Using Triggers¶

A trigger represents a desire to subscribe to events from a specific broker.

The subscriber value must be a Destination.

Example Triggers¶

The following trigger receives all the events from the default broker and delivers them to the Knative Serving service my-service:

Create a YAML file using the following example:

apiVersion: eventing.knative.dev/v1
kind: Trigger
metadata:
  name: my-service-trigger
spec:
  broker: default
  subscriber:
    ref:
      apiVersion: serving.knative.dev/v1
      kind: Service
      name: my-service

Apply the YAML file by running the command:
```
kubectl apply -f <filename>.yaml
```
Where <filename> is the name of the file you created in the previous step.

The following trigger receives all the events from the default broker and delivers them to the custom path /my-custom-path for the Kubernetes service my-service:

Create a YAML file using the following example:

apiVersion: eventing.knative.dev/v1
kind: Trigger
metadata:
  name: my-service-trigger
spec:
  broker: default
  subscriber:
    ref:
      apiVersion: v1
      kind: Service
      name: my-service
    uri: /my-custom-path

Apply the YAML file by running the command:
```
kubectl apply -f <filename>.yaml
```
Where <filename> is the name of the file you created in the previous step.

Trigger filtering¶

Exact match filtering on any number of CloudEvents attributes as well as extensions are supported. If your filter sets multiple attributes, an event must have all of the attributes for the trigger to filter it. Note that we only support exact matching on string values.

Example¶

This example filters events from the default broker that are of type dev.knative.foo.bar and have the extension myextension with the value my-extension-value.

Create a YAML file using the following example:

apiVersion: eventing.knative.dev/v1
kind: Trigger
metadata:
  name: my-service-trigger
spec:
  broker: default
  filter:
    attributes:
      type: dev.knative.foo.bar
      myextension: my-extension-value
  subscriber:
    ref:
      apiVersion: serving.knative.dev/v1
      kind: Service
      name: my-service

Apply the YAML file by running the command:
```
kubectl apply -f <filename>.yaml
```
Where <filename> is the name of the file you created in the previous step.

New trigger filters¶

If you need more powerful filtering options, you can use the new trigger filters.

Trigger annotations¶

You can modify a Trigger's behavior by setting the following two annotations:

eventing.knative.dev/injection: if set to enabled, Eventing automatically creates a Broker for a Trigger if it doesn't exist. The Broker is created in the namespace where the Trigger is created. This annotation only works if you have the Sugar Controller enabled, which is optional and not enabled by default.
knative.dev/dependency: this annotation is used to mark the sources that the Trigger depends on. If one of the dependencies is not ready, the Trigger will not be ready.

The following YAML is an example of a Trigger with a dependency:

apiVersion: eventing.knative.dev/v1
kind: Trigger
metadata:
  name: my-service-trigger
  annotations:
    knative.dev/dependency: '{"kind":"PingSource","name":"test-ping-source","apiVersion":"sources.knative.dev/v1"}'
spec:
  broker: default
  filter:
    attributes:
      type: dev.knative.foo.bar
      myextension: my-extension-value
    subscriber:
      ref:
        apiVersion: serving.knative.dev/v1
        kind: Service
        name: my-service