API Observability System - Requirement Specification¶
1. Introduction¶
1.1 Purpose¶
This document specifies the functional and non-functional requirements for the API Observability System, which provides comprehensive monitoring, performance tracking, and operational visibility for the TQPro API platform.
1.2 Scope¶
The API Observability System provides: - Real-time performance monitoring and metrics collection - Authorization and authentication tracking - Error and exception monitoring - Time-series data storage and retention - Visual dashboards and alerting capabilities - Operational insights for capacity planning and optimization
1.3 Document Conventions¶
- SHALL indicates mandatory requirements
- SHOULD indicates recommended requirements
- MAY indicates optional requirements
2. System Overview¶
The API Observability System captures, stores, and visualizes operational metrics from the TQPro API platform. It provides system operators, developers, and stakeholders with real-time visibility into API performance, security events, and error conditions to support proactive monitoring and rapid incident response.
2.1 Key Components¶
- Metrics Collection - Captures performance and operational metrics from API endpoints
- Time-Series Storage - Stores metrics data with configurable retention policies
- Visualization Layer - Provides dashboards and graphs for metrics analysis
- Alerting Engine - Monitors metrics and triggers notifications based on thresholds
- Query Interface - Enables ad-hoc metric queries and analysis
3. Functional Requirements¶
3.1 API Performance Metrics¶
3.1.1 Request Timing Metrics¶
REQ-PERF-001: The system SHALL capture timing information for every API request including: - Request start timestamp - Request completion timestamp - Total request duration in milliseconds/seconds - Request processing time excluding network latency
REQ-PERF-002: The system SHALL calculate and expose latency percentiles: - 50th percentile (median) response time - 95th percentile response time - 99th percentile response time - Maximum response time
REQ-PERF-003: The system SHALL track request timing with the following dimensions: - API endpoint path - HTTP method (GET, POST, PUT, DELETE, etc.) - Response status code - Response status category (2xx, 3xx, 4xx, 5xx)
3.1.2 Throughput Metrics¶
REQ-PERF-004: The system SHALL measure API throughput: - Total number of requests received - Request rate (requests per second) - Request distribution across endpoints - Request distribution across time intervals
REQ-PERF-005: The system SHALL track response metrics: - Total number of responses sent - Response rate by status code - Response distribution by endpoint - Success rate vs error rate ratios
REQ-PERF-006: The system SHALL calculate request/response metrics over configurable time windows: - 1-minute intervals - 5-minute intervals - 15-minute intervals - 1-hour intervals - Custom time ranges
3.2 Authorization and Authentication Metrics¶
3.2.1 Authentication Tracking¶
REQ-AUTH-001: The system SHALL track all authentication attempts including: - Total authentication requests - Successful authentications - Failed authentications - Authentication method used
REQ-AUTH-002: The system SHALL record authentication context: - User identifier (anonymized or hashed if required) - API endpoint being accessed - User roles and permissions - Timestamp of authentication attempt
REQ-AUTH-003: The system SHALL track development mode authentication bypasses: - Total bypass events - User identifiers using bypass - Timestamp of bypass usage - Warning indicators for production environments
3.2.2 Authorization Tracking¶
REQ-AUTH-004: The system SHALL track all authorization checks including: - Total authorization checks performed - Successful authorizations - Rejected authorizations - Authorization check duration
REQ-AUTH-005: The system SHALL capture authorization context: - API endpoint requiring authorization - User roles presented for authorization - Required roles for the endpoint - User identifier (anonymized or hashed if required) - Reason for rejection (if applicable)
REQ-AUTH-006: The system SHALL identify authorization patterns: - Most frequently rejected endpoints - Users with highest rejection rates - Role combinations most often rejected - Time-based authorization trends
