ljmsc / wal

write ahead log

WAL (Write ahead log)

wal is a write ahead log written in go.

Installation

The code was tested with go version 1.15. Older versions can also work but have not been tested.

go get -u github.com/ljmsc/wal

Currently, only unix systems are supported.

Usage

Note: since version 0.7.0 the wal is no longer safe for concurrent write. It is up to the developer to protect the wal. e.g. Mutex, Channels. Since this kind of functionality is not always needed I removed it for performance's sake.

basic

package main

import (
	"fmt"

	"github.com/ljmsc/wal"
)

type entry []byte

func (t *entry) Unmarshal(_data []byte) error {
	*t = _data
	return nil
}

func main() {
	storage, err := wal.Open("./path/to/wal", 4, 100)
	if err != nil {
		// handle error
		panic(err)
	}
	defer storage.Close()

	data := []byte("this is my awesome test data")
	seqNum, err := storage.Write(data)
	if err != nil {
		// handle write error
		panic(err)
	}
	fmt.Printf("successful wrote entry. Sequence Number: %d\n", seqNum)

	re := entry{}
	if err := storage.ReadAt(&re, seqNum); err != nil {
		// handle error
		panic(err)
	}

	fmt.Printf("successful read entry from log. value: %s \n", re)
}

License

The project (and all code) is licensed under the Mozilla Public License Version 2.0.

wal's Issues

Getting error when getting module

Running go get github.com/ljmsc/wal with go 1.16 returns (on windows):

go: downloading github.com/ljmsc/wal v0.9.0
# github.com/ljmsc/wal
..\..\..\..\go\pkg\mod\github.com\ljmsc\[email protected]\segment.go:93:13: undefined: pageSize