Unprefixed Hosting Environment Variable is ignored

[astorDev]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Unprefixed hosting environment variable (ENVIRONMENT) does not affect the value of IHostEnvironment.EnvironmentName.

Expected Behavior

Setting ENVIRONMENT=X should set IHostEnvironment.EnvironmentName with precedence over ASPNETCORE_ENVIRONMENT and DOTNET_ENVIRONMENT. In the same fashion in which it's applied to any other configuration value.

Steps To Reproduce

repo: https://github.com/astorDev/hosting-env-unprefixed-variable-repro

Simple steps:

1. Create a new web project

dotnet new web

2. Run it setting "ENVIRONMENT" environment variable

export ENVIRONMENT=Repro && dotnet run

3. Search the logs for Hosting environment:

Expected	Actual
Hosting environment: Repro	Hosting environment: Development

Exceptions (if any)

No response

.NET Version

8.0.101

Anything else?

I was leaning toward assuming that the variable is ignored since it's overridden by launchSettings. But first, deleting launchSettings doesn't make a difference in the problem (only changing Development to Production). And for other variables unprefixed variables take precedence over variables prefixed with ASPNETCORE_

[davidfowl]

Why should this work? Is there some reason you can’t use the ASPNETCORE or DOTNET prefix?

[astorDev]

I expected it to work because it would be consistent with the way all other environment variables are read.

This variable seemed like a logical choice for experimenting with environment variables and ASP.NET Core and (at least for me) experimenting brought confusion as to whether unprefixed variables are used in general. While I can certainly use a prefixed variable, I wanted to at least figure out if this decision about the ENVIRONMENT variable was intentional.

[davidfowl]

It was intentional. You can set and read any environment variable via IConfiguration, but IHostingEnvironment is only impacted by ASPNETCORE_ENVIRONMENT or DOTNET_ENVIRONMENT intentionally.

[astorDev]

@davidfowl thank you for the clarification