REQ-AUTH-007: The system SHALL calculate authorization metrics: - Authorization success rate by endpoint - Authorization rejection rate by user role - Authorization rejection trends over time - Ratio of authorized to rejected requests
3.3 Error and Exception Tracking¶
3.3.1 Error Capture¶
REQ-ERR-001: The system SHALL capture all errors and exceptions including: - Total error count - Error rate (errors per second) - Error distribution by endpoint - Error distribution by type
REQ-ERR-002: The system SHALL classify errors by category: - Client errors (4xx status codes) - Server errors (5xx status codes) - Application exceptions - System exceptions - Timeout errors - Connection errors
REQ-ERR-003: The system SHALL record error context: - API endpoint where error occurred - Error code or error identifier - Exception type or class - Timestamp of error occurrence - User context (if available)
REQ-ERR-004: The system SHALL track error metadata: - Error message or description - Error severity level - Related request identifier - Stack trace or error location (for debugging)
3.3.2 Error Analysis¶
REQ-ERR-005: The system SHALL provide error analytics: - Error rate trends over time - Top errors by frequency - Error distribution by endpoint - Error patterns and correlations
REQ-ERR-006: The system SHALL calculate error metrics: - Overall error rate - Error rate per endpoint - Error rate per error type - Ratio of errors to total requests
REQ-ERR-007: The system SHALL support error grouping: - Group similar errors by error code - Group errors by exception type - Group errors by endpoint - Group errors by time interval
3.4 Metrics Exposition and Access¶
3.4.1 Metrics Endpoint¶
REQ-EXPO-001: The system SHALL provide a dedicated metrics endpoint: - HTTP/HTTPS accessible endpoint - Standard metrics format output - Human-readable and machine-parsable format - Low latency response time
REQ-EXPO-002: The system SHALL support metrics scraping: - Pull-based metrics collection - Configurable scrape intervals - Support for multiple concurrent scrapers - Efficient metric serialization
REQ-EXPO-003: The system SHOULD secure the metrics endpoint: - Authentication required for access - Authorization based on roles - Rate limiting to prevent abuse - Network access controls
3.4.2 Metrics Format¶
REQ-EXPO-004: The system SHALL expose metrics in standardized format: - Metric name and description - Metric type (counter, gauge, histogram, summary) - Metric labels/dimensions - Metric values with timestamps - Metric units and scale
REQ-EXPO-005: The system SHALL support metric labels for dimensionality: - Application identifier - Module or service name - Environment (development, staging, production) - Custom business dimensions
3.5 Time-Series Data Storage¶
3.5.1 Data Collection¶
REQ-STOR-001: The system SHALL collect metrics at regular intervals: - Configurable collection frequency (default: 15-30 seconds) - Automatic retry on collection failure - Collection timestamps in UTC - Support for batch collection
REQ-STOR-002: The system SHALL store collected metrics: - Time-series optimized storage - Efficient compression for historical data - Fast query performance - Scalable storage capacity
3.5.2 Data Retention¶
REQ-STOR-003: The system SHALL support configurable data retention: - Default retention period: 15 days minimum - Extended retention for critical metrics - Automatic data pruning after retention period - Data archival capabilities for long-term storage
REQ-STOR-004: The system MAY support data downsampling: - Higher resolution for recent data - Lower resolution for historical data - Configurable downsampling rules - Preservation of important statistical properties
3.5.3 Data Integrity¶
REQ-STOR-005: The system SHALL ensure data integrity: - Protection against data corruption - Checksums or validation mechanisms - Backup and recovery capabilities - Data consistency guarantees
3.6 Visualization and Dashboards¶
3.6.1 Dashboard Requirements¶
REQ-VIS-001: The system SHALL provide pre-built dashboards: - API Overview Dashboard (request rates, error rates, latency) - Authorization Metrics Dashboard (auth success/rejection, patterns) - Performance Dashboard (latency heatmaps, slowest endpoints) - Error Analysis Dashboard (error distribution, trends)
