# 事件内容转换 事件网格通过事件内容转换将CloudEvents标准事件转换成事件目标可以处理的类型。 事件网格支持的转换类型如下：透传、变量、常量。 #### 约束与限制 事件网格转换类型为变量时，事件流不支持将源端消息内容中的字段进行转换。 #### 透传 事件网格不对事件进行转换，将CloudEvents标准事件直接路由到事件目标。示例如下： | 转换前的事件 | 转换类型 | 转换后的事件 | |:---|:---|:---| | ``` { "events":[{ "id": "4b26115b-73e-cf74a******", "specversion": "1.0", "source": "HC.OBS", "type": "object:put", "datacontenttype": "application/json", "subject": "xxx.jpg", "time": "2022-01-17T12:07:48.955Z", "data": { "name": "test01", "state": "enable" } }] } ``` | 透传 | ``` { "events":[{ "id": "4b26115b-73e-cf74******", "specversion": "1.0", "source": "HC.OBS", "type": "object:put", "datacontenttype": "application/json", "subject": "xxx.jpg", "time": "2022-01-17T12:07:48.955Z", "data": { "name": "test01", "state": "enable" } }] } ``` | #### 变量 从CloudEvents标准事件中获取变量值，将变量值按照模板定义的格式路由到事件目标。示例如下： | 转换前的事件 | 转换类型 | 转换后的事件 | |:---|:---|:---| | ``` { "events":[{ "id": "4b26115b-73e-cf74a******", "specversion": "1.0", "source": "HC.OBS", "type": "object:put", "datacontenttype": "application/json", "subject": "xxx.jpg", "time": "2022-01-17T12:07:48.955Z", "data": { "name": "test01", "state": "enable" } }] } ``` | 参数 ``` {"name":"$.data.name"} ``` 模板 ``` My name is ${name} ``` 当事件目标为"FunctionGraph（函数计算）"，模板需为JSON格式，示例如下： ``` {"name":"${name}"} ``` | ``` My name is test01 ``` 说明： 当事件目标为"FunctionGraph（函数计算）"，转换后的事件结果如下： ``` {"name": "test01"} ``` | 例子: 从OBS-\>EG-\>FG全链路中复杂转换内容举例: | 转换前的事件 | 转换类型 | 转换后的事件 | |:---|:---|:---| | ``` { "specversion": "1.0", "id": "******9db447aa3******", "source": "HC.OBS.DWR", "type": "OBS:DWR:ObjectCreated:PUT", "datacontenttype": "application/json", "dataschema": "", "subject": "test.txt", "time": "2023-08-01T11:41:51.712759419Z", "ttl": "4000", "data": { "eventVersion": "3.0", "eventSource": "OBS", "eventRegion": "cn-north-4", "eventTime": "2023-08-01T19:41:47.879Z", "eventName": "ObjectCreated:Put", "userIdentity": { "ID": "******fef0f08c******" }, "requestParameters": { "sourceIPAddress": "1**.1**.1**.1**" }, "responseElements": { "x-obs-request-id": "******47aa3cdafb******", "x-obs-id-2": "", "x-amz-request-id": "", "x-amz-id-2": "" }, "obs": { "Version": "1.0", "configurationId": "******4aaac1******", "bucket": { "name": "test", "ownerIdentity": { "ID": "******f1234567******" }, "bucket": "test", "arn": "" }, "object": { "key": "test.txt", "eTag": "******48ce552c3******", "size": 13, "versionId": "******BE7FFFF******", "sequencer": "1", "oldpsxpth": "" } } } } ``` | 参数 ``` { "eventVersion": "$.data.eventVersion", "eventTime": "$.data.eventTime", "requestParameters": "$.data.requestParameters.sourceIPAddress", "configurationId": "$.data.obs.configurationId", "eTag": "$.data.obs.object.eTag", "sequencer": "$.data.obs.object.sequencer", "key": "$.data.obs.object.key", "size": "$.data.obs.object.size", "arn": "$.data.obs.bucket.arn", "name": "$.data.obs.bucket.name", "ownerIdentity": "$.data.obs.bucket.ownerIdentity.ID", "Region": "$.data.eventRegion", "eventName": "$.type", "userIdentity": "$.data.userIdentity.ID" } ``` 模板 ``` { "Records": [ { "eventVersion": "${eventVersion}", "eventTime": "${eventTime}", "requestParameters": { "sourceIPAddress": "${requestParameters}" }, "obs": { "configurationId": "${configurationId}", "object": { "eTag": "${eTag}", "sequencer": "${sequencer}", "key": "${key}", "size": "${size}" }, "bucket": { "arn": "${arn}", "name": "${name}", "ownerIdentity": { "PrincipalId": "${ownerIdentity}" } } }, "Region": "${Region}", "eventName": "${eventName}", "userIdentity": { "principalId": "${userIdentity}" } } ] } ``` 模板的value值是取参数的key值。 | ``` { "Records": [ { "eventVersion": "3.0", "eventTime": "2023-08-01T19:41:47.879Z", "requestParameters": { "sourceIPAddress": "1**.1**.1**.1**" }, "obs": { "configurationId": "******4aaac1******", "object": { "eTag": "******48ce552c3******", "sequencer": "1", "key": "test.txt", "size": "13" }, "bucket": { "arn": "", "name": "test", "ownerIdentity": { "PrincipalId": "******f1234567******" } } }, "Region": "cn-north-4", "eventName": "OBS:DWR:ObjectCreated:PUT", "userIdentity": { "principalId": "******fef0f08c******" } } ] } ``` | #### 常量 事件只能触发事件目标，但是不会传送事件内容到事件目标，事件网格将您设置的常量路由到事件目标。示例如下： | 转换前的事件 | 规则配置 | 转换后的事件 | |:---|:---|:---| | ``` { "events":[{ "id": "4b26115b-73cf74a******", "specversion": "1.0", "source": "HC.OBS", "type": "object:put", "datacontenttype": "application/json", "subject": "xxx.jpg", "time": "2022-01-17T12:07:48.955Z", "data": { "name": "test01", "state": "enable" } }] } ``` | 参数 ``` test01 ``` 当事件目标为"FunctionGraph（函数计算）"，规则配置参数需为JSON格式，示例如下： ``` {"name": "test01"} ``` | ``` test01 ``` 说明： 当事件目标为"FunctionGraph（函数计算）"，转换后的事件结果如下： ``` {"name": "test01"} ``` | #### 其他示例 1. 在创建事件订阅-[配置事件源](https://support.huaweicloud.com/usermanual-eg/eg-ug-007.html#eg-ug-007__li5331195351415)为"分布式消息服务RabbitMQ版"或"分布式消息服务RocketMQ版"，消息转换为CloudEvents格式事件后，data字段下将包含context字段，在创建事件订阅-[配置事件目标](https://support.huaweicloud.com/usermanual-eg/eg-ug-007.html#eg-ug-007__li15471118342)，规则类型配置为"变量"时，规则必须包含context字段，示例如下： | 转换前的事件 | 转换类型 | 转换后的事件 | |:---|:---|:---| | ``` { "type": "ROCKETMQ:CloudTrace:RocketmqCall", "data": { "context": { "name": "test01", "state": "enable" } }, "source": "zhang_roc", "time": "2023-02-01T10:47:07Z", "datacontenttype": "application/json", "specversion": "1.0", "id": "2f885496-570c-4925-82fd-d1ad09******", "subject": "ROCKETMQ:cn-north-7:eec88b34-9470-483e-8961-edb168******/0de095e33e00d36e2fd2c0019a******:ROCKETMQ:zhang_roc" } ``` | 参数 ``` {"name":"$.data.context.name"} ``` 模板 ``` My name is ${name} ``` | ``` My name is test01 ``` | 2. 在创建事件订阅-[配置事件目标](https://support.huaweicloud.com/usermanual-eg/eg-ug-007.html#eg-ug-007__li15471118342)，事件目标配置为"FunctionGraph（函数计算）"时，若内容转换规则配置为"透传"，无法将事件内容作为输入值传递至事件目标。如需将事件内容作为函数流输入值，可以通过"变量"或"常量"的内容转换规则，规则必须包含input字段，示例如下： 表1变量示例 | 转换前的事件 | 规则配置 | 转换后的事件 | |:---|:---|:---| | ``` { "events":[{ "id": "4b26115b-73cf74a******", "specversion": "1.0", "source": "HC.OBS", "type": "object:put", "datacontenttype": "application/json", "subject": "xxx.jpg", "time": "2022-01-17T12:07:48.955Z", "data": { "name": "test01", "state": "enable" } }] } ``` | 变量 ``` {"data": "$.data"} ``` 模板 ``` {"input": ${data}} ``` | ``` { "input": { "name": "test01", "state": "enable" } } ``` | 表2常量示例 | 转换前的事件 | 规则配置 | 转换后的事件 | |:---|:---|:---| | ``` { "events":[{ "id": "4b26115b-73cf74a******", "specversion": "1.0", "source": "HC.OBS", "type": "object:put", "datacontenttype": "application/json", "subject": "xxx.jpg", "time": "2022-01-17T12:07:48.955Z", "data": { "name": "test01", "state": "enable" } }] } ``` | 常量 ``` { "input": { "name": "test01" } } ``` | ``` { "input": { "name": "test01" } } ``` |