Error restoring WebAPI project using .NET 9

[FraserElectronics]

I have created a WebAPI on a Linux machine using:

dotnet new webapi -n myapp.

I wish to host this API in a docker container so I have followed the instructions here: https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/docker/building-net-docker-images?view=aspnetcore-9.0

When I run docker build -t myapp . I get the error:

error NETSDK1045: The current .NET SDK does not support targeting .NET 9.0.  Either target .NET 8.0 or lower, or use a version of the .NET SDK that supports .NET 9.0.

If I list the installed sdk's with dotnet --list-sdks I get:

9.0.100 [/usr/lib/dotnet/sdk]

What am I missing?

Andy

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[julealgon]

@FraserElectronics do you have a global.json file in your solution?

[vcsjones]

The Dockerfile on the linked page might need to be updated. It has a line like this:

FROM mcr.microsoft.com/dotnet/sdk:8.0 AS build

If you are using .NET 9, which it looks like you are, you should change the version numbers in the Dockerfile to 9.0 instead of 8.0.

[Clockwork-Muse]

Side note: recent version of the SDK have build-pack-like capabilities (if not using that tool itself), so you probably don't need to write/maintain the dockerfile yourself. Unless you're doing something unusual, you probably want to do that instead.

[FraserElectronics]

@julealgon No, there is no global.json file in my solution - do I need one?
@vcsjones Thanks for that, I had completely missed the SDK specified in Dockerfile, I was thinking it was an issue with my Linux install.

Thanks all for the help.

Andy

[julealgon]

@julealgon No, there is no global.json file in my solution - do I need one?

@FraserElectronics Nah you don't need one. I was just wondering if maybe that could be a reason why it was trying to use a different version of the SDK, because you can do stuff like that with a global.json file.