pulsar/message.go

//
// Licensed to the Apache Software Foundation (ASF) 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 pulsar

import "time"

type ProducerMessage struct {
	// Payload for the message
	Payload []byte

	// Sets the key of the message for routing policy
	Key string

	// Attach application defined properties on the message
	Properties map[string]string

	// Set the event time for a given message
	EventTime *time.Time

	// Override the replication clusters for this message.
	ReplicationClusters []string

	// Set the sequence id to assign to the current message
	SequenceID *int64
}

type Message interface {
	// Get the topic from which this message originated from
	Topic() string

	// Return the properties attached to the message.
	// Properties are application defined key/value pairs that will be attached to the message
	Properties() map[string]string

	// Get the payload of the message
	Payload() []byte

	// Get the unique message ID associated with this message.
	// The message id can be used to univocally refer to a message without having the keep the entire payload in memory.
	ID() MessageID

	// Get the publish time of this message. The publish time is the timestamp that a client publish the message.
	PublishTime() time.Time

	// Get the event time associated with this message. It is typically set by the applications via
	// `ProducerMessage.EventTime`.
	// If there isn't any event time associated with this event, it will be nil.
	EventTime() *time.Time

	// Get the key of the message, if any
	Key() string
}

// Identifier for a particular message
type MessageID interface {
	// Serialize the message id into a sequence of bytes that can be stored somewhere else
	Serialize() []byte
}

// Reconstruct a MessageID object from its serialized representation
func DeserializeMessageID(data []byte) (MessageID, error) {
	return deserializeMessageID(data)
}

var (
	// EarliestMessage messageID that points to the earliest message available in a topic
	EarliestMessage = earliestMessageID()

	// LatestMessage messageID that points to the latest message
	LatestMessage = latestMessageID()
)