Quality Requirements¶

This document specifies the quality requirements for the geOrchestra Gateway, focusing on the key quality attributes that drive the architecture and implementation decisions.

Quality Attributes Overview¶

The geOrchestra Gateway prioritizes the following quality attributes:

Security: Protection of sensitive data and systems
Reliability: Consistent performance under various conditions
Performance: Response time and throughput
Maintainability: Ease of making changes and extensions
Scalability: Ability to handle increased load
Interoperability: Integration with other systems
Usability: User experience for administrators and end users
Testability: Ease of verifying behavior

Security Requirements¶

Authentication Strength¶

Requirement: The Gateway must support multiple authentication methods with industry-standard security.

Scenarios:

Scenario 1: An attacker attempts to bypass authentication by manipulating HTTP headers. The system must detect and reject such attempts.
Scenario 2: A brute force attack against the login page is initiated. The system must implement rate limiting and account lockout mechanisms.

Measures:

Support for OAuth2/OpenID Connect with current security practices
LDAP authentication with secure password handling
Header pre-authentication with verification

Authorization Control¶

Requirement: The Gateway must enforce fine-grained access control based on user roles and request patterns.

Scenarios:

Scenario 1: A user attempts to access a protected resource without appropriate permissions. The access must be denied with a 403 status code.
Scenario 2: An authenticated user with appropriate roles requests access to a permitted resource. The access must be granted.

Measures:

Role-based access control with pattern matching
Configurable access rules for different routes
Default-deny security posture

Data Protection¶

Requirement: The Gateway must protect sensitive data in transit and ensure secure communication.

Scenarios:

Scenario 1: An external eavesdropper attempts to intercept communication between the client and Gateway. All sensitive data must be encrypted.
Scenario 2: A backend service attempts to access user credentials. The Gateway must not forward raw credentials.

Measures:

TLS for all external communication
Secure headers (HSTS, CSP, etc.)
Credential isolation and protection

Reliability Requirements¶

Availability¶

Requirement: The Gateway must maintain high availability as the central entry point to the platform.

Scenarios:

Scenario 1: One Gateway instance fails in a multi-instance deployment. The system continues to function with minimal user impact.
Scenario 2: A downstream service becomes unavailable. The Gateway properly handles and reports the failure without becoming unavailable itself.

Measures:

99.9% uptime target
Support for horizontal scaling
Circuit breaker patterns for dependency failures

Fault Tolerance¶

Requirement: The Gateway must handle errors gracefully and continue functioning despite partial system failures.

Scenarios:

Scenario 1: The LDAP server becomes temporarily unavailable. The Gateway should retry connections and provide clear error messages.
Scenario 2: An invalid configuration is deployed. The Gateway should fail fast with clear error messages rather than behave unpredictably.

Measures:

Graceful degradation when dependencies fail
Comprehensive error handling
Detailed logging of error conditions
Automatic recovery mechanisms

Data Consistency¶

Requirement: The Gateway must maintain consistent state during authentication and session management.

Scenarios:

Scenario 1: A user is authenticated while the system is under heavy load. The authentication state must be consistently maintained.
Scenario 2: Session data is modified concurrently. The system must prevent data corruption or inconsistency.

Measures:

Atomic operations for critical state changes
Proper synchronization in session management
Idempotent API operations where appropriate

Performance Requirements¶

Response Time¶

Requirement: The Gateway must add minimal latency to request processing.

Scenarios:

Scenario 1: Under normal load, the Gateway should add no more than 50ms of latency to requests.
Scenario 2: For authentication operations, 95% of requests should complete within 500ms.

Measures:

Latency monitoring at percentiles (50th, 95th, 99th)
Performance testing as part of CI/CD
Optimization of critical request paths

Throughput¶

Requirement: The Gateway must handle the expected traffic volume with headroom for growth.

Scenarios:

Scenario 1: The system must support at least 100 requests per second per instance under normal conditions.
Scenario 2: During peak loads, the system should maintain acceptable performance up to 200 requests per second per instance.

Measures:

Load testing as part of release process
Monitoring of request rates and response times
Capacity planning based on observed patterns

Resource Utilization¶

Requirement: The Gateway must use resources efficiently.

Scenarios:

Scenario 1: Under normal load, CPU utilization should remain below 60%.
Scenario 2: Memory consumption should be stable over time without significant leaks.

Measures:

Maximum 1GB heap size per instance under normal load
CPU usage monitoring
Memory leak detection

Maintainability Requirements¶

Modularity¶

Requirement: The Gateway code should be modular to allow isolated changes and extensions.

Scenarios:

Scenario 1: A developer needs to add a new authentication provider. This should be possible without modifying existing authentication code.
Scenario 2: A configuration option needs to be added. This should not require changes to core logic.

