feat: Add OpenTelemetry instrumentation and configuration for enhanced telemetry tracking

3 files changed, 29 insertions, 3 deletions

diff --git a/src/Enmarcha.Backend/Controllers/ArrivalsController.cs b/src/Enmarcha.Backend/Controllers/ArrivalsController.cs
index a23c69c..eb147fc 100644
--- a/src/Enmarcha.Backend/Controllers/ArrivalsController.cs
+++ b/src/Enmarcha.Backend/Controllers/ArrivalsController.cs
@@ -46,6 +46,10 @@ public partial class ArrivalsController : ControllerBase
         [FromQuery] bool reduced
     )
     {
+        using var activity = Telemetry.Source.StartActivity("GetArrivals");
+        activity?.SetTag("stop.id", id);
+        activity?.SetTag("reduced", reduced);
+
         var tz = TimeZoneInfo.FindSystemTimeZoneById("Europe/Madrid");
         var nowLocal = TimeZoneInfo.ConvertTime(DateTime.UtcNow, tz);
         var todayLocal = nowLocal.Date;
@@ -65,12 +69,14 @@ public partial class ArrivalsController : ControllerBase
 
         if (responseBody is not { IsSuccess: true } || responseBody.Data?.Stop == null)
         {
+            activity?.SetStatus(System.Diagnostics.ActivityStatusCode.Error, "Error fetching stop data from OTP");
             LogErrorFetchingStopData(response.StatusCode, await response.Content.ReadAsStringAsync());
             return StatusCode(500, "Error fetching stop data");
         }
 
         var stop = responseBody.Data.Stop;
         _logger.LogInformation("Fetched {Count} arrivals for stop {StopName} ({StopId})", stop.Arrivals.Count, stop.Name, id);
+        activity?.SetTag("arrivals.count", stop.Arrivals.Count);
 
         List<Arrival> arrivals = [];
         foreach (var item in stop.Arrivals)
diff --git a/src/Enmarcha.Backend/Controllers/TileController.cs b/src/Enmarcha.Backend/Controllers/TileController.cs
index 4065ecd..3fdedfb 100644
--- a/src/Enmarcha.Backend/Controllers/TileController.cs
+++ b/src/Enmarcha.Backend/Controllers/TileController.cs
@@ -43,12 +43,19 @@ public class TileController : ControllerBase
     [HttpGet("stops/{z:int}/{x:int}/{y:int}")]
     public async Task<IActionResult> Stops(int z, int x, int y)
     {
+        using var activity = Telemetry.Source.StartActivity("GenerateStopsTile");
+        activity?.SetTag("tile.z", z);
+        activity?.SetTag("tile.x", x);
+        activity?.SetTag("tile.y", y);
+
         if (z is < 9 or > 20)
         {
             return BadRequest("Zoom level out of range (9-20)");
         }
 
         var cacheHit = _cache.TryGetValue($"stops-tile-{z}-{x}-{y}", out byte[]? cachedTile);
+        activity?.SetTag("cache.hit", cacheHit);
+
         if (cacheHit && cachedTile != null)
         {
             Response.Headers.Append("X-Cache-Hit", "true");
@@ -78,6 +85,7 @@ public class TileController : ControllerBase
 
         if (responseBody is not { IsSuccess: true })
         {
+            activity?.SetStatus(System.Diagnostics.ActivityStatusCode.Error, "Error fetching stop data from OTP");
             _logger.LogError(
                 "Error fetching stop data, received {StatusCode} {ResponseBody}",
                 response.StatusCode,
diff --git a/src/Enmarcha.Backend/Controllers/TransitController.cs b/src/Enmarcha.Backend/Controllers/TransitController.cs
index 00e5fb7..4853e66 100644
--- a/src/Enmarcha.Backend/Controllers/TransitController.cs
+++ b/src/Enmarcha.Backend/Controllers/TransitController.cs
@@ -38,14 +38,19 @@ public class TransitController : ControllerBase
     [HttpGet("routes")]
     public async Task<ActionResult<List<RouteDto>>> GetRoutes([FromQuery] string[] feeds)
     {
+        using var activity = Telemetry.Source.StartActivity("GetRoutes");
         if (feeds.Length == 0)
         {
             feeds = ["tussa", "vitrasa", "tranvias", "feve"];
         }
+        activity?.SetTag("feeds", string.Join(",", feeds));
 
         var serviceDate = DateTime.Now.ToString("yyyy-MM-dd");
         var cacheKey = $"routes_{string.Join("_", feeds)}_{serviceDate}";
-        if (_cache.TryGetValue(cacheKey, out List<RouteDto>? cachedRoutes))
+        var cacheHit = _cache.TryGetValue(cacheKey, out List<RouteDto>? cachedRoutes);
+        activity?.SetTag("cache.hit", cacheHit);
+
+        if (cacheHit && cachedRoutes != null)
         {
             return Ok(cachedRoutes);
         }
@@ -71,6 +76,7 @@ public class TransitController : ControllerBase
         }
         catch (Exception e)
         {
+            activity?.SetStatus(System.Diagnostics.ActivityStatusCode.Error, e.Message);
             _logger.LogError(e, "Error fetching routes");
             return StatusCode(500, "An error occurred while fetching routes.");
         }
@@ -79,10 +85,16 @@ public class TransitController : ControllerBase
     [HttpGet("routes/{id}")]
     public async Task<ActionResult<RouteDetailsDto>> GetRouteDetails(string id)
     {
+        using var activity = Telemetry.Source.StartActivity("GetRouteDetails");
+        activity?.SetTag("route.id", id);
+
         var serviceDate = DateTime.Now.ToString("yyyy-MM-dd");
         var cacheKey = $"route_details_{id}_{serviceDate}";
 
-        if (_cache.TryGetValue(cacheKey, out RouteDetailsDto? cachedDetails))
+        var cacheHit = _cache.TryGetValue(cacheKey, out RouteDetailsDto? cachedDetails);
+        activity?.SetTag("cache.hit", cacheHit);
+
+        if (cacheHit && cachedDetails != null)
         {
             return Ok(cachedDetails);
         }
@@ -104,7 +116,7 @@ public class TransitController : ControllerBase
         }
         catch (Exception e)
         {
-            _logger.LogError(e, "Error fetching route details for {Id}", id);
+            activity?.SetStatus(System.Diagnostics.ActivityStatusCode.Error, e.Message); _logger.LogError(e, "Error fetching route details for {Id}", id);
             return StatusCode(500, "An error occurred while fetching route details.");
         }
     }