Are you tired of manually triggering your Composer DAGs? Do you want to automate the process and save time? Look no further! In this article, we’ll show you how to trigger a Composer DAG using Cloud Scheduler, a fully managed enterprise-grade scheduling service offered by Google Cloud.
What is Cloud Scheduler?
Cloud Scheduler is a fully managed service that allows you to schedule tasks to run at specific times or intervals. It’s a powerful tool that integrates with other Google Cloud services, including Cloud Composer, to provide a seamless and automated workflow.
Why Use Cloud Scheduler with Composer?
Using Cloud Scheduler with Composer provides several benefits, including:
- Automation**: Automate the triggering of your DAGs, saving you time and effort.
- Reliability**: Ensure that your DAGs run consistently and reliably, without the need for manual intervention.
- Flexibility**: Schedule your DAGs to run at specific times or intervals, giving you greater control over your workflow.
- Scalability**: Scale your workflow to meet the demands of your business, without worrying about manual triggers.
Prerequisites
Before we dive into the tutorial, make sure you have the following prerequisites:
- Google Cloud Account**: You need an active Google Cloud account to use Cloud Scheduler and Cloud Composer.
- Cloud Composer Environment**: You need to have a Cloud Composer environment set up and running.
- DAG Created**: You need to have a DAG created in Cloud Composer that you want to trigger using Cloud Scheduler.
Step 1: Create a Cloud Scheduler Job
Log in to your Google Cloud Console and navigate to the Cloud Scheduler page. Click on the “Create Job” button to create a new job.
gcloud scheduler jobs create \
--schedule "0 0 * * *" \
--time-zone "US/Eastern" \
--description "Trigger Composer DAG"
In the above code:
--schedule "0 0 * * *specifies the schedule for the job, in this case, every day at midnight.--time-zone "US/Eastern"specifies the time zone for the job.--description "Trigger Composer DAG"adds a description to the job.
Step 2: Create a Cloud Function to Trigger the DAG
Create a new Cloud Function that will trigger the DAG when called by Cloud Scheduler.
gcloud functions create trigger-dag \
--runtime python38 \
--trigger-http \
--region us-central1 \
--allow-unauthenticated
In the above code:
trigger-dagis the name of your Cloud Function.--runtime python38specifies the runtime environment for the function.--trigger-httpspecifies that the function should be triggered via an HTTP request.--region us-central1specifies the region where the function will be deployed.--allow-unauthenticatedallows the function to be triggered without authentication.
Step 3: Write the Cloud Function Code
Write the code for the Cloud Function that will trigger the DAG.
import os
from google.oauth2 import service_account
from googleapiclient.discovery import build
def trigger_dag(request):
# Replace with your Composer environment name
COMPOSER_ENVIRONMENT = 'your-composer-env'
# Replace with your DAG name
DAG_NAME = 'your-dag-name'
# Authenticate with Composer using a service account
credentials = service_account.Credentials.from_service_account_file(
'path/to/service-account-key.json')
# Build the Composer client
composer = build('composer', 'v1', credentials=credentials)
# Trigger the DAG
response = composer.projects().locations().environments().dagRuns().create(
parent=f'projects/your-project/locations/us-central1/environments/{COMPOSER_ENVIRONMENT}/dagRuns',
body={'dag_id': DAG_NAME}
).execute()
return 'DAG triggered successfully!'
In the above code:
COMPOSER_ENVIRONMENTis the name of your Composer environment.DAG_NAMEis the name of your DAG.- The code authenticates with Composer using a service account and triggers the DAG using the Composer API.
Step 4: Configure the Cloud Scheduler Job
Configure the Cloud Scheduler job to call the Cloud Function.
gcloud scheduler jobs update \
--uri "https://us-central1-your-project.cloudfunctions.net/trigger-dag"
In the above code:
--uri "https://us-central1-your-project.cloudfunctions.net/trigger-dag"specifies the URI of the Cloud Function to call.
Step 5: Verify the Setup
Verify that the Cloud Scheduler job is triggering the DAG correctly.
Wait for the scheduled time for the job to run, or run the job manually using the following command:
gcloud scheduler jobs run
Check the Cloud Composer console to verify that the DAG has been triggered successfully.
Conclusion
In this article, we’ve shown you how to trigger a Composer DAG using Cloud Scheduler, a fully managed enterprise-grade scheduling service offered by Google Cloud. By following these steps, you can automate the triggering of your DAGs, saving you time and effort.
Remember to replace the placeholders in the code with your actual values, and to test the setup thoroughly to ensure that it’s working correctly.
| Keyword | Description |
|---|---|
| Cloud Scheduler | A fully managed service that allows you to schedule tasks to run at specific times or intervals. |
| Cloud Composer | A fully managed service that allows you to create and manage Apache Airflow environments. |
| DAG | A directed acyclic graph that represents a workflow in Apache Airflow. |
We hope you found this article helpful! If you have any questions or need further assistance, please don’t hesitate to ask.
Here are 5 Questions and Answers about “Trigger a Composer DAG using Cloud Scheduler”:
Frequently Asked Question
Wondering how to trigger a Composer DAG using Cloud Scheduler? Here are some frequently asked questions to get you started!
What is Cloud Scheduler and how does it work with Composer?
Cloud Scheduler is a fully managed enterprise-grade cron job scheduler that allows you to schedule tasks to run at specific times or intervals. With Composer, you can use Cloud Scheduler to trigger DAGs (directed acyclic graphs) to run on a schedule, ensuring that your workflows are executed consistently and reliably.
How do I create a Cloud Scheduler job to trigger a Composer DAG?
To create a Cloud Scheduler job, navigate to the Cloud Scheduler console, click on “Create Job”, and enter the required details such as the job name, schedule, and target. In the target section, select “Cloud Composer” as the target type and specify the DAG ID and the Cloud Composer environment. Then, click “Create” to create the job.
Can I trigger multiple DAGs with a single Cloud Scheduler job?
No, each Cloud Scheduler job can only trigger a single DAG. However, you can create multiple Cloud Scheduler jobs to trigger different DAGs, and each job can have its own schedule and configuration.
How do I monitor and troubleshoot Cloud Scheduler jobs that trigger Composer DAGs?
You can monitor Cloud Scheduler jobs in the Cloud Scheduler console, where you can view the job’s execution history, including any errors or failures. Additionally, you can use Cloud Composer’s logging and monitoring features to troubleshoot issues with your DAGs. You can also use Cloud Logging to view logs from both Cloud Scheduler and Cloud Composer.
What are the benefits of using Cloud Scheduler to trigger Composer DAGs?
Using Cloud Scheduler to trigger Composer DAGs provides a scalable, reliable, and managed way to schedule your workflows. It allows you to decouple your scheduling needs from your workflow logic, making it easier to manage and maintain your workflows. Additionally, Cloud Scheduler provides a centralized console for managing and monitoring your scheduled tasks.
