C#•4mo ago

My Discord app is using all my memory. What am I doing wrong?

I'm making what I thought was a simple dice rolling app for Discord. The user tells it how many dice to roll, any static modifiers to the total, and an optional description for the action being taken. However, when I run the app I can only do a small handful of commands before my computer tells me that VS Code is using too much memory and I need to close it down. Sometimes the console even says something about heartbeat being too slow and a possible thread starvation. I don't have that much code written so I'm not sure what's going on, but here's what I currently have:

// Program.cs
using D6.Api.Commands;
using D6.Api.Discord;
using Microsoft.AspNetCore.Mvc;
using System.Text.Json;
using System.Text.Json.Nodes;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddSingleton<DiscordHelper>();

var app = builder.Build();

app.MapPost("/", async (HttpContext ctx,
                [FromHeader(Name = "X-Signature-Ed25519")] string sig,
                [FromHeader(Name = "X-Signature-Timestamp")] string timestamp,
                [FromServices] DiscordHelper DiscordHelper) =>
{

    using StreamReader reader = new(ctx.Request.Body);
    string body = await reader.ReadToEndAsync();
    JsonDocument jsonBody = JsonDocument.Parse(body);
    JsonElement interaction = jsonBody.RootElement.Clone();
    jsonBody.Dispose();

    bool is_verified = DiscordHelper.VerifySignature(body, timestamp, sig);

    if (!is_verified)
    {
        return Results.Unauthorized();
    }

    int interaction_type = interaction.GetProperty("type").GetInt32();

    if (interaction_type == 1)
    {
        return Results.Ok(new JsonObject
        {
            ["type"] = 1
        });
    }

    string CommandName = interaction.GetProperty("data").GetProperty("name").GetString()!;

    JsonObject JsonReply = CommandName switch
    {
        "d6" => Commands.D6(interaction),
        _ => new JsonObject()
    };

    return Results.Ok(JsonReply);
});

app.Run();

// Program.cs
using D6.Api.Commands;
using D6.Api.Discord;
using Microsoft.AspNetCore.Mvc;
using System.Text.Json;
using System.Text.Json.Nodes;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddSingleton<DiscordHelper>();

var app = builder.Build();

app.MapPost("/", async (HttpContext ctx,
                [FromHeader(Name = "X-Signature-Ed25519")] string sig,
                [FromHeader(Name = "X-Signature-Timestamp")] string timestamp,
                [FromServices] DiscordHelper DiscordHelper) =>
{

    using StreamReader reader = new(ctx.Request.Body);
    string body = await reader.ReadToEndAsync();
    JsonDocument jsonBody = JsonDocument.Parse(body);
    JsonElement interaction = jsonBody.RootElement.Clone();
    jsonBody.Dispose();

    bool is_verified = DiscordHelper.VerifySignature(body, timestamp, sig);

    if (!is_verified)
    {
        return Results.Unauthorized();
    }

    int interaction_type = interaction.GetProperty("type").GetInt32();

    if (interaction_type == 1)
    {
        return Results.Ok(new JsonObject
        {
            ["type"] = 1
        });
    }

    string CommandName = interaction.GetProperty("data").GetProperty("name").GetString()!;

    JsonObject JsonReply = CommandName switch
    {
        "d6" => Commands.D6(interaction),
        _ => new JsonObject()
    };

    return Results.Ok(JsonReply);
});

app.Run();

43 Replies

13eckOP•4mo ago

// DiscordHelper.cs
using System.Text;
using NSec.Cryptography;


namespace D6.Api.Discord;

public class DiscordHelper
{
  private readonly PublicKey public_key;
  private readonly SignatureAlgorithm algo;

  public DiscordHelper()
  {
    ReadOnlySpan<byte> string_key = Convert.FromHexString("acda45c91f61e68d267d51d44a3fbd8142859875b77a1f7198421b7ab32f654d");
    public_key = PublicKey.Import(SignatureAlgorithm.Ed25519, string_key, KeyBlobFormat.RawPublicKey);
    algo = SignatureAlgorithm.Ed25519;
  }

  public bool VerifySignature(string jsonString, string timestamp, string signature)
  {

    ReadOnlySpan<byte> signatureSpan = Convert.FromHexString(signature);
    ReadOnlySpan<byte> data = Encoding.UTF8.GetBytes($"{timestamp}{jsonString}");
    bool isVerified = algo.Verify(public_key, data, signatureSpan);
    return isVerified;
  }
  
