Fix concurrent map iteration & write issue

pkg/cover/store.go

@@ -287,7 +287,11 @@ func (l *memoryStore) Set(services map[string][]string) error {
 	l.mu.Lock()
 	defer l.mu.Unlock()
 
-	l.servicesMap = services
+	newMap := make(map[string][]string)
+	for k, v := range services {
+		newMap[k] = append(make([]string, 0), v...)
+	}
+	l.servicesMap = newMap
 
 	return nil
 }

pkg/cover/store_test.go

@@ -18,10 +18,10 @@ package cover
 
 import (
 	"fmt"
+	"github.com/stretchr/testify/assert"
 	"os"
 	"testing"
-
-	"github.com/stretchr/testify/assert"
+	"time"
 )
 
 func TestLocalStore(t *testing.T) {
@@ -130,3 +130,22 @@ func TestFileStoreRemove(t *testing.T) {
 	err = store.Remove("http")
 	assert.Error(t, err, fmt.Errorf("no service found"))
 }
+
+// verify issue fix https://github.com/golang/go/issues/56552
+func TestConcurrentRemoval(t *testing.T) {
+	store, _ := NewFileStore("_svrs_address.txt")
+	_ = store.Init()
+
+	for i := 0; i < 100; i++ {
+		_ = store.Add(ServiceUnderTest{
+			Name:    fmt.Sprintf("test%d", i),
+			Address: fmt.Sprintf("http://127.0.0.1:890%d", i),
+		})
+	}
+
+	for i := 0; i < 100; i++ {
+		go store.Remove(fmt.Sprintf("http://127.0.0.1:890%d", i))
+	}
+
+	time.Sleep(time.Second * 5) // if no issue then pass.
+}