dailz
cf913b1d52
- go.mod with github.com/dailz/go-kv, Go 1.26.3, testify - config/config.go with WalConfig, Validate() with checked arithmetic - errors.go with sentinel errors (ErrCommitUnknown, ErrWriteStopped, etc.) - wal/constants.go with all WAL format constants and enums - wal/header.go with WAL File Header encode/decode (CRC32 IEEE) - wal/record.go with Physical Record codec, block boundary, SplitIntoRecords - wal/entry.go with WAL Entry codec (varint keys/values, OpType, ValueKind) - wal/sequence.go with SequenceManager (atomic, CAS, overflow-safe) - manifest/manifest.go with MANIFEST stub (Load/Save atomic) - manifest/current.go with CURRENT file (WriteCurrent/ReadCurrent) - Comprehensive tests for all modules - .golangci.yml configuration
53 lines
1.5 KiB
Go
53 lines
1.5 KiB
Go
package manifest
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import (
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"fmt"
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"os"
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"strconv"
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"strings"
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)
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// Manifest holds database metadata used for recovery.
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// The MANIFEST file stores the recovery checkpoint so that
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// recovery knows which segments are already confirmed durable.
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type Manifest struct {
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RecoverySegmentID uint64
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}
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// Load reads the MANIFEST file from dir.
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// If the file does not exist, it returns a zero-value Manifest with no error (fresh DB).
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func Load(dir string) (*Manifest, error) {
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path := dir + "/MANIFEST"
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data, err := os.ReadFile(path)
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if err != nil {
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if os.IsNotExist(err) {
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return &Manifest{RecoverySegmentID: 0}, nil
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}
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return nil, fmt.Errorf("read manifest: %w", err)
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}
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line := strings.TrimSpace(string(data))
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if !strings.HasPrefix(line, "recovery_segment_id:") {
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return nil, fmt.Errorf("manifest: invalid format: %q", line)
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}
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idStr := strings.TrimPrefix(line, "recovery_segment_id:")
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id, err := strconv.ParseUint(idStr, 10, 64)
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if err != nil {
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return nil, fmt.Errorf("manifest: parse recovery_segment_id: %w", err)
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}
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return &Manifest{RecoverySegmentID: id}, nil
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}
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// Save atomically writes the MANIFEST file to dir with the given recoverySegmentID.
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func Save(dir string, recoverySegmentID uint64) error {
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content := fmt.Sprintf("recovery_segment_id:%d\n", recoverySegmentID)
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tmpPath := dir + "/MANIFEST.tmp"
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if err := os.WriteFile(tmpPath, []byte(content), 0o644); err != nil {
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return fmt.Errorf("write manifest tmp: %w", err)
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}
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if err := os.Rename(tmpPath, dir+"/MANIFEST"); err != nil {
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return fmt.Errorf("rename manifest: %w", err)
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}
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return nil
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}
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