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事件总线EventBridge支持事件内容转换，即在事件被路由到事件目标前，事件总线EventBridge可以把CloudEvents标准事件转换为事件目标能接收的事件类型。本文介绍事件总线EventBridge提供的事件转换类型。

背景信息

事件总线EventBridge支持的事件内容转换类型如下：

完整事件
部分事件
固定值
模板

完整事件

当转化类型为完整事件时，事件总线EventBridge不对事件进行转换，将原生CloudEvents的完整结构路由到事件目标。下表介绍经过完整事件转换前后的事件示例。

说明

更多CloudEvents相关信息，请参见CloudEvents 1.0。

转换前的事件

转换类型

转换后的事件

{
    "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****",
    "source":"acs.oss",
    "specversion":"1.0",
    "type":"oss:ObjectCreated:PostObject",
    "datacontenttype":"application/json",
    "dataschema":"http://example.com/test.json",
    "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg",
    "time":"2020-08-17T16:04:46.149Asia/Shanghai",
    "aliyuneventbusname":"demo-bus",
    "aliyunregionid":"Shanghai",
    "data":{
        "name":"test",
        "scope":100
    }
}

完整事件

{
    "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****",
    "source":"acs.oss",
    "specversion":"1.0",
    "type":"oss:ObjectCreated:PostObject",
    "datacontenttype":"application/json",
    "dataschema":"http://example.com/test.json",
    "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg",
    "time":"2020-08-17T16:04:46.149Asia/Shanghai",
    "aliyuneventbusname":"demo-bus",
    "aliyunregionid":"Shanghai",
    "data":{
        "name":"test",
        "scope":100
    }
}

部分事件

当转换类型为部分事件时，事件总线EventBridge通过JSONPath从CloudEvents中提取事件中的参数，将指定的事件内容路由到事件目标。下表介绍经过部分事件转换前后的事件示例。

转换前的事件

转换类型

转换后的事件

{
    "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****",
    "source":"acs.oss",
    "specversion":"1.0",
    "type":"oss:ObjectCreated:PostObject",
    "datacontenttype":"application/json",
    "dataschema":"http://example.com/test.json",
    "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg",
    "time":"2020-08-17T16:04:46.149Asia/Shanghai",
    "aliyuneventbusname":"demo-bus",
    "aliyunregionid":"Shanghai",
    "data":{
        "name":"test",
        "scope":100
    }
}

部分事件

$.data.name

说明

部分事件只支持定义一个变量。
value不超过10240个字符。

test

固定值

当转换类型为固定值时，事件只起到触发器的作用，不管事件内容是什么，事件总线EventBridge都把固定值路由到事件目标。下表介绍经过固定值转换前后的事件示例。

转换前的事件

转换类型

转换后的事件

{
    "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****",
    "source":"acs.oss",
    "specversion":"1.0",
    "type":"oss:ObjectCreated:PostObject",
    "datacontenttype":"application/json",
    "dataschema":"http://example.com/test.json",
    "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg",
    "time":"2020-08-17T16:04:46.149Asia/Shanghai",
    "aliyuneventbusname":"demo-bus",
    "aliyunregionid":"Shanghai",
    "data":{
        "name":"test",
        "scope":100
    }
}

固定值

test1

说明

value不超过10240个字符。

test1

模板

当转换类型为模板时，通过自定义模板、定义模板里需要的变量，事件总线EventBridge通过JSONPath从CloudEvents提取事件中的参数，把这些值存放在变量中，然后按照模板定义的格式路由到事件目标。下表介绍经过模板转换前后的事件示例。

转换前的事件

转换类型

转换后的事件

{
    "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****",
    "source":"acs.oss",
    "specversion":"1.0",
    "type":"oss:ObjectCreated:PostObject",
    "datacontenttype":"application/json",
    "dataschema":"http://example.com/test.json",
    "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg",
    "time":"2020-08-17T16:04:46.149Asia/Shanghai",
    "aliyuneventbusname":"demo-bus",
    "aliyunregionid":"Shanghai",
    "data":{
        "name":"test",
        "scope":100
    }
}

模板

变量
```
{
    "name":"$.data.name",
    "constant":"Please deal with it timely."
}
```
说明
- JSONPath提取的值可以是变量，也可以是固定值。
- 定义变量不支持嵌套多层结构。
- value不超过10240个字符。

模板

The instance is broken，which name is ${name}, ${constant}

说明

template最大为10240字符。

The instance is broken，which name is test, Please deal with it timely.

