fix(concurrency): wait when channel slots are saturated

Add a channel concurrency wait plan so saturated account/channel selection can distinguish no-wait, queue-full, and wait-for-slot outcomes while preserving fallback to other available channels first.

middleware/distributor.go

@@ -1,6 +1,7 @@
 package middleware
 
 import (
+	"context"
 	"errors"
 	"fmt"
 	"net/http"
@@ -16,6 +17,7 @@ import (
 	"github.com/QuantumNous/new-api/model"
 	relayconstant "github.com/QuantumNous/new-api/relay/constant"
 	"github.com/QuantumNous/new-api/service"
+	"github.com/QuantumNous/new-api/setting/operation_setting"
 	"github.com/QuantumNous/new-api/setting/ratio_setting"
 	"github.com/QuantumNous/new-api/types"
 
@@ -27,6 +29,21 @@ type ModelRequest struct {
 	Group string `json:"group,omitempty"`
 }
 
+type distributorConcurrencyResponse struct {
+	statusCode int
+	message    string
+	code       types.ErrorCode
+}
+
+var (
+	checkChannelQuotaForDistribute                   = model.CheckChannelQuota
+	acquireChannelConcurrencyForDistribute           = service.AcquireChannelConcurrency
+	cacheGetRandomSatisfiedChannelForDistribute      = service.CacheGetRandomSatisfiedChannel
+	getChannelConcurrencyWaitPlanForDistribute       = service.GetChannelConcurrencyWaitPlan
+	tryEnterChannelConcurrencyWaitQueueForDistribute = service.TryEnterChannelConcurrencyWaitQueue
+	waitForChannelConcurrencySlotForDistribute       = service.WaitForChannelConcurrencySlot
+)
+
 func Distribute() func(c *gin.Context) {
 	return func(c *gin.Context) {
 		var channel *model.Channel
@@ -155,22 +172,28 @@ func Distribute() func(c *gin.Context) {
 				}
 			}
 		}
-		common.SetContextKey(c, constant.ContextKeyRequestStartTime, time.Now())
-		SetupContextForSelectedChannel(c, channel, modelRequest.Model)
 		if channel != nil {
-			if err := model.CheckChannelQuota(channel.Id); err != nil {
+			selectedChannel, releaseChannelConcurrency, response := acquireDistributedChannelConcurrency(
-				abortWithOpenAiMessage(c, http.StatusTooManyRequests, err.Error())
+				c,
+				channel,
+				modelRequest.Model,
+				common.GetContextKeyString(c, constant.ContextKeyUsingGroup),
+			)
+			if response != nil {
+				if response.code != "" {
+					abortWithOpenAiMessage(c, response.statusCode, response.message, response.code)
+				} else {
+					abortWithOpenAiMessage(c, response.statusCode, response.message)
+				}
 				return
 			}
-			if channel.ConcurrencyLimit > 0 {
+			channel = selectedChannel
-				allowed, release := service.AcquireChannelConcurrency(channel.Id, channel.ConcurrencyLimit)
+			if releaseChannelConcurrency != nil {
-				if !allowed {
+				defer releaseChannelConcurrency()
-					abortWithOpenAiMessage(c, http.StatusTooManyRequests, "渠道并发请求数超过限制")
-					return
-				}
-				defer release()
 			}
 		}
+		common.SetContextKey(c, constant.ContextKeyRequestStartTime, time.Now())
+		SetupContextForSelectedChannel(c, channel, modelRequest.Model)
 		c.Next()
 		if channel != nil && c.Writer != nil && c.Writer.Status() < http.StatusBadRequest {
 			service.RecordChannelAffinity(c, channel.Id)
@@ -178,6 +201,113 @@ func Distribute() func(c *gin.Context) {
 	}
 }
 
