How does IHostingEnvironment.EnvironmentName work?

Question

In a .NET Core console application, if I add the following line...

IHostingEnvironment env = new HostingEnvironment();
Console.WriteLine(env.EnvironmentName);

I get this result...

Production

But when I do the same thing in an ASP.NET Core application on the same machine...

public Startup(IHostingEnvironment env)
{
    Debug.WriteLine(env.EnvironmentName);
}

I get this result...

Development

• How exactly does EnvironmentName work?
• How can I specify that my local machine is a Development environment?
• How can I specify that Azure is a Production environment?

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As an extra point, can EnvironmentName be configured to work with Debug and Release configurations within the solution?

• Debug => Development
• Release => Production

The ultimate goal is to be able to connect to a local SQL database when built using Debug, and an Azure database when built using Release.

Answer 1

How exactly does EnvironmentName work?

.NET Core reads the name from an environmental variable.

How can I specify that my local machine is a Development environment?

Set the environmental variable to Development.

How can I specify that Azure is a Production environment?

Set the environmental variable to Production.

As an extra point, can EnvironmentName be configured to work with Debug and Release configurations within the solution?

You can create a launch profile that sets the environment name and use that profile with either Debug or Release configuration. The launch profile impacts the EnvironmentName when you launch from Visual Studio; you will need to use other means to set it, when you run the app in other environments.

The image below shows running the application in Release configuration and a MyDevProfile that sets EnvironmentName to Development.