How to use Boto3 to start a trigger in AWS Glue Data Catalog

In this article, we will see how to start a trigger in AWS Glue Data Catalog using the boto3 Python library. Triggers in AWS Glue are used to start ETL jobs based on schedules or events.

Prerequisites

Before starting, ensure you have ?

• AWS credentials configured (access key, secret key)
• Appropriate IAM permissions for AWS Glue operations
• An existing trigger in your AWS Glue Data Catalog
• The boto3 library installed

Approach to Start a Glue Trigger

Follow these steps to start a trigger programmatically ?

• Step 1: Import boto3 and botocore exceptions to handle errors.

• Step 2: Define the trigger name as a parameter.

• Step 3: Create an AWS session using boto3. Ensure region_name is configured in your AWS profile.

• Step 4: Create a Glue client using the session.

• Step 5: Call the start_trigger() method with the trigger name.

• Step 6: Handle exceptions for better error management.

Implementation

Here's the complete code to start a Glue trigger ?

import boto3
from botocore.exceptions import ClientError

def start_a_trigger(trigger_name):
    """
    Start an AWS Glue trigger by name
    
    Args:
        trigger_name (str): Name of the trigger to start
    
    Returns:
        dict: Response from AWS Glue service
    """
    session = boto3.session.Session()
    glue_client = session.client('glue')
    
    try:
        response = glue_client.start_trigger(Name=trigger_name)
        print(f"Successfully started trigger: {trigger_name}")
        return response
    except ClientError as e:
        raise Exception("boto3 client error in start_a_trigger: " + e.__str__())
    except Exception as e:
        raise Exception("Unexpected error in start_a_trigger: " + e.__str__())

# Example usage
trigger_name = "test-daily"
result = start_a_trigger(trigger_name)
print(result)

Output

When the trigger starts successfully, you'll receive a response like this ?

Successfully started trigger: test-daily
{
    'Name': 'test-daily', 
    'ResponseMetadata': {
        'RequestId': 'b2109689-*******************-d', 
        'HTTPStatusCode': 200, 
        'HTTPHeaders': {
            'date': 'Sun, 28 Mar 2021 08:00:04 GMT', 
            'content-type': 'application/x-amz-json-1.1', 
            'content-length': '26', 
            'connection': 'keep-alive', 
            'x-amzn-requestid': 'b2109689-***********************-d'
        }, 
        'RetryAttempts': 0
    }
}

Key Points

• The start_trigger() method starts the trigger immediately, regardless of its schedule
• A successful response returns HTTP status code 200
• The trigger must exist in your AWS Glue Data Catalog before starting
• Proper error handling prevents unexpected application crashes
• Starting a trigger may incur AWS charges based on the jobs it executes

Error Handling

Common errors you might encounter ?

• EntityNotFoundException: Trigger doesn't exist
• InvalidInputException: Invalid trigger name format
• InternalServiceException: AWS service error
• OperationTimeoutException: Request timeout

Conclusion

Using boto3 to start AWS Glue triggers provides programmatic control over your ETL workflows. This approach is useful for building automated data pipelines and integrating Glue operations into larger applications.