+func acquireDistributedChannelConcurrency(c *gin.Context, channel *model.Channel, modelName string, tokenGroup string) (*model.Channel, func(), *distributorConcurrencyResponse) {
+	release := func() {}
+	if channel == nil {
+		return nil, release, nil
+	}
+	if err := checkChannelQuotaForDistribute(channel.Id); err != nil {
+		return nil, nil, &distributorConcurrencyResponse{
+			statusCode: http.StatusTooManyRequests,
+			message:    err.Error(),
+		}
+	}
+	if channel.ConcurrencyLimit <= 0 {
+		return channel, release, nil
+	}
+	if allowed, release := acquireChannelConcurrencyForDistribute(channel.Id, channel.ConcurrencyLimit); allowed {
+		return channel, release, nil
+	}
+
+	excludedChannelIDs := map[int]struct{}{channel.Id: {}}
+	if _, specificChannel := common.GetContextKey(c, constant.ContextKeyTokenSpecificChannelId); !specificChannel {
+		if selected, release, response := acquireAlternativeChannelConcurrency(c, modelName, tokenGroup, excludedChannelIDs); selected != nil || response != nil {
+			return selected, release, response
+		}
+	}
+
+	waitPlan := getChannelConcurrencyWaitPlanForDistribute()
+	if !channelConcurrencyWaitPlanEnabled(waitPlan) {
+		return nil, nil, &distributorConcurrencyResponse{
+			statusCode: http.StatusServiceUnavailable,
+			message:    "No available accounts",
+			code:       types.ErrorCodeGetChannelFailed,
+		}
+	}
+
+	canWait, releaseWait := tryEnterChannelConcurrencyWaitQueueForDistribute(channel.Id, waitPlan.MaxWaitingRequests)
+	if !canWait {
+		return nil, nil, &distributorConcurrencyResponse{
+			statusCode: http.StatusTooManyRequests,
+			message:    "Too many pending requests, please retry later",
+			code:       types.ErrorCodeGetChannelFailed,
+		}
+	}
+	defer releaseWait()
+
+	acquired, release, err := waitForChannelConcurrencySlotForDistribute(distributorRequestContext(c), channel.Id, channel.ConcurrencyLimit, time.Duration(waitPlan.TimeoutSeconds)*time.Second)
+	if err != nil || !acquired {
+		return nil, nil, &distributorConcurrencyResponse{
+			statusCode: http.StatusTooManyRequests,
+			message:    "Concurrency limit exceeded for account, please retry later",
+			code:       types.ErrorCodeGetChannelFailed,
+		}
+	}
+	return channel, release, nil
+}
+
+func acquireAlternativeChannelConcurrency(c *gin.Context, modelName string, tokenGroup string, excludedChannelIDs map[int]struct{}) (*model.Channel, func(), *distributorConcurrencyResponse) {
+	release := func() {}
+	for retry := 0; retry <= common.RetryTimes; retry++ {
+		for {
+			retryValue := retry
+			candidate, _, err := cacheGetRandomSatisfiedChannelForDistribute(&service.RetryParam{
+				Ctx:                c,
+				ModelName:          modelName,
+				TokenGroup:         tokenGroup,
+				Retry:              &retryValue,
+				ExcludedChannelIDs: excludedChannelIDs,
+			})
+			if err != nil {
+				return nil, nil, &distributorConcurrencyResponse{
+					statusCode: http.StatusServiceUnavailable,
+					message:    err.Error(),
+					code:       types.ErrorCodeGetChannelFailed,
+				}
+			}
+			if candidate == nil {
+				break
+			}
+			if _, excluded := excludedChannelIDs[candidate.Id]; excluded {
+				break
+			}
+			if err := checkChannelQuotaForDistribute(candidate.Id); err != nil {
+				excludedChannelIDs[candidate.Id] = struct{}{}
+				continue
+			}
+			if candidate.ConcurrencyLimit <= 0 {
+				return candidate, release, nil
+			}
+			if allowed, release := acquireChannelConcurrencyForDistribute(candidate.Id, candidate.ConcurrencyLimit); allowed {
+				return candidate, release, nil
+			}
+			excludedChannelIDs[candidate.Id] = struct{}{}
+		}
+	}
+	return nil, nil, nil
+}
+
+func channelConcurrencyWaitPlanEnabled(waitPlan operation_setting.ChannelConcurrencyWaitPlanSetting) bool {
+	return waitPlan.Enabled && waitPlan.TimeoutSeconds > 0 && waitPlan.MaxWaitingRequests > 0
+}
+
+func distributorRequestContext(c *gin.Context) context.Context {
+	if c != nil && c.Request != nil {
+		return c.Request.Context()
+	}
+	return context.Background()
+}
+
 // getModelFromRequest 从请求中读取模型信息
 // 根据 Content-Type 自动处理：
 // - application/json