}

// DiscordHelper.cs
using System.Text;
using NSec.Cryptography;


namespace D6.Api.Discord;

public class DiscordHelper
{
  private readonly PublicKey public_key;
  private readonly SignatureAlgorithm algo;

  public DiscordHelper()
  {
    ReadOnlySpan<byte> string_key = Convert.FromHexString("acda45c91f61e68d267d51d44a3fbd8142859875b77a1f7198421b7ab32f654d");
    public_key = PublicKey.Import(SignatureAlgorithm.Ed25519, string_key, KeyBlobFormat.RawPublicKey);
    algo = SignatureAlgorithm.Ed25519;
  }

  public bool VerifySignature(string jsonString, string timestamp, string signature)
  {

    ReadOnlySpan<byte> signatureSpan = Convert.FromHexString(signature);
    ReadOnlySpan<byte> data = Encoding.UTF8.GetBytes($"{timestamp}{jsonString}");
    bool isVerified = algo.Verify(public_key, data, signatureSpan);
    return isVerified;
  }
  
}

// Commands.cs
using System.Text.Json;
using System.Text.Json.Nodes;
using D6.Api.Dice;

namespace D6.Api.Commands;

public class Commands
{

  public static JsonObject D6(JsonElement interaction)
  {
    // get data from the interaction

    int numDiceToRoll = 0;
    int numPip = 0;
    string description = "";

    foreach (JsonElement option in interaction.GetProperty("data").GetProperty("options").EnumerateArray())
    {
      string name = option.GetProperty("name").GetString()!;
      if (name == "description") { description = option.GetProperty("value").GetString()!; }
      else if (name == "die_code") { numDiceToRoll = option.GetProperty("value").GetInt32(); }
      else if (name == "pips") { numPip = option.GetProperty("value").GetInt32(); }
    };

    // roll xD6
    DiceRoller dice = new();

    List<DieCode> normalDice = dice.RollDieCode(numDiceToRoll - 1);
    List<DieCode> wildDie = dice.RollWild();
    List<DieCode> combined = [.. normalDice, .. wildDie];

    int total = numPip;
    string emojis = combined.Aggregate("", (a, d) =>
    {
      total += d.Value;
      a += $"{d.Markdown} ";
      return a;
    });


    return new JsonObject()
    {
      ["type"] = 4,
      ["data"] = new JsonObject
      {
        ["embeds"] = new JsonArray{
            new JsonObject{
              ["title"] = $"You got {total}!",
              ["description"] = emojis
            }
          }
      }
    };
  }
}

// Commands.cs
using System.Text.Json;
using System.Text.Json.Nodes;
using D6.Api.Dice;

namespace D6.Api.Commands;

public class Commands
{

  public static JsonObject D6(JsonElement interaction)
  {
    // get data from the interaction

    int numDiceToRoll = 0;
    int numPip = 0;
    string description = "";

    foreach (JsonElement option in interaction.GetProperty("data").GetProperty("options").EnumerateArray())
    {
      string name = option.GetProperty("name").GetString()!;
      if (name == "description") { description = option.GetProperty("value").GetString()!; }
      else if (name == "die_code") { numDiceToRoll = option.GetProperty("value").GetInt32(); }
      else if (name == "pips") { numPip = option.GetProperty("value").GetInt32(); }
    };

    // roll xD6
    DiceRoller dice = new();

    List<DieCode> normalDice = dice.RollDieCode(numDiceToRoll - 1);
    List<DieCode> wildDie = dice.RollWild();
    List<DieCode> combined = [.. normalDice, .. wildDie];

    int total = numPip;
    string emojis = combined.Aggregate("", (a, d) =>
    {
      total += d.Value;
      a += $"{d.Markdown} ";
      return a;
    });


    return new JsonObject()
    {
      ["type"] = 4,
      ["data"] = new JsonObject
      {
        ["embeds"] = new JsonArray{
            new JsonObject{
              ["title"] = $"You got {total}!",
              ["description"] = emojis
            }
          }
      }
    };
  }
}

