feat: replace App.Metrics with prometheus-net

Catalogger.Backend/Bot/Commands/MetaCommands.cs

@@ -1,8 +1,8 @@
 using System.ComponentModel;
 using System.Diagnostics;
 using System.Runtime.InteropServices;
-using App.Metrics;
+using System.Text.Json;
-using Catalogger.Backend.Cache;
+using System.Web;
 using Catalogger.Backend.Cache.InMemoryCache;
 using Catalogger.Backend.Extensions;
 using Humanizer;
@@ -10,10 +10,7 @@ using Remora.Commands.Attributes;
 using Remora.Commands.Groups;
 using Remora.Discord.API.Abstractions.Objects;
 using Remora.Discord.API.Abstractions.Rest;
-using Remora.Discord.Commands.Contexts;
-using Remora.Discord.Commands.Extensions;
 using Remora.Discord.Commands.Feedback.Services;
-using Remora.Discord.Commands.Services;
 using Remora.Discord.Extensions.Embeds;
 using Remora.Discord.Gateway;
 using Remora.Results;
@@ -24,16 +21,18 @@ namespace Catalogger.Backend.Bot.Commands;
 
 [Group("catalogger")]
 public class MetaCommands(
+    ILogger logger,
     IClock clock,
-    IMetrics metrics,
+    Config config,
     DiscordGatewayClient client,
     IFeedbackService feedbackService,
-    ContextInjectionService contextInjection,
-    IInviteCache inviteCache,
     GuildCache guildCache,
     ChannelCache channelCache,
     IDiscordRestChannelAPI channelApi) : CommandGroup
 {
+    private readonly ILogger _logger = logger.ForContext<MetaCommands>();
+    private readonly HttpClient _client = new();
+
     [Command("ping")]
     [Description("Ping pong! See the bot's latency")]
     public async Task<IResult> PingAsync()
@@ -53,16 +52,15 @@ public class MetaCommands(
             inline: true);
         embed.AddField("Memory usage", memoryUsage.Bytes().Humanize(), inline: true);
 
-        var messagesReceived = metrics.Snapshot.GetForContext("Bot").Meters
+        var messageRate = await MessagesRate();
-            .FirstOrDefault(m => m.MultidimensionalName == CataloggerMetrics.MessagesReceived.Name)?.Value;
+        embed.AddField("Messages received",
-        if (messagesReceived != null)
+            messageRate != null
-            embed.AddField("Messages received", $"{messagesReceived.OneMinuteRate * 60:F1}/m", true);
+                ? $"{messageRate / 5:F1}/m\n({CataloggerMetrics.MessagesReceived.Value:N0} since last restart)"
-
+                : $"{CataloggerMetrics.MessagesReceived.Value:N0} since last restart",
-        var messageCount = metrics.Snapshot.GetForContext("Bot").Gauges
+            true);
-            .FirstOrDefault(m => m.MultidimensionalName == CataloggerMetrics.MessagesStored.Name)?.Value ?? 0;
 
         embed.AddField("Numbers",
-            $"{messageCount:N0} messages from {guildCache.Size:N0} servers\nCached {channelCache.Size:N0} channels",
+            $"{CataloggerMetrics.MessagesStored.Value:N0} messages from {guildCache.Size:N0} servers\nCached {channelCache.Size:N0} channels",
             inline: false);
 
         IEmbed[] embeds = [embed.Build().GetOrThrow()];
@@ -70,16 +68,35 @@ public class MetaCommands(
         return (Result)await channelApi.EditMessageAsync(msg.ChannelID, msg.ID, content: "", embeds: embeds);
     }
 
-    [Command("debug-invites")]
+    // TODO: add more checks around response format, configurable prometheus endpoint
-    [Description("Show a representation of this server's invites")]
+    private async Task<double?> MessagesRate()
-    public async Task<IResult> DebugInvitesAsync()
     {
-        if (contextInjection.Context is not IInteractionCommandContext ctx) throw new CataloggerError("No context");
+        if (!config.Logging.EnableMetrics) return null;
-        if (!ctx.TryGetGuildID(out var guildId)) throw new CataloggerError("No guild ID in context");
 
