62 lines
1.2 KiB
Go
62 lines
1.2 KiB
Go
package raft
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import (
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"encoding/json"
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"fmt"
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"hash/crc32"
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"os"
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)
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// Snapshot represents an in-memory representation of the current state of the system.
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type Snapshot struct {
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LastIndex uint64 `json:"lastIndex"`
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LastTerm uint64 `json:"lastTerm"`
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// Cluster configuration.
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Peers []*Peer `json:"peers"`
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State []byte `json:"state"`
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Path string `json:"path"`
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}
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// save writes the snapshot to file.
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func (ss *Snapshot) save() error {
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// Open the file for writing.
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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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// Serialize to JSON.
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b, err := json.Marshal(ss)
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if err != nil {
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return err
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}
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// Generate checksum and write it to disk.
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checksum := crc32.ChecksumIEEE(b)
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if _, err = fmt.Fprintf(file, "%08x\n", checksum); err != nil {
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return err
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}
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// Write the snapshot to disk.
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if _, err = file.Write(b); err != nil {
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return err
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}
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// Ensure that the snapshot has been flushed to disk before continuing.
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if err := file.Sync(); err != nil {
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return err
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}
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return nil
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}
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// remove deletes the snapshot file.
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func (ss *Snapshot) remove() error {
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if err := os.Remove(ss.Path); err != nil {
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return err
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}
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return nil
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}
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