brunneus

var logRecords = ReadLogFile(logFilePath);

var grouping = logRecords.GroupBy(l => l.StatusCode);

foreach (var group in grouping)
{
    Console.WriteLine($"StatusCode: {group.Key} - Count: {group.Count()}");
}

brunneus

var repository = new CustomerRepository();

var id = 1;

var existingCustomer = repository.GetCustomerById(id)
    .Match(
        some: (foundCustomer) => foundCustomer,
        none: () => throw new Exception($"Customer with id {id} does not exists");

Console.WriteLine($"Hello customer {existingCustomer.Name}");

brunneus

public class CustomerRepository
{
    public Maybe<Customer> GetCustomerById(int id)
    {
        var customer = SomeDatabaseAbstraction.GetUser(id);
        return new Maybe<Customer>(customer, customer != null);
    }
}

brunneus

public class Maybe<T>
{
    private T Value { get; }

    private bool IsSome { get; }

    public Maybe(T value, bool isSome)
    {
        Value = value;
        IsSome = isSome;

brunneus

using Flurl.Http;
using Polly;
using Polly.Retry;
using System;
using System.Linq;
using System.Net;
using System.Threading.Tasks;

namespace ResilientHttpClient
{

brunneus

public async Task<T> GetJsonAsync<T>(string url, object headers = null)
{
    var policy = BuildRetryPolicy();

    return await policy.ExecuteAsync(() => url
        .WithHeaders(headers)
        .GetJsonAsync<T>()
    );
}

brunneus

public async Task<T> GetJsonAsync<T>(string url, object headers = null)
{
    return await url
        .WithHeaders(headers)
        .GetJsonAsync<T>();
}

brunneus

private bool IsTransientError(FlurlHttpException exception)
{
    int[] httpStatusCodesWorthRetrying =
    {
        (int)HttpStatusCode.RequestTimeout, // 408
        (int)HttpStatusCode.BadGateway, // 502
        (int)HttpStatusCode.ServiceUnavailable, // 503
        (int)HttpStatusCode.GatewayTimeout // 504
    };

brunneus

private AsyncRetryPolicy BuildRetryPolicy()
{
    var retryPolicy = Policy
       .Handle<FlurlHttpException>(IsTransientError)
       .WaitAndRetryAsync(3, retryAttempt =>
       {
           var nextAttemptIn = TimeSpan.FromSeconds(Math.Pow(2, retryAttempt));
           Console.WriteLine($"Retry attempt {retryAttempt} to make request. Next try on {nextAttemptIn.TotalSeconds} seconds.");
           return nextAttemptIn;
       });

brunneus

public class HttpClient
{
    public HttpClient()
    {

    }
}