REQ-VIS-002: The system SHALL support dashboard customization: - Create custom dashboards - Add, remove, and arrange panels - Configure panel data sources - Save and share dashboard configurations
REQ-VIS-003: The system SHALL provide visualization types: - Time-series line graphs - Bar charts and histograms - Pie charts for distribution - Heatmaps for density visualization - Tables for detailed data - Gauge/stat panels for single values
3.6.2 Dashboard Features¶
REQ-VIS-004: The system SHALL support interactive dashboards: - Real-time data updates (configurable refresh interval) - Time range selection (last 15m, 1h, 6h, 24h, 7d, custom) - Zoom and pan on graphs - Drill-down capabilities - Legend filtering
REQ-VIS-005: The system SHALL provide dashboard organization: - Folder/hierarchy structure - Dashboard tagging - Search and filter dashboards - Dashboard versioning - Dashboard templates
REQ-VIS-006: The system SHOULD support dashboard sharing: - Public/private dashboard access - Snapshot creation - URL-based sharing - Embedding in other applications - Export capabilities (PDF, PNG)
3.6.3 Metrics Query Language¶
REQ-VIS-007: The system SHALL support a query language for metrics: - Select specific metrics - Filter by labels/dimensions - Aggregate functions (sum, avg, min, max, count) - Rate and derivative calculations - Percentile calculations - Mathematical operations on metrics
REQ-VIS-008: The system SHALL provide query capabilities: - Ad-hoc metric queries - Query validation and syntax checking - Query history and favorites - Query auto-completion - Query performance indicators
3.7 Alerting and Notifications¶
3.7.1 Alert Definition¶
REQ-ALERT-001: The system SHALL support alert rule configuration: - Metric-based alert conditions - Threshold-based triggers (greater than, less than, equals) - Time-window specifications - Alert severity levels (critical, warning, info) - Alert evaluation intervals
REQ-ALERT-002: The system SHALL provide pre-configured alert rules: - High API error rate alert - High authorization rejection rate alert - Slow API response time alert - Service availability alert - Abnormal traffic patterns alert
REQ-ALERT-003: The system SHALL support complex alert conditions: - Multiple metric conditions (AND, OR logic) - Rate of change detection - Anomaly detection - Comparison with historical baselines - Missing data detection
3.7.2 Alert Notification¶
REQ-ALERT-004: The system SHALL deliver alert notifications through multiple channels: - Email notifications - Webhook/HTTP POST notifications - Integration with incident management systems - In-dashboard notifications - Mobile push notifications (optional)
REQ-ALERT-005: The system SHALL provide alert notification features: - Alert deduplication - Alert grouping by category - Escalation policies - Quiet periods/maintenance windows - Notification templates
REQ-ALERT-006: The system SHALL track alert history: - Alert firing timestamp - Alert resolution timestamp - Alert duration - Alert frequency - Alert acknowledgment status
3.8 Security and Access Control¶
3.8.1 Authentication and Authorization¶
REQ-SEC-001: The system SHALL require authentication for access: - User login with credentials - Session management - Support for single sign-on (SSO) - Multi-factor authentication (optional)
REQ-SEC-002: The system SHALL implement role-based access control: - Administrator role (full access) - Operator role (view and manage dashboards/alerts) - Viewer role (read-only access) - Custom role definitions
REQ-SEC-003: The system SHALL control access to metrics: - Restrict access to sensitive metrics - Per-dashboard access control - Per-alert access control - Audit logging of access attempts
3.8.2 Data Protection¶
REQ-SEC-004: The system SHALL protect sensitive data: - Anonymization of personally identifiable information (PII) - Masking of sensitive metric labels - Encryption of data at rest - Encryption of data in transit (HTTPS/TLS)
REQ-SEC-005: The system SHALL prevent unauthorized data exposure: - Secure default configurations - Rate limiting on metric endpoints - Protection against injection attacks - Input validation and sanitization
4. Non-Functional Requirements¶
4.1 Performance Requirements¶
