Build a BigQuery processing pipeline with Eventarc

This tutorial shows you how to use Eventarc to build a processing pipeline that schedules queries to a public BigQuery dataset, generates charts based on the data, and shares links to the charts through email.

Create a SendGrid API key

SendGrid is a cloud-based email provider that lets you send email without having to maintain email servers.

1. Sign in to SendGrid and go to Settings > API Keys.
2. Click Create API Key.
3. Select the permissions for the key. At a minimum, the key must have Mail Send permissions to send email.
4. Name your key and to create the key, click Save.
5. SendGrid generates a new key. This is the only copy of the key, so make sure that you copy the key and save it for later.

Create an Artifact Registry standard repository

Create an Artifact Registry standard repository to store your Docker container image:

gcloud artifacts repositories create REPOSITORY \
    --repository-format=docker \
    --location=$REGION

Replace REPOSITORY with a unique name for the repository.

Create a Cloud Storage bucket

Create a unique Cloud Storage bucket to save the charts. Make sure that the bucket and the charts are publicly available, and in the same region as your Cloud Run service:

export BUCKET="$(gcloud config get-value core/project)-charts"
gcloud storage buckets create gs://${BUCKET} --location=$(gcloud config get-value run/region)
gcloud storage buckets update gs://${BUCKET} --uniform-bucket-level-access
gcloud storage buckets add-iam-policy-binding gs://${BUCKET} --member=allUsers --role=roles/storage.objectViewer

Deploy the Notifier service

Deploy a Cloud Run service that receives Chart Creator events and uses SendGrid to email links to the generated charts.

1. Clone the GitHub repository and change to the notifier/python directory:

   git clone https://github.com/GoogleCloudPlatform/eventarc-samples
   cd eventarc-samples/processing-pipelines/bigquery/notifier/python/

2. Build and push the container image:

   export SERVICE_NAME=notifier
   docker build -t $REGION-docker.pkg.dev/$(gcloud config get-value project)/REPOSITORY/${SERVICE_NAME}:v1 .
   docker push $REGION-docker.pkg.dev/$(gcloud config get-value project)/REPOSITORY/${SERVICE_NAME}:v1

3. Deploy the container image to Cloud Run, passing in an address to send emails to, and the SendGrid API key:

   export TO_EMAILS=EMAIL_ADDRESS
   export SENDGRID_API_KEY=YOUR_SENDGRID_API_KEY
   gcloud run deploy ${SERVICE_NAME} \
       --image $REGION-docker.pkg.dev/$(gcloud config get-value project)/REPOSITORY/${SERVICE_NAME}:v1 \
       --update-env-vars TO_EMAILS=${TO_EMAILS},SENDGRID_API_KEY=${SENDGRID_API_KEY},BUCKET=${BUCKET} \
       --allow-unauthenticated

   Replace the following:

   • EMAIL_ADDRESS with an email address to send the links to the generated charts
   • YOUR_SENDGRID_API_KEY with the SendGrid API key you noted previously

When you see the service URL, the deployment is complete.

Note: It can take a few minutes before permissions are propagated to the service and before you can create a trigger.

Create a trigger for the Notifier service

The Eventarc trigger for the Notifier service deployed on Cloud Run filters for Cloud Storage audit logs where the methodName is storage.objects.create.

1. Create the trigger:

   gcloud eventarc triggers create trigger-${SERVICE_NAME} \
       --destination-run-service=${SERVICE_NAME} \
       --destination-run-region=${REGION} \
       --event-filters="type=google.cloud.audit.log.v1.written" \
       --event-filters="serviceName=storage.googleapis.com" \
       --event-filters="methodName=storage.objects.create" \
       --service-account=${PROJECT_NUMBER}[e-mail]

   This creates a trigger called trigger-notifier.

Deploy the Chart Creator service

Deploy a Cloud Run service that receives Query Runner events, retrieves data from a BigQuery table for a specific country, and then generates a chart, using Matplotlib, from the data. The chart is uploaded to a Cloud Storage bucket.

1. Change to the chart-creator/python directory:

   cd ../../chart-creator/python

2. Build and push the container image:

   export SERVICE_NAME=chart-creator
   docker build -t $REGION-docker.pkg.dev/$(gcloud config get-value project)/REPOSITORY/${SERVICE_NAME}:v1 .
   docker push $REGION-docker.pkg.dev/$(gcloud config get-value project)/REPOSITORY/${SERVICE_NAME}:v1

3. Deploy the container image to Cloud Run, passing in BUCKET:

   gcloud run deploy ${SERVICE_NAME} \
       --image $REGION-docker.pkg.dev/$(gcloud config get-value project)/REPOSITORY/${SERVICE_NAME}:v1 \
       --update-env-vars BUCKET=${BUCKET} \
       --allow-unauthenticated

When you see the service URL, the deployment is complete.

Create a trigger for the Chart Creator service

The Eventarc trigger for the Chart Creator service deployed on Cloud Run filters for messages published to a Pub/Sub topic.