// Dice.cs
using System.Text;

namespace D6.Api.Dice;

public class DiceRoller()
{
  private readonly Random rand = new();
  private readonly DieCode[] normalDice = [new(":dn1:", 1),
                                          new(":dn2:", 2),
                                          new(":dn3:", 3),
                                          new(":dn4:", 4),
                                          new(":dn5:", 5),
                                          new(":dn6:", 6)];
  private readonly DieCode[] WildDice = [new(":wn1:", 1),
                                        new(":wn2:", 2),
                                        new(":wn3:", 3),
                                        new(":wn4:", 4),
                                        new(":wn5:", 5),
                                        new(":wn6:", 6)];


  public List<DieCode> RollDieCode(int numToRoll)
  {
    if (numToRoll < 1) { numToRoll = 1; }
    IEnumerable<DieCode> storage = Enumerable.Range(0, numToRoll).Select(_ =>
    {
      int idx = rand.Next(6);
      return normalDice[idx];
    });

    return storage.ToList();
  }

  public List<DieCode> RollWild()
  {

    int idx = rand.Next(6);
    List<DieCode> storage = new();

    do
    {
      storage.Add(WildDice[idx]);
    } while (idx == 5);

    return storage;
  }

}
public record DieCode(
  string Markdown,
  int Value
);

// Dice.cs
using System.Text;

namespace D6.Api.Dice;

public class DiceRoller()
{
  private readonly Random rand = new();
  private readonly DieCode[] normalDice = [new(":dn1:", 1),
                                          new(":dn2:", 2),
                                          new(":dn3:", 3),
                                          new(":dn4:", 4),
                                          new(":dn5:", 5),
                                          new(":dn6:", 6)];
  private readonly DieCode[] WildDice = [new(":wn1:", 1),
                                        new(":wn2:", 2),
                                        new(":wn3:", 3),
                                        new(":wn4:", 4),
                                        new(":wn5:", 5),
                                        new(":wn6:", 6)];


  public List<DieCode> RollDieCode(int numToRoll)
  {
    if (numToRoll < 1) { numToRoll = 1; }
    IEnumerable<DieCode> storage = Enumerable.Range(0, numToRoll).Select(_ =>
    {
      int idx = rand.Next(6);
      return normalDice[idx];
    });

    return storage.ToList();
  }

  public List<DieCode> RollWild()
  {

    int idx = rand.Next(6);
    List<DieCode> storage = new();

    do
    {
      storage.Add(WildDice[idx]);
    } while (idx == 5);

    return storage;
  }

}
public record DieCode(
  string Markdown,
  int Value
);

Becquerel•4mo ago

nothing stands out as immediately wrong... the warning about potential thread starvation is interesting, since the only thing here I can see which would spin up more threads is just receiving requests to your endpoint. i would try trimming out as much of the code as you can (sticking a 'return' at some early point in your MapPost, for instance) to see what minimal example you can get which reproduces the issue

Keswiik•4mo ago

if you're doing this in visual studio, use the memory profiler and observe how memory usage changes as you execute commands

Becquerel•4mo ago

they're in vscode but i would second that recommendation

Keswiik•4mo ago

shit, missed that part need more caffeine :Smug:

13eckOP•4mo ago

VS Code on Mac Though now I'm wondering if it's the VS Code terminal. I'll try running it from the actual terminal to see if anything changes Well I was able to run a lot more commands before the out of memory alert popped up…but it still popped up. I guess I'll throw up some early return statements to see what I can find out

Becquerel•4mo ago

what is the specific error message you're getting related to heartbeats and thread starvation, out of curiosity?

13eckOP•4mo ago

As of "08/16/2024 17:16:46 +00:00", the heartbeat has been running for "00:00:01.0572152" which is longer than "00:00:01". This could be caused by thread pool starvation.

Becquerel•4mo ago

ah, ok. searching that up confirmed this error is coming from within aspnet core

Becquerel•4mo ago

i would suggest reading through this https://learn.microsoft.com/en-us/dotnet/core/diagnostics/debug-threadpool-starvation

Debug ThreadPool Starvation - .NET

A tutorial that walks you through debugging and fixing a ThreadPool starvation issue on .NET Core

Becquerel•4mo ago

and specifically trying out dotnet-counters it should let you hopefully get a better view on when new threads are being spawned how are you testing this, by the way? could it be an issue where you're triggering your endpoint way more frequently than intended, by some misconfiguration with discord?

13eckOP•4mo ago

I added in early return statements at various parts of the code and have found the error to happen somewhere in here:

// In Commands.cs
DiceRoller dice = new();

List<DieCode> normalDice = dice.RollDieCode(numDiceToRoll - 1);
List<DieCode> wildDie = dice.RollWild();
List<DieCode> combined = [.. normalDice, .. wildDie];

// In Commands.cs
DiceRoller dice = new();

List<DieCode> normalDice = dice.RollDieCode(numDiceToRoll - 1);
List<DieCode> wildDie = dice.RollWild();
List<DieCode> combined = [.. normalDice, .. wildDie];

I'm running it on localhost and using NGrok to tunnel to my machine and running the slash command in a test server

Becquerel•4mo ago

🤔 how strange...

