Receive events using Pub/Sub messages (gcloud CLI)
This quickstart shows you how to set up a Google Kubernetes Engine (GKE) service as a destination to receive Pub/Sub topic events using Eventarc.
In this quickstart, you will:
- Complete preparatory tasks such as enabling APIs and setting up a service account.
- Create a GKE cluster.
- Initialize GKE destinations in Eventarc.
- Deploy a GKE service that receives events.
- Create an Eventarc trigger that connects a Pub/Sub topic to the GKE service.
- Generate and view a Pub/Sub event.
Before you begin
- Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
- Install the Google Cloud CLI.
-
To initialize the gcloud CLI, run the following command:
gcloud init
-
Create or select a Google Cloud project.
-
Create a Google Cloud project:
gcloud projects create PROJECT_ID
Replace
PROJECT_ID
with a name for the Google Cloud project you are creating. -
Select the Google Cloud project that you created:
gcloud config set project PROJECT_ID
Replace
PROJECT_ID
with your Google Cloud project name.
-
-
Make sure that billing is enabled for your Google Cloud project.
- Install the Google Cloud CLI.
-
To initialize the gcloud CLI, run the following command:
gcloud init
-
Create or select a Google Cloud project.
-
Create a Google Cloud project:
gcloud projects create PROJECT_ID
Replace
PROJECT_ID
with a name for the Google Cloud project you are creating. -
Select the Google Cloud project that you created:
gcloud config set project PROJECT_ID
Replace
PROJECT_ID
with your Google Cloud project name.
-
-
Make sure that billing is enabled for your Google Cloud project.
- Update Google Cloud CLI components:
gcloud components update
- Enable the Eventarc, Resource Manager, and Google Kubernetes Engine
APIs:
gcloud services enable eventarc.googleapis.com \ cloudresourcemanager.googleapis.com \ container.googleapis.com
- Set the configuration variables used in this quickstart:
PROJECT_ID=$(gcloud config get-value project) CLUSTER_NAME=events-cluster SERVICE_NAME=hello-gke LOCATION=us-central1
-
If you are the project creator, you are granted the basic Owner role (
roles/owner
). By default, this Identity and Access Management (IAM) role includes the permissions necessary for full access to most Google Cloud resources and you can skip this step.If you are not the project creator, required permissions must be granted on the project to the appropriate principal. For example, a principal can be a Google Account (for end users) or a service account (for applications and compute workloads). For more information, see the Roles and permissions page for your event destination.
Required permissions
To get the permissions that you need to complete this quickstart, ask your administrator to grant you the following IAM roles on your project:
-
Eventarc Admin (
roles/eventarc.admin
) -
Kubernetes Engine Admin (
roles/container.admin
) -
Logs View Accessor (
roles/logging.viewAccessor
) -
Project IAM Admin (
roles/resourcemanager.projectIamAdmin
) -
Pub/Sub Publisher (
roles/pubsub.publisher
) -
Service Account Admin (
roles/iam.serviceAccountAdmin
) -
Service Account User (
roles/iam.serviceAccountUser
) -
Service Usage Admin (
roles/serviceusage.serviceUsageAdmin
)
For more information about granting roles, see Manage access to projects, folders, and organizations.
You might also be able to get the required permissions through custom roles or other predefined roles.
-
Eventarc Admin (
Make note of the Compute Engine default service account as you will you attach it to an Eventarc trigger to represent the identity of the trigger for testing purposes. This service account is automatically created after enabling or using a Google Cloud service that uses Compute Engine, and with the following email format:
PROJECT_NUMBER-compute@developer.gserviceaccount.com
Replace
PROJECT_NUMBER
with your Google Cloud project number. You can find your project number on the Welcome page of the Google Cloud console or by running the following command:gcloud projects describe PROJECT_ID --format='value(projectNumber)'
For production environments, we strongly recommend creating a new service account and granting it one or more IAM roles that contain the minimum permissions required and follow the principle of least privilege.
- Grant the
Pub/Sub
Subscriber role (
roles/pubsub.subscriber
) on the project to the Compute Engine default service account so that the Eventarc trigger can pull events from Pub/Sub.gcloud projects add-iam-policy-binding PROJECT_ID \ --member=serviceAccount:PROJECT_NUMBER-compute@developer.gserviceaccount.com \ --role=roles/pubsub.subscriber
- If you enabled the Cloud Pub/Sub service agent on or before April
8, 2021, to support authenticated Pub/Sub push requests, grant
the Service
Account Token Creator role (
roles/iam.serviceAccountTokenCreator
) to the service agent. Otherwise, this role is granted by default:gcloud projects add-iam-policy-binding PROJECT_ID \ --member=serviceAccount:service-PROJECT_NUMBER@gcp-sa-pubsub.iam.gserviceaccount.com \ --role=roles/iam.serviceAccountTokenCreator
Create a GKE cluster
A GKE cluster consists of at least one cluster control plane machine and multiple worker machines called nodes. Nodes are Compute Engine virtual machine (VM) instances that run the Kubernetes processes necessary to make them part of the cluster. You deploy applications to clusters, and the applications run on the nodes.
Create an Autopilot cluster named events-cluster
:
gcloud container clusters create-auto $CLUSTER_NAME \ --region $LOCATION
It might take several minutes for the creation of the cluster to complete. Once the cluster is created, the output should be similar to the following:
Creating cluster events-cluster...done.
