fix: limit number of concurrent requests

go.mod

@@ -65,6 +65,7 @@ require (
 	github.com/wealdtech/go-ens/v3 v3.5.0
 	github.com/wealdtech/go-multicodec v1.4.0
 	github.com/xeipuuv/gojsonschema v1.2.0
+	github.com/zenthangplus/goccm v0.0.0-20211005163543-2f2e522aca15
 	go.uber.org/zap v1.19.0
 	golang.org/x/crypto v0.0.0-20211202192323-5770296d904e
 	golang.org/x/image v0.0.0-20210220032944-ac19c3e999fb

go.sum

@@ -1308,6 +1308,8 @@ github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9de
 github.com/yuin/goldmark v1.1.32/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
 github.com/yuin/goldmark v1.3.5/go.mod h1:mwnBkeHKe2W/ZEtQ+71ViKU8L12m81fl3OWwC1Zlc8k=
+github.com/zenthangplus/goccm v0.0.0-20211005163543-2f2e522aca15 h1:0UwX38TojH86Dl0n4OwPMNYy8hNs2NhtzwY4RlvANlA=
+github.com/zenthangplus/goccm v0.0.0-20211005163543-2f2e522aca15/go.mod h1:DUzu/BC4TkgUfXP8J1P6Md73Djt+0l0CHq001Pt4weA=
 gitlab.com/nyarla/go-crypt v0.0.0-20160106005555-d9a5dc2b789b/go.mod h1:T3BPAOm2cqquPa0MKWeNkmOM5RQsRhkrwMWonFMN7fE=
 go.etcd.io/bbolt v1.3.3/go.mod h1:IbVyRI1SCnLcuJnV2u8VeU0CEYM7e686BmAb1XKL+uU=
 go.etcd.io/etcd v0.0.0-20191023171146-3cf2f69b5738/go.mod h1:dnLIgRNXwCJa5e+c6mIZCrds/GIG4ncV9HhK5PX7jPg=

services/stickers/api.go

@@ -7,12 +7,12 @@ import (
 	"io/ioutil"
 	"math/big"
 	"net/http"
-	"sync"
 	"time"
 
 	"github.com/ipfs/go-cid"
 	"github.com/multiformats/go-multibase"
 	"github.com/wealdtech/go-multicodec"
+	"github.com/zenthangplus/goccm"
 	"olympos.io/encoding/edn"
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
@@ -31,6 +31,7 @@ import (
 )
 
 const ipfsGateway = ".ipfs.cf-ipfs.com"
+const maxConcurrentRequests = 3
 
 // ConnectionType constants
 type stickerStatus int
@@ -104,7 +105,6 @@ func NewAPI(ctx context.Context, appDB *sql.DB, rpcClient *rpc.Client, accountsM
 
 func (api *API) Market(chainID uint64) ([]StickerPack, error) {
 	// TODO: eventually this should be changed to include pagination
-
 	accounts, err := api.accountsDB.GetAccounts()
 	if err != nil {
 		return nil, err
@@ -163,13 +163,17 @@ func (api *API) execTokenPackID(chainID uint64, tokenIDs []*big.Int, resultChan
 		return
 	}
 
+	if len(tokenIDs) == 0 {
+		return
+	}
+
 	callOpts := &bind.CallOpts{Context: api.ctx, Pending: false}
 
-	wg := sync.WaitGroup{}
+	c := goccm.New(maxConcurrentRequests)
-	wg.Add(len(tokenIDs))
 	for _, tokenID := range tokenIDs {
+		c.Wait()
 		go func(tokenID *big.Int) {
-			defer wg.Done()
+			defer c.Done()
 			packID, err := stickerPack.TokenPackId(callOpts, tokenID)
 			if err != nil {
 				errChan <- err
@@ -178,7 +182,7 @@ func (api *API) execTokenPackID(chainID uint64, tokenIDs []*big.Int, resultChan
 			resultChan <- packID
 		}(tokenID)
 	}
-	wg.Wait()
+	c.WaitAllDone()
 }
 
 func (api *API) getTokenPackIDs(chainID uint64, tokenIDs []*big.Int) ([]*big.Int, error) {
@@ -292,11 +296,15 @@ func (api *API) fetchStickerPacks(chainID uint64, resultChan chan<- *StickerPack
 		return
 	}
 
-	wg := sync.WaitGroup{}
+	if numPacks.Uint64() == 0 {
-	wg.Add(int(numPacks.Int64()))
+		return
+	}
+
+	c := goccm.New(maxConcurrentRequests)
 	for i := uint64(0); i < numPacks.Uint64(); i++ {
+		c.Wait()
 		go func(i uint64) {
-			defer wg.Done()
+			defer c.Done()
 
 			packID := new(big.Int).SetUint64(i)
 
