grpc/grpc-go · error

rls_csp: validation error from rls lb policy parsing: %v

Error message

rls_csp: validation error from rls lb policy parsing: %v

What it means

Returned when the RLS balancer's ConfigParser.ParseConfig rejects the JSON assembled by the cluster specifier plugin (RouteLookupConfig JSON plus the hardcoded cds_experimental child policy). The plugin pre-validates by asking the RLS balancer to parse the config; any rejection propagates as this error.

Source

Thrown at internal/xds/clusterspecifier/rls/rls.go:91

		ChildPolicy: []map[string]json.RawMessage{
			{
				"cds_experimental": json.RawMessage(`{"isDynamic":true}`),
			},
		},
		ChildPolicyConfigTargetFieldName: "cluster",
	}

	rawJSON, err := json.Marshal(lbCfgJSON)
	if err != nil {
		return nil, fmt.Errorf("rls_csp: error marshaling load balancing config %v: %v", lbCfgJSON, err)
	}

	rlsBB := balancer.Get(internal.RLSLoadBalancingPolicyName)
	if rlsBB == nil {
		return nil, fmt.Errorf("RLS LB policy not registered")
	}
	if _, err = rlsBB.(balancer.ConfigParser).ParseConfig(rawJSON); err != nil {
		return nil, fmt.Errorf("rls_csp: validation error from rls lb policy parsing: %v", err)
	}

	return clusterspecifier.BalancerConfig{{internal.RLSLoadBalancingPolicyName: lbCfgJSON}}, nil
}

View on GitHub (pinned to 03255a9237)

Solutions

1. Read the wrapped %v (the RLS balancer's parse error) — it names the missing/invalid field.
2. Fix the RouteLookupConfig on the server to include all fields the RLS LB policy requires (grpc_keybuilders, lookup_service, etc.).
3. Align client and server gRPC/RLS versions so the validator's expectations match.

When it happens

Trigger: The server-supplied RouteLookupConfig, while serializable, is semantically invalid per the RLS LB policy — e.g. missing grpc_keybuilders, empty lookup_service, invalid child policy target field, or a malformed lookup_service_timeout.

Common situations: Control plane pushing an incomplete RLS config (missing required fields), version skew between the RLS proto the server used and the balancer's validator, or a hand-crafted config that omits required RLS fields.

Related errors

• rls_csp: nil configuration message provided
• rls_csp: error parsing config %v: %v
• RLS LB policy not registered
• missing server_listener_resource_name_template in the bootst
• no priority is provided, all priorities are removed

AI-assisted analysis of grpc/grpc-go@03255a9237 (2026-08-07). Data as JSON: /api/errors/887d7bd8fb64890b. Report an issue: GitHub.