+
+	// find the topic partitions on the filer
+	// if the topic is not found
+	//   if the request is_for_publish
+	//     create the topic
+	//   if the request is_for_subscribe
+	//     return error not found
+	// t := topic.FromPbTopic(request.Topic)
+	return allocateTopicPartitions(b.Brokers, 6), nil
+}