Add sample for concurrent request limitation

apier/v1/accounts.go

@@ -38,6 +38,11 @@ type AccountActionTiming struct {
 }
 
 func (apierSv1 *APIerSv1) GetAccountActionPlan(attrs *utils.TenantAccount, reply *[]*AccountActionTiming) error {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
+
 	if missing := utils.MissingStructFields(attrs, []string{"Tenant", "Account"}); len(missing) != 0 {
 		return utils.NewErrMandatoryIeMissing(strings.Join(missing, ","), "")
 	}
@@ -86,6 +91,10 @@ type AttrRemoveActionTiming struct {
 
 // Removes an ActionTimings or parts of it depending on filters being set
 func (apierSv1 *APIerSv1) RemoveActionTiming(attrs *AttrRemoveActionTiming, reply *string) (err error) {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
 	if missing := utils.MissingStructFields(attrs, []string{"ActionPlanId"}); len(missing) != 0 { // Only mandatory ActionPlanId
 		return utils.NewErrMandatoryIeMissing(missing...)
 	}
@@ -173,6 +182,10 @@ func (apierSv1 *APIerSv1) RemoveActionTiming(attrs *AttrRemoveActionTiming, repl
 
 // Ads a new account into dataDb. If already defined, returns success.
 func (apierSv1 *APIerSv1) SetAccount(attr *utils.AttrSetAccount, reply *string) (err error) {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
 	if missing := utils.MissingStructFields(attr, []string{"Tenant", "Account"}); len(missing) != 0 {
 		return utils.NewErrMandatoryIeMissing(missing...)
 	}
@@ -294,6 +307,10 @@ func (apierSv1 *APIerSv1) SetAccount(attr *utils.AttrSetAccount, reply *string)
 }
 
 func (apierSv1 *APIerSv1) RemoveAccount(attr *utils.AttrRemoveAccount, reply *string) (err error) {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
 	if missing := utils.MissingStructFields(attr, []string{"Tenant", "Account"}); len(missing) != 0 {
 		return utils.NewErrMandatoryIeMissing(missing...)
 	}
@@ -352,6 +369,10 @@ func (apierSv1 *APIerSv1) RemoveAccount(attr *utils.AttrRemoveAccount, reply *st
 }
 
 func (apierSv1 *APIerSv1) GetAccounts(attr *utils.AttrGetAccounts, reply *[]interface{}) error {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
 	if len(attr.Tenant) == 0 {
 		return utils.NewErrMandatoryIeMissing("Tenant")
 	}
@@ -421,9 +442,17 @@ type AttrAddBalance struct {
 }
 
 func (apierSv1 *APIerSv1) AddBalance(attr *AttrAddBalance, reply *string) error {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
 	return apierSv1.modifyBalance(utils.TOPUP, attr, reply)
 }
 func (apierSv1 *APIerSv1) DebitBalance(attr *AttrAddBalance, reply *string) error {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
 	return apierSv1.modifyBalance(utils.DEBIT, attr, reply)
 }
 
@@ -501,6 +530,10 @@ func (apierSv1 *APIerSv1) modifyBalance(aType string, attr *AttrAddBalance, repl
 // SetBalance sets the balance for the given account
 // if the account is not already created it will create the account also
 func (apierSv1 *APIerSv1) SetBalance(attr *utils.AttrSetBalance, reply *string) (err error) {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
 	if missing := utils.MissingStructFields(attr, []string{"Tenant", "Account", "BalanceType"}); len(missing) != 0 {
 		return utils.NewErrMandatoryIeMissing(missing...)
 	}
@@ -573,6 +606,10 @@ func (apierSv1 *APIerSv1) SetBalance(attr *utils.AttrSetBalance, reply *string)
 
