Using appsettings.json to configure Kestrel listen port Dotnet core 2 preview 2

Question

From what I understand the correct way of setting listen ports for ASP Dotnet Core 2 preview 1/2 is by creating a Kestrel section in the appsettings.json in the following format:

"Kestrel": {
    "EndPoints": { //Could also be Endpoints, it's a bit unclear
        "Http": {
        "Address": "127.0.0.1",
    "Port": 9001 //the port you want Kestrel to run on
},

I have tried to set up the sample webapp on a Debian machine, but when I start the app, it writes out that the app is listing on port 5000, the default port..

I know that the appsettings.json is read, because when I change the logging level to Trace, I get more info upon startup, including that no Endpoints are found and the app will use the standard 5000 port.

I have tried to search the aspnet source code on Github, and I can find a area where the Kestrel section is read from configuration (https://github.com/aspnet/Identity/blob/e38759b8a2de1b7a4a1c19462e40214b43c1cf3b/samples/IdentityOIDCWebApplicationSample/MetaPackage/KestrelServerOptionsSetup.cs), but as you can see it looks like a sample project.

What am I missing, isn't this the standard way to configure Kestrel in ASP Dotnet core 2?

score 65 · Answer 1 · edited Mar 29 '21 at 00:35

As mentioned in a comment on the accepted answer, 2.1 has support for appsettings.json, see https://blogs.msdn.microsoft.com/webdev/2018/02/02/asp-net-core-2-1-roadmap/#security

A working appsettings.json:

"Kestrel": {
  "EndPoints": {
    "Http": {
      "Url": "http://localhost:5555"
    }
  }
}

This is for a Program.cs using (created by "dotnet new webapi"):

WebHost.CreateDefaultBuilder(args)

Relevant source code in GitHub https://github.com/aspnet/MetaPackages/blob/master/src/Microsoft.AspNetCore/WebHost.cs#L163

options.Configure(builderContext.Configuration.GetSection("Kestrel"));

and https://github.com/aspnet/MetaPackages/blob/master/src/Microsoft.AspNetCore/WebHost.cs#L169

config.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)

score 12 · Accepted Answer · edited Mar 29 '21 at 00:24

12

Support for Kestrel configuration via appsettings.json has been dropped in 2.0.

See this issue comment:

kestrel config file support was cut from 2.0.0. Config values need to be read manually in your initialization code.

To get around this, you can do something like this in program.cs:

public static IWebHost BuildWebHost(string[] args) =>
 WebHost.CreateDefaultBuilder(args)
 .UseStartup < Startup > ()
 .UseKestrel((hostingContext, options) => 
 { 
  if (hostingContext.HostingEnvironment.IsDevelopment) {
   options.Listen(IPAddress.Loopback, 9001);
   options.Listen(IPAddress.Loopback, 9002, listenOptions => {
    listenOptions.UseHttps("certificate.pfx", "password");
   });
  }
 })
 .Build();

edited Mar 29 '21 at 00:24

Pang

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answered Oct 12 '17 at 01:42

marcusturewicz

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.UseKestrel((hostingContext, options) => { var env = hostingContext.HostingEnvironment; } Cleaner than: var env = Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT"); – dotnet-provoke Apr 09 '18 at 11:42
6

This will become redundant when 2.1 is released as suuport for Kestrel via configuration will be back, and HTTPS in development will be on by default https://blogs.msdn.microsoft.com/webdev/2018/02/02/asp-net-core-2-1-roadmap/#security. – marcusturewicz Apr 11 '18 at 01:31

score 3 · Answer 3 · edited Nov 13 '19 at 23:16

3

I am using Program.cs and hosting.json file to configure Kestrel. Example:

    var config = new ConfigurationBuilder()
                    .SetBasePath(Directory.GetCurrentDirectory())
                    .AddJsonFile("hosting.json", optional: true, reloadOnChange: true)
                    .Build();

    var host = new WebHostBuilder()
                    .UseConfiguration(config)
                    .UseKestrel()
                    .UseContentRoot(Directory.GetCurrentDirectory())
                    .UseStartup<Startup>();

hosting.json:

{
    "urls": "http://localhost:4444;http://localhost:4445;"
}

This above is an example for the latest version dotnet core.

For earlier versions:

hosting.json:

{
    "server.urls": "http://localhost:4444;http://localhost:4445;"
}

edited Nov 13 '19 at 23:16

Trevor Reid

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answered Jul 28 '17 at 18:11

Алексей Сидоров

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1
4

This his the similar way I have configured Kestrel in core 1.1, and it's i possible to do it this way, but I have read multiple places that the future way of doing it should be by using the Kestrel section in appsettings.json. https://codingblast.com/asp-net-core-2-preview/ – Niklas Gislum Jul 29 '17 at 11:02
I saw that video and it looked so simple. I've been trying myself using the same method and I cannot get it to work either. Anyone else have any luck with this? – sshirley Aug 29 '17 at 17:16
I'm also having this problem with asp.net core 2.0. Nothing I put in appsettings.json gets used. I don't understand it because appsettings should be read by default in the new asp.net core with the default configuration builder. – marcusturewicz Sep 25 '17 at 08:54
@tura08 , its possible to use appsettings.json, see here: https://stackoverflow.com/questions/46696115/whats-the-point-of-hosting-json-since-appsettings-json-is-sufficient – Jawad Al Shaikh Oct 11 '17 at 20:33

score 2 · Answer 4 · edited Mar 29 '21 at 00:41

2

To run Visual Studio with Kestrel, just edit appsettings.json and add the config like this (tested with NetCore 2.0 and 2.1):

"profiles" : {
    "Kestrel": {
      "commandName": "Project",
      "launchBrowser": true,
      "applicationUrl": "http://localhost:6969/"
    }
}

edited Mar 29 '21 at 00:41

Pang

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answered Apr 03 '18 at 19:37

ealvess

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score 0 · Answer 5 · edited Mar 29 '21 at 00:33

I had the same issue whereby my Kestrel configuration in appsettings.json is not being picked up. From this article about migrating from asp.net core 2.0 to 2.1, I updated the bootstraping code to become like the below, and it worked for me.

public static void Main(string[] args)
{
    CreateWebHostBuilder(args).Build().Run();
}

public static IWebHostBuilder CreateWebHostBuilder(string[] args)
{
    return WebHost.CreateDefaultBuilder(args) 
        .UseStartup<Startup>();
}

Using appsettings.json to configure Kestrel listen port Dotnet core 2 preview 2

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