-        var invites = await inviteCache.TryGetAsync(guildId);
+        try
-        var text = invites.Select(i => $"{i.Code} in {i.Channel?.ID.Value}");
+        {
+            var query = HttpUtility.UrlEncode("delta(catalogger_received_messages[5m])");
+            var resp = await _client.GetAsync($"http://localhost:9090/api/v1/query?query={query}");
+            resp.EnsureSuccessStatusCode();
 
-        return await feedbackService.SendContextualAsync(string.Join("\n", text));
+            var data = await resp.Content.ReadFromJsonAsync<PrometheusResponse>();
+            _logger.Debug("Raw json: {Data}", JsonSerializer.Serialize(data));
+            var rawNumber = (data?.data.result[0].value[1] as JsonElement?)?.GetString();
+            _logger.Debug("Raw data: {Raw}", rawNumber);
+            return double.TryParse(rawNumber, out var rate) ? rate : null;
         }
+        catch (Exception e)
+        {
+            _logger.Warning(e, "Failed querying Prometheus for message rate");
+            return null;
+        }
+    }
+
+    // ReSharper disable InconsistentNaming, ClassNeverInstantiated.Local
+    private record PrometheusResponse(PrometheusData data);
+
+    private record PrometheusData(PrometheusResult[] result);
+
+    private record PrometheusResult(object[] value);
+    // ReSharper restore InconsistentNaming, ClassNeverInstantiated.Local
 }

Catalogger.Backend/Bot/Responders/MessageCreateResponder.cs

@@ -1,5 +1,4 @@
 using System.Text.RegularExpressions;
-using App.Metrics;
 using Catalogger.Backend.Cache.InMemoryCache;
 using Catalogger.Backend.Database;
 using Catalogger.Backend.Database.Models;
@@ -19,8 +18,7 @@ public class MessageCreateResponder(
     DatabaseContext db,
     MessageRepository messageRepository,
     UserCache userCache,
-    PkMessageHandler pkMessageHandler,
+    PkMessageHandler pkMessageHandler)
-    IMetrics metrics)
     : IResponder<IMessageCreate>
 {
     private readonly ILogger _logger = logger.ForContext<MessageCreateResponder>();
@@ -28,7 +26,7 @@ public class MessageCreateResponder(
     public async Task<Result> RespondAsync(IMessageCreate msg, CancellationToken ct = default)
     {
         userCache.UpdateUser(msg.Author);
-        metrics.Measure.Meter.Mark(CataloggerMetrics.MessagesReceived);
+        CataloggerMetrics.MessagesReceived.Inc();
 
         if (!msg.GuildID.IsDefined())
         {

Catalogger.Backend/Catalogger.Backend.csproj

@@ -7,7 +7,6 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <PackageReference Include="App.Metrics" Version="4.3.0"/>
         <PackageReference Include="EFCore.NamingConventions" Version="8.0.3"/>
         <PackageReference Include="EntityFrameworkCore.Exceptions.PostgreSQL" Version="8.1.2"/>
         <PackageReference Include="LazyCache" Version="2.4.0"/>
@@ -24,6 +23,8 @@
         <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL.NodaTime" Version="8.0.4"/>
         <PackageReference Include="Polly.Core" Version="8.4.1"/>
         <PackageReference Include="Polly.RateLimiting" Version="8.4.1"/>
+        <PackageReference Include="prometheus-net" Version="8.2.1" />
+        <PackageReference Include="prometheus-net.AspNetCore" Version="8.2.1" />
         <PackageReference Include="Remora.Discord" Version="2024.2.0"/>
         <PackageReference Include="Serilog" Version="4.0.1"/>
         <PackageReference Include="Serilog.AspNetCore" Version="8.0.1"/>

Catalogger.Backend/CataloggerMetrics.cs

@@ -1,88 +1,39 @@
-using App.Metrics;
+using Prometheus;
-using App.Metrics.Gauge;
-using App.Metrics.Meter;
-using App.Metrics.Timer;
 
 namespace Catalogger.Backend;
 
 public static class CataloggerMetrics
 {
-    public static MeterOptions MessagesReceived => new()
+    public static readonly Gauge MessagesReceived =
-    {
+        Metrics.CreateGauge("catalogger_received_messages", "Number of messages Catalogger has received");
-        Name = "Messages received",
-        MeasurementUnit = Unit.Events,
-        RateUnit = TimeUnit.Seconds,
-        Context = "Bot"
-    };
 