Created [https://container.googleapis.com/v1/projects/MY_PROJECT
/zones/us-central1/clusters/events-cluster].
[...]
STATUS: RUNNING
This creates a GKE cluster named events-cluster
in a project
with a Google Cloud project ID of MY_PROJECT
.
Enable GKE destinations
For each trigger that targets a GKE service, Eventarc creates an event forwarder component that pulls events from Pub/Sub and forwards it to the target. To create the component and manage resources in the GKE cluster, grant permissions to the Eventarc service agent:
Enable GKE destinations for Eventarc:
gcloud eventarc gke-destinations init
At the prompt to bind the required roles, enter
y
.The following roles are bound to the service account:
compute.viewer
container.developer
iam.serviceAccountAdmin
Create a GKE service destination
Deploy a GKE service that will receive and log events using a
prebuilt image, us-docker.pkg.dev/cloudrun/container/hello
:
Kubernetes uses a YAML file called
kubeconfig
to store cluster authentication information forkubectl
. Update thekubeconfig
file with credentials and endpoint information to pointkubectl
at the GKE cluster:gcloud container clusters get-credentials $CLUSTER_NAME \ --region $LOCATION
Create a Kubernetes deployment:
kubectl create deployment $SERVICE_NAME \ --image=us-docker.pkg.dev/cloudrun/container/hello
Expose it as a Kubernetes service:
kubectl expose deployment $SERVICE_NAME \ --type ClusterIP \ --port 80 \ --target-port 8080
Create an Eventarc trigger
When a message is published to the Pub/Sub topic, the
Eventarc trigger sends messages to the hello-gke
GKE service.
Create a GKE trigger to listen for Pub/Sub messages:
New Pub/Sub topic
gcloud eventarc triggers create gke-trigger-pubsub \ --location="$LOCATION" \ --destination-gke-cluster=$CLUSTER_NAME \ --destination-gke-location=$LOCATION \ --destination-gke-namespace=default \ --destination-gke-service=$SERVICE_NAME \ --destination-gke-path=/ \ --event-filters="type=google.cloud.pubsub.topic.v1.messagePublished" \ --service-account="PROJECT_NUMBER-compute@developer.gserviceaccount.com"
This creates a new Pub/Sub topic and a trigger for it called
gke-trigger-pubsub
.Existing Pub/Sub topic
gcloud eventarc triggers create gke-trigger-pubsub \ --location="$LOCATION" \ --destination-gke-cluster=$CLUSTER_NAME \ --destination-gke-location=$LOCATION \ --destination-gke-namespace=default \ --destination-gke-service=$SERVICE_NAME \ --destination-gke-path=/ \ --event-filters="type=google.cloud.pubsub.topic.v1.messagePublished" \ --service-account="PROJECT_NUMBER-compute@developer.gserviceaccount.com" \ --transport-topic=projects/PROJECT_ID/topics/TOPIC_ID
Replace the following:
PROJECT_ID
: your Google Cloud project IDTOPIC_ID
: the ID of the existing Pub/Sub topic This creates a trigger calledgke-trigger-pubsub
for the existing Pub/Sub topic.
Confirm the trigger was successfully created. It can take up to two minutes for the trigger to be fully functional.
gcloud eventarc triggers list
The output should be similar to the following:
NAME: gke-trigger-pubsub TYPE: google.cloud.pubsub.topic.v1.messagePublished DESTINATION: GKE: hello-gke ACTIVE: Yes LOCATION: us-central1
Generate and viewing an event
You can generate an event to trigger the GKE service by publishing a message to the Pub/Sub topic. You can then view the message in the pod logs.
Find and set the Pub/Sub topic as an environment variable:
TOPIC=$(gcloud eventarc triggers describe gke-trigger-pubsub \ --location=us-central1 \ --format='value(transport.pubsub.topic)')
Send a message to the Pub/Sub topic to generate an event:
gcloud pubsub topics publish $TOPIC --message="Hello World"
The GKE service logs the event's message.
To view the event message:
Find the pod ID:
kubectl get pods
The output should be similar to the following:
NAME READY STATUS RESTARTS AGE hello-gke-645964f578-2mjjt 1/1 Running 0 35s
Copy the
NAME
of the pod to use in the next step.Check the logs of the pod:
kubectl logs NAME
Replace
NAME
with the name of the pod you copied.Look for a log entry similar to:
2022/02/24 22:23:49 Hello from Cloud Run! The container started successfully and is listening for HTTP requests on $PORT {"severity":"INFO","eventType":"google.cloud.pubsub.topic.v1.messagePublished","message":"Received event of type google.cloud.pubsub.topic.v1.messagePublished. Event data: Hello World"[...]}
Clean up
When you finish the tasks that are described in this document, you can avoid continued billing by deleting the resources that you created.
You can:
-
This also deletes the associated Pub/Sub topic.
Alternatively, you can delete your Google Cloud project to avoid incurring charges. Deleting your Google Cloud project stops billing for all the resources used within that project.
Delete a Google Cloud project:
gcloud projects delete PROJECT_ID
If you plan to explore multiple tutorials and quickstarts, reusing projects can help you avoid exceeding project quota limits.