How do I get the current environment (QA/Prod/DEV) name in net core C#?

Question

I want to get the name of the current environment (QA/Prod/DEV) in my code, so I can then use that name when calling AddJsonFile

*Note that this code is not for an application, but instead for selenium Unit tests using the test explorer test runner with NUNIT, so I do not have a Startup.cs class or ihostingenvironment that I can use.

I thought to do this, I would need to retrieve the "Hosting:Environment" or "ASPNETCORE_ENVIRONMENT" value inside the launchsettings.json, which I thought should represent the CURRENT Visual Studio process/session/environment. See Environment.GetEnvironmentVariable("Hosting:Environment") below for how I am retreiving this launchsettings.json value.

    public static IConfiguration InitConfiguration()
    {
        LaunchSettingsFixture LaunchSettings = new LaunchSettingsFixture();

        var environmentName = Environment.GetEnvironmentVariable("Hosting:Environment");

        var builder = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
            .AddJsonFile($"appsettings.{environmentName}.json", true)
            .AddEnvironmentVariables();
        var configuration = builder.Build();

        // Testing to see if the above worked
        string url = configuration["url"];
        string driverdirectory = configuration["driverdirectory"];

        return configuration;
    }

In the above code, I am expecting Environment.GetEnvironmentVariable("Hosting:Environment") to return me a string with a value of "blah" because I selected "blah" in the current process/profile/environment drop down (the drop down next to the Run button). See photo below for my current process/profile selection, and see my json text inside my launchsettings.json file below...

    {
    "profiles": {
          "Wikipedia.UITest": {
            "commandName": "Project"
               },
          "UAT": {
            "commandName": "Executable",
            "environmentVariables": {
               "Hosting:Environment": "UAT"
               }
           },
          "blah": {
            "commandName": "Executable",
            "environmentVariables": {
              "Hosting:Environment": "Development",
              "containerName": "Testing"
            }
          },
          "Prod": {
            "commandName": "Executable",
            "environmentVariables": {
              "Hosting:Environment": "prod"
            }
          }
        }
      }

Instead Environment.GetEnvironmentVariable("Hosting:Environment") returns me the last instance inside the launchsettings.json file (regardless of what I choose in the drop down as shown above in the screenshot). i.e. It is returning a value of "prod". Again, I want to mention that this is an NUNIT NET CORE project and I am using the Test Explorer to Run and Debug tests (See screenshot below)

Also, I dont know if the below code is relavent, but the below is how I set the environment variables...

    public class LaunchSettingsFixture
    {
        public LaunchSettingsFixture()
        {
            using (var file = File.OpenText("Properties\\launchSettings.json"))
            {
                var reader = new JsonTextReader(file);
                var jObject = JObject.Load(reader);

                var variables = jObject
                    .GetValue("profiles")
                    //select a proper profile here
                    .SelectMany(profiles => profiles.Children())
                    .SelectMany(profile => profile.Children<JProperty>())
                    .Where(prop => prop.Name == "environmentVariables")
                    .SelectMany(prop => prop.Value.Children<JProperty>())
                    .ToList();

                foreach (var variable in variables)
                {
                    Environment.SetEnvironmentVariable(variable.Name, variable.Value.ToString());
                }
            }
        }

    }  

Answer 1

As @Mike Zboray correctly wrote, neither VS nor Rider passes current launch profile to the test runner, so there is no way to set environment variables via launchSettings.json as of today.

Regarding LaunchSettingsFixture, it indeed goes through all the settings and add each environment variable from every profile, that's why you always see latest production configuration. Probably in the answer you referring the author implied the use of single launch profile in the project.

One possible way to approach it is to use build configuration setting and conditionally copy appsettings.*.json to the output folder. Similar to how it was done with Full .NET Framework before .NET Core.

In the project file you can configure which files to copy based on the build profile:

<ItemGroup>
  <None Update="appsettings.$(Configuration).json">
    <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
  </None>
  <None Update="appsettings.json">
    <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
  </None>
</ItemGroup>

And having required config files copied, you can add them to the configuration builder:

public static IConfiguration InitConfiguration()
{
    var settingsFiles = Directory.GetFiles(Directory.GetCurrentDirectory(), "appsettings.*.json"));
    if (settingsFiles.Length != 1) throw new Exception($"Expect to have exactly one configuration-specfic settings file, but found {string.Join(", ", settingsFiles)}.");
    var settingsFile = settingsFiles.First();

    var builder = new ConfigurationBuilder()
        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
        .AddJsonFile(settingsFile)
        .AddEnvironmentVariables();
    var configuration = builder.Build();

    // Testing to see if the above worked
    string url = configuration["url"];
    string driverdirectory = configuration["driverdirectory"];

    return configuration;
}

Remember that now you have to change Build Configuration instead of the Launch Profile to run tests against the environment of choice.