多个环境.NET Core

Question

I have a .NET Core project and I need to manage multiple environments. Let's say I have Development, Staging and Production environment. I have to manage different variables for each environment. In my Startup.cs I have already managed to have appsettings.{env.EnvironmentName}.json working, so that when i start my application with --launch-profile "ProfileName" I have the right configuration.

Now my problem is that I have to deploy this solution, so I have to do something like dotnet publish --launch-profile "ProfileName" ; i know that this syntax doesn't exist , that's why I am asking this question. I can't set the ASPNETCORE_ENVIRONMENT variable machine wide on the host , since I have multiple deploys (with multiple environments) on the same machine. I need a way to deploy with the right profile, so that the right appsettings.json is recognized by the right application. Thank you.

Answer 1

No, dotnet publish does not provide possibility to deploy specific version of configuration file for specified environment. And I believe it's good because follows separation of concerns principle.

You still have several options for covering your use case:

1.Powershell allows setting environment variable only for current PowerShell session with $Env command. You could create simple powershell launcher that sets ASPNETCORE_ENVIRONMENT environment variable and then launches the application:

$Env:ASPNETCORE_ENVIRONMENT = "Production"
# Command for launching your application

ASPNETCORE_ENVIRONMENT environment variable will be accessible only within current session and will not conflict will other deployments of your application.

This solution is somehow similar to approach suggested by Tomas Lycken, but does not require creation of service account for each environment.

2.You could also shift away from dynamic selection of configuration file ( appsettings.{env.EnvironmentName}.json ). You could put all environment-specific settings to one file (eg appSettings.environemntSpecific.json ) and deploy only one version required for some particular environment (eg Development or Production). In this case you don't need setting ASPNETCORE_ENVIRONMENT at all.

To do this, load new configuration file from BuildWebHost method:

public static IWebHost BuildWebHost(string[] args) =>
    WebHost.CreateDefaultBuilder(args)
        .ConfigureAppConfiguration((hostingContext, config) =>
        {
            config.AddJsonFile("appSettings.environemntSpecific.json", optional: true);
        }).UseStartup<Startup>()
        .Build();

The final step here is to put required version of appSettings.environemntSpecific.json file after dotnet publish command. Again, dotnet publish does not provide any possibility for such selection, so you should do it by yourself with simplest copy command.