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/*
*
* Copyright 2017 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package grpc
import (
"encoding/json"
"fmt"
"strconv"
"strings"
"time"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/grpclog"
)
const maxInt = int(^uint(0) >> 1)
// MethodConfig defines the configuration recommended by the service providers for a
// particular method.
//
// Deprecated: Users should not use this struct. Service config should be received
// through name resolver, as specified here
// https://github.com/grpc/grpc/blob/master/doc/service_config.md
type MethodConfig struct {
// WaitForReady indicates whether RPCs sent to this method should wait until
// the connection is ready by default (!failfast). The value specified via the
// gRPC client API will override the value set here.
WaitForReady *bool
// Timeout is the default timeout for RPCs sent to this method. The actual
// deadline used will be the minimum of the value specified here and the value
// set by the application via the gRPC client API. If either one is not set,
// then the other will be used. If neither is set, then the RPC has no deadline.
Timeout *time.Duration
// MaxReqSize is the maximum allowed payload size for an individual request in a
// stream (client->server) in bytes. The size which is measured is the serialized
// payload after per-message compression (but before stream compression) in bytes.
// The actual value used is the minimum of the value specified here and the value set
// by the application via the gRPC client API. If either one is not set, then the other
// will be used. If neither is set, then the built-in default is used.
MaxReqSize *int
// MaxRespSize is the maximum allowed payload size for an individual response in a
// stream (server->client) in bytes.
MaxRespSize *int
// RetryPolicy configures retry options for the method.
retryPolicy *retryPolicy
}
// ServiceConfig is provided by the service provider and contains parameters for how
// clients that connect to the service should behave.
//
// Deprecated: Users should not use this struct. Service config should be received
// through name resolver, as specified here
// https://github.com/grpc/grpc/blob/master/doc/service_config.md
type ServiceConfig struct {
// LB is the load balancer the service providers recommends. The balancer specified
// via grpc.WithBalancer will override this.
LB *string
// Methods contains a map for the methods in this service. If there is an
// exact match for a method (i.e. /service/method) in the map, use the
// corresponding MethodConfig. If there's no exact match, look for the
// default config for the service (/service/) and use the corresponding
// MethodConfig if it exists. Otherwise, the method has no MethodConfig to
// use.
Methods map[string]MethodConfig
// If a retryThrottlingPolicy is provided, gRPC will automatically throttle
// retry attempts and hedged RPCs when the client’s ratio of failures to
// successes exceeds a threshold.
//
// For each server name, the gRPC client will maintain a token_count which is
// initially set to maxTokens, and can take values between 0 and maxTokens.
//
// Every outgoing RPC (regardless of service or method invoked) will change
// token_count as follows:
//
// - Every failed RPC will decrement the token_count by 1.
// - Every successful RPC will increment the token_count by tokenRatio.
//
// If token_count is less than or equal to maxTokens / 2, then RPCs will not
// be retried and hedged RPCs will not be sent.
retryThrottling *retryThrottlingPolicy
// healthCheckConfig must be set as one of the requirement to enable LB channel
// health check.
healthCheckConfig *healthCheckConfig
}
// healthCheckConfig defines the go-native version of the LB channel health check config.
type healthCheckConfig struct {
// serviceName is the service name to use in the health-checking request.
ServiceName string
}
// retryPolicy defines the go-native version of the retry policy defined by the
// service config here:
// https://github.com/grpc/proposal/blob/master/A6-client-retries.md#integration-with-service-config
type retryPolicy struct {
// MaxAttempts is the maximum number of attempts, including the original RPC.
//
// This field is required and must be two or greater.
maxAttempts int
// Exponential backoff parameters. The initial retry attempt will occur at
// random(0, initialBackoffMS). In general, the nth attempt will occur at
// random(0,
// min(initialBackoffMS*backoffMultiplier**(n-1), maxBackoffMS)).
//
// These fields are required and must be greater than zero.
initialBackoff time.Duration
maxBackoff time.Duration
backoffMultiplier float64
// The set of status codes which may be retried.
//
// Status codes are specified as strings, e.g., "UNAVAILABLE".
//
// This field is required and must be non-empty.
// Note: a set is used to store this for easy lookup.
retryableStatusCodes map[codes.Code]bool
}
type jsonRetryPolicy struct {
MaxAttempts int
InitialBackoff string
MaxBackoff string
BackoffMultiplier float64
RetryableStatusCodes []codes.Code
}
// retryThrottlingPolicy defines the go-native version of the retry throttling
// policy defined by the service config here:
// https://github.com/grpc/proposal/blob/master/A6-client-retries.md#integration-with-service-config
type retryThrottlingPolicy struct {
// The number of tokens starts at maxTokens. The token_count will always be
// between 0 and maxTokens.
//
// This field is required and must be greater than zero.
MaxTokens float64
// The amount of tokens to add on each successful RPC. Typically this will
// be some number between 0 and 1, e.g., 0.1.
//
// This field is required and must be greater than zero. Up to 3 decimal
// places are supported.
