milvus/internal/mq/msgstream/mqwrapper/consumer.go

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// Licensed to the LF AI & Data foundation under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you 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 mqwrapper
// 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
// SubscriptionPositionUnkown indicates we don't care about the consumer location, since we are doing another seek or only some meta api over that
SubscriptionPositionUnknown
)
const DefaultPartitionIdx = 0
// 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
}
// Consumer is the interface that provides operations of a consumer
type Consumer interface {
// returns the subscription for the consumer
Subscription() string
// Get Message channel, once you chan you can not seek again
Chan() <-chan Message
// Seek to the uniqueID position
Seek(MessageID, bool) error //nolint:govet
// Ack make sure that msg is received
Ack(Message)
// Close consumer
Close()
// GetLatestMsgID return the latest message ID
GetLatestMsgID() (MessageID, error)
}