[How To] Install Linux Dependencies in Container

[LanceMcCarthy]

Hi Folks!

Until now, I've always have been able to just install my required Linux dependencies at the top of my Dockerfile in the base section. For example:

However, I can't find a way to do this when building a .NET Aspire project 🙁

Attempts

I tried finagling it by defining a command in the aspire-manifest, but it's not an option when using a "project.v0" type (I only see expressing args when using the "docker.v0" type).

A better question might be "Can I run a bash command when a .NET Aspire container is first created?".

Thanks!
Lance

[timheuer]

I assume when running locally these are no issue as this is an ASP.NET project right? And you want to eliminate your previous dockerfile?

[LanceMcCarthy]

There is no Dockerfile right now, it's using the default project.v0 approach that seems to use the donet SDK container build commands internally?

You can see everything here => https://github.com/LanceMcCarthy/DevCraftAspire

[LanceMcCarthy]

To explain a little further, my API project has a Telerik.Drawing.Skia NuGet package reference (link to csproj).

That needs the following Linux dependencies to be available at runtime:

• libfreetype6
• libfontconfig1

I have no problem meeting this requirement when I'm deploying a standard ASP.NET project with a Dockerfile. Here's a great real-world example wher eI use Dockerfile to meet this requirement. Proving that it works, you can spin up the image using the Dockerhub

docker run -d -p 8080:8080 lancemccarthy/myaspnetcoreapp:latest

the problem arises when I am using Aspire to create the image. Where can I tell .NET to include those two dependencies in the image?

[timheuer]

I'm not able to get the project running locally to try things out. I was hoping to see if .WithArgs on the web project would work in this regard...this would be translated to args in the manifest and I'm not sure how we pass those into the container image right now. @davidfowl thoughts on this approach of adding image-specific dependencies on the resulting container image for a project-based resource easily (other than changing the base image to be an aspnet+yourdependencies image)?

[timheuer]

Ok, chatting with a few folks, you'd have to rely on a base image that has these dependencies already (assuming you don't want to use a dockerfile). So you'd need an image that is your aspnet+dependencies added, then can set that as containerbaseimage in the web project and the rest of the workflow would work.

[LanceMcCarthy]

That makes sense and what I figured would be the JustWorks™ answer.

I'll just need to figure out the best workflow to make sure I get new base images generated whenever a new aspire image is released. Is there any guidance David and crew might be able to point me to automatically generate a new base image when aspire releases one?

I am very familiar with publishing new multi-arch images to dockerhub in a workflow, but not how to trigger a new build when an upstream repo has published something.

[timheuer]

I don't think your base image (which I interpret as aspnet:8.0 + your dependencies) needs to sync with aspire. All the Aspire packages (as of now) are part of your app pieces during deployment. So you likely just want to sync an image of aspnet: with your dependencies...much less rebuild.

[richlander]

The key point is that Lance is now on the hook to update this image separately as a new workflow.

[richlander]

This q is covered in the FAQ section: https://devblogs.microsoft.com/dotnet/streamline-container-build-dotnet-8/#frequently-asked-questions

[raffaeler]

A while ago I opened this issue to support dockerfiles in Aspire instead of just relying on images.

IMO this would simplify this scenario as well. Creating an intermediate image is good when you consolidate, but certainly not in the developer loop which is where Aspire should provide the stronger support.

[davidfowl]

Yep that’s on our list of things to do post GA. It assumes you’ve written a docker file though…

[raffaeler]

Fair enough :)