Use Trigger Conditions

This document describes how to use Trigger conditions.

Prerequisites

You have finished the steps described in Use EventBus and Trigger.

Use Trigger Conditions

Create two event sources

  1. Use the following content to create an EventSource configuration file (for example, eventsource-a.yaml).

    1. apiVersion: events.openfunction.io/v1alpha1
    2. kind: EventSource
    3. metadata:
    4.   name: eventsource-a
    5. spec:
    6.   logLevel: "2"
    7.   eventBus: "default"
    8.   kafka:
    9.     sample-five:
    10.       brokers: "kafka-server-kafka-brokers.default.svc.cluster.local:9092"
    11.       topic: "events-sample"
    12.       authRequired: false

  2. Use the following content to create another EventSource configuration file (for example, eventsource-b.yaml).

    1. apiVersion: events.openfunction.io/v1alpha1
    2. kind: EventSource
    3. metadata:
    4.   name: eventsource-b
    5. spec:
    6.   logLevel: "2"
    7.   eventBus: "default"
    8.   cron:
    9.     sample-five:
    10.       schedule: "@every 5s"

  3. Run the following commands to apply these two configuration files.

    1. kubectl apply -f eventsource-a.yaml
    2. kubectl apply -f eventsource-b.yaml

Create a trigger with condition

  1. Use the following content to create a configuration file (for example, condition-trigger.yaml) for a Trigger with condition.

    1. apiVersion: events.openfunction.io/v1alpha1
    2. kind: Trigger
    3. metadata:
    4.   name: condition-trigger
    5. spec:
    6.   logLevel: "2"
    7.   eventBus: "default"
    8.   inputs:
    9.     eventA:
    10.       eventSource: "eventsource-a"
    11.       event: "sample-five"
    12.     eventB:
    13.       eventSource: "eventsource-b"
    14.       event: "sample-five"
    15.   subscribers:
    16.   - condition: eventB
    17.     sink:
    18.       uri: "http://openfunction.io.svc.cluster.local/default/sink"
    19.   - condition: eventA && eventB
    20.     topic: "metrics"

    Note

    In this example, two input sources and two subscribers are defined, and their triggering relationship is described as follows:

    • When input eventB is received, the input event is sent to the Knative service.
    • When input eventB and input eventA are received, the input event is sent to the metrics topic of the event bus and sent to the Knative service at the same time.

  2. Run the following commands to apply the configuration files.

    1. kubectl apply -f condition-trigger.yaml

  3. Run the following commands to check the results.

    1. $ kubectl get eventsources.events.openfunction.io
    2. NAME            EVENTBUS   SINK   STATUS
    3. eventsource-a   default           Ready
    4. eventsource-b   default           Ready
    6. $ kubectl get triggers.events.openfunction.io
    7. NAME                EVENTBUS   STATUS
    8. condition-trigger   default    Ready
    10. $ kubectl get eventbus.events.openfunction.io
    11. NAME      AGE
    12. default   12s

  4. Run the following command and you can see from the output that the eventB condition in the Trigger is matched and the Knative service is triggered because the event source eventsource-b is a cron task.

    1. $ kubectl get functions.core.openfunction.io
    2. NAME                                  BUILDSTATE   SERVINGSTATE   BUILDER   SERVING         URL                                   AGE
    3. sink                                  Skipped      Running                  serving-4x5wh   http://openfunction.io/default/sink   3h25m
    5. $ kubectl get po
    6. NAME                                                        READY   STATUS    RESTARTS   AGE
    7. serving-4x5wh-ksvc-wxbf2-v100-deployment-5c495c84f6-k2jdg   2/2     Running   0          46s

  5. Create an event producer by referring to Create an Event Producer.

  6. Run the following command and you can see from the output that the eventA && eventB condition in the Trigger is matched and the event is sent to the metrics topic of the event bus at the same time. The OpenFuncAsync function is triggered.

    1. $ kubectl get functions.core.openfunction.io
    2. NAME                                  BUILDSTATE   SERVINGSTATE   BUILDER   SERVING         URL                                   AGE
    3. trigger-target                        Skipped      Running                  serving-7hghp                                         103s
    5. $ kubectl get po
    6. NAME                                                        READY   STATUS    RESTARTS   AGE
    7. serving-7hghp-deployment-v100-z8wrf-946b4854d-svf55         2/2     Running   0          18s

Last modified June 18, 2022: Add function inputs and outputs docs (#105) (dd9d200)