1 /* 2 * 3 * Copyright 2018 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 dns implements a dns resolver to be installed as the default resolver 20 // in grpc. 21 package dns 22 23 import ( 24 "time" 25 26 "google.golang.org/grpc/internal/resolver/dns" 27 "google.golang.org/grpc/resolver" 28 ) 29 30 // SetResolvingTimeout sets the maximum duration for DNS resolution requests. 31 // 32 // This function affects the global timeout used by all channels using the DNS 33 // name resolver scheme. 34 // 35 // It must be called only at application startup, before any gRPC calls are 36 // made. Modifying this value after initialization is not thread-safe. 37 // 38 // The default value is 30 seconds. Setting the timeout too low may result in 39 // premature timeouts during resolution, while setting it too high may lead to 40 // unnecessary delays in service discovery. Choose a value appropriate for your 41 // specific needs and network environment. 42 func SetResolvingTimeout(timeout time.Duration) { 43 dns.ResolvingTimeout = timeout 44 } 45 46 // NewBuilder creates a dnsBuilder which is used to factory DNS resolvers. 47 // 48 // Deprecated: import grpc and use resolver.Get("dns") instead. 49 func NewBuilder() resolver.Builder { 50 return dns.NewBuilder() 51 } 52 53 // SetMinResolutionInterval sets the default minimum interval at which DNS 54 // re-resolutions are allowed. This helps to prevent excessive re-resolution. 55 // 56 // It must be called only at application startup, before any gRPC calls are 57 // made. Modifying this value after initialization is not thread-safe. 58 func SetMinResolutionInterval(d time.Duration) { 59 dns.MinResolutionInterval = d 60 } 61