Purview.Telemetry.SourceGenerator 4.0.0-alpha.3

Purview Telemetry Source Generator

Generates ActivitySource, ILogger, and Metrics based telemetry from methods you define on an interface.

Features

• Zero boilerplate - define methods on an interface, get full telemetry implementation generated
• Multi-target generation - generate Activities, Logging, and Metrics from a single interface
• Testable - easy mocking/substitution for unit testing
• DI-ready - automatic dependency injection registration helpers

Supported Frameworks

• .NET Framework 4.8
• .NET 8 or higher

Installation

Add to your Directory.Build.props or .csproj file:

<PackageReference Include="Purview.Telemetry.SourceGenerator" Version="4.0.0-alpha.1">
  <PrivateAssets>all</PrivateAssets>
  <IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
</PackageReference>

Quick Start

Define an interface with telemetry methods and the generator creates the implementation:

using Purview.Telemetry;

// Multi-target interface: generates Activities, Logging, AND Metrics from combined methods
[ActivitySource]
[Logger]
[Meter]
interface IEntityStoreTelemetry
{
    // MULTI-TARGET: Creates Activity + Logs Info + Increments Counter - all from one method!
    [Activity]
    [Info]
    [AutoCounter]
    Activity? GettingEntityFromStore(int entityId, [Baggage]string serviceUrl);

    // MULTI-TARGET: Adds ActivityEvent + Logs the duration
    [Event]
    [Log]
    void GetDuration(Activity? activity, int durationInMS);

    // Single-target examples (when you only need one telemetry type):
    
    // Activity-only: Adds Baggage to the Activity
    [Context]
    void RetrievedEntity(Activity? activity, float totalValue, int lastUpdatedByUserId);

    // Log-only: Structured log message
    [Warning]
    void EntityNotFound(int entityId);

    // Metric-only: Histogram for tracking values
    [Histogram]
    void RecordEntitySize(int sizeInBytes);
}

Register with dependency injection:

// Generated extension method
services.AddEntityStoreTelemetry();

Then inject and use - a single method call emits an Activity, Log, and Metric simultaneously:

public class EntityService(IEntityStoreTelemetry telemetry)
{
    public async Task<Entity> GetEntityAsync(int id, string serviceUrl, CancellationToken cancellationToken)
    {
        // Single call creates Activity AND logs AND increments counter
        using var activity = telemetry.GettingEntityFromStore(id, serviceUrl);
        
        var entity = await _repository.GetAsync(id, cancellationToken);
                        
        // Adds event to activity AND logs duration
        telemetry.GetDuration(activity, stopwatch.ElapsedMilliseconds);

        if (entity == null)
        {
            // Logs warning if entity not found
            telemetry.EntityNotFound(id);
            return null;
        })

        // Activity context addition
        telemetry.RetrievedEntity(activity, entity.TotalValue, entity.LastUpdatedByUserId);
        
        // Histogram only records size
        telemetry.RecordEntitySize(entity.SizeInBytes);

        return entity;
    }
}

Telemetry Types

Documentation

• Full Wiki
• Generated Output Examples
• Multi-Targeting Guide
• Logging Configuration

Sample Project

The .NET Aspire Sample demonstrates Activities, Logs, and Metrics generation working together with the Aspire Dashboard.

v4 Breaking Changes

Namespace Consolidation

v4 consolidates all attributes into a single namespace. Update your using statements:

Before (v3):

using Purview.Telemetry.Activities;
using Purview.Telemetry.Logging;
using Purview.Telemetry.Metrics;

After (v4):

using Purview.Telemetry;

All attributes ([ActivitySource], [Logger], [Meter], [Activity], [Event], [Log], [Counter], etc.) are now in the unified Purview.Telemetry namespace.