chore: Enhance Locust load testing and optimize database settings (#6265)

* feat: Enhance Locust load testing for Langflow run endpoint

Refactor locustfile to provide more robust and configurable load testing:
- Add dynamic configuration via environment variables
- Improve error handling and logging
- Implement realistic flow run simulation
- Add connection and timeout handling
- Support API key authentication
- Enhance stats tracking and error reporting

* fix: Improve transaction logging error handling and performance

- Add `no_autoflush` context to prevent unnecessary database operations
- Change transaction logging error from exception to error level logging
- Simplify error handling in log_transaction function

* chore: Add Locust to development dependencies

Update project dependencies by adding Locust (version 2.32.9) to the development requirements, supporting load testing capabilities

* feat: Optimize database connection settings for improved performance and scalability

- Increase default pool_size from 10 to 20 for better connection handling
- Adjust max_overflow to 40 to support higher concurrent connections
- Extend db_connect_timeout from 20 to 30 seconds
- Add pool_recycle and echo settings to db_connection_settings
- Enhance documentation for database connection settings, highlighting SQLite limitations

* feat: Add Locust load testing configuration to Makefile

- Introduce comprehensive Locust load testing target with configurable parameters
- Support flexible testing scenarios with customizable users, spawn rate, and host
- Enable headless and interactive testing modes
- Add environment variable support for API key, flow ID, and other testing parameters
- Provide sensible default values for load testing configuration

* refactor: Remove unused retry configuration in Locust load testing

- Remove RETRY_DELAY and MAX_RETRIES environment variables
- Simplify FlowRunUser configuration by eliminating unused retry settings
- Maintain existing wait time configuration for load testing

* feat: Enforce FLOW_ID requirement for Locust load testing

- Add mandatory validation for FLOW_ID environment variable
- Raise a clear ValueError if FLOW_ID is not provided
- Remove default flow ID to ensure explicit configuration
- Improve load testing configuration robustness

* feat: Add configurable request timeout for Locust load testing

- Introduce `locust_request_timeout` parameter in Makefile
- Update locustfile to use configurable request timeout from environment variable
- Set dynamic connection and network timeout based on REQUEST_TIMEOUT
- Improve request handling with flexible timeout configuration

* revert change to database connection retry

pyproject.toml

@@ -191,6 +191,7 @@ dev-dependencies = [
     "types-aiofiles>=24.1.0.20240626",
     "codeflash>=0.8.4",
     "hypothesis>=6.123.17",
+    "locust>=2.32.9",
 ]