56 lines
1.2 KiB
Go
56 lines
1.2 KiB
Go
package config
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import (
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"fmt"
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"os"
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"path/filepath"
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)
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// AtomicWrite writes data to the target path atomically by writing to a temp file
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// in the same directory, fsyncing, then renaming over the target.
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func AtomicWrite(path string, data []byte, perm os.FileMode) error {
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dir := filepath.Dir(path)
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if err := os.MkdirAll(dir, 0o755); err != nil {
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return fmt.Errorf("create directory: %w", err)
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}
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tmp, err := os.CreateTemp(dir, ".tmp-*")
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if err != nil {
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return fmt.Errorf("create temp file: %w", err)
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}
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tmpName := tmp.Name()
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cleanup := func() {
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tmp.Close()
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os.Remove(tmpName)
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}
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if _, err := tmp.Write(data); err != nil {
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cleanup()
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return fmt.Errorf("write temp file: %w", err)
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}
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if err := tmp.Sync(); err != nil {
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cleanup()
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return fmt.Errorf("fsync temp file: %w", err)
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}
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if err := tmp.Close(); err != nil {
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os.Remove(tmpName)
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return fmt.Errorf("close temp file: %w", err)
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}
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if err := os.Chmod(tmpName, perm); err != nil {
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os.Remove(tmpName)
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return fmt.Errorf("chmod temp file: %w", err)
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}
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if err := os.Rename(tmpName, path); err != nil {
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os.Remove(tmpName)
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return fmt.Errorf("rename temp to target: %w", err)
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}
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return nil
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}
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