query market config with cache

pkg/bbgo/cache.go

@@ -0,0 +1,52 @@
+package bbgo
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+	"path"
+	"reflect"
+
+	"github.com/pkg/errors"
+)
+
+func WithCache(file string, obj interface{}, do func() (interface{}, error)) error {
+	cacheDir := CacheDir()
+	cacheFile := path.Join(cacheDir, file)
+
+	if _, err := os.Stat(cacheFile); os.IsNotExist(err) {
+		data, err := do()
+		if err != nil {
+			return err
+		}
+
+		out, err := json.Marshal(data)
+		if err != nil {
+			return err
+		}
+
+		if err := ioutil.WriteFile(cacheFile, out, 0666); err != nil {
+			return err
+		}
+
+		rv := reflect.ValueOf(obj).Elem()
+		if !rv.CanSet() {
+			return errors.New("can not set cache object value")
+		}
+
+		rv.Set(reflect.ValueOf(data))
+
+	} else {
+
+		data, err := ioutil.ReadFile(cacheFile)
+		if err != nil {
+			return err
+		}
+
+		if err := json.Unmarshal(data, obj); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

pkg/bbgo/environment.go

@@ -2,10 +2,12 @@ package bbgo
 
 import (
 	"context"
+	"fmt"
 	"strings"
 	"time"
 
 	"github.com/jmoiron/sqlx"
+	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
 	"github.com/spf13/viper"
 
@@ -59,11 +61,19 @@ func (environ *Environment) AddExchange(name string, exchange types.Exchange) (s
 
 func (environ *Environment) Init(ctx context.Context) (err error) {
 	for _, session := range environ.sessions {
-		markets, err := session.Exchange.QueryMarkets(ctx)
+		var markets types.MarketMap
+
+		err = WithCache(fmt.Sprintf("%s-markets.json", session.Exchange.Name()), &markets, func() (interface{}, error) {
+			return session.Exchange.QueryMarkets(ctx)
+		})
 		if err != nil {
 			return err
 		}
 
+		if len(markets) == 0 {
+			return errors.Errorf("market config should not be empty")
+		}
+
 		session.markets = markets
 		session.Account = &types.Account{}
 		session.Stream = session.Exchange.NewStream()