-    public static GaugeOptions GuildsCached => new()
+    public static long MessageRateMinute { get; set; }
-    {
-        Name = "Guilds cached",
-        MeasurementUnit = Unit.Items,
-        Context = "Bot"
-    };
 
-    public static GaugeOptions ChannelsCached => new()
+    public static readonly Gauge GuildsCached =
-    {
+        Metrics.CreateGauge("catalogger_cache_guilds", "Number of guilds in the cache");
-        Name = "Channels cached",
-        MeasurementUnit = Unit.Items,
-        Context = "Bot"
-    };
 
-    public static GaugeOptions UsersCached => new()
+    public static readonly Gauge ChannelsCached =
-    {
+        Metrics.CreateGauge("catalogger_cache_channels", "Number of channels in the cache");
-        Name = "Users cached",
-        MeasurementUnit = Unit.Items,
-        Context = "Bot"
-    };
 
-    public static GaugeOptions MessagesStored => new()
+    public static readonly Gauge UsersCached =
-    {
+        Metrics.CreateGauge("catalogger_cache_users", "Number of users in the cache");
-        Name = "Messages stored",
-        MeasurementUnit = Unit.Items,
-        Context = "Bot"
-    };
 
-    public static TimerOptions MetricsCollectionTime => new()
+    public static readonly Gauge MessagesStored =
-    {
+        Metrics.CreateGauge("catalogger_stored_messages", "Number of users in the cache");
-        Name = "Metrics collection time",
-        MeasurementUnit = Unit.Events,
-        DurationUnit = TimeUnit.Milliseconds,
-        Context = "Bot"
-    };
 
-    public static GaugeOptions ProcessPhysicalMemory => new()
+    public static readonly Summary MetricsCollectionTime =
-    {
+        Metrics.CreateSummary("catalogger_time_metrics", "Time it took to collect metrics");
-        Name = "Process physical memory",
-        MeasurementUnit = Unit.Bytes,
-        Context = "Process"
-    };
 
-    public static GaugeOptions ProcessVirtualMemory => new()
+    public static Gauge ProcessPhysicalMemory =>
-    {
+        Metrics.CreateGauge("catalogger_process_physical_memory", "Process physical memory");
-        Name = "Process virtual memory",
-        MeasurementUnit = Unit.Bytes,
-        Context = "Process"
-    };
 
-    public static GaugeOptions ProcessPrivateMemory => new()
+    public static Gauge ProcessVirtualMemory =>
-    {
+        Metrics.CreateGauge("catalogger_process_virtual_memory", "Process virtual memory");
-        Name = "Process private memory",
-        MeasurementUnit = Unit.Bytes,
-        Context = "Process"
-    };
 
-    public static GaugeOptions ProcessThreads => new()
+    public static Gauge ProcessPrivateMemory =>
-    {
+        Metrics.CreateGauge("catalogger_process_private_memory", "Process private memory");
-        Name = "Process thread count",
-        MeasurementUnit = Unit.Threads,
-        Context = "Process"
-    };
 
-    public static GaugeOptions ProcessHandles => new()
+    public static Gauge ProcessThreads => Metrics.CreateGauge("catalogger_process_threads", "Process thread count");
-    {
+
-        Name = "Process handle count",
+    public static Gauge ProcessHandles => Metrics.CreateGauge("catalogger_process_handles", "Process handle count");
-        MeasurementUnit = Unit.Items,
-        Context = "Process"
-    };
 }

Catalogger.Backend/Config.cs

@@ -13,6 +13,9 @@ public class Config
     {
         public LogEventLevel LogEventLevel { get; init; } = LogEventLevel.Debug;
         public bool LogQueries { get; init; } = false;
+        
+        public int MetricsPort { get; init; } = 5001;
+        public bool EnableMetrics { get; init; } = true;
     }
 
     public class DatabaseConfig
@@ -37,9 +40,7 @@ public class Config
     {
         public string Host { get; init; } = "localhost";
         public int Port { get; init; } = 5000;
-        public int? MetricsPort { get; init; }
         public string BaseUrl { get; init; } = null!;
         public string Address => $"http://{Host}:{Port}";
-        public string MetricsAddress => $"http://{Host}:{MetricsPort ?? Port}";
     }
 }