13eckOP•4mo ago

So it seems the issue is in the DiceRoller class

Becquerel•4mo ago

the only possible thing I can think of is that you're maybe instantiating the diceroller way more than you expect to, somehow since there's nothing in there doing anything relating to threading what if you remove all the calls to Random.Next() and replace them with hardcoded values?

13eckOP•4mo ago

Would it be better to register it as a singleton or something? So I'm not making a new one for each API call?

Keswiik•4mo ago

i'd register it as a singleton, don't see much point in making a new instance of it every time

Becquerel•4mo ago

plausibly, though i would be really surprised if a class that lightweight is causing issues

Keswiik•4mo ago

my only guess is that something could maintain a reference to it, so it (or something it uses) never gets GC'd.... but it doesn't look like that should be the case anyways so i'm not sure

Becquerel•4mo ago

i will be fascinated to find out what the root cause of this is

Keswiik•4mo ago

memory profiler of any kind would make this super simple to debug :pepeHands:

13eckOP•4mo ago

Is there a memory profiler for VS Code for Mac? Or is that something I need to find on the machine itself?

Keswiik•4mo ago

honestly not aware of any good profilers for mac not sure if visual studio community has a mac build either (iirc VS for mac is getting discontinued soon anyways?) but it's something you could check but i would go with bec's advice and see what happens when you get rid of your Random calls you can also make your normalDice and WildDice arrays static, no reason to instantiate those each time

13eckOP•4mo ago

If I do that would I need to instantiate a new Random inside each, then? Or how does class properites work for static methods? I'm still pretty new to C# and .NET so I apologize that I don't know how things work

Becquerel•4mo ago

you can use the Random.Shared property to have only one instance of it

13eckOP•4mo ago

How do I do that?

Becquerel•4mo ago

a static property inside a class means it essentially only exists once, no matter how many times you new() up the class

13eckOP•4mo ago

Oh, I see how!

Becquerel•4mo ago

as in, you can write 'var number = Random.Shared.Next()';

Keswiik•4mo ago

https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/static-classes-and-static-class-members

Static Classes and Static Class Members - C#

Static classes can't be instantiated in C#. You access the members of a static class by using the class name itself.

Keswiik•4mo ago

some relevant docs on statics in c#

13eckOP•4mo ago

Thanks! Well, tried to replace the Random.next() calls with a pre-defined array of indices and I wasn't even able to call the command once before it shat the bed 😭

public static List<DieCode> RollDieCode(int numToRoll)
  {
    int[] fakeRand = [5,1,3,2,5,3,0,2,3,4,1,5,0,3,1,4,5,0];
    if (numToRoll < 1) { numToRoll = 1; }
    int i = 0;
    IEnumerable<DieCode> storage = Enumerable.Range(0, numToRoll).Select(_ =>
    {
      int idx = fakeRand[i];
      i++;
      return normalDice[idx];
    });

    return storage.ToList();
  }
public static List<DieCode> RollWild()
  {
    int[] fakeRand = [5,1,3,2,5,3,0,2,3,4,1,5,0,3,1,4,5,0];
    int i = 0; 
    int idx = fakeRand[i];
    List<DieCode> storage = new();

    do
    {
      storage.Add(WildDice[idx]);
      i++;
    } while (idx == 5);

    return storage;
  }

public static List<DieCode> RollDieCode(int numToRoll)
  {
    int[] fakeRand = [5,1,3,2,5,3,0,2,3,4,1,5,0,3,1,4,5,0];
    if (numToRoll < 1) { numToRoll = 1; }
    int i = 0;
    IEnumerable<DieCode> storage = Enumerable.Range(0, numToRoll).Select(_ =>
    {
      int idx = fakeRand[i];
      i++;
      return normalDice[idx];
    });

    return storage.ToList();
  }
public static List<DieCode> RollWild()
  {
    int[] fakeRand = [5,1,3,2,5,3,0,2,3,4,1,5,0,3,1,4,5,0];
    int i = 0; 
    int idx = fakeRand[i];
    List<DieCode> storage = new();

    do
    {
      storage.Add(WildDice[idx]);
      i++;
    } while (idx == 5);

    return storage;
  }

Is it because I'm using records instead of classes? I Thought they were supposed to be more efficient for "dumb data containers". It can't be that I'm doing too many lists, right? I'm gonna take a break and come back later with fresh eyes. Maybe something will pop out at me… (I also made the two dice arrays static so the static methods could use them)

Becquerel•4mo ago

there is definitely something extremely strange going on here that is not at all obvious from your code so i highly suspect something weird in your environment or testing mechanism it's a shame you don't have good profiling tools on mac... maybe you can resort to logging Thread.CurrentThread or something lmao to see when new threads are being spawned

13eckOP•4mo ago

So I have no idea WTF I did or didn't do…but it's been fixed?

