README
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Toy chunked log
This is a very basic implementation of a chunked log. It creates a new chunk once the old one reaches the size limit. Once the chunk count limit is reached, old chunks expire.
A ChunkedLogReader can seek within the chunks and change
chunks automatically providing a regular ReadSeeker API.
That's all the lib does.
Documentation
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Index ¶
- Constants
- Variables
- type ChunkedLog
- func (log *ChunkedLog) ChunkCount() int
- func (log *ChunkedLog) Close() error
- func (log *ChunkedLog) CurrentSize() int64
- func (log *ChunkedLog) Drain(recs toyqueue.Records) (err error)
- func (log *ChunkedLog) ExpiredSize() int64
- func (log *ChunkedLog) Locate(pos int64, whence int) (fd int, off, fpos int64, err error)
- func (log *ChunkedLog) Open(dir string) (err error)
- func (log *ChunkedLog) Reader(pos int64, whence int) (*ChunkedLogReader, error)
- func (log *ChunkedLog) Sync() error
- func (log *ChunkedLog) TotalSize() int64
- func (log *ChunkedLog) Write(rec []byte) (n int, err error)
- type ChunkedLogReader
Constants ¶
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const ( ChunkSeekStart = 3 // seek relative to the origin of the file ChunkSeekCurrent = 4 // seek relative to the current offset ChunkSeekEnd = 5 // seek relative to the end )
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const Suffix = ".log.chunk"
Variables ¶
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var ErrAlreadyOpen = errors.New("the log is already open")
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var ErrChunkMissing = errors.New("the requested chunk is missing")
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var ErrNotOpen = errors.New("the log is not open")
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var ErrOmission = errors.New("the log has missing chunks")
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var ErrOutOfRange = errors.New("the requested offset is out of range")
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var ErrOverlap = errors.New("the log has overlapping chunks")
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var ErrSeekModeUnsupported = errors.New("seek mode not supported")
Functions ¶
This section is empty.
Types ¶
type ChunkedLog ¶
type ChunkedLog struct {
// Chunk size never exceeds this number (can not make a bigger write)
MaxChunkSize int64
// Old chunks above this number are dropped
MaxChunks int
// whether all writes are `fsynced` *before* `Write()` returns
Synced bool
// header maker for new chunks
Header toyqueue.Feeder
// contains filtered or unexported fields
}
Concurrent access guarantees: one writer, many readers.
func (*ChunkedLog) ChunkCount ¶
func (log *ChunkedLog) ChunkCount() int
func (*ChunkedLog) Close ¶
func (log *ChunkedLog) Close() error
func (*ChunkedLog) CurrentSize ¶
func (log *ChunkedLog) CurrentSize() int64
func (*ChunkedLog) Drain ¶
func (log *ChunkedLog) Drain(recs toyqueue.Records) (err error)
We expect a dense stream of tiny ops here, so we bundle writes here. Note: a slice goes into one chunk of the log, no torn writes.
func (*ChunkedLog) ExpiredSize ¶
func (log *ChunkedLog) ExpiredSize() int64
func (*ChunkedLog) Open ¶
func (log *ChunkedLog) Open(dir string) (err error)
func (*ChunkedLog) Reader ¶
func (log *ChunkedLog) Reader(pos int64, whence int) (*ChunkedLogReader, error)
func (*ChunkedLog) Sync ¶
func (log *ChunkedLog) Sync() error
func (*ChunkedLog) TotalSize ¶
func (log *ChunkedLog) TotalSize() int64
type ChunkedLogReader ¶
type ChunkedLogReader struct {
// contains filtered or unexported fields
}
func (*ChunkedLogReader) Close ¶ added in v0.1.3
func (r *ChunkedLogReader) Close() (err error)
Source Files
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