milvus/internal/util/mqclient/reader.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 mqclient
import (
"context"
)
// ReaderMessage package Reader and Message as a struct to use
type ReaderMessage struct {
Reader
Message
}
// ReaderOptions abstraction Reader options to use.
type ReaderOptions struct {
// Topic specify the topic this consumer will subscribe on.
// This argument is required when constructing the reader.
Topic string
// Name set the reader name.
Name string
// Attach a set of application defined properties to the reader
// This properties will be visible in the topic stats
Properties map[string]string
// StartMessageID initial reader positioning is done by specifying a message id. The options are:
// * `MessageID` : Start reading from a particular message id, the reader will position itself on that
// specific position. The first message to be read will be the message next to the specified
// messageID
StartMessageID MessageID
// If true, the reader will start at the `StartMessageID`, included.
// Default is `false` and the reader will start from the "next" message
StartMessageIDInclusive bool
// SubscriptionRolePrefix set the subscription role prefix. The default prefix is "reader".
SubscriptionRolePrefix string
}
// Reader can be used to scan through all the messages currently available in a topic.
type Reader interface {
// Topic from which this reader is reading from
Topic() string
// Next read the next message in the topic, blocking until a message is available
Next(context.Context) (Message, error)
// HasNext check if there is any message available to read from the current position
HasNext() bool
// Close the reader and stop the broker to push more messages
Close()
// Reset the subscription associated with this reader to a specific message id.
Seek(MessageID) error
}