REQ-NFR-PERF-001: The metrics collection SHALL have minimal performance impact: - Less than 5ms overhead per API request - Less than 1% CPU utilization for metrics collection - Less than 50MB memory footprint for metrics collection
REQ-NFR-PERF-002: The metrics endpoint SHALL respond with low latency: - 95th percentile response time under 500ms - Support for 10+ concurrent scraping clients - Efficient metric serialization
REQ-NFR-PERF-003: The visualization system SHALL provide responsive dashboards: - Dashboard load time under 2 seconds - Graph rendering time under 1 second - Real-time updates with 1-30 second refresh rates
REQ-NFR-PERF-004: The query engine SHALL execute queries efficiently: - Simple queries return within 1 second - Complex queries return within 5 seconds - Support for concurrent queries (50+ simultaneous users)
4.2 Scalability Requirements¶
REQ-NFR-SCALE-001: The system SHALL scale with API traffic: - Support for 1000+ requests per second metric collection - Support for 100+ API endpoints - Support for 1000+ unique metric time series
REQ-NFR-SCALE-002: The storage system SHALL scale horizontally: - Add storage capacity without downtime - Distribute data across multiple storage nodes - Support for petabyte-scale metric storage (long-term)
REQ-NFR-SCALE-003: The visualization system SHALL support multiple users: - Support for 100+ concurrent dashboard viewers - Support for 1000+ dashboards - Support for 10,000+ alert rules
4.3 Reliability Requirements¶
REQ-NFR-REL-001: The metrics collection SHALL be highly available: - Metrics collection continues during system degradation - Graceful handling of collection failures - Automatic recovery from transient failures - No impact on API functionality if metrics collection fails
REQ-NFR-REL-002: The storage system SHALL ensure data durability: - Data replication for redundancy - Protection against data loss - Point-in-time recovery capabilities - Backup and restore procedures
REQ-NFR-REL-003: The system SHALL provide high availability: - 99.5% uptime for metrics collection - 99.9% uptime for visualization and dashboards - Automatic failover for critical components - No single point of failure
4.4 Maintainability Requirements¶
REQ-NFR-MAINT-001: The system SHALL support easy configuration: - Configuration files in standard formats - Environment-specific configurations - Configuration validation - Configuration version control
REQ-NFR-MAINT-002: The system SHALL provide operational monitoring: - Health check endpoints - Self-monitoring metrics - Diagnostic logging - Status pages
REQ-NFR-MAINT-003: The system SHALL support upgrades and maintenance: - Rolling updates without service interruption - Backward compatibility for metrics format - Database migration tools - Rollback capabilities
4.5 Usability Requirements¶
REQ-NFR-USE-001: The dashboard interface SHALL be intuitive: - Clear navigation structure - Consistent visual design - Helpful tooltips and documentation - Responsive design for different screen sizes
REQ-NFR-USE-002: The system SHALL provide comprehensive documentation: - User guides for dashboard creation - Query language reference - Alert configuration examples - Troubleshooting guides
REQ-NFR-USE-003: The system SHALL support multiple users with different skill levels: - Pre-built dashboards for operators - Advanced query capabilities for engineers - Executive summary views for management - Contextual help and tutorials
4.6 Deployment Requirements¶
REQ-NFR-DEPLOY-001: The system SHALL support containerized deployment: - Container images for all components - Orchestration support for container platforms - Service discovery and networking - Health checks and readiness probes
REQ-NFR-DEPLOY-002: The system SHALL support multiple deployment environments: - Development environment (single-node) - Testing/staging environment - Production environment (highly available) - Disaster recovery environment
REQ-NFR-DEPLOY-003: The system SHALL provide deployment automation: - Infrastructure-as-code templates - Automated configuration provisioning - Deployment scripts and playbooks - Smoke tests and validation
5. Metrics Specification¶
5.1 Core Metrics Catalog¶
5.1.1 API Request Metrics¶
| Metric Name | Type | Description | Labels/Dimensions |
|---|---|---|---|