Catalogger.Backend/Extensions/StartupExtensions.cs

@@ -73,11 +73,11 @@ public static class StartupExtensions
         .AddSingleton<UserCache>()
         .AddSingleton<PluralkitApiService>()
         .AddScoped<IEncryptionService, EncryptionService>()
+        .AddSingleton<MetricsCollectionService>()
         .AddScoped<MessageRepository>()
         .AddSingleton<WebhookExecutorService>()
         .AddSingleton<PkMessageHandler>()
         .AddSingleton(InMemoryDataService<Snowflake, ChannelCommandData>.Instance)
-        .AddHostedService<MetricsCollectionService>()
         .AddSingleton<GuildFetchService>()
         .AddHostedService(serviceProvider => serviceProvider.GetRequiredService<GuildFetchService>());
 

Catalogger.Backend/Program.cs

@@ -1,8 +1,9 @@
-using App.Metrics;
 using Catalogger.Backend.Bot.Commands;
 using Catalogger.Backend.Database;
 using Catalogger.Backend.Extensions;
+using Catalogger.Backend.Services;
 using Newtonsoft.Json.Serialization;
+using Prometheus;
 using Remora.Commands.Extensions;
 using Remora.Discord.API.Abstractions.Gateway.Commands;
 using Remora.Discord.Commands.Extensions;
@@ -12,6 +13,7 @@ using Remora.Discord.Hosting.Extensions;
 using Remora.Discord.Interactivity.Extensions;
 using Remora.Discord.Pagination.Extensions;
 using Serilog;
+using Metrics = Prometheus.Metrics;
 
 var builder = WebApplication.CreateBuilder(args);
 var config = builder.AddConfiguration();
@@ -50,10 +52,12 @@ builder.Host
             .AddInteractionGroup<ChannelCommandsComponents>()
     );
 
-// Add metrics
+// Add metric server
-// TODO: add actual reporter
+// If metrics are disabled (Logging.EnableMetrics = false), also add a background service that updates
-var metricsBuilder = AppMetrics.CreateDefaultBuilder();
+// metrics every minute, as some commands rely on them.
-builder.Services.AddSingleton<IMetrics>(metricsBuilder.Build());
+builder.Services.AddMetricServer(o => o.Port = (ushort)config.Logging.MetricsPort);
+if (!config.Logging.EnableMetrics)
+    builder.Services.AddHostedService<BackgroundMetricsCollectionService>();
 
 builder.Services
     .AddDbContext<DatabaseContext>()
@@ -68,6 +72,7 @@ await app.Initialize();
 
 app.UseSerilogRequestLogging();
 app.UseRouting();
+app.UseHttpMetrics();
 app.UseSwagger();
 app.UseSwaggerUI();
 app.UseCors();
@@ -76,5 +81,9 @@ app.MapControllers();
 app.Urls.Clear();
 app.Urls.Add(config.Web.Address);
 
+// Make sure metrics are updated whenever Prometheus scrapes them
+Metrics.DefaultRegistry.AddBeforeCollectCallback(async ct =>
+    await app.Services.GetRequiredService<MetricsCollectionService>().CollectMetricsAsync(ct));
+
 app.Run();
 Log.CloseAndFlush();

Catalogger.Backend/Services/MetricsCollectionService.cs

@@ -1,10 +1,9 @@
 using System.Diagnostics;
-using App.Metrics;
 using Catalogger.Backend.Cache.InMemoryCache;
 using Catalogger.Backend.Database;
 using Humanizer;
 using Microsoft.EntityFrameworkCore;
-using NodaTime.Extensions;
+using Prometheus;
 
 namespace Catalogger.Backend.Services;
 
