fix: add sls initialize before creating server

Author: yugasun

README.md

@@ -102,6 +102,32 @@ TENCENT_SECRET_ID=123
 TENCENT_SECRET_KEY=123
 ```
 
+### slsInitialize 应用初始化
+
+有些时候，Koa 服务在启动前，需要进行一个初始化操作，比如数据库建连，就可以通过在 Koa 实例对象上添加 `slsInitialize` 函数来实现，如下：
+
+```js
+const Koa = require('koa')
+const mysql = require('mysql2/promise')
+
+const app = new Koa()
+
+// ...
+
+app.slsInitialize = async () => {
+  app.db = await mysql.createConnection({
+    host: 'localhost',
+    user: 'root',
+    database: 'test'
+  })
+}
+
+// don't forget to export!
+module.exports = app
+```
+
+这样应用部署到云函数后，在函数服务逻辑执行前，会先执行 `slsInitialize()` 函数，来初始化数据库连接。
+
 ### 还支持哪些组件？
 
 可以在 [Serverless Components](https://github.com/serverless/components) repo 中查询更多组件的信息。

serverless.component.yml

@@ -1,5 +1,5 @@
 name: koa
-version: 0.3.1
+version: 0.3.2
 author: 'Tencent Cloud, Inc.'
 org: 'Tencent Cloud, Inc.'
 description: Deploy a serverless Koa.js application onto Tencent SCF and API Gateway.

src/_shims/handler.js

@@ -18,6 +18,10 @@ exports.handler = async (event, context) => {
   app.request.__SLS_EVENT__ = event
   app.request.__SLS_CONTEXT__ = context
 
+  if (app.slsInitialize && typeof app.slsInitialize === 'function') {
+    await app.slsInitialize()
+  }
+
   // cache server, not create repeatly
   if (!server) {
     server = createServer(app.callback(), null, app.binaryTypes || [])
@@ -26,10 +30,6 @@ exports.handler = async (event, context) => {
   context.callbackWaitsForEmptyEventLoop =
     app.callbackWaitsForEmptyEventLoop === true ? true : false
 
-  if (app.slsInitialize && typeof app.slsInitialize === 'function') {
-    await app.slsInitialize()
-  }
-
   const result = await proxy(server, event, context, 'PROMISE')
   return result.promise
 }

src/package.json

@@ -1,7 +1,7 @@
 {
   "dependencies": {
     "download": "^8.0.0",
-    "tencent-component-toolkit": "^1.19.8",
+    "tencent-component-toolkit": "^1.20.6",
     "type": "^2.1.0"
   }
 }