middleware/distributor_concurrency_test.go

@@ -0,0 +1,182 @@
+package middleware
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/QuantumNous/new-api/model"
+	"github.com/QuantumNous/new-api/service"
+	"github.com/QuantumNous/new-api/setting/operation_setting"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+func restoreDistributorConcurrencyStubs(t *testing.T) {
+	t.Helper()
+
+	previousCheckQuota := checkChannelQuotaForDistribute
+	previousAcquire := acquireChannelConcurrencyForDistribute
+	previousSelect := cacheGetRandomSatisfiedChannelForDistribute
+	previousWaitPlan := getChannelConcurrencyWaitPlanForDistribute
+	previousEnterWaitQueue := tryEnterChannelConcurrencyWaitQueueForDistribute
+	previousWaitForSlot := waitForChannelConcurrencySlotForDistribute
+	t.Cleanup(func() {
+		checkChannelQuotaForDistribute = previousCheckQuota
+		acquireChannelConcurrencyForDistribute = previousAcquire
+		cacheGetRandomSatisfiedChannelForDistribute = previousSelect
+		getChannelConcurrencyWaitPlanForDistribute = previousWaitPlan
+		tryEnterChannelConcurrencyWaitQueueForDistribute = previousEnterWaitQueue
+		waitForChannelConcurrencySlotForDistribute = previousWaitForSlot
+	})
+}
+
+func newDistributorTestContext() *gin.Context {
+	gin.SetMode(gin.TestMode)
+	c, _ := gin.CreateTestContext(nil)
+	return c
+}
+
+func TestAcquireDistributedChannelConcurrencyReturns503WithoutWaitPlan(t *testing.T) {
+	restoreDistributorConcurrencyStubs(t)
+
+	checkChannelQuotaForDistribute = func(channelId int) error { return nil }
+	acquireChannelConcurrencyForDistribute = func(channelId, limit int) (bool, func()) {
+		return false, func() {}
+	}
+	cacheGetRandomSatisfiedChannelForDistribute = func(param *service.RetryParam) (*model.Channel, string, error) {
+		return nil, param.TokenGroup, nil
+	}
+	getChannelConcurrencyWaitPlanForDistribute = func() operation_setting.ChannelConcurrencyWaitPlanSetting {
+		return operation_setting.ChannelConcurrencyWaitPlanSetting{Enabled: false}
+	}
+
+	selected, release, response := acquireDistributedChannelConcurrency(
+		newDistributorTestContext(),
+		&model.Channel{Id: 1, ConcurrencyLimit: 1},
+		"gpt-test",
+		"default",
+	)
+
+	require.Nil(t, selected)
+	require.Nil(t, release)
+	require.NotNil(t, response)
+	require.Equal(t, http.StatusServiceUnavailable, response.statusCode)
+	require.Equal(t, "No available accounts", response.message)
+}
+
+func TestAcquireDistributedChannelConcurrencyReturns429WhenWaitQueueFull(t *testing.T) {
+	restoreDistributorConcurrencyStubs(t)
+
+	checkChannelQuotaForDistribute = func(channelId int) error { return nil }
+	acquireChannelConcurrencyForDistribute = func(channelId, limit int) (bool, func()) {
+		return false, func() {}
+	}
+	cacheGetRandomSatisfiedChannelForDistribute = func(param *service.RetryParam) (*model.Channel, string, error) {
+		return nil, param.TokenGroup, nil
+	}
+	getChannelConcurrencyWaitPlanForDistribute = func() operation_setting.ChannelConcurrencyWaitPlanSetting {
+		return operation_setting.ChannelConcurrencyWaitPlanSetting{
+			Enabled:            true,
+			TimeoutSeconds:     30,
+			MaxWaitingRequests: 1,
+		}
+	}
+	tryEnterChannelConcurrencyWaitQueueForDistribute = func(channelId, maxWaiting int) (bool, func()) {
