348 lines
10 KiB
Go
348 lines
10 KiB
Go
/*
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*
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* Copyright 2017 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 grpc
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import (
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"encoding/json"
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"errors"
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"fmt"
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"reflect"
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"time"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/internal"
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internalserviceconfig "google.golang.org/grpc/internal/serviceconfig"
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"google.golang.org/grpc/serviceconfig"
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)
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const maxInt = int(^uint(0) >> 1)
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// MethodConfig defines the configuration recommended by the service providers for a
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// particular method.
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//
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// Deprecated: Users should not use this struct. Service config should be received
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// through name resolver, as specified here
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// https://github.com/grpc/grpc/blob/master/doc/service_config.md
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type MethodConfig = internalserviceconfig.MethodConfig
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type lbConfig struct {
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name string
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cfg serviceconfig.LoadBalancingConfig
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}
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// ServiceConfig is provided by the service provider and contains parameters for how
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// clients that connect to the service should behave.
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//
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// Deprecated: Users should not use this struct. Service config should be received
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// through name resolver, as specified here
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// https://github.com/grpc/grpc/blob/master/doc/service_config.md
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type ServiceConfig struct {
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serviceconfig.Config
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// LB is the load balancer the service providers recommends. This is
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// deprecated; lbConfigs is preferred. If lbConfig and LB are both present,
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// lbConfig will be used.
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LB *string
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// lbConfig is the service config's load balancing configuration. If
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// lbConfig and LB are both present, lbConfig will be used.
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lbConfig *lbConfig
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// Methods contains a map for the methods in this service. If there is an
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// exact match for a method (i.e. /service/method) in the map, use the
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// corresponding MethodConfig. If there's no exact match, look for the
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// default config for the service (/service/) and use the corresponding
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// MethodConfig if it exists. Otherwise, the method has no MethodConfig to
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// use.
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Methods map[string]MethodConfig
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// If a retryThrottlingPolicy is provided, gRPC will automatically throttle
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// retry attempts and hedged RPCs when the client’s ratio of failures to
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// successes exceeds a threshold.
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//
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// For each server name, the gRPC client will maintain a token_count which is
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// initially set to maxTokens, and can take values between 0 and maxTokens.
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//
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// Every outgoing RPC (regardless of service or method invoked) will change
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// token_count as follows:
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//
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// - Every failed RPC will decrement the token_count by 1.
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// - Every successful RPC will increment the token_count by tokenRatio.
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//
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// If token_count is less than or equal to maxTokens / 2, then RPCs will not
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// be retried and hedged RPCs will not be sent.
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retryThrottling *retryThrottlingPolicy
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// healthCheckConfig must be set as one of the requirement to enable LB channel
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// health check.
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healthCheckConfig *healthCheckConfig
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// rawJSONString stores service config json string that get parsed into
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// this service config struct.
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rawJSONString string
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}
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// healthCheckConfig defines the go-native version of the LB channel health check config.
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type healthCheckConfig struct {
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// serviceName is the service name to use in the health-checking request.
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ServiceName string
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}
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type jsonRetryPolicy struct {
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MaxAttempts int
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InitialBackoff internalserviceconfig.Duration
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MaxBackoff internalserviceconfig.Duration
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BackoffMultiplier float64
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RetryableStatusCodes []codes.Code
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}
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// retryThrottlingPolicy defines the go-native version of the retry throttling
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// policy defined by the service config here:
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// https://github.com/grpc/proposal/blob/master/A6-client-retries.md#integration-with-service-config
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type retryThrottlingPolicy struct {
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// The number of tokens starts at maxTokens. The token_count will always be
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// between 0 and maxTokens.
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//
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// This field is required and must be greater than zero.
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MaxTokens float64
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// The amount of tokens to add on each successful RPC. Typically this will
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// be some number between 0 and 1, e.g., 0.1.
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//
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// This field is required and must be greater than zero. Up to 3 decimal
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// places are supported.
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TokenRatio float64
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}
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type jsonName struct {
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Service string
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Method string
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}
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var (
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errDuplicatedName = errors.New("duplicated name")
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errEmptyServiceNonEmptyMethod = errors.New("cannot combine empty 'service' and non-empty 'method'")
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)
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func (j jsonName) generatePath() (string, error) {
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if j.Service == "" {
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if j.Method != "" {
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return "", errEmptyServiceNonEmptyMethod
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}
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return "", nil
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}
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res := "/" + j.Service + "/"
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if j.Method != "" {
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res += j.Method
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}
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return res, nil
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}
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// TODO(lyuxuan): delete this struct after cleaning up old service config implementation.
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type jsonMC struct {
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Name *[]jsonName
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WaitForReady *bool
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Timeout *internalserviceconfig.Duration
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MaxRequestMessageBytes *int64
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MaxResponseMessageBytes *int64
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RetryPolicy *jsonRetryPolicy
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}
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// TODO(lyuxuan): delete this struct after cleaning up old service config implementation.
