mirror of https://github.com/grpc/grpc-go.git
83 lines
2.9 KiB
Go
83 lines
2.9 KiB
Go
/*
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*
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* Copyright 2023 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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// Package xdslbregistry provides a registry of converters that convert proto
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// from load balancing configuration, defined by the xDS API spec, to JSON load
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// balancing configuration.
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package xdslbregistry
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import (
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"encoding/json"
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"fmt"
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v3clusterpb "github.com/envoyproxy/go-control-plane/envoy/config/cluster/v3"
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)
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var (
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// m is a map from proto type to Converter.
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m = make(map[string]Converter)
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)
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// Register registers the converter to the map keyed on a proto type. Must be
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// called at init time. Not thread safe.
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func Register(protoType string, c Converter) {
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m[protoType] = c
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}
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// SetRegistry sets the xDS LB registry. Must be called at init time. Not thread
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// safe.
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func SetRegistry(registry map[string]Converter) {
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m = registry
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}
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// Converter converts raw proto bytes into the internal Go JSON representation
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// of the proto passed. Returns the json message, and an error. If both
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// returned are nil, it represents continuing to the next proto.
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type Converter func([]byte, int) (json.RawMessage, error)
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// ConvertToServiceConfig converts a proto Load Balancing Policy configuration
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// into a json string. Returns an error if:
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// - no supported policy found
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// - there is more than 16 layers of recursion in the configuration
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// - a failure occurs when converting the policy
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func ConvertToServiceConfig(lbPolicy *v3clusterpb.LoadBalancingPolicy, depth int) (json.RawMessage, error) {
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// "Configurations that require more than 16 levels of recursion are
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// considered invalid and should result in a NACK response." - A51
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if depth > 15 {
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return nil, fmt.Errorf("lb policy %v exceeds max depth supported: 16 layers", lbPolicy)
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}
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// "This function iterate over the list of policy messages in
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// LoadBalancingPolicy, attempting to convert each one to gRPC form,
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// stopping at the first supported policy." - A52
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for _, policy := range lbPolicy.GetPolicies() {
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converter := m[policy.GetTypedExtensionConfig().GetTypedConfig().GetTypeUrl()]
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// "Any entry not in the above list is unsupported and will be skipped."
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// - A52
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if converter == nil {
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continue
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}
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json, err := converter(policy.GetTypedExtensionConfig().GetTypedConfig().GetValue(), depth)
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if json == nil && err == nil {
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continue
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}
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return json, err
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}
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return nil, fmt.Errorf("no supported policy found in policy list +%v", lbPolicy)
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}
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