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
44 lines
1.3 KiB
Go
44 lines
1.3 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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// WriteCurrent writes the CURRENT file to dir with a best-effort atomic rename.
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// The file contains the active WAL segment filename (e.g. "segment-5.wal").
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// CURRENT is only a write-side hint; it may be missing or stale after a crash.
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func WriteCurrent(dir string, segmentID uint64) error {
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content := fmt.Sprintf("segment-%d.wal\n", segmentID)
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tmpPath := dir + "/CURRENT.tmp"
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if err := os.WriteFile(tmpPath, []byte(content), 0o644); err != nil {
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return fmt.Errorf("write current tmp: %w", err)
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}
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if err := os.Rename(tmpPath, dir+"/CURRENT"); err != nil {
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return fmt.Errorf("rename current: %w", err)
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}
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return nil
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}
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// ReadCurrent reads the CURRENT file from dir and returns the segment ID.
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// If the file does not exist or cannot be parsed, it returns 0, false with no error.
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func ReadCurrent(dir string) (segmentID uint64, ok bool) {
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data, err := os.ReadFile(dir + "/CURRENT")
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if err != nil {
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return 0, false
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}
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line := strings.TrimSpace(string(data))
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// Expected format: "segment-N.wal"
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if !strings.HasPrefix(line, "segment-") || !strings.HasSuffix(line, ".wal") {
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return 0, false
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}
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idStr := strings.TrimSuffix(strings.TrimPrefix(line, "segment-"), ".wal")
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id, err := strconv.ParseUint(idStr, 10, 64)
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if err != nil {
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return 0, false
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}
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return id, true
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}
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