Metrics Export Architecture

Requirements and Dataflow

Core Requirements

Multi-format metrics export supporting Prometheus and JSON standards
Configurable metrics endpoint with authentication and access control
Real-time metrics snapshot generation with performance optimization
Prometheus-compatible metric formatting with proper metadata
Content negotiation for different metric export formats
Metrics availability control with feature flag integration

Data Flow Patterns

Metrics Collection: Global Metrics → Snapshot Generation → Format Conversion → HTTP Response
Prometheus Export: Metrics Request → Authentication Check → Snapshot Retrieval → Prometheus Format → Response
JSON Export: API Request → Permission Validation → Metrics Aggregation → JSON Serialization → Response
Format Negotiation: Accept Headers → Format Selection → Appropriate Serialization → Content-Type Response
Access Control: Request → Authentication → Authorization → Metrics Filtering → Secure Response

High-level Purpose and Responsibilities

Provides standardized metrics export capabilities that enable integration with monitoring systems like Prometheus, Grafana, and custom dashboards while ensuring secure access and proper data formatting.

Core Responsibilities

Multi-Format Export: Support for Prometheus text format and JSON APIs
Secure Access: Authentication and authorization for metrics endpoints
Performance Optimization: Efficient snapshot generation and serialization
Standard Compliance: Prometheus metric format specification adherence
Content Negotiation: Automatic format selection based on client preferences
Configuration Management: Feature flag control and endpoint customization

Key Abstractions and Interfaces

Export Interfaces

prometheus_metrics(): Prometheus text format export with standard metadata
json_metrics(): JSON format export with structured metric data
format_prometheus_metrics(): Prometheus format conversion with proper naming
MetricsSnapshot: Unified metrics data structure for format conversion

Access Control

Authentication Check: Configurable authentication requirements for metrics access
Feature Flag Integration: Metrics availability control via configuration
Permission Validation: Role-based access control for sensitive metrics
Rate Limiting: Request throttling for metrics endpoints

Format Conversion

PrometheusFormatter: Text format conversion with proper escaping and metadata
JSONSerializer: Structured JSON output with hierarchical organization
ContentTypeNegotiation: Automatic format selection based on Accept headers
MetricNormalization: Consistent naming and value formatting across formats

Data Transformations and Flow

Prometheus Export Pipeline

Global Metrics → Snapshot Generation → Prometheus Format Conversion → Text Response → Client

JSON Export Pipeline

Metrics Collection → Data Aggregation → JSON Serialization → Structured Response → Dashboard

Authentication Flow

HTTP Request → Configuration Check → Authentication Validation → Metrics Access → Response Generation

Format Selection Process

Client Request → Accept Header Analysis → Format Determination → Appropriate Serialization → Response

Dependencies and Interactions

External Dependencies

axum: HTTP framework integration for endpoint handling and response generation
serde: JSON serialization for structured metric export
std::sync: Thread-safe access to shared metrics data
HeaderMap: HTTP header processing for content negotiation and authentication

Internal System Interactions

Global Metrics: Direct integration with centralized metrics collection system
Configuration: Feature flag and security configuration integration
Authentication: User authentication and authorization system integration
State Management: Application state access for configuration and security context