elsa-core/src/modules/Elsa.OpenTelemetry/Middleware/OpenTelemetryTracingActivityExecutionMiddleware.cs

using System.Diagnostics;
using Elsa.OpenTelemetry.Helpers;
using Elsa.Workflows;
using Elsa.Workflows.Contracts;
using Elsa.Workflows.Pipelines.ActivityExecution;
using Elsa.Workflows.Pipelines.WorkflowExecution;
using JetBrains.Annotations;
using Activity = System.Diagnostics.Activity;
using ActivityKind = System.Diagnostics.ActivityKind;

namespace Elsa.OpenTelemetry.Middleware;

/// <inheritdoc />
[UsedImplicitly]
public class OpenTelemetryTracingActivityExecutionMiddleware(ActivityMiddlewareDelegate next) : IActivityExecutionMiddleware
{
    /// <inheritdoc />
    public async ValueTask InvokeAsync(ActivityExecutionContext context)
    {
        var activity = context.Activity;
        using var span = ElsaOpenTelemetry.ActivitySource.StartActivity($"ActivityExecution {context.ActivityDescriptor.TypeName}", ActivityKind.Internal, Activity.Current?.Context ?? default);
        span?.AddTag("activity.nodeId", activity.NodeId);
        span?.AddTag("activity.type", activity.Type);
        span?.AddTag("activity.name", activity.Name);
        span?.AddTag("activityInstance.id", context.Id);
        span?.AddTag("activityInstance.originalStatus", context.Status.ToString());
        span?.AddEvent(new ActivityEvent("Executing"));
        await next(context);
        span?.AddEvent(new ActivityEvent("Executed"));
        span?.AddTag("activityInstance.newStatus", context.Status.ToString());
    }
}

/// <summary>
/// Contains extension methods for <see cref="OpenTelemetryTracingActivityExecutionMiddleware"/>.
/// </summary>
[UsedImplicitly]
public static class OpenTelemetryTracingActivityExecutionMiddlewareExtensions
{
    /// Installs the <see cref="OpenTelemetryTracingActivityExecutionMiddleware"/> component in the workflow execution pipeline.
    public static IActivityExecutionPipelineBuilder UseActivityExecutionTracing(this IActivityExecutionPipelineBuilder pipelineBuilder) => pipelineBuilder.Insert<OpenTelemetryTracingActivityExecutionMiddleware>(0);
}