Trigger Sources

A trigger source is the source of trigger resource. It can be either external source such as Git, S3, K8s Configmap, File, any valid URL that hosts the resource or an internal resource which is defined in the sensor object itself like Inline or Resource.

In the previous sections, you have been dealing with the Resource trigger source. In this tutorial, we will explore other trigger sources.

Prerequisites

1. The Webhook event-source is already set up.

Git

Git trigger source refers to K8s trigger refers to the K8s resource stored in Git.

The specification for the Git source is available here.

1. In order to fetch data from git, you need to set up the private SSH key in sensor.

2. If you don't have ssh keys available, create them following this guide.

3. Create a K8s secret that holds the SSH keys.

   kubectl -n argo-events create secret generic git-ssh --from-file=key=.ssh/<YOUR_SSH_KEY_FILE_NAME>
   

4. Create a K8s secret that holds known hosts.

   kubectl -n argo-events create secret generic git-known-hosts --from-file=ssh_known_hosts=.ssh/known_hosts
   

5. Create a sensor with the git trigger source and refer it to the hello world workflow stored on the Argo Git project.

   kubectl -n argo-events apply -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/tutorials/03-trigger-sources/sensor-git.yaml
   

6. Use either Curl or Postman to send a post request to the http://localhost:12000/example.

   curl -d '{"message":"ok"}' -H "Content-Type: application/json" -X POST http://localhost:12000/example
   

7. Now, you should see an Argo workflow being created.

   kubectl -n argo-events get wf
   

S3

You can refer to the K8s resource stored on S3 compliant store as the trigger source.

For this tutorial, lets set up a minio server which is S3 compliant store.

1. Create a K8s secret called artifacts-minio that holds your minio access key and secret key. The access key must be stored under accesskey key and secret key must be stored under secretkey.

2. Follow steps described here to set up the minio server.

3. Make sure a service is available to expose the minio server.

4. Create a bucket called workflows and store a basic hello world Argo workflow with key name hello-world.yaml.

5. Create the sensor with trigger source as S3.

   kubectl -n argo-events apply -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/tutorials/03-trigger-sources/sensor-minio.yaml
   

6. Use either Curl or Postman to send a post request to the http://localhost:12000/example.

   curl -d '{"message":"ok"}' -H "Content-Type: application/json" -X POST http://localhost:12000/example
   

7. Now, you should see an Argo workflow being created.

   kubectl -n argo-events get wf
   

K8s Configmap

K8s configmap can be treated as trigger source if needed.

1. Lets create a configmap called trigger-store.

   kubectl -n argo-events apply -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/tutorials/03-trigger-sources/trigger-store.yaml
   

2. Create a sensor with trigger source as configmap and refer it to the trigger-store.

   kubectl -n argo-events apply -f https://raw.githubusercontent.com/argoproj/argo-events/stable/examples/tutorials/03-trigger-sources/sensor-cm.yaml
   

3. Use either Curl or Postman to send a post request to the http://localhost:12000/example.

   curl -d '{"message":"ok"}' -H "Content-Type: application/json" -X POST http://localhost:12000/example
   

4. Now, you should see an Argo workflow being created.

   kubectl -n argo-events get wf
   

File & URL

File and URL trigger sources are pretty self explanatory. The example sensors are available under examples/sensors folder.