An event is a data record of status changes. When a resource is created, a configuration is updated, or a user performs an action, the responsible service captures that change and publishes it to EventBridge.
All events conform to the CloudEvents 1.0 specification, an open standard maintained by the Cloud Native Computing Foundation (CNCF). This provides a consistent, portable event format across all event sources.
Event structure
Every event consists of two parts:
Context attributes: Metadata that identifies and describes the event (
source,type,id, and others defined by the CloudEvents spec).Data payload: The event content, which varies by event source.
The two most important fields are source and type, which together identify where the event came from and what happened:
{
"source": "acs:aliyuncvc",
"type": "aliyuncvc:MeetingEvent:MemberOperate",
...
}In this snippet, source identifies the originating service, and type identifies the specific event (a member operation in a meeting).
The following example shows a complete event published to EventBridge:
{
"specversion": "1.0",
"id": "45ef4dewdwe1-7c35-447a-bd93-fab****",
"source": "acs:aliyuncvc",
"type": "aliyuncvc:MeetingEvent:MemberOperate",
"subject": "acs.aliyuncvc:cn-hangzhou:{AccountId}:215672",
"time": "2020-11-19T21:04:41+08:00",
"data": {
"meetingName": "swqd",
"groupId": "456",
"action": "camera_off",
"time": 1590592527490,
"userId": "199525",
"meetingUUID": "hz-20864c8f-b10d-45cd-9935-884bca1b****"
},
"aliyunaccountid": "123456789098****",
"aliyunpublishtime": "2020-11-19T21:04:42.179PRC",
"aliyuneventbusname": "default",
"aliyunregionid": "cn-hangzhou",
"aliyunpublishaddr": "172.25.XX.XX"
}CloudEvents standard attributes
These attributes are defined by the CloudEvents 1.0 specification. EventBridge uses these attributes for event routing, querying, and deduplication.
Required attributes
id (String)
A unique identifier for the event. The combination of source + id must be unique for each distinct event. If the same event is re-sent due to a network error, it may carry the same id. Consumers consider events with identical source and id values as duplicates. EventBridge uses id to track events as they move through routing to targets.
Example: 45ef4dewdwe1-7c35-447a-bd93-fab****
source (String)
The service that produced the event. This value identifies the context in which the event occurred, including the event source type and publishing mechanism. Producers must make sure that source + id is unique for each event.
Example: acs:aliyuncvc
specversion (String)
The version of the CloudEvents specification that the event conforms to.
Example: 1.0
type (String)
The event type, related to the event source. EventBridge uses this value for event routing, querying, and policy enforcement. The producer defines the format, which may include version information.
Example: aliyuncvc:MeetingEvent:MemberOperate
Optional attributes
datacontenttype (String)
The content type of the data attribute. EventBridge supports only application/json;charset=utf-8.
dataschema (URI)
A URI that points to the schema of the data attribute.
subject (String)
The subject of the event within the context of the event source. Contains Alibaba Cloud Resource Names (ARNs) that identify the resources involved in the event. Use this attribute for subscription filtering when source alone is not specific enough.
Example: acs.aliyuncvc:cn-hangzhou:{AccountId}:215672
time (Timestamp)
The timestamp of when the event occurred. If the exact time is unknown, the producer may set this to another value such as the current time. However, all producers of the same source must set the source parameter to the same value.
Example: 2020-11-19T21:04:41+08:00
data (Struct)
The event payload. The event source determines the structure, which contains the details of what happened.
Alibaba Cloud extension attributes
EventBridge adds the following attributes to every event after receiving it. These attributes are not part of the CloudEvents specification.
| Attribute | Type | Required | Description | Example |
|---|---|---|---|---|
aliyunaccountid | String | No | Alibaba Cloud account ID of the event producer. | 123456789098**** |
aliyunpublishtime | Timestamp | No | Timestamp when EventBridge received the event. | 2020-11-19T21:04:42.179PRC |
aliyuneventbusname | String | Yes | Name of the event bus that received the event. | default |
aliyunregionid | String | No | Region where EventBridge received the event. | cn-hangzhou |
aliyunpublishaddr | String | No | IP address of the EventBridge server that received the event. | 172.25.XX.XX |
Event types
EventBridge supports two categories of events:
Alibaba Cloud service events
Alibaba Cloud services automatically integrate with EventBridge as event sources. For a list of supported services, see Alibaba Cloud service event sources.
Custom application events
To publish events from your own applications, connect your application to EventBridge through an SDK.