Add Prometheus support

Author: MusicMoveArr

MiniMediaMetadataAPI/Middlewares/RequestMiddleware.cs

@@ -0,0 +1,62 @@
+using Microsoft.Extensions.Options;
+using MiniMediaMetadataAPI.Options;
+using Prometheus;
+
+namespace MiniMediaMetadataAPI.Middlewares;
+
+public class RequestMiddleware  
+{  
+    private readonly RequestDelegate _next;  
+    private readonly ILogger _logger;  
+    private readonly PrometheusOptions _prometheusOptions;
+  
+    public RequestMiddleware(  
+        RequestDelegate next  
+        , ILoggerFactory loggerFactory
+        , IOptions<PrometheusOptions> prometheusOptions
+    )  
+    {  
+        _next = next;  
+        _logger = loggerFactory.CreateLogger<RequestMiddleware>();
+        _prometheusOptions = prometheusOptions.Value;
+    }  
+      
+    public async Task Invoke(HttpContext httpContext)  
+    {  
+        var path = httpContext.Request.Path.Value;  
+        var method = httpContext.Request.Method;  
+  
+        var counter = Metrics.CreateCounter("MiniMediaMetadataAPI_request_total", "HTTP Requests Total", new CounterConfiguration  
+        {  
+            LabelNames = new[] { "path", "method", "status" }  
+        });  
+  
+        var statusCode = 200;  
+  
+        try  
+        {  
+            await _next.Invoke(httpContext);  
+        }  
+        catch (Exception)  
+        {  
+            statusCode = 500;  
+            counter.Labels(path, method, statusCode.ToString()).Inc();  
+  
+            throw;  
+        }  
+          
+        if (path != _prometheusOptions.MetricsUrl)  
+        {  
+            statusCode = httpContext.Response.StatusCode;  
+            counter.Labels(path, method, statusCode.ToString()).Inc();  
+        }  
+    }  
+}  
+  
+public static class RequestMiddlewareExtensions  
+{          
+    public static IApplicationBuilder UseRequestMiddleware(this IApplicationBuilder builder)  
+    {  
+        return builder.UseMiddleware<RequestMiddleware>();  
+    }  
+}  

MiniMediaMetadataAPI/MiniMediaMetadataAPI.csproj

@@ -18,6 +18,8 @@
         <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
         <PackageReference Include="Npgsql" Version="9.0.3" />
         <PackageReference Include="Polly" Version="8.5.2" />
+        <PackageReference Include="prometheus-net" Version="8.2.1" />
+        <PackageReference Include="prometheus-net.AspNetCore" Version="8.2.1" />
         <PackageReference Include="Quartz" Version="3.14.0" />
         <PackageReference Include="Quartz.AspNetCore" Version="3.14.0" />
         <PackageReference Include="Quartz.Jobs" Version="3.14.0" />

MiniMediaMetadataAPI/Options/PrometheusOptions.cs

@@ -0,0 +1,6 @@
+namespace MiniMediaMetadataAPI.Options;
+
+public class PrometheusOptions
+{
+    public string MetricsUrl { get; set; }
+}

MiniMediaMetadataAPI/Program.cs

@@ -2,6 +2,9 @@
 using MiniMediaMetadataAPI.Application.Configurations;
 using MiniMediaMetadataAPI.Application.Repositories;
 using MiniMediaMetadataAPI.Application.Services;
+using MiniMediaMetadataAPI.Middlewares;
+using MiniMediaMetadataAPI.Options;
+using Prometheus;
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -13,6 +16,7 @@
 builder.Services.AddEndpointsApiExplorer();
 builder.Services.AddSwaggerGen();
 builder.Services.Configure<DatabaseConfiguration>(builder.Configuration.GetSection("DatabaseConfiguration"));
+builder.Services.Configure<PrometheusOptions>(builder.Configuration.GetSection("Prometheus"));
 
 builder.Services.AddScoped<JobRepository>();
 builder.Services.AddScoped<MusicBrainzRepository>();
@@ -28,12 +32,15 @@
 // Configure the HTTP request pipeline.
 app.UseSwagger();
 app.UseSwaggerUI();
+app.UseRequestMiddleware();
 
 //app.UseHttpsRedirection();
 
 app.UseRouting();
 app.UseCors();
 app.UseEndpoints(endpoints => endpoints.MapControllers());
+app.UseMetricServer(url: builder.Configuration.GetSection("Prometheus")["MetricsUrl"]);
+
 
 app.Run();
 

MiniMediaMetadataAPI/appsettings.json

@@ -6,7 +6,10 @@
     }
   },
   "AllowedHosts": "*",
-  "DatabaseConfiguration":{
+  "DatabaseConfiguration": {
     "ConnectionString": ""
+  },
+  "Prometheus": {
+    "MetricsUrl": "/metrics"
   }
 }