OpenShift docs are moving and will soon only be available at docs.redhat.com, the home of all Red Hat product documentation. Explore the new docs experience today.
  1. Documentation
    2. history bug_report picture_as_pdf
×

Subscribing functions to CloudEvents

You can subscribe a function to a set of events. This links your function to CloudEvent objects defined by your filters and enables automated responses.

Subscribing a function to CloudEvents

The subscribe command connects the function to a set of events, matching a series of filters for CloudEvent metadata and a Knative Broker as the source of events, from where they are consumed.

Prerequisites

  • You have installed Knative Eventing on the cluster.

  • You have configured a Knative Broker.

  • You have installed the Knative (kn) CLI.

Procedure

  1. Subscribe the function to events for a given broker by running the following command:

    Example command
    $ kn func subscribe --filter type=com.example.Hello --source my-broker

    Use the --source flag to specify the broker and one or more --filter flags to specify your filters.

    You can also omit the --source flag to use the default broker:

    Example command
    $ kn func subscribe --filter type=com.example --filter extension=my-extension-value

  2. Deploy the function with Knative Triggers:

    Example command
    $ kn func deploy
    Example output
    🙌 Function image built: <registry>/hello:latest
🎯 Creating Triggers on the cluster
✅ Function deployed in namespace "default" and exposed at URL:
http://hello.default.my-cluster.example.com