1 /* 2 * Copyright 2020 The gRPC Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package io.grpc.xds; 18 19 import static com.google.common.base.Preconditions.checkArgument; 20 import static com.google.common.base.Preconditions.checkNotNull; 21 22 import com.google.common.base.MoreObjects; 23 import io.grpc.Internal; 24 import io.grpc.LoadBalancer; 25 import io.grpc.LoadBalancer.Helper; 26 import io.grpc.LoadBalancerProvider; 27 import io.grpc.NameResolver.ConfigOrError; 28 import io.grpc.Status; 29 import io.grpc.internal.ServiceConfigUtil.PolicySelection; 30 import java.util.Collections; 31 import java.util.HashSet; 32 import java.util.List; 33 import java.util.Map; 34 35 /** Provider for priority load balancing policy. */ 36 @Internal 37 public final class PriorityLoadBalancerProvider extends LoadBalancerProvider { 38 39 @Override isAvailable()40 public boolean isAvailable() { 41 return true; 42 } 43 44 @Override getPriority()45 public int getPriority() { 46 return 5; 47 } 48 49 @Override getPolicyName()50 public String getPolicyName() { 51 return XdsLbPolicies.PRIORITY_POLICY_NAME; 52 } 53 54 @Override newLoadBalancer(Helper helper)55 public LoadBalancer newLoadBalancer(Helper helper) { 56 return new PriorityLoadBalancer(helper); 57 } 58 59 @Override parseLoadBalancingPolicyConfig(Map<String, ?> rawConfig)60 public ConfigOrError parseLoadBalancingPolicyConfig(Map<String, ?> rawConfig) { 61 return ConfigOrError.fromError( 62 Status.INTERNAL.withDescription(getPolicyName() + " cannot be used from service config")); 63 } 64 65 static final class PriorityLbConfig { 66 final Map<String, PriorityChildConfig> childConfigs; 67 final List<String> priorities; 68 PriorityLbConfig(Map<String, PriorityChildConfig> childConfigs, List<String> priorities)69 PriorityLbConfig(Map<String, PriorityChildConfig> childConfigs, List<String> priorities) { 70 this.childConfigs = Collections.unmodifiableMap(checkNotNull(childConfigs, "childConfigs")); 71 this.priorities = Collections.unmodifiableList(checkNotNull(priorities, "priorities")); 72 checkArgument(!priorities.isEmpty(), "priority list is empty"); 73 checkArgument( 74 childConfigs.keySet().containsAll(priorities), 75 "missing child config for at lease one of the priorities"); 76 checkArgument( 77 priorities.size() == new HashSet<>(priorities).size(), 78 "duplicate names in priorities"); 79 checkArgument( 80 priorities.size() == childConfigs.keySet().size(), 81 "some names in childConfigs are not referenced by priorities"); 82 } 83 84 @Override toString()85 public String toString() { 86 return MoreObjects.toStringHelper(this) 87 .add("childConfigs", childConfigs) 88 .add("priorities", priorities) 89 .toString(); 90 } 91 92 static final class PriorityChildConfig { 93 final PolicySelection policySelection; 94 final boolean ignoreReresolution; 95 PriorityChildConfig(PolicySelection policySelection, boolean ignoreReresolution)96 PriorityChildConfig(PolicySelection policySelection, boolean ignoreReresolution) { 97 this.policySelection = checkNotNull(policySelection, "policySelection"); 98 this.ignoreReresolution = ignoreReresolution; 99 } 100 101 @Override toString()102 public String toString() { 103 return MoreObjects.toStringHelper(this) 104 .add("policySelection", policySelection) 105 .add("ignoreReresolution", ignoreReresolution) 106 .toString(); 107 } 108 } 109 } 110 } 111