Docs: add inputs and outputs in workflow (#266)

* Docs: add inputs and outputs in workflow

* optimize the en version

* fix the doc

docs/end-user/component-dependency-parameter.md

@@ -4,6 +4,50 @@ title:  Data Pass Between Components
 
 This section will introduce how to pass data between components.
 
+## Inputs and Outputs
+
+In KubeVela, we can use inputs and outputs in Components to pass data.
+
+### Outputs
+
+Outputs is made of `name` and `valueFrom`. Input will use `name` to reference output.
+
+We can write `valueFrom` in the following ways:
+1. Fill string value in the field, eg. `valueFrom: testString`.
+2. Use expression, eg. `valueFrom: output.metadata.name`. Note that `output` is a built-in field referring to the resource in the component that is rendered and deployed to the cluster.
+3. Use `+` to combine above two ways, the computed value will be the result, eg. `valueFrom: output.metadata.name + "testString"`.
+
+### Inputs
+
+Inputs is made of `name` and `parameterKey`. Input uses `name` to reference output, `parameterKey` is a expression that assigns the value of the input to the corresponding field.
+
+eg.
+
+1. Specify inputs:
+
+```yaml
+...
+- name: wordpress
+  type: helm
+  inputs:
+    - from: mysql-svc
+      parameterKey: properties.values.externalDatabase.host
+```
+
+2. The field parameterKey specifies the field path of the parameter key in component to be assigned after rendering:
+
+Which means the input value will be passed into the below properties:
+
+```yaml
+...
+- name: wordpress
+  type: helm
+  properties:
+    values:
+      externalDatabase:
+        host: <input value>
+```
+
 ## How to use
 
 In the following we will apply a WordPress server with the MySQL address passed from a MySQL component:

docs/platform-engineers/workflow/workflow.md

@@ -130,8 +130,8 @@ spec:
         type: my-helm
         outputs:
           - name: msg
-            # export the deployment status in my-helm
-            exportKey: resource.value.status.conditions[0].message
+            # get value from the deployment status in my-helm
+            valueFrom: resource.value.status.conditions[0].message
       - name: send-message
         type: webhook-notification
         inputs:

i18n/zh/docusaurus-plugin-content-docs/current/end-user/component-dependency-parameter.md

@@ -4,6 +4,47 @@ title:  应用组件间的依赖和参数传递
 
 本节将介绍如何在 KubeVela 中进行组件间的参数传递。
 
+## 参数传递
+
+在 KubeVela 中，可以在组件中通过 outputs 和 inputs 来指定要传输的数据。
+
+### Outputs
+
+outputs 由 `name` 和 `valueFrom` 组成。`name` 声明了这个 output 的名称，在 input 中将通过 `name` 引用 output。
+
+`valueFrom` 有以下几种写法：
+1. 直接通过字符串表示值，如：`valueFrom: testString`。
+2. 通过表达式来指定值，如：`valueFrom: output.metadata.name`。注意，`output` 为固定内置字段，指向组件中被部署在集群里的资源。
+3. 通过 `+` 来任意连接以上两种写法，最终值是计算后的字符串拼接结果，如：`valueFrom: output.metadata.name + "testString"`。
+
+### Inputs
+
+inputs 由 `name` 和 `parameterKey` 组成。`name` 声明了这个 input 从哪个 output 中取值，`parameterKey` 为一个表达式，将会把 input 取得的值赋给对应的字段。
+
+如：
+1. 指定 inputs:
+
+```yaml
+...
+- name: wordpress
+  type: helm
+  inputs:
+    - from: mysql-svc
+      parameterKey: properties.values.externalDatabase.host
+```
+
+2. 经过渲染后，该组件的 `properties.values.externalDatabase.host` 字段中会被赋上值，效果如下所示：
+
+```yaml
+...
+- name: wordpress
+  type: helm
+  properties:
+    values:
+      externalDatabase:
+        host: <input value>
+```
+
 ## 如何使用
 
 假设我们希望在本地启动一个 WordPress，而这个 Wordpress 的数据存放在一个 MySQL 数据库中，我们需要将这个 MySQL 的地址传递给 WordPress。
@@ -23,7 +64,7 @@ spec:
       outputs:
         # 将 service 地址作为 output
         - name: mysql-svc
-          exportKey: output.metadata.name + ".default.svc.cluster.local"
+          valueFrom: output.metadata.name + ".default.svc.cluster.local"
       properties:
         repoType: helm
         url: https://charts.bitnami.com/bitnami

i18n/zh/docusaurus-plugin-content-docs/current/platform-engineers/workflow/workflow.md

@@ -131,7 +131,7 @@ spec:
         outputs:
           - name: msg
             # 将 my-helm 中读取到的 deployment status 作为信息导出
-            exportKey: resource.value.status.conditions[0].message
+            valueFrom: resource.value.status.conditions[0].message
       - name: send-message
         type: webhook-notification
         inputs: