Kafka notify: support batched commits for queue store (#20377)

The items will be saved per target batch and will
be committed to the queue store when the batch is full

Also, periodically commit the batched items to the queue store
based on configured commit_timeout; default is 30s;

Bonus: compress queue store multi writes

internal/config/notify/help.go

@@ -274,6 +274,18 @@ var (
 			Optional:    true,
 			Type:        "number",
 		},
+		config.HelpKV{
+			Key:         target.KafkaBatchSize,
+			Description: "batch size of the events; used only when queue_dir is set",
+			Optional:    true,
+			Type:        "number",
+		},
+		config.HelpKV{
+			Key:         target.KafkaBatchCommitTimeout,
+			Description: "commit timeout set for the batch; used only when batch_size > 1",
+			Optional:    true,
+			Type:        "duration",
+		},
 	}
 
 	HelpMQTT = config.HelpKVS{

internal/config/notify/parse.go

@@ -374,6 +374,10 @@ var (
 			Key:   target.KafkaBatchSize,
 			Value: "0",
 		},
+		config.KV{
+			Key:   target.KafkaBatchCommitTimeout,
+			Value: "0s",
+		},
 		config.KV{
 			Key:   target.KafkaCompressionCodec,
 			Value: "",
@@ -463,14 +467,23 @@ func GetNotifyKafka(kafkaKVS map[string]config.KVS) (map[string]target.KafkaArgs
 			return nil, err
 		}
 
+		batchCommitTimeoutEnv := target.EnvKafkaBatchCommitTimeout
+		if k != config.Default {
+			batchCommitTimeoutEnv = batchCommitTimeoutEnv + config.Default + k
+		}
+		batchCommitTimeout, err := time.ParseDuration(env.Get(batchCommitTimeoutEnv, kv.Get(target.KafkaBatchCommitTimeout)))
+		if err != nil {
+			return nil, err
+		}
 		kafkaArgs := target.KafkaArgs{
-			Enable:     enabled,
-			Brokers:    brokers,
-			Topic:      env.Get(topicEnv, kv.Get(target.KafkaTopic)),
-			QueueDir:   env.Get(queueDirEnv, kv.Get(target.KafkaQueueDir)),
-			QueueLimit: queueLimit,
-			Version:    env.Get(versionEnv, kv.Get(target.KafkaVersion)),
-			BatchSize:  uint32(batchSize),
+			Enable:             enabled,
+			Brokers:            brokers,
+			Topic:              env.Get(topicEnv, kv.Get(target.KafkaTopic)),
+			QueueDir:           env.Get(queueDirEnv, kv.Get(target.KafkaQueueDir)),
+			QueueLimit:         queueLimit,
+			Version:            env.Get(versionEnv, kv.Get(target.KafkaVersion)),
+			BatchSize:          uint32(batchSize),
+			BatchCommitTimeout: batchCommitTimeout,
 		}
 
 		tlsEnableEnv := target.EnvKafkaTLS