github.com/pingcap/ticdc@v0.0.0-20220526033649-485a10ef2652/pkg/pipeline/message.go (about)

     1  // Copyright 2020 PingCAP, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package pipeline
    15  
    16  import "github.com/pingcap/ticdc/cdc/model"
    17  
    18  // MessageType is the type of Message
    19  type MessageType int
    20  
    21  // types of Message
    22  const (
    23  	MessageTypeUnknown MessageType = iota
    24  	MessageTypeCommand
    25  	MessageTypePolymorphicEvent
    26  	MessageTypeBarrier
    27  	MessageTypeTick
    28  )
    29  
    30  // Message is a vehicle for transferring information between nodes
    31  type Message struct {
    32  	// TODO add more kind of messages
    33  	// Tp is the type of Message
    34  	Tp MessageType
    35  	// Command is the command in this message
    36  	Command *Command
    37  	// PolymorphicEvent represents the row change event
    38  	PolymorphicEvent *model.PolymorphicEvent
    39  	// BarrierTs
    40  	BarrierTs model.Ts
    41  }
    42  
    43  // PolymorphicEventMessage creates the message of PolymorphicEvent
    44  func PolymorphicEventMessage(event *model.PolymorphicEvent) Message {
    45  	return Message{
    46  		Tp:               MessageTypePolymorphicEvent,
    47  		PolymorphicEvent: event,
    48  	}
    49  }
    50  
    51  // CommandMessage creates the message of Command
    52  func CommandMessage(command *Command) Message {
    53  	return Message{
    54  		Tp:      MessageTypeCommand,
    55  		Command: command,
    56  	}
    57  }
    58  
    59  // BarrierMessage creates the message of Command
    60  func BarrierMessage(barrierTs model.Ts) Message {
    61  	return Message{
    62  		Tp:        MessageTypeBarrier,
    63  		BarrierTs: barrierTs,
    64  	}
    65  }
    66  
    67  // TickMessage creates the message of Tick
    68  // Note: the returned message is READ-ONLY.
    69  func TickMessage() Message {
    70  	return Message{
    71  		Tp: MessageTypeTick,
    72  	}
    73  }
    74  
    75  // CommandType is the type of Command
    76  type CommandType int
    77  
    78  const (
    79  	// CommandTypeUnknown is unknown message type
    80  	CommandTypeUnknown CommandType = iota
    81  	// CommandTypeStop means the table pipeline should stop at once
    82  	CommandTypeStop
    83  )
    84  
    85  // Command is the command about table pipeline
    86  type Command struct {
    87  	Tp CommandType
    88  }