thanos-io/thanos · error

read compressed config file

Error message

read compressed config file

What it means

Wraps io.ReadAll(zr) in Reloader.normalize: the gzip header was valid but reading the decompressed config content to EOF failed mid-stream (truncated or corrupt archive). The expanded bytes are discarded.

Solutions

1. Regenerate the gzipped rule/config file.
2. Check disk/network integrity of the source.
3. Validate the gzip archive with gzip -t.

When it happens

Trigger: Thrown at pkg/reloader/reloader.go:377 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/906b43c1bcd0464c. Report an issue: GitHub.

Appendix: source

Thrown at pkg/reloader/reloader.go:377

}

func (r *Reloader) normalize(inputFile, outputFile string) error {
	b, err := os.ReadFile(inputFile)
	if err != nil {
		return errors.Wrap(err, "read file")
	}

	// Detect and extract gzipped file.
	if bytes.Equal(b[0:3], firstGzipBytes) {
		zr, err := gzip.NewReader(bytes.NewReader(b))
		if err != nil {
			return errors.Wrap(err, "create gzip reader")
		}
		defer runutil.CloseWithLogOnErr(r.logger, zr, "gzip reader close")

		b, err = io.ReadAll(zr)
		if err != nil {
			return errors.Wrap(err, "read compressed config file")
		}
	}

	b, err = r.expandEnv(b)
	if err != nil {
		return errors.Wrap(err, "expand environment variables")
	}

	tmpFile := outputFile + ".tmp"
	defer func() {
		_ = os.Remove(tmpFile)
	}()
	if err := os.WriteFile(tmpFile, b, 0644); err != nil {
		return errors.Wrap(err, "write file")
	}
	if err := os.Rename(tmpFile, outputFile); err != nil {
		return errors.Wrap(err, "rename file")
	}

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