+		return false, func() {}
+	}
+
+	selected, release, response := acquireDistributedChannelConcurrency(
+		newDistributorTestContext(),
+		&model.Channel{Id: 1, ConcurrencyLimit: 1},
+		"gpt-test",
+		"default",
+	)
+
+	require.Nil(t, selected)
+	require.Nil(t, release)
+	require.NotNil(t, response)
+	require.Equal(t, http.StatusTooManyRequests, response.statusCode)
+	require.Equal(t, "Too many pending requests, please retry later", response.message)
+}
+
+func TestAcquireDistributedChannelConcurrencyWaitsForSlot(t *testing.T) {
+	restoreDistributorConcurrencyStubs(t)
+
+	released := false
+	checkChannelQuotaForDistribute = func(channelId int) error { return nil }
+	acquireChannelConcurrencyForDistribute = func(channelId, limit int) (bool, func()) {
+		return false, func() {}
+	}
+	cacheGetRandomSatisfiedChannelForDistribute = func(param *service.RetryParam) (*model.Channel, string, error) {
+		return nil, param.TokenGroup, nil
+	}
+	getChannelConcurrencyWaitPlanForDistribute = func() operation_setting.ChannelConcurrencyWaitPlanSetting {
+		return operation_setting.ChannelConcurrencyWaitPlanSetting{
+			Enabled:            true,
+			TimeoutSeconds:     30,
+			MaxWaitingRequests: 1,
+		}
+	}
+	tryEnterChannelConcurrencyWaitQueueForDistribute = func(channelId, maxWaiting int) (bool, func()) {
+		return true, func() {}
+	}
+	waitForChannelConcurrencySlotForDistribute = func(ctx context.Context, channelId, limit int, timeout time.Duration) (bool, func(), error) {
+		return true, func() { released = true }, nil
+	}
+
+	selected, release, response := acquireDistributedChannelConcurrency(
+		newDistributorTestContext(),
+		&model.Channel{Id: 1, ConcurrencyLimit: 1},
+		"gpt-test",
+		"default",
+	)
+
+	require.Nil(t, response)
+	require.NotNil(t, selected)
+	require.Equal(t, 1, selected.Id)
+	require.NotNil(t, release)
+	release()
+	require.True(t, released)
+}
+
+func TestAcquireDistributedChannelConcurrencyUsesAnotherAvailableChannel(t *testing.T) {
+	restoreDistributorConcurrencyStubs(t)
+
+	checkChannelQuotaForDistribute = func(channelId int) error {
+		if channelId == 2 {
+			return nil
+		}
+		return nil
+	}
+	acquireChannelConcurrencyForDistribute = func(channelId, limit int) (bool, func()) {
+		if channelId == 2 {
+			return true, func() {}
+		}
+		return false, func() {}
+	}
+	cacheGetRandomSatisfiedChannelForDistribute = func(param *service.RetryParam) (*model.Channel, string, error) {
+		if _, excluded := param.ExcludedChannelIDs[1]; excluded {
+			return &model.Channel{Id: 2, ConcurrencyLimit: 1}, param.TokenGroup, nil
+		}
+		return nil, param.TokenGroup, errors.New("expected saturated channel to be excluded")
+	}
+	getChannelConcurrencyWaitPlanForDistribute = func() operation_setting.ChannelConcurrencyWaitPlanSetting {
+		return operation_setting.ChannelConcurrencyWaitPlanSetting{Enabled: false}
+	}
+
+	selected, release, response := acquireDistributedChannelConcurrency(
+		newDistributorTestContext(),
+		&model.Channel{Id: 1, ConcurrencyLimit: 1},
+		"gpt-test",
+		"default",
+	)
+
+	require.Nil(t, response)
+	require.NotNil(t, selected)
+	require.Equal(t, 2, selected.Id)
+	require.NotNil(t, release)
+	release()
+}

