channel-addresses-unique

Since 0.9.0

This rule checks that no two channels of an AsyncAPI document share the same address, including addresses that differ only by the names of their parameters.

Rule Details

In AsyncAPI 3.x the key of a channel in the channels map is only an identifier; the actual topic, queue or routing key is given by the channel’s address. Two channels with the same address describe the same destination, which is usually a copy-and-paste mistake and makes it unclear which of the two definitions (and which set of messages) is authoritative.

The channel-addresses-unique rule compares the addresses of all channels defined in the root channels map. Before comparing, the name of every parameter expression is dropped, so users.{userId}.events and users.{id}.events are considered duplicates, as they match exactly the same set of concrete addresses.

The rule reports Duplicate channel address found on every channel whose address duplicates the address of a channel defined earlier in the document.

Channels without an address (or with address: null, meaning the address is dynamic or unknown) are ignored. Channels defined under components/channels are not checked.

Configuration

None.

Examples

Good. Each channel has its own address.

asyncapi: 3.0.0
info:
  title: Pet Events
  version: 1.0.0
channels:
  petCreated:
    address: pets.{petId}.created
    parameters:
      petId:
        description: Identifier of the pet.
  petDeleted:
    address: pets.{petId}.deleted
    parameters:
      petId:
        description: Identifier of the pet.

Bad. Both channels point to the same destination; they differ only by the parameter name.

asyncapi: 3.0.0
info:
  title: Pet Events
  version: 1.0.0
channels:
  petEvents:
    address: pets.{petId}.events
    parameters:
      petId:
        description: Identifier of the pet.
  animalEvents:
    address: pets.{animalId}.events
    parameters:
      animalId:
        description: Identifier of the animal.

When Not to Use It

You may disable this rule if you intentionally describe the same destination with several channels, for example when the channels are available on different servers and carry different messages.

Compatibility

This rule is compatible with AsyncAPI 3.x documents. AsyncAPI 2.x documents are rejected by the reader and are not linted.

Related rules

• channel-parameters-defined