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type jsonSC struct {
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LoadBalancingPolicy *string
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LoadBalancingConfig *internalserviceconfig.BalancerConfig
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MethodConfig *[]jsonMC
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RetryThrottling *retryThrottlingPolicy
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HealthCheckConfig *healthCheckConfig
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}
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func init() {
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internal.ParseServiceConfig = parseServiceConfig
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}
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func parseServiceConfig(js string) *serviceconfig.ParseResult {
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if len(js) == 0 {
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return &serviceconfig.ParseResult{Err: fmt.Errorf("no JSON service config provided")}
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}
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var rsc jsonSC
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err := json.Unmarshal([]byte(js), &rsc)
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if err != nil {
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logger.Warningf("grpc: unmarshaling service config %s: %v", js, err)
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return &serviceconfig.ParseResult{Err: err}
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}
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sc := ServiceConfig{
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LB: rsc.LoadBalancingPolicy,
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Methods: make(map[string]MethodConfig),
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retryThrottling: rsc.RetryThrottling,
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healthCheckConfig: rsc.HealthCheckConfig,
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rawJSONString: js,
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}
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if c := rsc.LoadBalancingConfig; c != nil {
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sc.lbConfig = &lbConfig{
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name: c.Name,
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cfg: c.Config,
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}
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}
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if rsc.MethodConfig == nil {
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return &serviceconfig.ParseResult{Config: &sc}
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}
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paths := map[string]struct{}{}
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for _, m := range *rsc.MethodConfig {
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if m.Name == nil {
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continue
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}
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mc := MethodConfig{
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WaitForReady: m.WaitForReady,
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Timeout: (*time.Duration)(m.Timeout),
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}
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if mc.RetryPolicy, err = convertRetryPolicy(m.RetryPolicy); err != nil {
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logger.Warningf("grpc: unmarshaling service config %s: %v", js, err)
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return &serviceconfig.ParseResult{Err: err}
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}
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if m.MaxRequestMessageBytes != nil {
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if *m.MaxRequestMessageBytes > int64(maxInt) {
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mc.MaxReqSize = newInt(maxInt)
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} else {
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mc.MaxReqSize = newInt(int(*m.MaxRequestMessageBytes))
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}
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}
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if m.MaxResponseMessageBytes != nil {
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if *m.MaxResponseMessageBytes > int64(maxInt) {
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mc.MaxRespSize = newInt(maxInt)
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} else {
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mc.MaxRespSize = newInt(int(*m.MaxResponseMessageBytes))
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}
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}
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for i, n := range *m.Name {
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path, err := n.generatePath()
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if err != nil {
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logger.Warningf("grpc: error unmarshaling service config %s due to methodConfig[%d]: %v", js, i, err)
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return &serviceconfig.ParseResult{Err: err}
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}
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if _, ok := paths[path]; ok {
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err = errDuplicatedName
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logger.Warningf("grpc: error unmarshaling service config %s due to methodConfig[%d]: %v", js, i, err)
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return &serviceconfig.ParseResult{Err: err}
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}
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paths[path] = struct{}{}
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sc.Methods[path] = mc
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}
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}
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if sc.retryThrottling != nil {
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if mt := sc.retryThrottling.MaxTokens; mt <= 0 || mt > 1000 {
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return &serviceconfig.ParseResult{Err: fmt.Errorf("invalid retry throttling config: maxTokens (%v) out of range (0, 1000]", mt)}
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}
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if tr := sc.retryThrottling.TokenRatio; tr <= 0 {
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return &serviceconfig.ParseResult{Err: fmt.Errorf("invalid retry throttling config: tokenRatio (%v) may not be negative", tr)}
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}
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}
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return &serviceconfig.ParseResult{Config: &sc}
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}
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func convertRetryPolicy(jrp *jsonRetryPolicy) (p *internalserviceconfig.RetryPolicy, err error) {
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if jrp == nil {
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return nil, nil
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}
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if jrp.MaxAttempts <= 1 ||
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jrp.InitialBackoff <= 0 ||
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jrp.MaxBackoff <= 0 ||
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jrp.BackoffMultiplier <= 0 ||
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len(jrp.RetryableStatusCodes) == 0 {
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logger.Warningf("grpc: ignoring retry policy %v due to illegal configuration", jrp)
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return nil, nil
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}
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rp := &internalserviceconfig.RetryPolicy{
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MaxAttempts: jrp.MaxAttempts,
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InitialBackoff: time.Duration(jrp.InitialBackoff),
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MaxBackoff: time.Duration(jrp.MaxBackoff),
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BackoffMultiplier: jrp.BackoffMultiplier,
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RetryableStatusCodes: make(map[codes.Code]bool),
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}
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if rp.MaxAttempts > 5 {
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// TODO(retry): Make the max maxAttempts configurable.
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rp.MaxAttempts = 5
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}
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for _, code := range jrp.RetryableStatusCodes {
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rp.RetryableStatusCodes[code] = true
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}
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return rp, nil
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}
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func min(a, b *int) *int {
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if *a < *b {
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return a
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}
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return b
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}
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func getMaxSize(mcMax, doptMax *int, defaultVal int) *int {
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if mcMax == nil && doptMax == nil {
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return &defaultVal
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}
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if mcMax != nil && doptMax != nil {
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return min(mcMax, doptMax)
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}
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if mcMax != nil {
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return mcMax
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}
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return doptMax
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}
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func newInt(b int) *int {
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return &b
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}
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func init() {
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internal.EqualServiceConfigForTesting = equalServiceConfig
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}
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// equalServiceConfig compares two configs. The rawJSONString field is ignored,
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// because they may diff in white spaces.
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//
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// If any of them is NOT *ServiceConfig, return false.
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func equalServiceConfig(a, b serviceconfig.Config) bool {
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if a == nil && b == nil {
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return true
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}
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aa, ok := a.(*ServiceConfig)
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if !ok {
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return false
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}
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bb, ok := b.(*ServiceConfig)
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if !ok {
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return false
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}
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aaRaw := aa.rawJSONString
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aa.rawJSONString = ""
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bbRaw := bb.rawJSONString
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bb.rawJSONString = ""
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defer func() {
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aa.rawJSONString = aaRaw
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bb.rawJSONString = bbRaw
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}()
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// Using reflect.DeepEqual instead of cmp.Equal because many balancer
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// configs are unexported, and cmp.Equal cannot compare unexported fields
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// from unexported structs.
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return reflect.DeepEqual(aa, bb)
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}
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