1. Create the trigger:

   gcloud eventarc triggers create trigger-${SERVICE_NAME} \
       --destination-run-service=${SERVICE_NAME} \
       --destination-run-region=${REGION} \
       --event-filters="type=google.cloud.pubsub.topic.v1.messagePublished"

   This creates a trigger called trigger-chart-creator.

2. Set the Pub/Sub topic environment variable.

   export TOPIC_QUERY_COMPLETED=$(basename $(gcloud eventarc triggers describe trigger-${SERVICE_NAME} --format='value(transport.pubsub.topic)'))

Deploy the Query Runner service

Deploy a Cloud Run service that receives Cloud Scheduler events, retrieves data from a public COVID-19 dataset, and saves the results in a new BigQuery table.

1. Change to the processing-pipelines directory:

   cd ../../..

2. Build and push the container image:

   export SERVICE_NAME=query-runner
   docker build -t $REGION-docker.pkg.dev/$(gcloud config get-value project)/REPOSITORY/${SERVICE_NAME}:v1 -f Dockerfile .
   docker push $REGION-docker.pkg.dev/$(gcloud config get-value project)/REPOSITORY/${SERVICE_NAME}:v1

3. Deploy the container image to Cloud Run, passing in PROJECT_ID and TOPIC_QUERY_COMPLETED:

   gcloud run deploy ${SERVICE_NAME} \
       --image $REGION-docker.pkg.dev/$(gcloud config get-value project)/REPOSITORY/${SERVICE_NAME}:v1 \
       --update-env-vars PROJECT_ID=$(gcloud config get-value project),TOPIC_ID=${TOPIC_QUERY_COMPLETED} \
       --allow-unauthenticated

When you see the service URL, the deployment is complete.

Create a trigger for the Query Runner service

The Eventarc trigger for the Query Runner service deployed on Cloud Run filters for messages published to a Pub/Sub topic.

1. Create the trigger:

   gcloud eventarc triggers create trigger-${SERVICE_NAME} \
       --destination-run-service=${SERVICE_NAME} \
       --destination-run-region=${REGION} \
       --event-filters="type=google.cloud.pubsub.topic.v1.messagePublished"

   This creates a trigger called trigger-query-runner.

2. Set an environment variable for the Pub/Sub topic.

   export TOPIC_QUERY_SCHEDULED=$(gcloud eventarc triggers describe trigger-${SERVICE_NAME} --format='value(transport.pubsub.topic)')

Schedule the jobs

The processing pipeline is triggered by two Cloud Scheduler jobs.

1. Create an App Engine app which is required by Cloud Scheduler and specify an appropriate location:

   export APP_ENGINE_LOCATION=LOCATION
   gcloud app create --region=${APP_ENGINE_LOCATION}

2. Create two Cloud Scheduler jobs that publish to a Pub/Sub topic once per day:

   gcloud scheduler jobs create pubsub cre-scheduler-uk \
       --schedule="0 16 * * *" \
       --topic=${TOPIC_QUERY_SCHEDULED} \
       --message-body="United Kingdom"

   gcloud scheduler jobs create pubsub cre-scheduler-cy \
       --schedule="0 17 * * *" \
       --topic=${TOPIC_QUERY_SCHEDULED} \
       --message-body="Cyprus"

   The schedule is specified in unix-cron format. For example, 0 16 * * * means that the jobs runs at 16:00 (4 PM) UTC every day.

Run the pipeline

1. First, confirm that all the triggers were successfully created:

   gcloud eventarc triggers list

   Note: It can take up to two minutes for triggers to be fully functional.

   The output should be similar to the following:

   NAME: trigger-chart-creator
   TYPE: google.cloud.pubsub.topic.v1.messagePublished
   DESTINATION: Cloud Run service: chart-creator
   ACTIVE: Yes
   LOCATION: us-central1
   
   NAME: trigger-notifier
   TYPE: google.cloud.audit.log.v1.written
   DESTINATION: Cloud Run service: notifier
   ACTIVE: Yes
   LOCATION: us-central1
   
   NAME: trigger-query-runner
   TYPE: google.cloud.pubsub.topic.v1.messagePublished
   DESTINATION: Cloud Run service: query-runner
   ACTIVE: Yes
   LOCATION: us-central1
   

2. Retrieve the Cloud Scheduler job IDs:

   gcloud scheduler jobs list

   The output should be similar to the following:

   ID                LOCATION      SCHEDULE (TZ)         TARGET_TYPE  STATE
   cre-scheduler-cy  us-central1   0 17 * * * (Etc/UTC)  Pub/Sub      ENABLED
   cre-scheduler-uk  us-central1   0 16 * * * (Etc/UTC)  Pub/Sub      ENABLED
   

3. Although the jobs are scheduled to run daily at 4 and 5 PM, you can also run the Cloud Scheduler jobs manually:

   gcloud scheduler jobs run cre-scheduler-cy
   gcloud scheduler jobs run cre-scheduler-uk

4. After a few minutes, confirm that there are two charts in the Cloud Storage bucket:

   gcloud storage ls gs://${BUCKET}

   The output should be similar to the following:

   gs://BUCKET/chart-cyprus.png
   gs://BUCKET/chart-unitedkingdom.png
   

Congratulations! You should also receive two emails with links to the charts.