thanos-io/thanos · info

res.GetWarning() (propagated warning)

Error message

res.GetWarning() (propagated warning)

What it means

This is the warning-propagation path of rulesServer.Send: when a RulesResponse carries a Warning, the server collects it into srv.warnings and returns nil instead of treating it as a group. The message 'res.GetWarning() (propagated warning)' labels this code path; no error is thrown here by design.

Solutions

1. Check the warnings returned alongside groups and log/act on them
2. If rules appear missing, the upstream probably emitted a warning explaining the truncation
3. Address the upstream-side condition (e.g. reduce rule count or fix ruler limits)

func isWarningResponse(res *rulespb.RulesResponse) bool {
    return res.GetWarning() != ""
}

When it happens

Trigger: An upstream ruler streams a rulespb.RulesResponse with the Warning field set (e.g. partial results, rule limit exceeded) while the client consumes the Rules stream.

Common situations: Large rule sets where upstream truncates results; deprecation or limit warnings surfaced by the ruler; callers ignoring resp warnings and seeing fewer rules than expected.

Related errors

• %s
• empty exemplars data
• Unknown
• res.GetWarning()
• no metadata

AI-assisted analysis of thanos-io/thanos@35b8b99117 (2026-09-07). Data as JSON: /api/errors/c6c9532989a1cb1d. Report an issue: GitHub.

Appendix: source

Thrown at pkg/rules/rules.go:280

	}
	return groups[:i+1]
}

type rulesServer struct {
	// This field just exist to pseudo-implement the unused methods of the interface.
	rulespb.Rules_RulesServer
	ctx context.Context

	warnings annotations.Annotations
	groups   []*rulespb.RuleGroup
	mu       sync.Mutex
}

func (srv *rulesServer) Send(res *rulespb.RulesResponse) error {
	if res.GetWarning() != "" {
		srv.mu.Lock()
		defer srv.mu.Unlock()
		srv.warnings.Add(errors.New(res.GetWarning()))
		return nil
	}

	if res.GetGroup() == nil {
		return errors.New("no group")
	}

	srv.mu.Lock()
	defer srv.mu.Unlock()
	srv.groups = append(srv.groups, res.GetGroup())
	return nil
}

func (srv *rulesServer) Context() context.Context {
	return srv.ctx
}

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