@@ -319,7 +327,7 @@ func (api *API) fetchStickerPacks(chainID uint64, resultChan chan<- *StickerPack
 			resultChan <- stickerPack
 		}(i)
 	}
-	wg.Wait()
+	c.WaitAllDone()
 }
 
 func (api *API) fetchPackData(stickerType *stickers.StickerType, packID *big.Int, translateHashes bool) (*StickerPack, error) {
@@ -469,11 +477,15 @@ func (api *API) getAccountsPurchasedPack(chainID uint64, accs []accounts.Account
 	defer close(errChan)
 	defer close(resultChan)
 
-	wg := sync.WaitGroup{}
+	if len(accs) == 0 {
-	wg.Add(len(accs))
+		return
+	}
+
+	c := goccm.New(maxConcurrentRequests)
 	for _, account := range accs {
+		c.Wait()
 		go func(acc accounts.Account) {
-			defer wg.Done()
+			defer c.Done()
 			packs, err := api.getPurchasedPackIDs(chainID, acc.Address)
 			if err != nil {
 				errChan <- err
@@ -485,7 +497,7 @@ func (api *API) getAccountsPurchasedPack(chainID uint64, accs []accounts.Account
 			}
 		}(account)
 	}
-	wg.Wait()
+	c.WaitAllDone()
 }
 
 func (api *API) execTokenOwnerOfIndex(chainID uint64, account types.Address, balance *big.Int, resultChan chan<- *big.Int, errChan chan<- error, doneChan chan<- struct{}) {
@@ -499,13 +511,17 @@ func (api *API) execTokenOwnerOfIndex(chainID uint64, account types.Address, bal
 		return
 	}
 
+	if balance.Int64() == 0 {
+		return
+	}
+
 	callOpts := &bind.CallOpts{Context: api.ctx, Pending: false}
 
-	wg := sync.WaitGroup{}
+	c := goccm.New(maxConcurrentRequests)
-	wg.Add(int(balance.Int64()))
 	for i := uint64(0); i < balance.Uint64(); i++ {
+		c.Wait()
 		go func(i uint64) {
-			defer wg.Done()
+			defer c.Done()
 			tokenID, err := stickerPack.TokenOfOwnerByIndex(callOpts, common.Address(account), new(big.Int).SetUint64(i))
 			if err != nil {
 				errChan <- err
@@ -515,7 +531,7 @@ func (api *API) execTokenOwnerOfIndex(chainID uint64, account types.Address, bal
 			resultChan <- tokenID
 		}(i)
 	}
-	wg.Wait()
+	c.WaitAllDone()
 }
 
 func (api *API) getTokenOwnerOfIndex(chainID uint64, account types.Address, balance *big.Int) ([]*big.Int, error) {

vendor/github.com/zenthangplus/goccm/.gitignore

@@ -0,0 +1 @@
+.idea

vendor/github.com/zenthangplus/goccm/.travis.yml

@@ -0,0 +1,16 @@
+language: go
+
+go:
+  - 1.x
+  - 1.10.x
+  - 1.11.x
+  - 1.12.x
+
+before_install:
+  - go get -t -v ./...
+
+script:
+  - go test -coverprofile=coverage.txt -covermode=atomic
+
+after_success:
+  - bash <(curl -s https://codecov.io/bash)

vendor/github.com/zenthangplus/goccm/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2019 ZENTHANG
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/zenthangplus/goccm/README.md

@@ -0,0 +1,76 @@
+# Golang Concurrency Manager [![Build Status](https://travis-ci.com/zenthangplus/goccm.svg?branch=master)](https://travis-ci.com/zenthangplus/goccm)
+
+Golang Concurrency Manager package limits the number of goroutines that are allowed to run concurrently.
+
+### Installation
+
+Run the following command to install this package:
+
+```
+$ go get -u github.com/zenthangplus/goccm
+```
+
+### Example
+
+```go
+package main
+
+import (
+    "fmt"
+    "github.com/zenthangplus/goccm"
+    "time"
+)
+
+func main()  {
+    // Limit 3 goroutines to run concurrently.
+    c := goccm.New(3)
+    
+    for i := 1; i <= 10; i++ {
+    	
+        // This function has to call before any goroutine
+        c.Wait()
+        
+        go func(i int) {
+            fmt.Printf("Job %d is running\n", i)
+            time.Sleep(2 * time.Second)
+            
+            // This function has to when a goroutine has finished
+            // Or you can use `defer c.Done()` at the top of goroutine.
+            c.Done()
+        }(i)
+    }
+    
+    // This function has to call to ensure all goroutines have finished 
+    // after close the main program.
+    c.WaitAllDone()
+}
+```
+
+### List of supported functions
+
+```go
+package main
+
+import "github.com/zenthangplus/goccm"
+
+func main() {
+    // Create the concurrency manager
+    // The first argument is the maximum number of goroutines to run concurrently.
+    c := goccm.New(10)
+    
+    // Wait until a slot is available for the new goroutine.
+    c.Wait()
+    
+    // Mark a goroutine as finished
+    c.Done()
+    
+    // Wait for all goroutines are done
+    c.WaitAllDone()
+    
+    // Close the manager manually
+    c.Close()
+    
+    // Returns the number of goroutines which are running
+    c.RunningCount()
+}
+```

