wal

package
v3.0.6+incompatible Latest Latest
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 Go to latest Published: Mar 28, 2019 License: LGPL-3.0 Imports: 18 Imported by: 0

Documentation

Overview

Package wal This Module is in so many aspects inspired by etcd's WAL.

Index

Constants

This section is empty.

Variables

View Source 
var (
	// SegmentSizeBytes is the preallocated size of each wal segment file.
	// The actual size might be larger than this. In general, the default
	// value should be used, but this is defined as an exported variable
	// so that tests can set a different segment size.
	SegmentSizeBytes int64 = 8 * 1000 * 1000 // 8MB

	// ErrMetadataConflict metadata not consist
	ErrMetadataConflict = errors.New("wal: conflicting metadata found")
	// ErrFileNotFound file not found
	ErrFileNotFound = errors.New("wal: file not found")
	// ErrCRCMismatch crc miss match
	ErrCRCMismatch = errors.New("wal: crc mismatch")
)
View Source 
var LogType_name = map[int32]string{
	0: "crcType",
	2: "metaDataType",
	3: "entryType",
}
View Source 
var LogType_value = map[string]int32{
	"crcType":      0,
	"metaDataType": 2,
	"entryType":    3,
}

Functions

func BytesToUint64 

func BytesToUint64(p []byte) uint64

BytesToUint64 convert byte array to uint64

func Exist 

func Exist(dir string) bool

Exist returns true if there are any files in a given directory.

func OpenDir 

func OpenDir(path string) (*os.File, error)

OpenDir open a dir

func Uint64ToBytes 

func Uint64ToBytes(i uint64) []byte

Uint64ToBytes convert uint64 to byte array

func ZeroToEnd 

func ZeroToEnd(f *os.File) error

ZeroToEnd write zero to file from current to end

Types

type Entry 

type Entry struct {
	Data                 []byte   `protobuf:"bytes,1,opt,name=data,proto3" json:"data,omitempty"`
	ExtraMeta            []byte   `protobuf:"bytes,2,opt,name=ExtraMeta,proto3" json:"ExtraMeta,omitempty"`
	Index                uint64   `protobuf:"varint,3,opt,name=index,proto3" json:"index,omitempty"`
	XXX_NoUnkeyedLiteral struct{} `json:"-"`
	XXX_unrecognized     []byte   `json:"-"`
	XXX_sizecache        int32    `json:"-"`
}

func (*Entry) Descriptor 

func (*Entry) Descriptor() ([]byte, []int)

func (*Entry) GetData 

func (m *Entry) GetData() []byte

func (*Entry) GetExtraMeta 

func (m *Entry) GetExtraMeta() []byte

func (*Entry) GetIndex 

func (m *Entry) GetIndex() uint64

func (*Entry) ProtoMessage 

func (*Entry) ProtoMessage()

func (*Entry) Reset 

func (m *Entry) Reset()

func (*Entry) String 

func (m *Entry) String() string

func (*Entry) XXX_DiscardUnknown 

func (m *Entry) XXX_DiscardUnknown()

func (*Entry) XXX_Marshal 

func (m *Entry) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*Entry) XXX_Merge 

func (m *Entry) XXX_Merge(src proto.Message)

func (*Entry) XXX_Size 

func (m *Entry) XXX_Size() int

func (*Entry) XXX_Unmarshal 

func (m *Entry) XXX_Unmarshal(b []byte) error

type Log 

type Log struct {
	Type                 LogType  `protobuf:"varint,1,opt,name=type,proto3,enum=wal.LogType" json:"type,omitempty"`
	Data                 []byte   `protobuf:"bytes,2,opt,name=data,proto3" json:"data,omitempty"`
	Checksum             uint64   `protobuf:"varint,3,opt,name=checksum,proto3" json:"checksum,omitempty"`
	XXX_NoUnkeyedLiteral struct{} `json:"-"`
	XXX_unrecognized     []byte   `json:"-"`
	XXX_sizecache        int32    `json:"-"`
}

func (*Log) Check 

func (log *Log) Check(crc uint64) error

Check check whether the log.checksum is same as crc

func (*Log) Descriptor 

func (*Log) Descriptor() ([]byte, []int)

func (*Log) GetChecksum 

func (m *Log) GetChecksum() uint64

func (*Log) GetData 

func (m *Log) GetData() []byte

func (*Log) GetType 

func (m *Log) GetType() LogType

func (*Log) ProtoMessage 

func (*Log) ProtoMessage()

func (*Log) Reset 

func (m *Log) Reset()

