Configuration

The config is a small YAML file passed with --config. The command-line flags override it, and it is optional when the flags say enough. The loader is internal/codegen/config.go.

language: go              # go or typescript, defaults to go
package: chat             # Go package name, required for Go
output: chat.gen.go       # defaults to asyncapi.gen.go, or asyncapi.gen.ts
generate:
  models: true            # types, codecs, validation (on by default)
  client: true            # decoding, Handler, Dispatch, Client (on by default, needs models)
output-options:
  message-matchers:       # see Message matching
    Notice:
      /messages/0/type: [notice, info]

Keys

Key	Default	What it does
language	go	go or typescript. Any other value fails. Flag: -language.
package	none	Go package name of the generated file. Required for Go, ignored for TypeScript. Flag: -package.
output	asyncapi.gen.go, or asyncapi.gen.ts for TypeScript	The file to write, relative to the directory the generator runs in. Flag: -o.
generate.models	true	Schema types, JSON codecs and validation.
generate.client	true	Message decoding, the Handler interface, Dispatch and the Client. Needs models.
output-options.message-matchers	none	Extra rules that tell incoming messages apart. See Message matching.

The generate block

Leave generate out and you get everything. Once the block is present, a key left out of it is false, so generate: {models: true} means models only. Turning both off, or turning on client without models, fails validation.

message-matchers

The keys under message-matchers are message keys from the spec: the name under components/messages, or <channel>_<message> for a message defined inline in a channel’s messages. Each one maps JSON pointers (RFC 6901) into the payload to the value that pointer must hold, or to a list of allowed values:

output-options:
  message-matchers:
    Notice:
      /messages/0/type: [notice, info]
    Alert:
      /messages/0/type: alert

A key that names no message in the spec fails generation, and so does an empty list. Message matching explains where these rules sit in the decoding order.

Validation

The config is checked after the flags are applied, before the spec is read:

• Unknown keys fail with commerr.ErrParseFailed. A typo such as ouput: is caught, not ignored.
• A Go run without package fails with commerr.ErrRequiredConfigValueNotSet.
• A language other than go or typescript fails with commerr.ErrInvalidValue.
• generate with nothing selected, or with client but not models, fails with commerr.ErrInvalidValue.

The exact messages are on the Troubleshooting page.