@@ -13,49 +12,49 @@ public class MetricsCollectionService(
     GuildCache guildCache,
     ChannelCache channelCache,
     UserCache userCache,
-    IMetrics metrics,
+    IServiceProvider services)
-    IServiceProvider services) : BackgroundService
 {
     private readonly ILogger _logger = logger.ForContext<MetricsCollectionService>();
 
-    private async Task CollectMetricsAsync()
+    public async Task CollectMetricsAsync(CancellationToken ct = default)
     {
-        var stopwatch = new Stopwatch();
+        var timer = CataloggerMetrics.MetricsCollectionTime.NewTimer();
-        stopwatch.Start();
 
         await using var scope = services.CreateAsyncScope();
         await using var db = scope.ServiceProvider.GetRequiredService<DatabaseContext>();
 
-        var messageCount = await db.Messages.CountAsync();
+        var messageCount = await db.Messages.CountAsync(ct);
 
-        metrics.Measure.Gauge.SetValue(CataloggerMetrics.GuildsCached, guildCache.Size);
+        CataloggerMetrics.GuildsCached.Set(guildCache.Size);
-        metrics.Measure.Gauge.SetValue(CataloggerMetrics.ChannelsCached, channelCache.Size);
+        CataloggerMetrics.ChannelsCached.Set(channelCache.Size);
-        metrics.Measure.Gauge.SetValue(CataloggerMetrics.UsersCached, userCache.Size);
+        CataloggerMetrics.UsersCached.Set(userCache.Size);
-        metrics.Measure.Gauge.SetValue(CataloggerMetrics.MessagesStored, messageCount);
+        CataloggerMetrics.MessagesStored.Set(messageCount);
+        CataloggerMetrics.MessageRateMinute = messageCount - CataloggerMetrics.MessageRateMinute;
 
         var process = Process.GetCurrentProcess();
-        metrics.Measure.Gauge.SetValue(CataloggerMetrics.ProcessPhysicalMemory, process.WorkingSet64);
+        CataloggerMetrics.ProcessPhysicalMemory.Set(process.WorkingSet64);
-        metrics.Measure.Gauge.SetValue(CataloggerMetrics.ProcessVirtualMemory, process.VirtualMemorySize64);
+        CataloggerMetrics.ProcessVirtualMemory.Set(process.VirtualMemorySize64);
-        metrics.Measure.Gauge.SetValue(CataloggerMetrics.ProcessPrivateMemory, process.PrivateMemorySize64);
+        CataloggerMetrics.ProcessPrivateMemory.Set(process.PrivateMemorySize64);
-        metrics.Measure.Gauge.SetValue(CataloggerMetrics.ProcessThreads, process.Threads.Count);
+        CataloggerMetrics.ProcessThreads.Set(process.Threads.Count);
-        metrics.Measure.Gauge.SetValue(CataloggerMetrics.ProcessHandles, process.HandleCount);
+        CataloggerMetrics.ProcessHandles.Set(process.HandleCount);
 
-        stopwatch.Stop();
+        _logger.Information("Collected metrics in {Duration}", timer.ObserveDuration());
-
-        metrics.Measure.Timer.Time(CataloggerMetrics.MetricsCollectionTime, stopwatch.ElapsedMilliseconds);
-        _logger.Information("Collected metrics in {Duration}", stopwatch.ElapsedDuration());
-
-        await Task.WhenAll(((IMetricsRoot)metrics).ReportRunner.RunAllAsync());
     }
+}
 
-    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+public class BackgroundMetricsCollectionService(ILogger logger, MetricsCollectionService innerService) : BackgroundService
+{
+    private readonly ILogger _logger = logger.ForContext<BackgroundMetricsCollectionService>();
+    
+    protected override async Task ExecuteAsync(CancellationToken ct)
     {
+        _logger.Information("Metrics are disabled, periodically collecting metrics manually");
+        
         using var timer = new PeriodicTimer(1.Minutes());
-        while (await timer.WaitForNextTickAsync(stoppingToken))
+        while (await timer.WaitForNextTickAsync(ct))
         {
-            _logger.Debug("Collecting periodic metrics");
+            _logger.Debug("Collecting metrics");
-            await CollectMetricsAsync();
+            await innerService.CollectMetricsAsync(ct);
-            _logger.Debug("Reported metrics to backend");
         }
     }
 }