Measures:

Clear component boundaries
Dependency injection for loose coupling
Interface-based design for extensibility

Code Quality¶

Requirement: The codebase should follow best practices for readability and maintainability.

Scenarios:

Scenario 1: A new developer joins the project and needs to understand the authentication flow. This should be clear from the code structure and documentation.
Scenario 2: A bug is reported in a specific component. A developer should be able to isolate and fix the issue without affecting other components.

Measures:

Static code analysis in CI pipeline
Coding standards enforcement
Comprehensive unit tests
Code review process

Documentation¶

Requirement: The system should be well-documented at all levels.

Scenarios:

Scenario 1: An administrator needs to configure a new authentication provider. Clear documentation should be available.
Scenario 2: A developer needs to understand the filter chain architecture. Technical documentation should explain this clearly.

Measures:

User documentation for administrators
Technical documentation for developers
Clear inline code documentation
Architecture documentation using arc42 template

Scalability Requirements¶

Horizontal Scalability¶

Requirement: The Gateway should scale horizontally by adding more instances.

Scenarios:

Scenario 1: Traffic increases by 200%. The system should handle this by adding more Gateway instances.
Scenario 2: During low traffic periods, the number of instances can be reduced without affecting availability.

Measures:

Stateless design where possible
External session storage
Support for load balancing

Vertical Scalability¶

Requirement: The Gateway should make efficient use of additional resources on a single instance.

Scenarios:

Scenario 1: A Gateway instance is allocated more CPU cores. The throughput should increase proportionally.
Scenario 2: Memory allocation is increased. The Gateway should utilize this for better caching or connection pooling.

Measures:

Multi-threaded architecture leveraging available cores
Configurable resource limits
Tunable performance parameters

Interoperability Requirements¶

API Compatibility¶

Requirement: The Gateway should maintain compatibility with existing geOrchestra services.

Scenarios:

Scenario 1: The Gateway replaces the legacy security-proxy. Existing services should continue to function without modification.
Scenario 2: A new version of a backend service is deployed. The Gateway should continue to route requests correctly.

Measures:

Backward compatible header schemes
Flexible routing rules
Versioned APIs where needed

Integration Standards¶

Requirement: The Gateway should use standard protocols and formats for integration.

Scenarios:

Scenario 1: Integration with a new OAuth2 provider is needed. This should be straightforward using standard OAuth2 flows.
Scenario 2: Integration with a monitoring system is required. Standard metrics formats should be available.

Measures:

Support for standard authentication protocols
RESTful APIs for management
Standard metrics formats (Prometheus, etc.)

Usability Requirements¶

Configuration Usability¶

Requirement: The Gateway should be easy to configure for administrators.

Scenarios:

Scenario 1: An administrator needs to add a new backend service. This should be possible with minimal configuration changes.
Scenario 2: An administrator needs to modify access rules. The configuration format should be intuitive and well-documented.

Measures:

Clear configuration structure
Well-documented configuration options
Validation of configuration with helpful error messages

User Interface¶

Requirement: The Gateway's user-facing components (login page, error pages) should be user-friendly.

Scenarios:

Scenario 1: A user encounters an error. The error page should provide clear information about what went wrong and how to proceed.
Scenario 2: A user needs to log in. The login page should be intuitive and support multiple authentication methods.

Measures:

Responsive design for different devices
Internationalization support
Clear error messages
Accessible user interface components

Testability Requirements¶

Unit Testing¶

Requirement: The Gateway code should be amenable to comprehensive unit testing.

Scenarios:

Scenario 1: A developer changes the authentication logic. Unit tests should verify the behavior without requiring a full deployment.
Scenario 2: A new filter is added to the chain. The filter should be testable in isolation.

Measures:

Dependency injection for testability
Mockable interfaces
Minimum 80% unit test coverage

Integration Testing¶

Requirement: The Gateway should support efficient integration testing.

Scenarios:

Scenario 1: A new release is being prepared. Integration tests should verify that all components work together correctly.
Scenario 2: A configuration change is made. Tests should verify that the system behaves as expected with the new configuration.

Measures:

Integration test suite that covers key scenarios
Test fixtures for common setup
Support for test profiles in Spring configuration

Quality Assurance Process¶

To ensure these quality requirements are met, the following processes are in place:

Automated Testing: CI pipeline includes unit tests, integration tests, and performance tests
Code Reviews: All changes are peer-reviewed before merging
Static Analysis: Automated code quality and security scanning
Performance Monitoring: Runtime metrics collection and analysis
Security Audits: Regular security reviews and vulnerability scanning
Documentation Reviews: Ensuring documentation stays up-to-date with code changes