vendor/google.golang.org/grpc/service_config.go - voltctl - Gitiles

 /*
  *
  * 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
 	// rawJSONString stores service config json string that get parsed into
 	// this service config struct.
 	rawJSONString string
 }

 // 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) {
 	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 nil, err
 	}
 	sc := ServiceConfig{
 		LB:                rsc.LoadBalancingPolicy,
 		Methods:           make(map[string]MethodConfig),
 		retryThrottling:   rsc.RetryThrottling,
 		healthCheckConfig: rsc.HealthCheckConfig,
 		rawJSONString:     js,
 	}
 	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 nil, 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 nil, 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
 }
	/*
	*
	* 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
	// rawJSONString stores service config json string that get parsed into
	// this service config struct.
	rawJSONString string
	}

	// 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(initialBackoffMSbackoffMultiplier*(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) {
	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 nil, err
	}
	sc := ServiceConfig{
	LB: rsc.LoadBalancingPolicy,
	Methods: make(map[string]MethodConfig),
	retryThrottling: rsc.RetryThrottling,
	healthCheckConfig: rsc.HealthCheckConfig,
	rawJSONString: js,
	}
	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 nil, 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 nil, 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
	}