How to publish environment specific appsettings in .Net core app?

Question

I have 3 environment specific appsettings files in my .Net core application

in project.json I have setup publishOptions

Answer 1

One possible way would be to run prepublish or postpublic scripts/commands, for example by running an gulp task executing dotnet publish-iis (alternatively use a task in prepublish section of scripts to copy the files to the before publishing.

Add this to your project.json:

"scripts": {
  "postpublish": [ "gulp cleanconfig", "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
}

You can also run a cmd or shell command here. But actually there shouldn't be any reasons why you would want to do this in the first place, just ship all 3 appconfig files, because on i.e. Azure App Service, you can switch the mode depending on the environment variables which is regulated via the Azure Portal and when publishing, the staging and production slots will be just swapped, but the environmental variables stay.

You shouldn't store secrets within the appsettings.json though (which I assume you doe and the reason you want to remove the files). Instead, use "user secrets" for development and environmental variables to set connection strings etc. for production. Works like a charm, especially with Azure App Services and docker containers.