github.com/pingcap/tiflow@v0.0.0-20240520035814-5bf52d54e205/pkg/sink/codec/encoder.go (about)

     1  // Copyright 2022 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 codec
    15  
    16  import (
    17  	"bytes"
    18  	"context"
    19  
    20  	"github.com/pingcap/tiflow/cdc/model"
    21  	"github.com/pingcap/tiflow/pkg/sink/codec/common"
    22  )
    23  
    24  const (
    25  	// BatchVersion1 represents the version of batch format
    26  	BatchVersion1 uint64 = 1
    27  
    28  	// MemBufShrinkThreshold represents the threshold of shrinking the buffer.
    29  	MemBufShrinkThreshold = 1024 * 1024
    30  )
    31  
    32  // DDLEventBatchEncoder is an abstraction for DDL event encoder.
    33  type DDLEventBatchEncoder interface {
    34  	// EncodeCheckpointEvent appends a checkpoint event into the batch.
    35  	// This event will be broadcast to all partitions to signal a global checkpoint.
    36  	EncodeCheckpointEvent(ts uint64) (*common.Message, error)
    37  	// EncodeDDLEvent appends a DDL event into the batch
    38  	EncodeDDLEvent(e *model.DDLEvent) (*common.Message, error)
    39  }
    40  
    41  // MessageBuilder is an abstraction to build message.
    42  type MessageBuilder interface {
    43  	// Build builds the batch and returns the bytes of key and value.
    44  	// Should be called after `AppendRowChangedEvent`
    45  	Build() []*common.Message
    46  }
    47  
    48  // RowEventEncoder is an abstraction for events encoder
    49  type RowEventEncoder interface {
    50  	DDLEventBatchEncoder
    51  	// AppendRowChangedEvent appends a row changed event into the batch or buffer.
    52  	AppendRowChangedEvent(context.Context, string, *model.RowChangedEvent, func()) error
    53  	MessageBuilder
    54  }
    55  
    56  // RowEventEncoderBuilder builds row encoder with context.
    57  type RowEventEncoderBuilder interface {
    58  	Build() RowEventEncoder
    59  	CleanMetrics()
    60  }
    61  
    62  // TxnEventEncoder is an abstraction for txn events encoder.
    63  type TxnEventEncoder interface {
    64  	// AppendTxnEvent append a txn event into the buffer.
    65  	AppendTxnEvent(*model.SingleTableTxn, func()) error
    66  	MessageBuilder
    67  }
    68  
    69  // TxnEventEncoderBuilder builds txn encoder with context.
    70  type TxnEventEncoderBuilder interface {
    71  	Build() TxnEventEncoder
    72  }
    73  
    74  // IsColumnValueEqual checks whether the preValue and updatedValue are equal.
    75  func IsColumnValueEqual(preValue, updatedValue interface{}) bool {
    76  	if preValue == nil || updatedValue == nil {
    77  		return preValue == updatedValue
    78  	}
    79  
    80  	preValueBytes, ok1 := preValue.([]byte)
    81  	updatedValueBytes, ok2 := updatedValue.([]byte)
    82  	if ok1 && ok2 {
    83  		return bytes.Equal(preValueBytes, updatedValueBytes)
    84  	}
    85  	// mounter use the same table info to parse the value,
    86  	// the value type should be the same
    87  	return preValue == updatedValue
    88  }
    89  
    90  // MockRowEventEncoderBuilder is a mock implementation of RowEventEncoderBuilder
    91  type MockRowEventEncoderBuilder struct{}
    92  
    93  // Build implement the RowEventEncoderBuilder interface
    94  func (m *MockRowEventEncoderBuilder) Build() RowEventEncoder {
    95  	return &MockRowEventEncoder{}
    96  }
    97  
    98  // CleanMetrics implement the RowEventEncoderBuilder interface
    99  func (m *MockRowEventEncoderBuilder) CleanMetrics() {
   100  	// Clean up metrics if needed
   101  }
   102  
   103  // MockRowEventEncoder is a mock implementation of RowEventEncoder
   104  type MockRowEventEncoder struct{}
   105  
   106  // EncodeCheckpointEvent implement the DDLEventBatchEncoder interface
   107  func (m *MockRowEventEncoder) EncodeCheckpointEvent(ts uint64) (*common.Message, error) {
   108  	// Implement the encoding logic for checkpoint event
   109  	return nil, nil
   110  }
   111  
   112  // EncodeDDLEvent implement the DDLEventBatchEncoder interface
   113  func (m *MockRowEventEncoder) EncodeDDLEvent(e *model.DDLEvent) (*common.Message, error) {
   114  	// Implement the encoding logic for DDL event
   115  	return nil, nil
   116  }
   117  
   118  // AppendRowChangedEvent implement the RowEventEncoder interface
   119  func (m *MockRowEventEncoder) AppendRowChangedEvent(
   120  	ctx context.Context, tableID string, event *model.RowChangedEvent, callback func(),
   121  ) error {
   122  	// Implement the logic for appending row changed event
   123  	return nil
   124  }
   125  
   126  // Build implement the RowEventEncoder interface
   127  func (m *MockRowEventEncoder) Build() []*common.Message {
   128  	// Implement the logic for building the batch and returning the bytes of key and value
   129  	return nil
   130  }