68 lines
1.2 KiB
Go
68 lines
1.2 KiB
Go
package raft
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import (
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"bytes"
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"fmt"
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"hash/crc32"
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"os"
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"syscall"
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)
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//------------------------------------------------------------------------------
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//
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// Typedefs
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//
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//------------------------------------------------------------------------------
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// the in memory SnapShot struct
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// TODO add cluster configuration
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type Snapshot struct {
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lastIndex uint64
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lastTerm uint64
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// cluster configuration.
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state []byte
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path string
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}
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// Save the snapshot to a file
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func (ss *Snapshot) Save() error {
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// Write machine state to temporary buffer.
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var b bytes.Buffer
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if _, err := fmt.Fprintf(&b, "%v", 2); err != nil {
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return err
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}
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// Generate checksum.
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checksum := crc32.ChecksumIEEE(b.Bytes())
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// open file
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file, err := os.OpenFile(ss.path, os.O_CREATE|os.O_WRONLY, 0600)
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if err != nil {
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return err
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}
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defer file.Close()
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// Write snapshot with checksum.
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if _, err = fmt.Fprintf(file, "%08x\n%v\n%v\n", checksum, ss.lastIndex,
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ss.lastTerm); err != nil {
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return err
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}
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if _, err = file.Write(ss.state); err != nil {
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return err
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}
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// force the change writting to disk
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syscall.Fsync(int(file.Fd()))
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return err
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}
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// remove the file of the snapshot
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func (ss *Snapshot) Remove() error {
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err := os.Remove(ss.path)
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return err
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}
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