| API Requests Total | Counter | Total number of API requests received | endpoint, method |
| API Responses Total | Counter | Total number of API responses sent | endpoint, method, status, status_category |
| API Request Duration | Histogram | Request processing duration | endpoint, method, status, status_category |
5.1.2 Authentication and Authorization Metrics¶
| Metric Name | Type | Description | Labels/Dimensions |
|---|---|---|---|
| Authentication Requests Total | Counter | Total authentication attempts | api_path, user_id, roles |
| Authorization Checks Total | Counter | Total authorization checks | result (success/rejected), api_path, role |
| Authorization Authorized Total | Counter | Successful authorizations | api_path, user_roles |
| Authorization Rejected Total | Counter | Rejected authorization attempts | api_path, user_id, user_roles |
| Dev Mode Bypass Total | Counter | Development mode authentication bypasses | user_id |
5.1.3 Error Metrics¶
| Metric Name | Type | Description | Labels/Dimensions |
|---|---|---|---|
| API Errors Total | Counter | Total API errors | endpoint, error_type, error_code |
| API Errors by Type | Counter | Errors grouped by exception type | exception_class |
| API Client Errors Total | Counter | 4xx status code responses | endpoint, status |
| API Server Errors Total | Counter | 5xx status code responses | endpoint, status |
5.2 Metric Label Conventions¶
REQ-METRIC-001: All metrics SHALL include standard labels:
- application - Application name identifier
- module - Module or service name
- environment - Deployment environment (dev, staging, production)
REQ-METRIC-002: Endpoint labels SHALL follow conventions:
- Use API path without query parameters
- Normalize path variables (e.g., /user/{id} not /user/123)
- Use consistent path separators
REQ-METRIC-003: User-related labels SHALL protect privacy: - Hash or anonymize user identifiers if required - Use internal user IDs, not email addresses - Comply with data protection regulations
6. Dashboard Specifications¶
6.1 API Overview Dashboard¶
REQ-DASH-001: The API Overview Dashboard SHALL display: - Request rate graph (requests per second over time) - Error rate graph (errors per second over time) - Request duration percentiles (p50, p95, p99) - Response status distribution (pie chart: 2xx, 3xx, 4xx, 5xx) - Top 10 endpoints by request volume - Current throughput statistics
6.2 Authorization Metrics Dashboard¶
REQ-DASH-002: The Authorization Metrics Dashboard SHALL display: - Authorization success vs rejection trend graph - Authorization rejection rate by API endpoint - Top rejected users table - Top rejected endpoints table - Dev mode bypass counter (with warning indicator) - Authorization success rate gauge
6.3 Performance Dashboard¶
REQ-DASH-003: The Performance Dashboard SHALL display: - Request duration heatmap - Slowest endpoints (p95 latency bar chart) - Request rate by endpoint - Latency distribution histogram - Performance trends over time - Endpoint comparison metrics
6.4 Error Analysis Dashboard¶
REQ-DASH-004: The Error Analysis Dashboard SHALL display: - Error rate trend graph - Error distribution by type - Error distribution by endpoint - Top errors table with frequency - Error rate vs total request rate comparison - Recent errors log table
7. Alert Specifications¶
7.1 Standard Alert Rules¶
REQ-ALERT-RULE-001: High API Error Rate Alert - Condition: Error rate > 0.1 errors/second for 2 minutes - Severity: Warning - Action: Notify operations team
REQ-ALERT-RULE-002: High Authorization Rejection Rate Alert - Condition: Authorization rejection rate > 0.05 rejections/second for 2 minutes - Severity: Warning - Action: Notify security team
REQ-ALERT-RULE-003: Slow API Response Alert - Condition: 95th percentile latency > 2 seconds for 5 minutes - Severity: Warning - Action: Notify operations and development teams
REQ-ALERT-RULE-004: Service Availability Alert - Condition: Request rate drops to 0 for 1 minute (during business hours) - Severity: Critical - Action: Immediate notification to on-call engineer
REQ-ALERT-RULE-005: Abnormal Traffic Pattern Alert - Condition: Request rate > 200% of baseline for 5 minutes - Severity: Warning - Action: Notify operations team (potential DDoS or traffic spike)
8. Testing and Validation Requirements¶
