[Feat] Implement metrics enhancements and testing scripts for issue #699

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Issue #699 - Metrics Enhancements

Overview

This document outlines the changes made to address a subset of the requirements in issue #699, which involved enhancing the metrics functionality in MCP Gateway, and provides instructions for testing these enhancements.

Changes Implemented

1. Enhanced Metrics Calculation Functions

Updated the following functions in mcpgateway/utils/metrics_common.py:

• calculate_success_rate(): Improved to handle edge cases such as:

  • Division by zero (when total is 0)
  • None inputs
  • Type conversion errors

• format_response_time(): Enhanced to format response times with:

  • Consistent 3 decimal places (x.xxx)
  • Proper handling of None values
  • Consistent display of trailing zeros

2. Admin API Enhancements

Modified mcpgateway/admin.py to:

• Export ALL rows in metrics CSV exports (previously limited to top 5)
• Format response times consistently with 3 decimal places
• Properly handle empty states (display "N/A" when no data exists)

3. Services Improvements

Updated metrics retrieval in service modules to support:

• Optional limit parameter to retrieve any number of results
• Unlimited results when exporting metrics data

How to Test

Follow these steps to verify the metrics enhancements:

Prerequisites

1. Create and activate a Python virtual environment
2. Install dependencies: pip install -e .

Testing Core Metrics Functions

1. Run the unit tests for the metrics functions:

   python -m pytest tests/test_metrics_functions.py -v
   

   This will verify:

   • Success rate calculation handles edge cases (0/0, None inputs)
   • Response time formatting is consistent with 3 decimal places
   • Empty states are handled correctly

Testing with Manual Data

1. Start the MCP Gateway server with admin features enabled:

   $env:MCPGATEWAY_ADMIN_API_ENABLED="true"
   $env:MCPGATEWAY_UI_ENABLED="true"
   python -m uvicorn mcpgateway.main:app --host 0.0.0.0 --port 8008 --reload
   

2. Create test data using the provided script:

   python tests/setup_test_data.py
   

   This creates test tools with different metrics patterns:

   • Tool 1: 80% success rate (8 successes, 2 failures)
   • Tool 2: 100% success rate (5 successes, 0 failures)
   • Tool 3: 0% success rate (0 successes, 3 failures)

3. Test the admin UI:

   • Access http://localhost:8008/admin (username: admin, password: changeme)
   • Navigate to the Metrics tab
   • Verify all test tools appear with correct success rates
   • Verify response times are shown with 3 decimal places

4. Test CSV export:

   • Click "Export Metrics" in the admin UI
   • Verify ALL rows are included (not just top 5)
   • Verify response times have 3 decimal places
   • Or directly access: http://localhost:8008/admin/metrics/export?entity_type=tools

5. Test empty state:
   • Using SQLite, delete all metrics for one tool
   • Verify the UI and export handle empty state by showing "N/A"

Verification Criteria

The issue is considered resolved when:

1. ✅ Success rate calculation handles all edge cases
2. ✅ Response times are consistently formatted with 3 decimal places
3. ✅ CSV exports include ALL rows, not just top 5
4. ✅ Empty states are handled gracefully with "N/A"

Additional Notes

• The metrics calculations happen in the metrics_common.py utility file
• The admin API handles converting None values to "N/A" for display
• The CSV export uses the same formatting logic as the UI display

Test Files Location

• Core tests: tests/test_metrics_functions.py
• Test data generation: tests/setup_test_data.py

Troubleshooting

If the server fails to start with database errors:

1. Check for unique constraint errors in the database
2. Update the test data generation script to use unique tool names
3. Try clearing the existing database or using a new one