feat(tools/Clickhouse): configurable connection pool settings

[ankurg03]

Description

Added capability to config hardcoded variable listed below
MaxOpenConns
MaxIdleConns
ConnMaxLifetime

PR Checklist

• [Done ] Make sure you reviewed
  CONTRIBUTING.md
• [Done] Make sure to open an issue as a
  Hardcoded Connection Pool Configurations #2243
• [Done] Ensure the tests and linter pass
• [Done] Code coverage does not decrease (if any source code was changed)
• [Done] Appropriate docs were updated (if necessary)
• [No Breaking changes ] Make sure to add ! if this involve a breaking change

🛠️ Fixes #2243

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[gemini-code-assist]

Summary of Changes

Hello @ankurg03, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the ClickHouse source configuration by externalizing key connection pool parameters. Users can now specify MaxOpenConns, MaxIdleConns, and ConnMaxLifetime in their YAML configurations, providing greater control over database connection behavior and resource management. This change improves the flexibility and adaptability of the ClickHouse integration.

Highlights

• Configurable Connection Pool Settings: Introduced the ability to configure MaxOpenConns, MaxIdleConns, and ConnMaxLifetime for ClickHouse connections via YAML, moving these from hardcoded values to user-definable parameters.
• Default Values and Validation: Established default values for connection pool settings and implemented logic to use these defaults if no custom values are provided. Added validation for ConnMaxLifetime to ensure it is a valid duration string.
• Enhanced Test Coverage: Expanded the test suite to include new test cases for parsing the connection pool settings from YAML and verifying the correct application and error handling of these settings within the ClickHouse connection initialization.

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[gemini-code-assist]

Code Review

This pull request successfully makes the ClickHouse connection pool settings (MaxOpenConns, MaxIdleConns, ConnMaxLifetime) configurable, replacing the previous hardcoded values. The changes are well-implemented, including updates to the configuration struct, initialization logic, and corresponding tests.

My review includes a few suggestions to further improve the code's robustness and maintainability:

• Adding validation tags to the new configuration fields to prevent invalid values.
• Refactoring the initClickHouseConnectionPool function to accept the Config struct directly, which will simplify its signature and improve maintainability.
• Enhancing the tests to verify that the connection pool settings are correctly applied, not just that error paths are handled.

[gemini-code-assist]

This test function TestInitClickHouseConnectionPoolWithPoolSettings primarily verifies error handling for connMaxLifetime, but it doesn't test the successful application of the pool settings (MaxOpenConns, MaxIdleConns). The 'happy path' test cases only confirm that a connection error occurs later, without verifying that the settings were applied correctly.

To properly test this logic, you could use a mocking library (like sqlmock) to provide a mock *sql.DB. This would allow you to assert that SetMaxOpenConns, SetMaxIdleConns, and SetConnMaxLifetime are called with the expected values based on the test case inputs. This would ensure the core logic of this feature is correctly tested.