Scribbles for my bad memory

Wen working with QuickFix/n ibrary , efficient logging is crucial for troubleshooting. Here's how to implement a custom logging solution that routes QuickFix logs through NLog to your ELK stack.

Key Components

1. NLogAdapter: A custom adapter that implements QuickFix's ILog interface:

public class NLogAdapter(ILogger logger) : ILog
{
    private const string HeartbeatPattern = @"\x0135=0\x01";
    private static readonly Regex HeartbeatRegex = new(HeartbeatPattern, RegexOptions.Compiled);

    private static bool IsHeartBeat(string message) => HeartbeatRegex.IsMatch(message);

    public void OnIncoming(string message)
    {
        if (!IsHeartBeat(message))
        {
            logger.Info("Incoming: {Message}", message);
        }
    }
    // ... other implementations
}

2. NLogQuickFixLogFactory: A factory class to create log instances:

public class NLogQuickFixLogFactory(ILog logger) : ILogFactory
{
    public ILog Create(SessionID sessionId) => logger;
    public ILog CreateNonSessionLog() => logger;
}

Implementation Steps

1. Register Dependencies in your DI container:

builder.Services.AddSingleton<NLog.ILogger>(_ => LogManager.GetCurrentClassLogger());
builder.Services.AddSingleton<ILog, NLogAdapter>();
builder.Services.AddSingleton<ILogFactory, NLogQuickFixLogFactory>();

2. Configure QuickFix to use the custom logger:

var initiator = new SocketInitiator(
    clientApp,
    storeFactory,
    sessionSettings,
    new NLogQuickFixLogFactory(quickfixLogger)  // Use custom logger injeted by ILog here 
);

Key Features

• Heartbeat Filtering: Reduces log noise by filtering out FIX heartbeat messages
• Structured Logging: Uses NLog's structured logging format for better parsing in ELK
• Separation of Concerns: Cleanly separates QuickFix logging from application logging

Benefits

1. Centralized logging in ELK stack
2. Better debugging apabilities
3. Reduced log volume through heartbeat filtering
4. Consistent logging format across your application