// Dice.cs
using System.Text;

namespace D6.Api.Dice;

public class DiceRoller
{
  private readonly static DieCode[] normalDice = [new(":dn1:", 1),
                                          new(":dn2:", 2),
                                          new(":dn3:", 3),
                                          new(":dn4:", 4),
                                          new(":dn5:", 5),
                                          new(":dn6:", 6)];
  private readonly static DieCode[] WildDice = [new(":wn1:", 1),
                                        new(":wn2:", 2),
                                        new(":wn3:", 3),
                                        new(":wn4:", 4),
                                        new(":wn5:", 5),
                                        new(":wn6:", 6)];

  


  public static List<DieCode> RollDieCode(int numToRoll)
  {
    if (numToRoll < 1) { numToRoll = 1; }

    IEnumerable<DieCode> storage = Enumerable.Range(0, numToRoll).Select(_ =>
    {
      int idx = Random.Shared.Next(6);
      return normalDice[idx];
    });

    return storage.ToList();
  }

  public static List<DieCode> RollWild()
  {
    List<DieCode> storage = new();
    int idx = 0;
    do
    {
      idx = Random.Shared.Next(6);
      storage.Add(WildDice[idx]);
    } while (idx == 5);

    return storage;
  }

}
public record DieCode(
  string Markdown,
  int Value
);

// Dice.cs
using System.Text;

namespace D6.Api.Dice;

public class DiceRoller
{
  private readonly static DieCode[] normalDice = [new(":dn1:", 1),
                                          new(":dn2:", 2),
                                          new(":dn3:", 3),
                                          new(":dn4:", 4),
                                          new(":dn5:", 5),
                                          new(":dn6:", 6)];
  private readonly static DieCode[] WildDice = [new(":wn1:", 1),
                                        new(":wn2:", 2),
                                        new(":wn3:", 3),
                                        new(":wn4:", 4),
                                        new(":wn5:", 5),
                                        new(":wn6:", 6)];

  


  public static List<DieCode> RollDieCode(int numToRoll)
  {
    if (numToRoll < 1) { numToRoll = 1; }

    IEnumerable<DieCode> storage = Enumerable.Range(0, numToRoll).Select(_ =>
    {
      int idx = Random.Shared.Next(6);
      return normalDice[idx];
    });

    return storage.ToList();
  }

  public static List<DieCode> RollWild()
  {
    List<DieCode> storage = new();
    int idx = 0;
    do
    {
      idx = Random.Shared.Next(6);
      storage.Add(WildDice[idx]);
    } while (idx == 5);

    return storage;
  }

}
public record DieCode(
  string Markdown,
  int Value
);

I ran the command over 30 times in a row and there's a bit of lag, but I assume that's because of NGrok and when it's on a real server it'll be faster The Dice.cs file is the only one I made any changes to

Becquerel•4mo ago

:thimking: what were the changes?

Keswiik•4mo ago

using shared random it seems

13eckOP•4mo ago

Shared random, yeah, and for some reason the class name was originally public class DiceRoller() instead of public class DiceRoller. I assume the () did something wonky

Becquerel•4mo ago

i think the () would've just added a 'primary constructor' that did nothing which was likely not relevant interesting that using random.shared had that big an impact it would imply you were creating a truly massive number of DiceRollers

13eckOP•4mo ago

No idea why that is, but at least it's working better now. Next step is to get the rest of the functionality working (asking for description of the action behind the dice roll) and then getting a single DLL or whatever to upload it to my linux server. My other Discord apps were written in Node.js and Go…so this is my first C#/.NET Discord app!

Becquerel•4mo ago

🙂 congrats!

13eckOP•4mo ago

Thanks for the help, (other) bec! lol

Becquerel•4mo ago

lol no worries

13eckOP•4mo ago

If y'all wanna see it in action it's up and running! https://discord.com/oauth2/authorize?client_id=1274372466642260072

Gaming

Programming

My Discord app is using all my memory. What am I doing wrong?