JuliusBrussee/caveman · error

cacheengine: invalid cache thresholds

Error message

cacheengine: invalid cache thresholds

What it means

Thrown by validatePlanRequest for any profile mode other than ModeUnsupported when threshold fields are out of range: MaxBreakpoints must be > 0, and MinPrefixTokens, MaxRPMPerKey, and TTL must all be >= 0. These thresholds drive breakpoint selection and key rotation, so zero/negative values would break planning.

Source

Thrown at cacheengine/engine.go:290

	if !validIdentity(request.Epoch, 4096, false) {
		return errors.New("cacheengine: invalid epoch")
	}
	if !validIdentity(request.PartitionKey, 4096, true) {
		return errors.New("cacheengine: invalid partition key")
	}
	if request.ExpectedCalls < 0 || request.ExpectedRequestsPerMinute < 0 {
		return errors.New("cacheengine: negative traffic expectation")
	}
	profile := normalizedProfile(request.Profile)
	if !validIdentity(profile.ID, 256, false) || !validIdentity(profile.Provider, 64, true) || !validIdentity(profile.OptimizerID, 256, true) {
		return errors.New("cacheengine: invalid profile identity")
	}
	if profile.Mode != ModeUnsupported && profile.Mode != ModeImplicit && profile.Mode != ModeAffinity && profile.Mode != ModeExplicit {
		return fmt.Errorf("cacheengine: unknown mode %q", profile.Mode)
	}
	if profile.Mode != ModeUnsupported {
		if profile.MaxBreakpoints <= 0 || profile.MinPrefixTokens < 0 || profile.MaxRPMPerKey < 0 || profile.TTL < 0 {
			return errors.New("cacheengine: invalid cache thresholds")
		}
		switch profile.Attribution {
		case AttributionNone, AttributionOrganic, AttributionAffinity, AttributionCausal:
		default:
			return fmt.Errorf("cacheengine: unknown attribution %q", profile.Attribution)
		}
		if profile.EconomicsKnown && (!finiteNonNegative(profile.WriteMultiplier) || !finiteNonNegative(profile.ReadMultiplier)) {
			return errors.New("cacheengine: invalid cache economics")
		}
	}
	return nil
}

func normalizedProfile(profile Profile) Profile {
	if profile.Mode == ModeUnsupported {
		if profile.ID == "" {
			profile.ID = "unsupported"
		}

View on GitHub (pinned to 27d5a3981a)

Solutions

1. Set MaxBreakpoints to a positive value (e.g. 4) whenever the mode is not ModeUnsupported
2. Use 0 rather than negative values for MinPrefixTokens/MaxRPMPerKey/TTL when you want the 'none' behavior
3. Validate loaded config numbers before building the PlanRequest

Example fix

// before
profile := cacheengine.Profile{ID: "p", Mode: cacheengine.ModeImplicit} // MaxBreakpoints zero value = 0

// after
profile := cacheengine.Profile{ID: "p", Mode: cacheengine.ModeImplicit, MaxBreakpoints: 4, MinPrefixTokens: 1024, TTL: 5 * time.Minute}

func thresholdsOK(p cacheengine.Profile) bool {
    if p.Mode == cacheengine.ModeUnsupported { return true }
    return p.MaxBreakpoints > 0 && p.MinPrefixTokens >= 0 && p.MaxRPMPerKey >= 0 && p.TTL >= 0
}

// n/a

When it happens

Trigger: Calling Plan with ModeImplicit/ModeAffinity/ModeExplicit and MaxBreakpoints == 0 (often the zero value of an unset struct field), a negative TTL, negative MinPrefixTokens, or negative MaxRPMPerKey.

Common situations: Constructing a Profile literal and forgetting MaxBreakpoints (int zero value is 0, which fails the > 0 check); loading thresholds from YAML/JSON where a typo yields 0; passing a negative TTL to mean 'no expiry'.

Related errors

• cacheengine: invalid partition key
• cacheengine: negative traffic expectation
• cacheengine: invalid profile identity
• cacheengine: invalid cache economics
• cacheengine: stable segment needs name and content

AI-assisted analysis of JuliusBrussee/caveman@27d5a3981a (2026-08-15). Data as JSON: /api/errors/176a27be5619ec5d. Report an issue: GitHub.