feat: added modules

core/utils/cache.go

@@ -0,0 +1,57 @@
+package utils
+
+import (
+	"github.com/crawlab-team/crawlab-db/mongo"
+	"github.com/crawlab-team/crawlab/core/constants"
+	"go.mongodb.org/mongo-driver/bson"
+	mongo2 "go.mongodb.org/mongo-driver/mongo"
+	"time"
+)
+
+func GetFromDbCache(key string, getFn func() (string, error)) (res string, err error) {
+	col := mongo.GetMongoCol(constants.CacheColName)
+
+	var d bson.M
+	if err := col.Find(bson.M{
+		constants.CacheColKey: key,
+	}, nil).One(&d); err != nil {
+		if err != mongo2.ErrNoDocuments {
+			return "", err
+		}
+
+		// get cache value
+		res, err = getFn()
+		if err != nil {
+			return "", err
+		}
+
+		// save cache
+		d = bson.M{
+			constants.CacheColKey:   key,
+			constants.CacheColValue: res,
+			constants.CacheColTime:  time.Now(),
+		}
+		if _, err := col.Insert(d); err != nil {
+			return "", err
+		}
+		return res, nil
+	}
+
+	// type conversion
+	r, ok := d[constants.CacheColValue]
+	if !ok {
+		if err := col.Delete(bson.M{constants.CacheColKey: key}); err != nil {
+			return "", err
+		}
+		return GetFromDbCache(key, getFn)
+	}
+	res, ok = r.(string)
+	if !ok {
+		if err := col.Delete(bson.M{constants.CacheColKey: key}); err != nil {
+			return "", err
+		}
+		return GetFromDbCache(key, getFn)
+	}
+
+	return res, nil
+}