.net core hosted as windows service - How to use configuration files?

Question

I have a .Net Core 2 WebAPI which I wish run as a Windows service. By default, the service runs on http://localhost:5000. When I run it locally I'm using a hosting.json file to set the IP and Port there but for some reason, the service won't start when I try to use the configuration files.

Here is my code:

public static void Main(string[] args)
{
    var config = new ConfigurationBuilder()
        .SetBasePath(Directory.GetCurrentDirectory())
        .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
        .AddJsonFile("hosting.json", optional: false, reloadOnChange: true)
        .AddCommandLine(args)
        .Build();

    if (Debugger.IsAttached || args.Contains("--console"))
        BuildWebHost(config, args).Run();
    else
        BuildServiceWebHost(config, args).RunAsService();
}

public static IWebHost BuildWebHost(IConfigurationRoot config, string[] args)
{
    return WebHost.CreateDefaultBuilder(args)
        .UseConfiguration(config)
        .UseStartup<Startup>()
        .Build();
}

public static IWebHost BuildServiceWebHost(IConfigurationRoot config, string[] args)
{
    var pathToExe = Process.GetCurrentProcess().MainModule.FileName;
    var pathToContentRoot = Path.GetDirectoryName(pathToExe);

    var webHostArgs = args.Where(arg => arg != "--console").ToArray();

    return WebHost.CreateDefaultBuilder(webHostArgs)
        .UseConfiguration(config)
        .UseContentRoot(pathToContentRoot)
        .UseStartup<Startup>()
        .Build();
}

It runs on Debug (e.g. not as service), but when I set it as a windows service sc create MyService binPath="..." and try to run it I'm getting this error:

Windows could not start the MyService service on Local Computer.

Error 1053:
The service did not respond to the start or control request in a timely fashion.

I checked the Event Viewer and found this error: Exception Info: System.IO.FileNotFoundException: The configuration file 'appsettings.json' was not found and is not optional. The physical path is 'C:\WINDOWS\system32\appsettings.json'.

How do I set the config file's path to be the same as the .exe when running as a service?

Answer 1

I've managed to solve this issue in the following way:

using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.ServiceProcess;

namespace WebAPI
{
    public class Program
    {
        public static void Main(string[] args)
        {
            if (Debugger.IsAttached || args.Contains("--console"))
                BuildWebHost(args).Run();
            else
            {
                var webHost = BuildServiceWebHost(args);

                var webHostService = new CustomWebHostService(webHost);
                ServiceBase.Run(webHostService);
            }
        }

        public static IWebHost BuildWebHost(string[] args)
        {
            var config = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)
                .AddJsonFile("hosting.json", optional: false, reloadOnChange: true)
                .AddCommandLine(args)
                .Build();

            return WebHost.CreateDefaultBuilder(args)
                .UseConfiguration(config)
                .UseStartup<Startup>()
                .Build();
        }

        public static IWebHost BuildServiceWebHost(string[] args)
        {
            var pathToExe = Process.GetCurrentProcess().MainModule.FileName;
            var pathToContentRoot = Path.GetDirectoryName(pathToExe);

            var webHostArgs = args.Where(arg => arg != "--console").ToArray();

            JObject hosting = JsonConvert.DeserializeObject<JObject>(File.ReadAllText($"{pathToContentRoot}/hosting.json"));
            return WebHost.CreateDefaultBuilder(webHostArgs)
                .UseUrls(hosting.Value<string>("server.urls"))
                .UseContentRoot(pathToContentRoot)
                .UseStartup<Startup>()
                .Build();
        }
    }
}

Hope this can help others struggling the same issue.