add some locks

grain-pool.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"log"
+	"sync"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
@@ -36,6 +37,7 @@ type Ttl struct {
 }
 
 type GrainLocalPool struct {
+	mu       sync.RWMutex
 	grains   map[CartId]*CartGrain
 	expiry   []Ttl
 	spawn    func(id CartId) (*CartGrain, error)
@@ -62,6 +64,8 @@ func NewGrainLocalPool(size int, ttl time.Duration, spawn func(id CartId) (*Cart
 }
 
 func (p *GrainLocalPool) SetAvailable(availableWithLastChangeUnix map[CartId]int64) {
+	p.mu.Lock()
+	defer p.mu.Unlock()
 	for id := range availableWithLastChangeUnix {
 		if _, ok := p.grains[id]; !ok {
 			p.grains[id] = nil
@@ -76,6 +80,8 @@ func (p *GrainLocalPool) SetAvailable(availableWithLastChangeUnix map[CartId]int
 func (p *GrainLocalPool) Purge() {
 	lastChangeTime := time.Now().Add(-p.Ttl)
 	keepChanged := lastChangeTime.Unix()
+	p.mu.Lock()
+	defer p.mu.Unlock()
 	for i := 0; i < len(p.expiry); i++ {
 		item := p.expiry[i]
 		if item.Expires.Before(time.Now()) {
@@ -100,6 +106,8 @@ func (p *GrainLocalPool) GetGrains() map[CartId]*CartGrain {
 
 func (p *GrainLocalPool) GetGrain(id CartId) (*CartGrain, error) {
 	var err error
+	p.mu.RLock()
+	defer p.mu.RUnlock()
 	grain, ok := p.grains[id]
 	grainLookups.Inc()
 	if grain == nil || !ok {