FeatureMetrics.md

Feature Metrics System

The Feature Metrics system tracks usage of application features to enable cost management, performance monitoring, and business intelligence. It automatically captures metrics for all MediatR requests and HTTP endpoints.

Overview

The system consists of several components that work together to collect, process, and deliver feature usage metrics:

1. Collection Layer - Captures feature usage data
2. Processing Layer - Resolves service resource information
3. Delivery Layer - Sends metrics to monitoring systems
4. Caching Layer - Optimizes performance for resource lookups

Architecture

graph TB
    A[HTTP Request] --> B[FeatureMetricMiddleware]
    B --> C[MediatR Pipeline]
    C --> D[FeatureMetricBehaviour]
    D --> E[Service Resource Resolver]
    E --> F[FeatureMetricRecorder]
    F --> G[Delivery Context]
    G --> H[OpenTelemetry/Logging]
    
    I[Cache Layer] --> E
    J[Resource Registry] --> I
    K[Database] --> J

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Components

1. Collection Layer

FeatureMetricBehaviour

• Location: src/Digdir.Domain.Dialogporten.Application/Common/Behaviours/FeatureMetric/FeatureMetricBehaviour.cs
• Purpose: MediatR pipeline behavior that captures feature usage for each request
• Data Collected:
  • Feature name (request type)
  • Environment
  • Performer organization
  • Owner organization
  • Service resource ID

FeatureMetricMiddleware

• Location: src/Digdir.Domain.Dialogporten.WebApi/Common/FeatureMetric/FeatureMetricMiddleware.cs
• Purpose: HTTP middleware that captures endpoint-level metrics
• Data Collected:
  • Presentation tag (HTTP method + route)
  • HTTP status code
  • Correlation ID
  • Success/failure status

2. Processing Layer

Service Resource Resolvers

The system uses different resolvers based on request type:

• IFeatureMetricServiceResourceThroughDialogIdRequest - For requests with DialogId
• IFeatureMetricServiceResourceRequest - For requests with no DialogId but with ServiceResource property
• IFeatureMetricServiceResourceIgnoreRequest - For requests that don't need tracking

Caching

• Cache Type: FusionCache with Redis + Memory cache
• Configuration: 5-minute duration
• Purpose: Optimizes service resource lookups

3. Delivery Layer

Delivery Contexts

Two delivery mechanisms based on environment:

Development (Console Logging):

• Uses LoggingFeatureMetricDeliveryContext
• Outputs structured logs to console
• Immediate visibility for debugging

Production (OpenTelemetry):

• Uses OtelFeatureMetricLoggingDeliveryContext
• Sends metrics to OpenTelemetry collector
• Integrates with monitoring infrastructure

4. Data Model

FeatureMetricRecord

public sealed record FeatureMetricRecord(
    string FeatureName,           // Full type name of the request
    string? Environment,          // Environment name (dev/staging/prod)
    string? CallerOrg,            // Organization performing the action
    string? OwnerOrg,             // Organization owning the resource
    string? ServiceResource)      // Resource being accessed

Presentation Tags

Format: {HTTP_METHOD}_{route_template} Examples:

• GET_api_v1_dialogs_{dialogId}
• POST_api_v1_serviceowner_dialogs
• PATCH_api_v1_enduser_dialogs_{dialogId}

Configuration

Service Registration

// In ApplicationExtensions.cs
services
    .AddScoped(typeof(IPipelineBehavior<,>), typeof(FeatureMetricBehaviour<,>))
    .AddScoped<FeatureMetricRecorder>()
    .AddServiceResourceResolvers(thisAssembly);

Middleware Registration

// In Program.cs - must be after all endpoint processing
app.UseFeatureMetrics();

Cache Configuration

// In InfrastructureExtensions.cs
.ConfigureFusionCache(nameof(IFeatureMetricServiceResourceCache), new()
{
    Duration = TimeSpan.FromMinutes(5)
});

Usage Patterns

Adding New Requests

All MediatR requests must implement one of the feature metric interfaces:

// For requests with DialogId
public sealed class GetDialogQuery : IRequest<DialogDto>, 
    IFeatureMetricServiceResourceThroughDialogIdRequest
{
    public Guid DialogId { get; set; }
}

// For requests with no DialogId but with ServiceResource property
public sealed class SearchDialogQuery : IRequest<SearchResult>, 
    IFeatureMetricServiceResourceRequest
{
    public string ServiceResource { get; set; }
}

// For requests that don't need tracking
public sealed class GetJwksQuery : IRequest<JwksDto>, 
    IFeatureMetricServiceResourceIgnoreRequest
{
}

Service Resource Resolution

The system automatically resolves service resource information:

1. Through DialogId: Looks up dialog → service resource → organization info
2. Direct ServiceResource: Uses resource registry to get organization info
3. Ignore: Skips resource resolution entirely

Monitoring and Observability

Metrics Collected

• Feature Usage: Which features are being used and how often
• Organization Attribution: Which organizations are using which resources
• Performance: Success/failure rates per feature
• Correlation: Grouping operations by HTTP request

Query Examples

Count Endpoint Calls

SELECT COUNT(DISTINCT CorrelationId) as EndpointCalls
FROM FeatureMetrics 
WHERE PresentationTag LIKE 'GET_%'

Feature Usage by Organization

SELECT CallerOrg, COUNT(*) as UsageCount
FROM FeatureMetrics
WHERE FeatureName = 'GetDialogQuery'
GROUP BY CallerOrg

Success Rate by Feature

SELECT 
    FeatureName,
    COUNT(CASE WHEN Status = 'success' THEN 1 END) as SuccessCount,
    COUNT(*) as TotalCount,
    (COUNT(CASE WHEN Status = 'success' THEN 1 END) * 100.0 / COUNT(*)) as SuccessRate
FROM FeatureMetrics 
GROUP BY FeatureName