From f9b7af64550be1320acc84d60184e8c8ce873b94 Mon Sep 17 00:00:00 2001
From: Ariel Costas Guerrero <ariel@costas.dev>
Date: Sun, 25 Jan 2026 21:05:33 +0100
Subject: feat: Add OpenTelemetry instrumentation and configuration for
 enhanced telemetry tracking

---
 src/Enmarcha.Backend/Program.cs | 111 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)

(limited to 'src/Enmarcha.Backend/Program.cs')

diff --git a/src/Enmarcha.Backend/Program.cs b/src/Enmarcha.Backend/Program.cs
index a13abec..8599a5c 100644
--- a/src/Enmarcha.Backend/Program.cs
+++ b/src/Enmarcha.Backend/Program.cs
@@ -1,14 +1,113 @@
 using System.Text.Json.Serialization;
+using Enmarcha.Backend;
 using Enmarcha.Backend.Configuration;
 using Enmarcha.Backend.Services;
 using Enmarcha.Backend.Services.Geocoding;
 using Enmarcha.Backend.Services.Processors;
 using Enmarcha.Backend.Services.Providers;
+using Microsoft.AspNetCore.WebUtilities;
+using OpenTelemetry.Logs;
+using OpenTelemetry.Resources;
+using OpenTelemetry.Trace;
 
 var builder = WebApplication.CreateBuilder(args);
 
 builder.Services.Configure<AppConfiguration>(builder.Configuration.GetSection("App"));
 
+var appConfig = builder.Configuration.GetSection("App").Get<AppConfiguration>();
+var otelConfig = appConfig?.OpenTelemetry;
+
+builder.Logging.AddOpenTelemetry(options =>
+{
+    options.SetResourceBuilder(ResourceBuilder.CreateDefault().AddService("Enmarcha.Backend"));
+    options.IncludeFormattedMessage = true;
+    options.IncludeScopes = true;
+
+    if (otelConfig?.Endpoint != null)
+    {
+        options.AddOtlpExporter(exporterOptions =>
+        {
+            exporterOptions.Endpoint = new Uri(otelConfig.Endpoint);
+            exporterOptions.Headers = otelConfig.Headers;
+        });
+    }
+
+#if DEBUG
+    options.AddOtlpExporter(exporterOptions =>
+    {
+        exporterOptions.Endpoint = new Uri("http://localhost:17011");
+    });
+#endif
+});
+
+builder.Services.AddOpenTelemetry()
+    .WithTracing(tracing =>
+    {
+        tracing
+            .SetResourceBuilder(ResourceBuilder.CreateDefault().AddService("Enmarcha.Backend"))
+            .AddSource(Telemetry.Source.Name)
+            .AddAspNetCoreInstrumentation()
+            .AddHttpClientInstrumentation(options =>
+            {
+                options.EnrichWithHttpRequestMessage = (activity, req) =>
+                {
+                    var host = req.RequestUri?.Host;
+                    if (host == null) return;
+
+                    // Set default peer service to host
+                    activity.SetTag("peer.service", host);
+                    activity.SetTag("server.address", host);
+
+                    if (host == "api.geoapify.com")
+                    {
+                        activity.SetTag("peer.service", "Geoapify");
+                        var query = QueryHelpers.ParseQuery(req.RequestUri!.Query);
+                        if (query.ContainsKey("apiKey"))
+                        {
+                            var uriBuilder = new UriBuilder(req.RequestUri);
+                            var newQuery = query.ToDictionary(x => x.Key, x => x.Value.ToString());
+                            newQuery["apiKey"] = "REDACTED";
+                            uriBuilder.Query = string.Join("&", newQuery.Select(x => $"{x.Key}={x.Value}"));
+                            activity.SetTag("http.url", uriBuilder.ToString());
+                        }
+                    }
+                    else if (host.Contains("tussa.org"))
+                    {
+                        activity.SetTag("peer.service", "TUSSA");
+                    }
+                    else if (host.Contains("itranvias.com"))
+                    {
+                        activity.SetTag("peer.service", "Tranvías Coruña");
+                    }
+                    else if (host.Contains("vigo.org"))
+                    {
+                        activity.SetTag("peer.service", "Vitrasa");
+                    }
+                    else if (appConfig?.OpenTripPlannerBaseUrl != null && req.RequestUri!.ToString().StartsWith(appConfig.OpenTripPlannerBaseUrl))
+                    {
+                        activity.SetTag("peer.service", "OpenTripPlanner");
+                    }
+                };
+            })
+            .SetSampler(new TraceIdRatioBasedSampler(0.75));
+
+        if (otelConfig?.Endpoint != null)
+        {
+            tracing.AddOtlpExporter(exporterOptions =>
+            {
+                exporterOptions.Endpoint = new Uri(otelConfig.Endpoint);
+                exporterOptions.Headers = otelConfig.Headers;
+            });
+        }
+
+#if DEBUG
+        tracing.AddOtlpExporter(exporterOptions =>
+        {
+            exporterOptions.Endpoint = new Uri("http://localhost:17011");
+        });
+#endif
+    });
+
 builder.Services
     .AddControllers()
     .AddJsonOptions(options =>
@@ -40,9 +139,21 @@ builder.Services.AddScoped<ArrivalsPipeline>();
 // builder.Services.AddKeyedScoped<IGeocodingService, NominatimGeocodingService>("Nominatim");
 builder.Services.AddHttpClient<IGeocodingService, GeoapifyGeocodingService>();
 builder.Services.AddHttpClient<OtpService>();
+builder.Services.AddHttpClient<Enmarcha.Sources.TranviasCoruna.CorunaRealtimeEstimatesProvider>();
+builder.Services.AddHttpClient<Enmarcha.Sources.Tussa.SantiagoRealtimeEstimatesProvider>();
+builder.Services.AddHttpClient<Costasdev.VigoTransitApi.VigoTransitApiClient>();
 
 var app = builder.Build();
 
+app.Use(async (context, next) =>
+{
+    if (context.Request.Headers.TryGetValue("X-Session-Id", out var sessionId))
+    {
+        System.Diagnostics.Activity.Current?.SetTag("session.id", sessionId.ToString());
+    }
+    await next();
+});
+
 app.MapControllers();
 
 app.Run();
-- 
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