thanos-io/thanos · error

opening file

Error message

opening file

What it means

Wraps os.Open in CalculateHash's SHA-256 branch: the local file whose hash is being computed (block file path p) could not be opened — missing, permission-denied, or a directory. Hashing for upload verification cannot proceed.

Solutions

1. Verify the file exists locally at the given path
2. Check file permissions
3. Retry after the file is restored/downloaded

When it happens

Trigger: Thrown at pkg/block/metadata/hash.go:47 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of thanos-io/thanos@35b8b99117 (2026-09-07). Data as JSON: /api/errors/36ed846d0e42cd4f. Report an issue: GitHub.

Appendix: source

Thrown at pkg/block/metadata/hash.go:47

// ObjectHash stores the hash of an object in the object storage.
type ObjectHash struct {
	Func  HashFunc `json:"hashFunc"`
	Value string   `json:"value"`
}

// Equal returns true if two hashes are equal.
func (oh *ObjectHash) Equal(other *ObjectHash) bool {
	return oh.Value == other.Value
}

// CalculateHash calculates the hash of the given type.
func CalculateHash(p string, hf HashFunc, logger log.Logger) (ObjectHash, error) {
	switch hf {
	case SHA256Func:
		f, err := os.Open(filepath.Clean(p))
		if err != nil {
			return ObjectHash{}, errors.Wrap(err, "opening file")
		}
		defer runutil.CloseWithLogOnErr(logger, f, "closing %s", p)

		h := sha256.New()

		if _, err := io.Copy(h, f); err != nil {
			return ObjectHash{}, errors.Wrap(err, "copying")
		}

		return ObjectHash{
			Func:  SHA256Func,
			Value: hex.EncodeToString(h.Sum(nil)),
		}, nil
	}
	return ObjectHash{}, fmt.Errorf("hash function %v is not supported", hf)

}

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