KubernetesExecutor, Airflow 3,SparkSubmitOperator with pod_overwrite fails with json validation error

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Summary

The KubernetesExecutor in Airflow 3 fails to run a DAG with SparkSubmitOperator due to a JSON validation error. The error occurs when the pod_overwrite feature is used, and the JSON string passed to the execute_workload command is missing double quotes, resulting in an invalid JSON.

Root Cause

The root cause of the issue is the stripping of double quotes from the JSON string when it is passed from the YAML configuration to the container’s CLI. This results in an invalid JSON that fails to validate. The possible causes of this issue are:

  • Incorrect handling of special characters in the YAML configuration
  • Inconsistent JSON parsing and string escaping in the KubernetesExecutor
  • Missing or incorrect double quote escaping in the JSON string

Why This Happens in Real Systems

This issue can occur in real systems due to:

  • Inconsistent configuration: Differences in configuration between development, testing, and production environments can lead to unexpected behavior.
  • Complexity of containerization: The use of containers and orchestration tools like Kubernetes can introduce additional complexity and potential points of failure.
  • JSON parsing and validation: The parsing and validation of JSON can be sensitive to special characters and escaping, leading to errors if not handled correctly.

Real-World Impact

The impact of this issue can be significant, including:

  • Failed workflows: The failure to validate the JSON string can cause the workflow to fail, resulting in lost productivity and delayed processing.
  • Debugging challenges: The inconsistent behavior and lack of clear error messages can make it difficult to debug and diagnose the issue.
  • Security risks: In some cases, invalid JSON can lead to security vulnerabilities, such as injection attacks or data corruption.

Example or Code

import json

# Example of valid JSON string
valid_json = '{"token":"some_value","somekey":"somevalue"}'

# Example of invalid JSON string (missing double quotes)
invalid_json = '{token:some_value,somekey:somevalue}'

# Attempt to parse the invalid JSON string
try:
    json.loads(invalid_json)
except json.JSONDecodeError as e:
    print(f"Error parsing JSON: {e}")

How Senior Engineers Fix It

To fix this issue, senior engineers can:

  • Verify the YAML configuration: Ensure that the YAML configuration is correct and consistent.
  • Use double quote escaping: Use double quote escaping to prevent the stripping of double quotes.
  • Validate the JSON string: Use JSON validation tools or libraries to ensure that the JSON string is valid before passing it to the execute_workload command.
  • Use –json-path instead of –json-string: Consider using –json-path instead of –json-string to avoid issues with special characters and escaping.

Why Juniors Miss It

Junior engineers may miss this issue due to:

  • Lack of experience: Limited experience with containerization, orchestration tools, and JSON parsing can make it difficult to identify and diagnose the issue.
  • Insufficient testing: Inadequate testing and validation of the JSON string can lead to undetected errors.
  • Inconsistent documentation: Poor or inconsistent documentation can make it challenging to understand the requirements and constraints of the KubernetesExecutor and SparkSubmitOperator.