Endpoint Traits

This wiki contains a mapping between Smithy Endpoint traits and generated Ruby code.

endpoint trait

Configures a custom operation endpoint. This trait has a required hostPrefix property. This trait is supported with Hearth middleware to augment the endpoint. The middleware will take the input params, the host prefix property from the @endpoint trait, and a configuration flag for disabling host prefix behavior.

@readonly
@endpoint(hostPrefix: "data.")
operation GetStatus {
    input: GetStatusInput,
    output: GetStatusOutput
}

The generated code is:

# client.rb in get_status operation
stack.use(
  Hearth::Middleware::HostPrefix,
  prefix: "data.",
  disable_host_prefix: options.fetch(:disable_host_prefix, @disable_host_prefix)
)

The request will have data. prefixed to the host URL. Note: the hostPrefix is applied to the Endpoint resolved by the Endpoints#endpoint-provider

hostLabel trait

Binds a top-level operation input structure member to a label in the hostPrefix of an endpoint trait. In Hearth::Middleware::HostPrefix, the middleware evaluates the host prefix, determines that a label is needed for foo, and then check the params for such a key. If the key doesn’t exist or is empty, an ArgumentError is raised.

@readonly
@endpoint(hostPrefix: "{foo}.data.")
operation GetStatus {
    input: GetStatusInput,
    output: GetStatusOutput
}

structure GetStatusInput {
    @required
    @hostLabel
    foo: String
}

If input[:foo] = ‘bar’ then the request will have bar.data. prefixed to the host URL.