Choice

Choice CRD provides a way to easily define a list of branches, each receiving the same CloudEvent sent to the Choice ingress channel. Typically, each branch consists of a filter function guarding the execution of the branch.

Choice creates Channels and Subscriptions under the hood.

Usage

Choice Spec

Choice has three parts for the Spec:

  1. cases defines the list of filter and subscriber pairs, one per branch, and optionally a reply object. For each branch:
    1. the filter is evaluated and when it returns an event the subscriber is executed. Both filter and subscriber must be Callable.
    2. the event returned by the subscriber is sent to the branch reply object. When the reply is empty, the event is sent to the spec.reply object (see below).
  2. (optional) channelTemplate defines the Template which will be used to create Channels.
  3. (optional) reply defines where the result of each branch is sent to when the branch does not have its own reply object.

Choice Status

Choice has three parts for the Status:

  1. conditions which details the overall status of the Choice object
  2. ingressChannelStatus and caseStatuses which convey the status of underlying Channel and Subscription resource that are created as part of this Choice.
  3. address which is exposed so that Choice can be used where Addressable can be used. Sending to this address will target the Channel which is fronting this Choice (same as ingressChannelStatus).

Examples

Learn how to use Choice by following the examples