Pull Request

Issue link(s): https://github.com/elastic/detection-rules/issues/3989

Summary - What I changed

Added error handling for CUSTOM_RULES_DIR, so that if the config file is not found in this directory, a more informative error message is now displayed suggesting to the user a method for fixing the issue.

How To Test

Set the CUSTOM_RULES_DIR environment variable to a non-existent directory, then run a detection rules command (e.g. setup-confg) as shown below.

(detection-rules-build) forteea1@forteea1-el1:/tmp/detection-rules$ export CUSTOM_RULES_DIR=/tmp/detection-rules/custom_rules_dir
(detection-rules-build) forteea1@forteea1-el1:/tmp/detection-rules$ python -m detection_rules custom-rules setup-config custom_rules_dir
Traceback (most recent call last):
  File "<frozen runpy>", line 189, in _run_module_as_main
  File "<frozen runpy>", line 148, in _get_module_details
  File "<frozen runpy>", line 112, in _get_module_details
  File "/tmp/detection-rules/detection_rules/__init__.py", line 13, in <module>
    from . import (  # noqa: E402
  File "/tmp/detection-rules/detection_rules/custom_schemas.py", line 17, in <module>
    RULES_CONFIG = parse_rules_config()
                   ^^^^^^^^^^^^^^^^^^^^
  File "/tmp/detection-rules/detection_rules/utils.py", line 323, in wrapped
    _cache[func_key][cache_key] = f(*args, **kwargs)
                                  ^^^^^^^^^^^^^^^^^^
  File "/tmp/detection-rules/detection_rules/config.py", line 215, in parse_rules_config
    raise FileNotFoundError(
FileNotFoundError: 
                Configuration file not found.
                Please create a configuration file. You may wish to use the 'setup-config' command
                and update the 'CUSTOM_RULES_DIR' environment variable as needed.

Checklist

[ ] Added a label for the type of pr: bug, enhancement, schema, Rule: New, Rule: Deprecation, Rule: Tuning, Hunt: New, or Hunt: Tuning so guidelines can be generated
[ ] Added the meta:rapid-merge label if planning to merge within 24 hours
[ ] Secret and sensitive material has been managed correctly
[ ] Automated testing was updated or added to match the most common scenarios
[ ] Documentation and comments were added for features that require explanation

Contributor checklist

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Enhancement - Guidelines

These guidelines serve as a reminder set of considerations when addressing adding a feature to the code.

Documentation and Context

[ ] Describe the feature enhancement in detail (alternative solutions, description of the solution, etc.) if not already documented in an issue.
[ ] Include additional context or screenshots.
[ ] Ensure the enhancement includes necessary updates to the documentation and versioning.

Code Standards and Practices

[ ] Code follows established design patterns within the repo and avoids duplication.
[ ] Code changes do not introduce new warnings or errors.
[ ] Variables and functions are well-named and descriptive.
[ ] Any unnecessary / commented-out code is removed.
[ ] Ensure that the code is modular and reusable where applicable.
[ ] Check for proper exception handling and messaging.

Testing

[ ] New unit tests have been added to cover the enhancement.
[ ] Existing unit tests have been updated to reflect the changes.
[ ] Provide evidence of testing and validating the enhancement (e.g., test logs, screenshots).
[ ] Validate that any rules affected by the enhancement are correctly updated.
[ ] Ensure that performance is not negatively impacted by the changes.
[ ] Verify that any release artifacts are properly generated and tested.

Additional Checks

[ ] Ensure that the enhancement does not break existing functionality.
[ ] Review the enhancement with a peer or team member for additional insights.
[ ] Verify that the enhancement works across all relevant environments (e.g., different OS versions).
[ ] Confirm that all dependencies are up-to-date and compatible with the changes.

elastic / detection-rules

[FR] Add Better Error Handling for CUSTOM_RULES_DIR #3990