From 389446ee2103593b8ef27b08e7b7393e3ed2c847 Mon Sep 17 00:00:00 2001
From: Spencer Twaddle <7374698+stwaddle@users.noreply.github.com>
Date: Mon, 4 May 2026 17:29:01 -0500
Subject: [PATCH] Phase 1: Wire up OpenTelemetry in Budget.Api
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Adds OTel packages (Extensions.Hosting, Instrumentation.AspNetCore/Http/EFCore,
Exporter.OTLP) and configures logging + tracing in Program.cs. Endpoint is
intentionally left unset in code — read from OTEL_EXPORTER_OTLP_ENDPOINT at runtime.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 src/Budget.Api/Budget.Api.csproj |  5 +++++
 src/Budget.Api/Program.cs        | 18 ++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/src/Budget.Api/Budget.Api.csproj b/src/Budget.Api/Budget.Api.csproj
index 48be54e..cb46c05 100644
--- a/src/Budget.Api/Budget.Api.csproj
+++ b/src/Budget.Api/Budget.Api.csproj
@@ -13,6 +13,11 @@
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
     <PackageReference Include="Microsoft.Extensions.Diagnostics.HealthChecks.EntityFrameworkCore" Version="10.0.7" />
+    <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.15.3" />
+    <PackageReference Include="OpenTelemetry.Extensions.Hosting" Version="1.15.3" />
+    <PackageReference Include="OpenTelemetry.Instrumentation.AspNetCore" Version="1.15.2" />
+    <PackageReference Include="OpenTelemetry.Instrumentation.EntityFrameworkCore" Version="1.15.1-beta.1" />
+    <PackageReference Include="OpenTelemetry.Instrumentation.Http" Version="1.15.1" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/Budget.Api/Program.cs b/src/Budget.Api/Program.cs
index 299c82e..43c9f50 100644
--- a/src/Budget.Api/Program.cs
+++ b/src/Budget.Api/Program.cs
@@ -10,9 +10,27 @@ using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Diagnostics.HealthChecks;
 using Microsoft.Extensions.Options;
 using Microsoft.IdentityModel.Tokens;
+using OpenTelemetry.Resources;
+using OpenTelemetry.Trace;
 
 var builder = WebApplication.CreateBuilder(args);
 
+builder.Logging.AddOpenTelemetry(logging =>
+{
+    logging.IncludeFormattedMessage = true;
+    logging.IncludeScopes = true;
+});
+
+builder.Services.AddOpenTelemetry()
+    .ConfigureResource(resource => resource
+        .AddService(serviceName: "budget", serviceVersion: "1.0.0"))
+    .WithLogging()
+    .WithTracing(tracing => tracing
+        .AddAspNetCoreInstrumentation()
+        .AddHttpClientInstrumentation()
+        .AddEntityFrameworkCoreInstrumentation()
+        .AddOtlpExporter());
+
 var connStr = builder.Configuration.GetConnectionString("DefaultConnection")
     ?? $"Host={builder.Configuration["POSTGRES_HOST"] ?? "localhost"};" +
        $"Port={builder.Configuration["POSTGRES_PORT"] ?? "5432"};" +