func (*Log) String 

func (m *Log) String() string

func (*Log) XXX_DiscardUnknown 

func (m *Log) XXX_DiscardUnknown()

func (*Log) XXX_Marshal 

func (m *Log) XXX_Marshal(b []byte, deterministic bool) ([]byte, error)

func (*Log) XXX_Merge 

func (m *Log) XXX_Merge(src proto.Message)

func (*Log) XXX_Size 

func (m *Log) XXX_Size() int

func (*Log) XXX_Unmarshal 

func (m *Log) XXX_Unmarshal(b []byte) error

type LogType 

type LogType int32
const (
	LogType_crcType      LogType = 0
	LogType_metaDataType LogType = 2
	LogType_entryType    LogType = 3
)

func (LogType) EnumDescriptor 

func (LogType) EnumDescriptor() ([]byte, []int)

func (LogType) String 

func (x LogType) String() string

type PageWriter 

type PageWriter struct {
	// contains filtered or unexported fields
}

PageWriter implements the io.Writer interface so that writes will either be in page chunks or from flushing.

func NewPageWriter 

func NewPageWriter(w io.Writer, pageBytes, pageOffset int) *PageWriter

NewPageWriter creates a new PageWriter. pageBytes is the number of bytes to write per page. pageOffset is the starting offset of io.Writer.

func (*PageWriter) Flush 

func (pw *PageWriter) Flush() error

Flush flush the page writer

func (*PageWriter) Write 

func (pw *PageWriter) Write(p []byte) (n int, err error)

type StreamFile 

type StreamFile struct {
	// contains filtered or unexported fields
}

StreamFile generate files like a endless stream

func (*StreamFile) Close 

func (st *StreamFile) Close() error

Close close the stream file

func (*StreamFile) GetNewFile 

func (st *StreamFile) GetNewFile() (f *os.File, err error)

GetNewFile get a new generated file

type WAL 

type WAL struct {
	// contains filtered or unexported fields
}

WAL is a logical representation of the stable storage. WAL is either in read mode or append mode but not both. A newly created WAL is in append mode, and ready for appending records. A just opened WAL is in read mode, and ready for reading records. The WAL will be ready for appending after reading out all the previous records.

func Create 

func Create(dirpath string, metadata []byte) (*WAL, error)

Create creates a WAL ready for appending records. The given metadata is recorded at the head of each WAL file, and can be retrieved with ReadAll. If there already are some wal files, it will try to recover from them.

func Open 

func Open(dirpath string) (*WAL, error)

Open opens the WAL at the given snap. The snap SHOULD have been previously saved to the WAL, or the following ReadAll will fail. The returned WAL is ready to read and the first record will be the one after the given snap. The WAL cannot be appended to before reading out all of its previous records.

func OpenForRead 

func OpenForRead(dirpath string) (*WAL, error)

OpenForRead only opens the wal files for read. Write on a read only wal panics.

func (*WAL) CleanDir 

func (w *WAL) CleanDir() error

CleanDir clean the wal dir

func (*WAL) Close 

func (w *WAL) Close() error

Close closes the current WAL file and directory.

func (*WAL) HasDecoder 

func (w *WAL) HasDecoder() bool

HasDecoder check whether wal has decoder, has decoder means there already are some wal files.

func (*WAL) ReadAll 

func (w *WAL) ReadAll() (metadata []byte, ents []Entry, err error)

nolint ReadAll reads out records of the current WAL. After ReadAll, the WAL will be ready for appending new records.

func (*WAL) ReleaseLockTo 

func (w *WAL) ReleaseLockTo(index uint64) error

ReleaseLockTo releases the files, which has smaller index than the given index except the largest one among them. For example, if WAL is holding lock 1,2,3,4,5,6, ReleaseLockTo(4) will release lock 1,2 but keep 3. ReleaseLockTo(5) will release 1,2,3 but keep 4.

func (*WAL) RemoveFiles 

func (w *WAL) RemoveFiles(index uint64) error

RemoveFiles remove files less than or equal to index

func (*WAL) RemoveFilesBefore 

func (w *WAL) RemoveFilesBefore(index uint64) error

RemoveFilesBefore remove files less than index

func (*WAL) Save 

func (w *WAL) Save(ents []Entry) (uint64, error)

Save save entries

func (*WAL) SaveSingle 

func (w *WAL) SaveSingle(ent Entry) (uint64, error)

SaveSingle save single entry, Return entry index and error

func (*WAL) Size 

func (w *WAL) Size() uint64

Size return WAL used data size include current tmp file.

Source Files

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