TokenRatio float64
}
func parseDuration(s *string) (*time.Duration, error) {
if s == nil {
return nil, nil
}
if !strings.HasSuffix(*s, "s") {
return nil, fmt.Errorf("malformed duration %q", *s)
}
ss := strings.SplitN((*s)[:len(*s)-1], ".", 3)
if len(ss) > 2 {
return nil, fmt.Errorf("malformed duration %q", *s)
}
// hasDigits is set if either the whole or fractional part of the number is
// present, since both are optional but one is required.
hasDigits := false
var d time.Duration
if len(ss[0]) > 0 {
i, err := strconv.ParseInt(ss[0], 10, 32)
if err != nil {
return nil, fmt.Errorf("malformed duration %q: %v", *s, err)
}
d = time.Duration(i) * time.Second
hasDigits = true
}
if len(ss) == 2 && len(ss[1]) > 0 {
if len(ss[1]) > 9 {
return nil, fmt.Errorf("malformed duration %q", *s)
}
f, err := strconv.ParseInt(ss[1], 10, 64)
if err != nil {
return nil, fmt.Errorf("malformed duration %q: %v", *s, err)
}
for i := 9; i > len(ss[1]); i-- {
f *= 10
}
d += time.Duration(f)
hasDigits = true
}
if !hasDigits {
return nil, fmt.Errorf("malformed duration %q", *s)
}
return &d, nil
}
type jsonName struct {
Service *string
Method *string
}
func (j jsonName) generatePath() (string, bool) {
if j.Service == nil {
return "", false
}
res := "/" + *j.Service + "/"
if j.Method != nil {
res += *j.Method
}
return res, true
}
// TODO(lyuxuan): delete this struct after cleaning up old service config implementation.
type jsonMC struct {
Name *[]jsonName
WaitForReady *bool
Timeout *string
MaxRequestMessageBytes *int64
MaxResponseMessageBytes *int64
RetryPolicy *jsonRetryPolicy
}
// TODO(lyuxuan): delete this struct after cleaning up old service config implementation.
type jsonSC struct {
LoadBalancingPolicy *string
MethodConfig *[]jsonMC
RetryThrottling *retryThrottlingPolicy
HealthCheckConfig *healthCheckConfig
}
func parseServiceConfig(js string) (ServiceConfig, error) {
if len(js) == 0 {
return ServiceConfig{}, fmt.Errorf("no JSON service config provided")
}
var rsc jsonSC
err := json.Unmarshal([]byte(js), &rsc)
if err != nil {
grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err)
return ServiceConfig{}, err
}
sc := ServiceConfig{
LB: rsc.LoadBalancingPolicy,
Methods: make(map[string]MethodConfig),
retryThrottling: rsc.RetryThrottling,
healthCheckConfig: rsc.HealthCheckConfig,
}
if rsc.MethodConfig == nil {
return sc, nil
}
for _, m := range *rsc.MethodConfig {
if m.Name == nil {
continue
}
d, err := parseDuration(m.Timeout)
if err != nil {
grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err)
return ServiceConfig{}, err
}
mc := MethodConfig{
WaitForReady: m.WaitForReady,
Timeout: d,
}
if mc.retryPolicy, err = convertRetryPolicy(m.RetryPolicy); err != nil {
grpclog.Warningf("grpc: parseServiceConfig error unmarshaling %s due to %v", js, err)
return ServiceConfig{}, err
}
if m.MaxRequestMessageBytes != nil {
if *m.MaxRequestMessageBytes > int64(maxInt) {
mc.MaxReqSize = newInt(maxInt)
} else {
mc.MaxReqSize = newInt(int(*m.MaxRequestMessageBytes))
}
}
if m.MaxResponseMessageBytes != nil {
if *m.MaxResponseMessageBytes > int64(maxInt) {
mc.MaxRespSize = newInt(maxInt)
} else {
mc.MaxRespSize = newInt(int(*m.MaxResponseMessageBytes))
}
}
for _, n := range *m.Name {
if path, valid := n.generatePath(); valid {
sc.Methods[path] = mc
}
}
}
if sc.retryThrottling != nil {
if sc.retryThrottling.MaxTokens <= 0 ||
sc.retryThrottling.MaxTokens >= 1000 ||
sc.retryThrottling.TokenRatio <= 0 {
// Illegal throttling config; disable throttling.
sc.retryThrottling = nil
}
}
return sc, nil
}
func convertRetryPolicy(jrp *jsonRetryPolicy) (p *retryPolicy, err error) {
if jrp == nil {
return nil, nil
}
ib, err := parseDuration(&jrp.InitialBackoff)
if err != nil {
return nil, err
}
mb, err := parseDuration(&jrp.MaxBackoff)
if err != nil {
return nil, err
}
if jrp.MaxAttempts <= 1 ||
*ib <= 0 ||
*mb <= 0 ||
jrp.BackoffMultiplier <= 0 ||
len(jrp.RetryableStatusCodes) == 0 {
grpclog.Warningf("grpc: ignoring retry policy %v due to illegal configuration", jrp)
return nil, nil
}
rp := &retryPolicy{
maxAttempts: jrp.MaxAttempts,
initialBackoff: *ib,
maxBackoff: *mb,
backoffMultiplier: jrp.BackoffMultiplier,
retryableStatusCodes: make(map[codes.Code]bool),
}
if rp.maxAttempts > 5 {
// TODO(retry): Make the max maxAttempts configurable.
rp.maxAttempts = 5
}
for _, code := range jrp.RetryableStatusCodes {
rp.retryableStatusCodes[code] = true
}
return rp, nil
}
func min(a, b *int) *int {
if *a < *b {
return a
}
return b
}
func getMaxSize(mcMax, doptMax *int, defaultVal int) *int {
if mcMax == nil && doptMax == nil {
return &defaultVal
}
if mcMax != nil && doptMax != nil {
return min(mcMax, doptMax)
}
if mcMax != nil {
return mcMax
}
return doptMax
}
func newInt(b int) *int {
return &b
}