Function parseChildPolicyConfigs

balancer/rls/config.go:284–323

parseChildPolicyConfigs iterates through the list of child policies and picks the first registered policy and validates its config.

(childPolicies []map[string]json.RawMessage, targetFieldName string)

// parseChildPolicyConfigs iterates through the list of child policies and picks
// the first registered policy and validates its config.
func parseChildPolicyConfigs(childPolicies []map[string]json.RawMessage, targetFieldName string) (string, map[string]json.RawMessage, error) {
	for i, config := range childPolicies {
		if len(config) != 1 {
			return "", nil, fmt.Errorf("rls: invalid childPolicy: entry %v does not contain exactly 1 policy/config pair: %q", i, config)
		}

		var name string
		var rawCfg json.RawMessage
		for name, rawCfg = range config {
		}
		builder := balancer.Get(name)
		if builder == nil {
			continue
		}
		parser, ok := builder.(balancer.ConfigParser)
		if !ok {
			return "", nil, fmt.Errorf("rls: childPolicy %q with config %q does not support config parsing", name, string(rawCfg))
		}

		// To validate child policy configs we do the following:
		// - unmarshal the raw JSON bytes of the child policy config into a map
		// - add an entry with key set to `target_field_name` and a dummy value
		// - marshal the map back to JSON and parse the config using the parser
		// retrieved previously
		var childConfig map[string]json.RawMessage
		if err := json.Unmarshal(rawCfg, &childConfig); err != nil {
			return "", nil, fmt.Errorf("rls: json unmarshal failed for child policy config %q: %v", string(rawCfg), err)
		}
		childConfig[targetFieldName], _ = json.Marshal(dummyChildPolicyTarget)
		jsonCfg, err := json.Marshal(childConfig)
		if err != nil {
			return "", nil, fmt.Errorf("rls: json marshal failed for child policy config {%+v}: %v", childConfig, err)
		}
		if _, err := parser.ParseConfig(jsonCfg); err != nil {
			return "", nil, fmt.Errorf("rls: childPolicy config validation failed: %v", err)
		}
		return name, childConfig, nil
	}
	return "", nil, fmt.Errorf("rls: invalid childPolicy config: no supported policies found in %+v", childPolicies)
}

func convertDuration(d *durationpb.Duration) (time.Duration, error) {
	if d == nil {