This topic describes the terms that are used in EventBridge.

CloudEvents 1.0

CloudEvents is an open source specification to describe event data in a standard manner. This simplifies event declaration and delivery across services and platforms.

The following terms are used in CloudEvents 1.0. For more information, see CloudEvents - Version 1.0.

Occurrence
An occurrence is an event status that is collected when a software system runs. An event may occur because a system signal is received, a signal monitored by the system is received, or a change in status or time happens. For example, a device may raise an alert because the battery is low or the virtual machine will restart as scheduled.
Producer
A producer is a specific instance, process, or device that generates a data structure that describes an event in the CloudEvents format.
Consumer
A consumer receives and manages events. It executes logic based on context and data to generate new events.
Intermediary
An intermediary receives a message that contains an event and then forwards the message to the next receiver. The next receiver can be a consumer or another intermediary. Typically, an intermediary is used to route an event to a consumer based on the information in the context.
Context
Tools and application code can use the information in the context to identify the relationships between an event and system events or other events.
Data
Data is domain-specific information about an occurrence. The data includes the information about the occurrence, details of data changes, or other information.
Event format
An event format specifies how an event in the CloudEvents format is serialized into a sequence of bytes. Standalone event formats, such as the JSON format, perform serialization that is independent of protocols or storage media. Protocol bindings can define formats that are dependent on the protocol.
Message
An event is transmitted from an event source to an event target by using a message.
  • Structured message

    A structured message is a message where the event is fully encoded based on a standalone event format. Event data is stored in the message body.

  • Binary message

    A binary message is a message where event attributes are stored as part of message metadata. Event data is stored in the message body.

EDA

The event-driven architecture (EDA) is an architectural paradigm that focuses on the following two features:

  • Implements asynchronous communication based on the production or consumption of events. This paradigm is an upgrade of the traditional thread-based synchronous system.
  • Produces, detects, and consumes events and evokes responses.

For more information, see EDA.

Event

An event is a data record about status changes.

For more information, see Overview.

Event source

An event source is the source that produces events. The following types of event sources are supported:

  • Alibaba Cloud service event sources: the Alibaba Cloud services that connect to EventBridge as event sources.
    Note For more information about Alibaba Cloud services that can be used as event sources for EventBridge, see Alibaba Cloud service events.
  • Custom event sources: custom applications or existing message data that are used as event sources and whose events are pulled to custom event buses.

For more information, see Overview.

Event bus

An event bus receives an event from an event source. The following types of event buses are supported:
  • System event bus: a built-in event bus that you do not need to create and cannot modify. This type of event bus is used to receive events of your Alibaba Cloud services. Events of Alibaba Cloud services can be published only to the system event bus.
  • Custom event bus: an event bus that you create and manage. This type of event bus is used to receive events of custom applications or existing message data. Events of custom applications or existing message data can be published only to a custom event bus.

For more information, see Overview.

Event rule

An event rule is used to monitor specific types of events. When a matched event occurs, the event is routed to the event target that is associated with the event rule. An event rule can be associated with one or more event targets. An event rule includes the following elements:

For more information, see Overview.

Event pattern

An event pattern is a module that filters events. Event patterns take effect for all the parameters of the CloudEvents specification, including the data parameter. An event pattern is described in the JSON format. The following types of event patterns are supported:

  • Alibaba Cloud service-specific event pattern: You can use the predefined event sources and event types to efficiently define an event pattern. This allows you to use simple matching rules to filter events that are received by the system event bus.
  • Custom event pattern: You can customize an event pattern based on the custom event source and the matching rules that are supported by the event pattern. This allows you to use complex matching rules to filter events that are received by custom event buses.

For more information, see Event patterns.

Event transformer

An event transformer transforms an event before the event is routed to an event target. The following transformation methods are supported:

  • Complete event: EventBridge routes a complete event to an event target.
  • Partial event: EventBridge extracts data from an event by using JSONPath and routes the specified part of the event to an event target.
  • Constant: EventBridge routes only constants to an event target regardless of event context.
  • Template: You can customize a template and define the required variables. Then, EventBridge extracts data from an event by using JSONPath and transforms the data based on the template.

For more information, see Event transformation.

Event target

An event target processes and consumes events. The following types of event targets are supported:
  • Alibaba Cloud services: the Alibaba Cloud services that connect to EventBridge as an event target.
    Note For more information about Alibaba Cloud services that can be used as event targets for EventBridge, see Overview.
  • HTTP gateways: the HTTP gateways for your applications.
  • HTTPS gateways: the HTTPS gateways for your applications.

For more information, see Overview.

Schema

A schema defines the data format of event bodies to help implement reliable data exchange across heterogeneous systems.

For more information, see Overview.