vendor/github.com/zenthangplus/goccm/go.mod

@@ -0,0 +1,3 @@
+module github.com/zenthangplus/goccm
+
+go 1.14

vendor/github.com/zenthangplus/goccm/goccm.go

@@ -0,0 +1,124 @@
+package goccm
+
+import "sync/atomic"
+
+type (
+	// ConcurrencyManager Interface
+	ConcurrencyManager interface {
+		// Wait until a slot is available for the new goroutine.
+		Wait()
+
+		// Mark a goroutine as finished
+		Done()
+
+		// Close the manager manually
+		Close()
+
+		// Wait for all goroutines are done
+		WaitAllDone()
+
+		// Returns the number of goroutines which are running
+		RunningCount() int32
+	}
+
+	concurrencyManager struct {
+		// The number of goroutines that are allowed to run concurrently
+		max int
+
+		// The manager channel to coordinate the number of concurrent goroutines.
+		managerCh chan interface{}
+
+		// The done channel indicates when a single goroutine has finished its job.
+		doneCh chan bool
+
+		// This channel indicates when all goroutines have finished their job.
+		allDoneCh chan bool
+
+		// The close flag allows we know when we can close the manager
+		closed bool
+
+		// The running count allows we know the number of goroutines are running
+		runningCount int32
+	}
+)
+
+// New concurrencyManager
+func New(maxGoRoutines int) *concurrencyManager {
+	// Initiate the manager object
+	c := concurrencyManager{
+		max:       maxGoRoutines,
+		managerCh: make(chan interface{}, maxGoRoutines),
+		doneCh:    make(chan bool),
+		allDoneCh: make(chan bool),
+	}
+
+	// Fill the manager channel by placeholder values
+	for i := 0; i < c.max; i++ {
+		c.managerCh <- nil
+	}
+
+	// Start the controller to collect all the jobs
+	go c.controller()
+
+	return &c
+}
+
+// Create the controller to collect all the jobs.
+// When a goroutine is finished, we can release a slot for another goroutine.
+func (c *concurrencyManager) controller() {
+	for {
+		// This will block until a goroutine is finished
+		<-c.doneCh
+
+		// Say that another goroutine can now start
+		c.managerCh <- nil
+
+		// When the closed flag is set,
+		// we need to close the manager if it doesn't have any running goroutine
+		if c.closed == true && c.runningCount == 0 {
+			break
+		}
+	}
+
+	// Say that all goroutines are finished, we can close the manager
+	c.allDoneCh <- true
+}
+
+// Wait until a slot is available for the new goroutine.
+// A goroutine have to start after this function.
+func (c *concurrencyManager) Wait() {
+
+	// Try to receive from the manager channel. When we have something,
+	// it means a slot is available and we can start a new goroutine.
+	// Otherwise, it will block until a slot is available.
+	<-c.managerCh
+
+	// Increase the running count to help we know how many goroutines are running.
+	atomic.AddInt32(&c.runningCount, 1)
+}
+
+// Mark a goroutine as finished
+func (c *concurrencyManager) Done() {
+	// Decrease the number of running count
+	atomic.AddInt32(&c.runningCount, -1)
+	c.doneCh <- true
+}
+
+// Close the manager manually
+func (c *concurrencyManager) Close() {
+	c.closed = true
+}
+
+// Wait for all goroutines are done
+func (c *concurrencyManager) WaitAllDone() {
+	// Close the manager automatic
+	c.Close()
+
+	// This will block until allDoneCh was marked
+	<-c.allDoneCh
+}
+
+// Returns the number of goroutines which are running
+func (c *concurrencyManager) RunningCount() int32 {
+	return c.runningCount
+}

vendor/modules.txt

@@ -556,6 +556,8 @@ github.com/xeipuuv/gojsonpointer
 github.com/xeipuuv/gojsonreference
 # github.com/xeipuuv/gojsonschema v1.2.0
 github.com/xeipuuv/gojsonschema
+# github.com/zenthangplus/goccm v0.0.0-20211005163543-2f2e522aca15
+github.com/zenthangplus/goccm
 # go.opencensus.io v0.23.0
 go.opencensus.io/internal/tagencoding
 go.opencensus.io/metric/metricdata