8.1 Functional Testing¶
REQ-TEST-001: The system SHALL be validated through functional testing: - Verify all metrics are collected correctly - Verify metrics endpoint responds with correct data - Verify dashboards display accurate information - Verify alerts trigger under specified conditions - Verify query language produces correct results
8.2 Performance Testing¶
REQ-TEST-002: The system SHALL undergo performance testing: - Load testing with production-like traffic volumes - Stress testing to identify system limits - Latency testing for metrics collection overhead - Query performance testing with large datasets - Dashboard rendering performance testing
8.3 Integration Testing¶
REQ-TEST-003: The system SHALL be tested for integration: - Verify metrics collection from API endpoints - Verify data flow from collection to storage to visualization - Verify alert notification delivery - Verify external system integrations - Verify backup and restore procedures
9. Documentation Requirements¶
REQ-DOC-001: The system SHALL include user documentation: - Getting started guide - Dashboard creation tutorials - Query language reference - Alert configuration guide - Troubleshooting guide
REQ-DOC-002: The system SHALL include operational documentation: - Installation and deployment guide - Configuration reference - Backup and recovery procedures - Upgrade procedures - Monitoring and maintenance guide
REQ-DOC-003: The system SHALL include developer documentation: - Metrics instrumentation guide - Custom metric creation guide - API reference - Extension and plugin development - Architecture documentation
10. Compliance and Regulatory Requirements¶
REQ-COMP-001: The system SHALL comply with data protection regulations: - GDPR compliance for EU users - Data minimization principles - Right to erasure support - Data retention policies - Privacy by design
REQ-COMP-002: The system SHALL maintain audit trails: - User access logs - Configuration change logs - Alert acknowledgment logs - Data export/sharing logs - System event logs
REQ-COMP-003: The system SHOULD support compliance reporting: - Availability reports - Performance SLA reports - Security incident reports - Data retention compliance reports - Access audit reports
11. Acceptance Criteria¶
11.1 Functional Acceptance¶
The system is considered functionally acceptable when: - All three core metric categories are captured (performance, authorization, errors) - Metrics endpoint is accessible and returns data in correct format - All four standard dashboards are operational and display accurate data - All five standard alert rules are configured and trigger correctly - Query language supports required operations (aggregation, filtering, percentiles)
11.2 Performance Acceptance¶
The system is considered performance acceptable when: - Metrics collection overhead is less than 5ms per request - Metrics endpoint responds in under 500ms (95th percentile) - Dashboard load time is under 2 seconds - Simple queries return in under 1 second - System handles 1000+ requests/second metric collection
11.3 Operational Acceptance¶
The system is considered operationally acceptable when: - System achieves 99.5% uptime over 30-day period - Successful collection of 99.9% of metrics (minimal data loss) - Alert notifications delivered within 1 minute of trigger - Documentation is complete and accessible - Support team is trained on system operation
12. Future Enhancements¶
The following enhancements MAY be considered for future releases:
REQ-FUTURE-001: Advanced Analytics - Machine learning-based anomaly detection - Predictive alerting based on trends - Automatic baseline establishment - Correlation analysis across metrics
REQ-FUTURE-002: Enhanced Integration - Integration with APM (Application Performance Monitoring) tools - Distributed tracing support - Log aggregation integration - CI/CD pipeline integration
REQ-FUTURE-003: Extended Visualization - Custom visualization plugins - Geographic distribution maps - Dependency graphs - Real-time streaming dashboards
REQ-FUTURE-004: Business Metrics - Revenue impact tracking - Customer experience metrics - Business KPI dashboards - Cost optimization insights
Document Version: 1.0 Status: Draft Date: 2025-11-23 Author: TQPro Platform Team