您也可以创建String格式和JSON格式的模板，通过自定义模板将事件转换成示例输出，然后路由到事件目标。以下为事件总线EventBridge支持的模板类型：

简单String
简单JSON
混合变量和固定值的JSON

表 1. 简单String
转换前的事件	转换类型	转换后的事件
`{ "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****", "source":"acs.oss", "specversion":"1.0", "type":"oss:ObjectCreated:PostObject", "datacontenttype":"application/json", "dataschema":"http://example.com/test.json", "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg", "time":"2020-08-17T16:04:46.149Asia/Shanghai", "aliyuneventbusname":"demo-bus", "aliyunregionid":"Shanghai", "data":{ "name":"test", "state":"RUNNING" } }`	模板变量 `{ "name":"$.data.name", "state":"$.data.state" }` 模板 `"name ${name} is in ${state}"`	`"name test is in RUNNING"`

转换前的事件

转换类型

转换后的事件

{
    "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****",
    "source":"acs.oss",
    "specversion":"1.0",
    "type":"oss:ObjectCreated:PostObject",
    "datacontenttype":"application/json",
    "dataschema":"http://example.com/test.json",
    "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg",
    "time":"2020-08-17T16:04:46.149Asia/Shanghai",
    "aliyuneventbusname":"demo-bus",
    "aliyunregionid":"Shanghai",
    "data":{
        "name":"test",
        "state":"RUNNING"
    }
}

模板

变量

{
    "name":"$.data.name",
    "state":"$.data.state"
}

模板
```
"name ${name} is in ${state}"
```

"name test is in RUNNING"

表 2. 简单JSON
转换前的事件	转换类型	转换后的事件
`{ "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****", "source":"acs.oss", "specversion":"1.0", "type":"oss:ObjectCreated:PostObject", "datacontenttype":"application/json", "dataschema":"http://example.com/test.json", "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg", "time":"2020-08-17T16:04:46.149Asia/Shanghai", "aliyuneventbusname":"demo-bus", "aliyunregionid":"Shanghai", "data":{ "name":"test", "state":"RUNNING" } }`	模板变量 `{ "name":"$.data.name", "state":"$.data.state" }` 模板 `{ "name":"${name}", "state":"${state}" }`	`{ "name":"test", "state":"RUNNING" }`

转换前的事件

转换类型

转换后的事件

{
    "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****",
    "source":"acs.oss",
    "specversion":"1.0",
    "type":"oss:ObjectCreated:PostObject",
    "datacontenttype":"application/json",
    "dataschema":"http://example.com/test.json",
    "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg",
    "time":"2020-08-17T16:04:46.149Asia/Shanghai",
    "aliyuneventbusname":"demo-bus",
    "aliyunregionid":"Shanghai",
    "data":{
        "name":"test",
        "state":"RUNNING"
    }
}

模板

变量

{
    "name":"$.data.name",
    "state":"$.data.state"
}

模板

{
    "name":"${name}",
    "state":"${state}"
}

{
    "name":"test",
    "state":"RUNNING"
}

表 3. 混合变量和固定值的JSON
转换前的事件	转换类型	转换后的事件
`{ "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****", "source":"acs.oss", "specversion":"1.0", "type":"oss:ObjectCreated:PostObject", "datacontenttype":"application/json", "dataschema":"http://example.com/test.json", "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg", "time":"2020-08-17T16:04:46.149Asia/Shanghai", "aliyuneventbusname":"demo-bus", "aliyunregionid":"Shanghai", "data":{ "name":"test", "state":"RUNNING" } }`	模板变量 `{ "name":"$.data.name", "state":"$.data.state" }` 模板 `{ "name":"${name}", "state":[ 9, "${state}", true ], "Transformed":"Yes" }`	`{ "name":"test", "state":[ 9, "RUNNING", true ], "Transformed":"Yes" }`

转换前的事件

转换类型

转换后的事件

{
    "id":"7adc8c1a-645d-4476-bdef-5d6fb57f****",
    "source":"acs.oss",
    "specversion":"1.0",
    "type":"oss:ObjectCreated:PostObject",
    "datacontenttype":"application/json",
    "dataschema":"http://example.com/test.json",
    "subject":"acs:oss:cn-hangzhou:1234567:xls-papk/game_apk/123.jpg",
    "time":"2020-08-17T16:04:46.149Asia/Shanghai",
    "aliyuneventbusname":"demo-bus",
    "aliyunregionid":"Shanghai",
    "data":{
        "name":"test",
        "state":"RUNNING"
    }
}

模板

变量

{
    "name":"$.data.name",
    "state":"$.data.state"
}

模板

{
    "name":"${name}",
    "state":[
        9,
        "${state}",
        true
    ],
    "Transformed":"Yes"
}

{
    "name":"test",
    "state":[
        9,
        "RUNNING",
        true
    ],
    "Transformed":"Yes"
}