model/ability.go

@@ -104,6 +104,10 @@ func getChannelQuery(group string, model string, retry int) (*gorm.DB, error) {
 }
 
 func GetChannel(group string, model string, retry int) (*Channel, error) {
+	return GetChannelExcluding(group, model, retry, nil)
+}
+
+func GetChannelExcluding(group string, model string, retry int, excluded map[int]struct{}) (*Channel, error) {
 	var abilities []Ability
 
 	var err error = nil
@@ -111,6 +115,9 @@ func GetChannel(group string, model string, retry int) (*Channel, error) {
 	if err != nil {
 		return nil, err
 	}
+	if len(excluded) > 0 {
+		channelQuery = channelQuery.Where("channel_id NOT IN ?", excludedChannelIDList(excluded))
+	}
 	if common.UsingSQLite || common.UsingPostgreSQL {
 		err = channelQuery.Order("weight DESC").Find(&abilities).Error
 	} else {
@@ -143,6 +150,14 @@ func GetChannel(group string, model string, retry int) (*Channel, error) {
 	return &channel, err
 }
 
+func excludedChannelIDList(excluded map[int]struct{}) []int {
+	ids := make([]int, 0, len(excluded))
+	for id := range excluded {
+		ids = append(ids, id)
+	}
+	return ids
+}
+
 func (channel *Channel) AddAbilities(tx *gorm.DB) error {
 	models_ := strings.Split(channel.Models, ",")
 	groups_ := strings.Split(channel.Group, ",")

model/channel_cache.go

@@ -94,9 +94,13 @@ func SyncChannelCache(frequency int) {
 }
 
 func GetRandomSatisfiedChannel(group string, model string, retry int) (*Channel, error) {
+	return GetRandomSatisfiedChannelExcluding(group, model, retry, nil)
+}
+
+func GetRandomSatisfiedChannelExcluding(group string, model string, retry int, excluded map[int]struct{}) (*Channel, error) {
 	// if memory cache is disabled, get channel directly from database
 	if !common.MemoryCacheEnabled {
-		return GetChannel(group, model, retry)
+		return GetChannelExcluding(group, model, retry, excluded)
 	}
 
 	channelSyncLock.RLock()
@@ -111,6 +115,19 @@ func GetRandomSatisfiedChannel(group string, model string, retry int) (*Channel,
 		channels = group2model2channels[group][normalizedModel]
 	}
 
+	if len(channels) == 0 {
+		return nil, nil
+	}
+	if len(excluded) > 0 {
+		filtered := make([]int, 0, len(channels))
+		for _, channelId := range channels {
+			if _, ok := excluded[channelId]; !ok {
+				filtered = append(filtered, channelId)
+			}
+		}
+		channels = filtered
+	}
+
 	if len(channels) == 0 {
 		return nil, nil
 	}

service/channel_select.go

@@ -12,11 +12,12 @@ import (
 )
 
 type RetryParam struct {
-	Ctx          *gin.Context
+	Ctx                *gin.Context
-	TokenGroup   string
+	TokenGroup         string
-	ModelName    string
+	ModelName          string
-	Retry        *int
+	Retry              *int
-	resetNextTry bool
+	ExcludedChannelIDs map[int]struct{}
+	resetNextTry       bool
 }
 
 func (p *RetryParam) GetRetry() int {
@@ -115,7 +116,7 @@ func CacheGetRandomSatisfiedChannel(param *RetryParam) (*model.Channel, string,
 			}
 			logger.LogDebug(param.Ctx, "Auto selecting group: %s, priorityRetry: %d", autoGroup, priorityRetry)
 
-			channel, _ = model.GetRandomSatisfiedChannel(autoGroup, param.ModelName, priorityRetry)
+			channel, _ = getRandomSatisfiedChannel(autoGroup, param.ModelName, priorityRetry, param.ExcludedChannelIDs)
 			if channel == nil {
 				// Current group has no available channel for this model, try next group
 				// 当前分组没有该模型的可用渠道，尝试下一个分组
@@ -153,10 +154,17 @@ func CacheGetRandomSatisfiedChannel(param *RetryParam) (*model.Channel, string,
 			break
 		}
 	} else {
-		channel, err = model.GetRandomSatisfiedChannel(param.TokenGroup, param.ModelName, param.GetRetry())
+		channel, err = getRandomSatisfiedChannel(param.TokenGroup, param.ModelName, param.GetRetry(), param.ExcludedChannelIDs)
 		if err != nil {
 			return nil, param.TokenGroup, err
 		}
 	}
 	return channel, selectGroup, nil
 }
+
+func getRandomSatisfiedChannel(group string, modelName string, retry int, excluded map[int]struct{}) (*model.Channel, error) {
+	if len(excluded) == 0 {
+		return model.GetRandomSatisfiedChannel(group, modelName, retry)
+	}
+	return model.GetRandomSatisfiedChannelExcluding(group, modelName, retry, excluded)
+}

service/concurrency.go

@@ -8,15 +8,18 @@ import (
 	"time"
 
 	"github.com/QuantumNous/new-api/common"
+	"github.com/QuantumNous/new-api/setting/operation_setting"
 )
 
 const (
 	userConcurrencyKeyPrefix    = "user:concurrency:"
 	channelConcurrencyKeyPrefix = "channel:concurrency:"
+	channelWaitingKeyPrefix     = "channel:concurrency_waiting:"
 	userRPMKeyPrefix            = "user:rpm:"
 
 	concurrencyTTL = 5 * time.Minute
 	rpmTTL         = 2 * time.Minute
+	waitingTTL     = 2 * time.Minute
 )
 
 type OpsConcurrencySnapshot struct {
@@ -45,6 +48,70 @@ func AcquireChannelConcurrency(channelId, limit int) (bool, func()) {
 	return acquireConcurrency(channelConcurrencyKeyPrefix+strconv.Itoa(channelId), limit)
 }
 
+func GetChannelConcurrencyWaitPlan() operation_setting.ChannelConcurrencyWaitPlanSetting {
+	return operation_setting.GetChannelConcurrencyWaitPlanSetting()
+}
+
+func TryEnterChannelConcurrencyWaitQueue(channelId, maxWaiting int) (bool, func()) {
+	release := func() {}
+	if channelId <= 0 || maxWaiting <= 0 {
+		return false, release
+	}
+	if !redisAvailable() {
+		return true, release
+	}
+
+	ctx := context.Background()
+	key := channelWaitingKeyPrefix + strconv.Itoa(channelId)
+	count, err := common.RDB.Incr(ctx, key).Result()
+	if err != nil {
+		return true, release
+	}
+
+	release = func() {
+		if redisAvailable() {
+			_ = common.RDB.Decr(context.Background(), key).Err()
+		}
+	}
+	if err = common.RDB.Expire(ctx, key, waitingTTL).Err(); err != nil {
+		return true, release
+	}
+	if count > int64(maxWaiting) {
+		release()
+		return false, func() {}
+	}
+	return true, release
+}
+
+func WaitForChannelConcurrencySlot(ctx context.Context, channelId, limit int, timeout time.Duration) (bool, func(), error) {
+	release := func() {}
+	if timeout <= 0 {
+		return false, release, context.DeadlineExceeded
+	}
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
+	waitCtx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+
+	ticker := time.NewTicker(100 * time.Millisecond)
+	defer ticker.Stop()
+
+	for {
+		allowed, release := AcquireChannelConcurrency(channelId, limit)
+		if allowed {
+			return true, release, nil
+		}
+
+		select {
+		case <-waitCtx.Done():
+			return false, func() {}, waitCtx.Err()
+		case <-ticker.C:
+		}
+	}
+}
+
 func CheckUserRPM(userId, limit int) bool {
 	if limit <= 0 || !redisAvailable() {
 		return true

service/concurrency_wait_test.go

@@ -0,0 +1,26 @@
+package service
+
+import (
+	"context"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestTryEnterChannelConcurrencyWaitQueueRejectsWhenPlanDisabled(t *testing.T) {
+	canWait, release := TryEnterChannelConcurrencyWaitQueue(1, 0)
+
+	require.False(t, canWait)
+	require.NotNil(t, release)
+	release()
+}
+
+func TestWaitForChannelConcurrencySlotTimesOut(t *testing.T) {
+	ctx := context.Background()
+	acquired, release, err := WaitForChannelConcurrencySlot(ctx, 1, 1, 0)
+
+	require.False(t, acquired)
+	require.NotNil(t, release)
+	require.Error(t, err)
+	release()
+}

setting/operation_setting/channel_concurrency_wait_plan.go

@@ -0,0 +1,23 @@
+package operation_setting
+
+import "github.com/QuantumNous/new-api/setting/config"
+
+type ChannelConcurrencyWaitPlanSetting struct {
+	Enabled            bool `json:"enabled"`
+	TimeoutSeconds     int  `json:"timeout_seconds"`
+	MaxWaitingRequests int  `json:"max_waiting_requests"`
+}
+
+var channelConcurrencyWaitPlanSetting = ChannelConcurrencyWaitPlanSetting{
+	Enabled:            false,
+	TimeoutSeconds:     30,
+	MaxWaitingRequests: 100,
+}
+
+func init() {
+	config.GlobalConfig.Register("channel_concurrency_wait_plan", &channelConcurrencyWaitPlanSetting)
+}
+
+func GetChannelConcurrencyWaitPlanSetting() ChannelConcurrencyWaitPlanSetting {
+	return channelConcurrencyWaitPlanSetting
+}