feat: Add MySQL connection string support (Issue #35)

[echarrod]

Summary

Implements support for MYSQL_CONNECTION_STRING environment variable as an alternative to individual connection parameters. This addresses Issue #35 and is particularly useful for organizations with rotating credentials that expire frequently (e.g., hourly).

Changes

Core Implementation

• Connection String Parser (src/utils/index.ts):

  • Parses MySQL CLI-format connection strings
  • Supports short flags (-h, -P, -u, -p, -S) and long options (--host, --port, etc.)
  • Handles quoted values and complex passwords
  • Validates port numbers (1-65535 range, NaN checks)

• Configuration Integration (src/config/index.ts):

  • Added MYSQL_CONNECTION_STRING environment variable support
  • Connection string takes precedence over individual env vars
  • Maintains backward compatibility with existing configurations
  • Fixed password fallback consistency in authPlugins

Documentation

• Updated README.md with connection string option (positioned as alternative, not primary method)
• Added examples and security notes about not storing in version control
• Updated .env.dist with connection string example

Code Quality

• All CodeRabbit review suggestions addressed
• Port validation with proper error handling
• Quote handling fixed to strip delimiters from values
• Password fallback consistency between main config and authPlugins

Testing

Tested with sample connection string:

mysql --default-auth=mysql_native_password -A -hrdsproxy.staging.luno.com -P3306 -uUSER -pPASS database_name

Successfully parses all connection parameters including complex usernames and passwords.

Use Cases

This feature is particularly valuable for:

• Rotating credentials that expire after a set time period (e.g., 1 hour)
• Temporary database connections for testing
• Quick configuration changes without updating multiple environment variables
• Integration with credential management systems that provide full connection strings

Future Considerations

For credentials that expire, users may want to:

1. Use environment variables that can be refreshed externally
2. Create wrapper scripts that prompt for connection strings
3. Integrate with credential management tools

Fixes #35

🤖 Generated with Claude Code

Co-Authored-By: Claude [email protected]