milvus/internal/util/mqclient/consumer.go
Xiaofan 0aaa87a79a
Fix MsgStream inconsistent seek (#12042)
Signed-off-by: xiaofan-luan <xiaofan.luan@zilliz.com>
2021-11-24 10:25:15 +08:00

87 lines
2.9 KiB
Go

// Copyright (C) 2019-2020 Zilliz. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software distributed under the License
// is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
// or implied. See the License for the specific language governing permissions and limitations under the License.
package mqclient
// SubscriptionInitialPosition is the type of a subscription initial position
type SubscriptionInitialPosition int
const (
// SubscriptionPositionLatest is latest position which means the start consuming position will be the last message
SubscriptionPositionLatest SubscriptionInitialPosition = iota
// SubscriptionPositionEarliest is earliest position which means the start consuming position will be the first message
SubscriptionPositionEarliest
)
// SubscriptionType is the type of subsription position
type SubscriptionType int
const (
// Exclusive there can be only 1 consumer on the same topic with the same subscription name
Exclusive SubscriptionType = iota
// Shared subscription mode, multiple consumer will be able to use the same subscription name
// and the messages will be dispatched according to
// a round-robin rotation between the connected consumers
Shared
// Failover subscription mode, multiple consumer will be able to use the same subscription name
// but only 1 consumer will receive the messages.
// If that consumer disconnects, one of the other connected consumers will start receiving messages.
Failover
// KeyShared subscription mode, multiple consumer will be able to use the same
// subscription and all messages with the same key will be dispatched to only one consumer
KeyShared
)
// UniqueID is the type of message id
type UniqueID = int64
// ConsumerOptions contains the options of a consumer
type ConsumerOptions struct {
// The topic that this consumer will subscribe on
Topic string
// The subscription name for this consumer
SubscriptionName string
// InitialPosition at which the cursor will be set when subscribe
// Default is `Latest`
SubscriptionInitialPosition
// Set receive channel size
BufSize int64
// Select the subscription type to be used when subscribing to the topic.
// Default is `Exclusive`
Type SubscriptionType
}
// Consumer is the interface that provides operations of a consumer
type Consumer interface {
// returns the subscription for the consumer
Subscription() string
// Message channel
Chan() <-chan Message
// Seek to the uniqueID position
Seek(MessageID, bool) error //nolint:govet
// Make sure that msg is received. Only used in pulsar
Ack(Message)
// Close consumer
Close()
}