 // RemoveBalances remove the matching balances for the account
 func (apierSv1 *APIerSv1) RemoveBalances(attr *utils.AttrSetBalance, reply *string) (err error) {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
 	if missing := utils.MissingStructFields(attr, []string{"Tenant", "Account", "BalanceType"}); len(missing) != 0 {
 		return utils.NewErrMandatoryIeMissing(missing...)
 	}
@@ -607,6 +644,10 @@ func (apierSv1 *APIerSv1) RemoveBalances(attr *utils.AttrSetBalance, reply *stri
 }
 
 func (apierSv1 *APIerSv1) GetAccountsCount(attr *utils.TenantArg, reply *int) (err error) {
+	if err := config.ConReqs().VerifyAndGet(); err != nil {
+		return err
+	}
+	defer config.ConReqs().Putback()
 	if len(attr.Tenant) == 0 {
 		return utils.NewErrMandatoryIeMissing("Tenant")
 	}

config/concureqs.go

@@ -0,0 +1,63 @@
+/*
+Real-time Online/Offline Charging System (OCS) for Telecom & ISP environments
+Copyright (C) ITsysCOM GmbH
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>
+*/
+
+package config
+
+import (
+	"fmt"
+
+	"github.com/cgrates/cgrates/utils"
+)
+
+type ConcReqs struct {
+	aReqs    chan struct{}
+	nAReqs   int
+	strategy string
+}
+
+func NewConReqs(reqs int, strategy string) *ConcReqs {
+	return &ConcReqs{
+		aReqs:    make(chan struct{}, reqs),
+		nAReqs:   reqs,
+		strategy: strategy,
+	}
+}
+
+func (cR *ConcReqs) VerifyAndGet() (err error) {
+	if cR.nAReqs == 0 {
+		return
+	}
+	switch cR.strategy {
+	case utils.MetaBusy:
+		if len(cR.aReqs) == 0 {
+			return fmt.Errorf("denying request due to maximum active requests reached")
+		}
+		fallthrough
+	case utils.MetaQueue:
+		<-cR.aReqs // get from channel
+	}
+	return
+}
+
+func (cR *ConcReqs) Putback() {
+	if cR.nAReqs == 0 {
+		return
+	}
+	cR.aReqs <- struct{}{}
+	return
+}

config/config.go

@@ -46,6 +46,7 @@ var (
 	dfltAstConnCfg           *AsteriskConnCfg
 	dfltLoaderConfig         *LoaderSCfg
 	dfltLoaderDataTypeConfig *LoaderDataType
+	conReqs                  *ConcReqs
 )
 
 func newDbDefaults() dbDefaults {
@@ -119,6 +120,7 @@ func (dbDflt dbDefaults) dbPass(dbType string, flagInput string) string {
 func init() {
 	cgrCfg, _ = NewDefaultCGRConfig()
 	dbDefaultsCfg = newDbDefaults()
+	conReqs = NewConReqs(cgrCfg.generalCfg.ConcurrentRequests, cgrCfg.generalCfg.ConcurrentStrategy)
 }
 
 // CgrConfig is used to retrieve system configuration from other packages
@@ -126,6 +128,11 @@ func CgrConfig() *CGRConfig {
 	return cgrCfg
 }
 
+// ConReqs is used to retrieve system ConcurrentRequests counter from other packages
+func ConReqs() *ConcReqs {
+	return conReqs
+}
+
 // SetCgrConfig is used to set system configuration from other places
 func SetCgrConfig(cfg *CGRConfig) {
 	cgrCfg = cfg
@@ -241,6 +248,7 @@ func NewCGRConfigFromPath(path string) (cfg *CGRConfig, err error) {
 		return
 	}
 	err = cfg.checkConfigSanity()
+	conReqs = NewConReqs(cfg.generalCfg.ConcurrentRequests, cfg.generalCfg.ConcurrentStrategy)
 	return
 }
 

utils/consts.go

@@ -767,6 +767,8 @@ const (
 	RateS                    = "RateS"
 	Underline                = "_"
 	MetaPartial              = "*partial"
+	MetaBusy                 = "*busy"
+	MetaQueue                = "*queue"
 )
 
 // Migrator Action