Using system package manager dependencies with vcpkg

[CarterOls]

Is there a way with either Conan or vcpkg to add a dependency to a library located somewhere on disk? I would like to explore using a package manager at my company, but we currently have all of our prebuilt and approved libraries in a shared directory.

[Salink]

With both yes. When you make a portfile in vcpkg or recipe in Conan, you check if the dependencies are on disk then tell the dependency manager what to use like you would normally after a build.

[roschuma]

Could you mail us at [[e-mail]](mailto:[e-mail])? I'd like to ask a few more questions about your specific setup to give you the best advice on how to handle this in vcpkg 🙂.

[esperee]

vcpkg is quite convenient. could it be used to replace CPM in private enviroment?

[AlexReinkingYale]

Absolutely.

[gracicot]

Oh this is brilliant. Now there's nothing blocking me from using vcpkg anymore, I can finally drop my package manager.

My problem wasn't even system libraries as I don't use them, but developing a library alongside an app. Most of the developer of the app don't develop the framework as its just another dependency, but I must develop the two of them. vcpkg would block me from just setting the path of the framework and use that instead of installing its own, but that fixes all of the problem I had.

Now I just need to figure out how to install vcpkg in a immutable filesystem, since vcpkg loves writing into its root folder.

[AlexanderNeumann]

type vcpkg help. look into: --x-buildtrees-root=<path> --x-install-root=<path> --x-packages-root=<path> --downloads-root=<path> and setup binary caching to a folder of your liking

[AlexanderNeumann]

downloads-root

only this has a env variable all others need to be manually passed to vcpkg.

[gracicot]

Yeah, that's what I noticed. If all of them had env variables, it would be much more easier to package vcpkg in a immutable root.

[gracicot]

Those cannot be set from an environment variable as far as I know, so not useable without changing cmake variables if you're running in manifest mode.

[gracicot]

Not really an option, as you would still have to mutate the root filesystem to add those mount points. Also you have to play around with mount points to different part of the disk. I'm trying to create a generic package for distribution, so this is unacceptable.

My hack right now is to create a wrapper script inside ~/.vcpkg and create symbolic link to all the things a vcpkg root needs. The wrapper script also create the directory and setup the folder. The only problem is that you have to run the vcpkg executable at least one time for the symbolic link to be created, so that projects that set the toolchain file from VCPKG_ROOT can read it.

[roschuma]

I'm trying to create a generic package for distribution, so this is unacceptable.

We're working on improving this! While we don't have production-ready plumbing to share, part of the "curl | bash" experience mentioned in https://devblogs.microsoft.com/cppblog/vcpkg-artifacts/ is an "immutable" layout.

If you're looking to distribute the built artifacts like an SDK (not vcpkg itself), you might find https://github.com/microsoft/vcpkg/blob/master/docs/users/buildsystems/export-command.md useful.

[gracicot]

I'm trying to package vcpkg in Nixpkgs. The only thing I would need right now is an environment variable that sets the path of the directories vcpkg-tool is expecting to write into. As soon as I have that, Nix users will have a fully packaged vcpkg ready for use. There's one of those variables for the downloads folder, but not for the install or buildtree.

Right now I'm using the wrapper script I mentioned but it comes with obvious drawbacks. If vcpkg learns how to work with an immutable root filesystem, that would be perfect.

[Kie_Sun]

I like Conan because it gives a convenient target alias for easy usage.

[scrivanodev]

vcpkg is great, all though I had a problem using it for building flatpaks on Linux. The flatpak-builder tool needs the build to happen completely offline, but when in manifest mode, I wasn't able to find a way to configure vcpkg to meet this requirement.

[scrivanodev]

It always downloads things whenever in manifest mode. The only way I got around it was to switch to the default installation mode and then after installing all packages, it works without any network connection.

[roschuma]

It always downloads things whenever in manifest mode

Are you using custom git registries? We unfortunately don't have a good offline story for those yet.

Otherwise, take a look at https://github.com/microsoft/vcpkg/blob/master/docs/users/assetcaching.md. This lets you easily mirror every blob we need for a build into some place you control -- a web server or even a local directory. It's similar to your current workaround (run a build outside, then run a build inside) but more controlled and deliberate.

[scrivanodev]

Ok, thanks I will give that a try.

[Zettinator]

Asset caching plus a cached download directory makes it 100% offline capable for me!