fengling-risk-control/Fengling.RiskControl.Client/RiskControlClient.cs

using Fengling.RiskControl.Configuration;
using Fengling.RiskControl.Counter;
using Fengling.RiskControl.Evaluation;
using Fengling.RiskControl.Events;
using Fengling.RiskControl.Failover;
using Fengling.RiskControl.Rules;
using Fengling.RiskControl.Sampling;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace Fengling.RiskControl;

public interface IRiskControlClient
{
    Task<RiskEvaluationResult> EvaluateRiskAsync(RiskEvaluationRequest request);
    Task<bool> IsAllowedAsync(RiskEvaluationRequest request);
    Task IncrementMetricAsync(string memberId, string metric, int value = 1);
    Task<Dictionary<string, int>> GetMemberMetricsAsync(string memberId);
    RiskControlMode GetCurrentMode();
}

public class RiskControlClient : IRiskControlClient, IDisposable
{
    private readonly IRiskEvaluator _evaluator;
    private readonly IRiskCounterService _counterService;
    private readonly IRiskEventPublisher _eventPublisher;
    private readonly ISamplingService _samplingService;
    private readonly IFailoverStrategy _failoverStrategy;
    private readonly RiskControlClientOptions _options;
    private readonly ILogger<RiskControlClient> _logger;
    private bool _disposed;

    public RiskControlClient(
        IRiskEvaluator evaluator,
        IRiskCounterService counterService,
        IRiskEventPublisher eventPublisher,
        ISamplingService samplingService,
        IFailoverStrategy failoverStrategy,
        RiskControlClientOptions options,
        ILogger<RiskControlClient> logger)
    {
        _evaluator = evaluator;
        _counterService = counterService;
        _eventPublisher = eventPublisher;
        _samplingService = samplingService;
        _failoverStrategy = failoverStrategy;
        _options = options;
        _logger = logger;
    }

    public async Task<RiskEvaluationResult> EvaluateRiskAsync(RiskEvaluationRequest request)
    {
        return await _failoverStrategy.ExecuteWithFailoverAsync(async () =>
        {
            var result = await _evaluator.EvaluateAsync(request);

            if (_samplingService.ShouldSample(result))
            {
                await _eventPublisher.PublishRiskAssessmentAsync(request, result);
            }

            if (result.Blocked)
            {
                await _eventPublisher.PublishRiskAlertAsync(request, result);
            }

            return result;
        });
    }

    public async Task<bool> IsAllowedAsync(RiskEvaluationRequest request)
    {
        var result = await EvaluateRiskAsync(request);
        return !result.Blocked;
    }

    public async Task IncrementMetricAsync(string memberId, string metric, int value = 1)
    {
        await _failoverStrategy.ExecuteWithFailoverAsync(async () =>
        {
            await _counterService.IncrementAsync(memberId, metric, value);
            return true;
        });
    }

    public async Task<Dictionary<string, int>> GetMemberMetricsAsync(string memberId)
    {
        return await _failoverStrategy.ExecuteWithFailoverAsync(async () =>
        {
            return await _counterService.GetAllValuesAsync(memberId);
        });
    }

    public RiskControlMode GetCurrentMode() => _failoverStrategy.GetCurrentMode();

    public void Dispose()
    {
        if (_disposed) return;
        _disposed = true;
    }
}

public class RiskControlClientHostedService : BackgroundService
{
    private readonly IRiskRuleLoader _ruleLoader;
    private readonly IFailoverStrategy _failoverStrategy;
    private readonly ILogger<RiskControlClientHostedService> _logger;

    public RiskControlClientHostedService(
        IRiskRuleLoader ruleLoader,
        IFailoverStrategy failoverStrategy,
        ILogger<RiskControlClientHostedService> logger)
    {
        _ruleLoader = ruleLoader;
        _failoverStrategy = failoverStrategy;
        _logger = logger;
    }

    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        _logger.LogInformation("RiskControl Client Hosted Service starting...");

        while (!stoppingToken.IsCancellationRequested)
        {
            try
            {
                var isHealthy = await _failoverStrategy.IsHealthyAsync();
                if (!isHealthy)
                {
                    _logger.LogWarning("Redis is unhealthy, client cannot function properly");
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error checking health");
            }

            await Task.Delay(TimeSpan.FromSeconds(30), stoppingToken);
        }
    }
}