rls.go

Documentation: google.golang.org/grpc/xds/internal/clusterspecifier/rls

     1  /*
     2   *
     3   * Copyright 2021 gRPC authors.
     4   *
     5   * Licensed under the Apache License, Version 2.0 (the "License");
     6   * you may not use this file except in compliance with the License.
     7   * You may obtain a copy of the License at
     8   *
     9   *     http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the License for the specific language governing permissions and
    15   * limitations under the License.
    16   *
    17   */
    18  
    19  // Package rls implements the RLS cluster specifier plugin.
    20  package rls
    21  
    22  import (
    23  	"encoding/json"
    24  	"fmt"
    25  
    26  	"google.golang.org/grpc/balancer"
    27  	"google.golang.org/grpc/internal"
    28  	rlspb "google.golang.org/grpc/internal/proto/grpc_lookup_v1"
    29  	"google.golang.org/grpc/xds/internal/clusterspecifier"
    30  	"google.golang.org/protobuf/encoding/protojson"
    31  	"google.golang.org/protobuf/proto"
    32  	"google.golang.org/protobuf/types/known/anypb"
    33  )
    34  
    35  func init() {
    36  	clusterspecifier.Register(rls{})
    37  
    38  	// TODO: Remove these once the RLS env var is removed.
    39  	internal.RegisterRLSClusterSpecifierPluginForTesting = func() {
    40  		clusterspecifier.Register(rls{})
    41  	}
    42  	internal.UnregisterRLSClusterSpecifierPluginForTesting = func() {
    43  		for _, typeURL := range rls.TypeURLs(rls{}) {
    44  			clusterspecifier.UnregisterForTesting(typeURL)
    45  		}
    46  	}
    47  }
    48  
    49  type rls struct{}
    50  
    51  func (rls) TypeURLs() []string {
    52  	return []string{"type.googleapis.com/grpc.lookup.v1.RouteLookupClusterSpecifier"}
    53  }
    54  
    55  // lbConfigJSON is the RLS LB Policies configuration in JSON format.
    56  // RouteLookupConfig will be a raw JSON string from the passed in proto
    57  // configuration, and the other fields will be hardcoded.
    58  type lbConfigJSON struct {
    59  	RouteLookupConfig                json.RawMessage              `json:"routeLookupConfig"`
    60  	ChildPolicy                      []map[string]json.RawMessage `json:"childPolicy"`
    61  	ChildPolicyConfigTargetFieldName string                       `json:"childPolicyConfigTargetFieldName"`
    62  }
    63  
    64  func (rls) ParseClusterSpecifierConfig(cfg proto.Message) (clusterspecifier.BalancerConfig, error) {
    65  	if cfg == nil {
    66  		return nil, fmt.Errorf("rls_csp: nil configuration message provided")
    67  	}
    68  	any, ok := cfg.(*anypb.Any)
    69  	if !ok {
    70  		return nil, fmt.Errorf("rls_csp: error parsing config %v: unknown type %T", cfg, cfg)
    71  	}
    72  	rlcs := new(rlspb.RouteLookupClusterSpecifier)
    73  
    74  	if err := any.UnmarshalTo(rlcs); err != nil {
    75  		return nil, fmt.Errorf("rls_csp: error parsing config %v: %v", cfg, err)
    76  	}
    77  	rlcJSON, err := protojson.Marshal(rlcs.GetRouteLookupConfig())
    78  	if err != nil {
    79  		return nil, fmt.Errorf("rls_csp: error marshaling route lookup config: %v: %v", rlcs.GetRouteLookupConfig(), err)
    80  	}
    81  	lbCfgJSON := &lbConfigJSON{
    82  		RouteLookupConfig: rlcJSON, // "JSON form of RouteLookupClusterSpecifier.config" - RLS in xDS Design Doc
    83  		ChildPolicy: []map[string]json.RawMessage{
    84  			{
    85  				"cds_experimental": json.RawMessage("{}"),
    86  			},
    87  		},
    88  		ChildPolicyConfigTargetFieldName: "cluster",
    89  	}
    90  
    91  	rawJSON, err := json.Marshal(lbCfgJSON)
    92  	if err != nil {
    93  		return nil, fmt.Errorf("rls_csp: error marshaling load balancing config %v: %v", lbCfgJSON, err)
    94  	}
    95  
    96  	rlsBB := balancer.Get(internal.RLSLoadBalancingPolicyName)
    97  	if rlsBB == nil {
    98  		return nil, fmt.Errorf("RLS LB policy not registered")
    99  	}
   100  	if _, err = rlsBB.(balancer.ConfigParser).ParseConfig(rawJSON); err != nil {
   101  		return nil, fmt.Errorf("rls_csp: validation error from rls lb policy parsing: %v", err)
   102  	}
   103  
   104  	return clusterspecifier.BalancerConfig{{internal.RLSLoadBalancingPolicyName: lbCfgJSON}}, nil
   105  }
   106
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