diff --git a/index.js b/index.js
index 6b1f619..da1c3e3 100644
--- a/index.js
+++ b/index.js
@@ -59,7 +59,7 @@ module.exports = async (o_params) => {
     });
 
     /* mysql */
-    var mysql = alias => new Promise((resolve, reject) => {
+    var mysql = alias => {
         let m = require('mysql');
         let s = {};
         let res;
@@ -67,20 +67,20 @@ module.exports = async (o_params) => {
             s = JSON.parse(fs.readFileSync(params.mysql.dbKeysDir + '/' + alias));
         }catch(e){
             tool.log('In mysql part, cannot read dbKeys from '+params.mysql.dbKeysDir+'/'+alias); 
-            reject(e);
         }
         try{
             res = m.createConnection(s); 
         }catch(e){
             tool.log('In mysql part, cannot create connection.'); 
-            reject(e);
         }
-        resolve(res);
-    });
+        return res;
+    };
 
 
     return new Promise((resolve, reject) => {
         o.redis = redis;
         o.mysql = mysql;
+        
+        resolve(o);
     });
 }
diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..e0b5375
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,115 @@
+{
+  "name": "ushio-env",
+  "version": "1.0.0",
+  "lockfileVersion": 1,
+  "requires": true,
+  "dependencies": {
+    "bignumber.js": {
+      "version": "9.0.0",
+      "resolved": "https://registry.npmjs.org/bignumber.js/-/bignumber.js-9.0.0.tgz",
+      "integrity": "sha512-t/OYhhJ2SD+YGBQcjY8GzzDHEk9f3nerxjtfa6tlMXfe7frs/WozhvCNoGvpM0P3bNf3Gq5ZRMlGr5f3r4/N8A=="
+    },
+    "core-util-is": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/core-util-is/-/core-util-is-1.0.2.tgz",
+      "integrity": "sha1-tf1UIgqivFq1eqtxQMlAdUUDwac="
+    },
+    "denque": {
+      "version": "1.4.1",
+      "resolved": "https://registry.npmjs.org/denque/-/denque-1.4.1.tgz",
+      "integrity": "sha512-OfzPuSZKGcgr96rf1oODnfjqBFmr1DVoc/TrItj3Ohe0Ah1C5WX5Baquw/9U9KovnQ88EqmJbD66rKYUQYN1tQ=="
+    },
+    "inherits": {
+      "version": "2.0.4",
+      "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.4.tgz",
+      "integrity": "sha512-k/vGaX4/Yla3WzyMCvTQOXYeIHvqOKtnqBduzTHpzpQZzAskKMhZ2K+EnBiSM9zGSoIFeMpXKxa4dYeZIQqewQ=="
+    },
+    "isarray": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/isarray/-/isarray-1.0.0.tgz",
+      "integrity": "sha1-u5NdSFgsuhaMBoNJV6VKPgcSTxE="
+    },
+    "mysql": {
+      "version": "2.18.1",
+      "resolved": "https://registry.npmjs.org/mysql/-/mysql-2.18.1.tgz",
+      "integrity": "sha512-Bca+gk2YWmqp2Uf6k5NFEurwY/0td0cpebAucFpY/3jhrwrVGuxU2uQFCHjU19SJfje0yQvi+rVWdq78hR5lig==",
+      "requires": {
+        "bignumber.js": "9.0.0",
+        "readable-stream": "2.3.7",
+        "safe-buffer": "5.1.2",
+        "sqlstring": "2.3.1"
+      }
+    },
+    "process-nextick-args": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/process-nextick-args/-/process-nextick-args-2.0.1.tgz",
+      "integrity": "sha512-3ouUOpQhtgrbOa17J7+uxOTpITYWaGP7/AhoR3+A+/1e9skrzelGi/dXzEYyvbxubEF6Wn2ypscTKiKJFFn1ag=="
+    },
+    "readable-stream": {
+      "version": "2.3.7",
+      "resolved": "https://registry.npmjs.org/readable-stream/-/readable-stream-2.3.7.tgz",
+      "integrity": "sha512-Ebho8K4jIbHAxnuxi7o42OrZgF/ZTNcsZj6nRKyUmkhLFq8CHItp/fy6hQZuZmP/n3yZ9VBUbp4zz/mX8hmYPw==",
+      "requires": {
+        "core-util-is": "~1.0.0",
+        "inherits": "~2.0.3",
+        "isarray": "~1.0.0",
+        "process-nextick-args": "~2.0.0",
+        "safe-buffer": "~5.1.1",
+        "string_decoder": "~1.1.1",
+        "util-deprecate": "~1.0.1"
+      }
+    },
+    "redis": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/redis/-/redis-3.0.2.tgz",
+      "integrity": "sha512-PNhLCrjU6vKVuMOyFu7oSP296mwBkcE6lrAjruBYG5LgdSqtRBoVQIylrMyVZD/lkF24RSNNatzvYag6HRBHjQ==",
+      "requires": {
+        "denque": "^1.4.1",
+        "redis-commands": "^1.5.0",
+        "redis-errors": "^1.2.0",
+        "redis-parser": "^3.0.0"
+      }
+    },
+    "redis-commands": {
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/redis-commands/-/redis-commands-1.5.0.tgz",
+      "integrity": "sha512-6KxamqpZ468MeQC3bkWmCB1fp56XL64D4Kf0zJSwDZbVLLm7KFkoIcHrgRvQ+sk8dnhySs7+yBg94yIkAK7aJg=="
+    },
+    "redis-errors": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/redis-errors/-/redis-errors-1.2.0.tgz",
+      "integrity": "sha1-62LSrbFeTq9GEMBK/hUpOEJQq60="
+    },
+    "redis-parser": {
+      "version": "3.0.0",
+      "resolved": "https://registry.npmjs.org/redis-parser/-/redis-parser-3.0.0.tgz",
+      "integrity": "sha1-tm2CjNyv5rS4pCin3vTGvKwxyLQ=",
+      "requires": {
+        "redis-errors": "^1.0.0"
+      }
+    },
+    "safe-buffer": {
+      "version": "5.1.2",
+      "resolved": "https://registry.npmjs.org/safe-buffer/-/safe-buffer-5.1.2.tgz",
+      "integrity": "sha512-Gd2UZBJDkXlY7GbJxfsE8/nvKkUEU1G38c1siN6QP6a9PT9MmHB8GnpscSmMJSoF8LOIrt8ud/wPtojys4G6+g=="
+    },
+    "sqlstring": {
+      "version": "2.3.1",
+      "resolved": "https://registry.npmjs.org/sqlstring/-/sqlstring-2.3.1.tgz",
+      "integrity": "sha1-R1OT/56RR5rqYtyvDKPRSYOn+0A="
+    },
+    "string_decoder": {
+      "version": "1.1.1",
+      "resolved": "https://registry.npmjs.org/string_decoder/-/string_decoder-1.1.1.tgz",
+      "integrity": "sha512-n/ShnvDi6FHbbVfviro+WojiFzv+s8MPMHBczVePfUpDJLwoLT0ht1l4YwBCbi8pJAveEEdnkHyPyTP/mzRfwg==",
+      "requires": {
+        "safe-buffer": "~5.1.0"
+      }
+    },
+    "util-deprecate": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/util-deprecate/-/util-deprecate-1.0.2.tgz",
+      "integrity": "sha1-RQ1Nyfpw3nMnYvvS1KKJgUGaDM8="
+    }
+  }
+}
diff --git a/package.json b/package.json
index 1be5d85..05170d5 100644
--- a/package.json
+++ b/package.json
@@ -7,6 +7,7 @@
   "author": "iotcat <i@iotcat.me>",
   "license": "MIT",
   "dependencies": {
+    "fs": "^0.0.1-security",
     "mysql": "^2.18.1",
     "redis": "^3.0.2"
   }
diff --git a/test.js b/test.js
new file mode 100644
index 0000000..25d777a
--- /dev/null
+++ b/test.js
@@ -0,0 +1,7 @@
+
+(async ()=>{
+const u = await require(__dirname+'/index.js')();
+
+var m = u.mysql('test');
+m.connect();
+})()
diff --git a/yarn.lock b/yarn.lock
index c69f3b2..1f0028d 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -17,6 +17,11 @@ denque@^1.4.1:
   resolved "https://registry.yarnpkg.com/denque/-/denque-1.4.1.tgz#6744ff7641c148c3f8a69c307e51235c1f4a37cf"
   integrity sha512-OfzPuSZKGcgr96rf1oODnfjqBFmr1DVoc/TrItj3Ohe0Ah1C5WX5Baquw/9U9KovnQ88EqmJbD66rKYUQYN1tQ==
 
+fs@^0.0.1-security:
+  version "0.0.1-security"
+  resolved "https://registry.yarnpkg.com/fs/-/fs-0.0.1-security.tgz#8a7bd37186b6dddf3813f23858b57ecaaf5e41d4"
+  integrity sha1-invTcYa23d84E/I4WLV+yq9eQdQ=
+
 inherits@~2.0.3:
   version "2.0.4"
   resolved "https://registry.yarnpkg.com/inherits/-/inherits-2.0.4.tgz#0fa2c64f932917c3433a0ded55363aae37416b7c"