How do I run the tools after BP_CARGO_INSTALL_TOOLS?

[chcoomilk]

I am currently trying to deploy a Rust application with Diesel. I successfully installed the diesel_cli tool after configuring the key: "BP_CARGO_INSTALL_TOOLS" and the value: "diesel_cli".

The build process basically printed

[200] => Installed package diesel_cli v2.0.0 (executable diesel)

But I have no idea where it is and how to run it.

[chcoomilk]

I'm sorry, but I'm really confused understanding this config in the docs

$BP_CARGO_INSTALL_TOOLS	Additional tools that should be installed by running cargo install. This should be a space separated list, and each item should contain the name of the tool to install like cargo-bloat or diesel_cli. Tools installed will be installed prior to compiling application source code and will be available on $PATH during build execution (but are not installed into the runtime container).

Tools will be available on $PATH, so I am assuming I can call it explicitly; for example (say diesel_cli installs the binary file called: diesel) and the command would be diesel migration run or diesel setup, right? But because it only exists during build execution, it's not going to be called in a Procfile. So is it going to be called after $BP_CARGO_INSTALL_TOOLS_ARGS, it will probably look like this cargo install diesel_cli --force --no-default-features --features postgres && diesel migration run or not at all?

[sophiewigmore]

cc @paketo-buildpacks/rust-maintainers

[dmikusa]

So this is kind of a new feature and we're still working out how people might want to use it. Your feedback on this is important.

What I can say is that the original intent was to be able to use this to install CLI tools that you might need to call from a build.rs file, or possibly call from another buildpack.

That's why we don't install the tools into the container at runtime. I can see where that might make sense for some tools though. You might want to run diesel to do a migration at runtime.

If you want to open an issue on https://github.com/paketo-community/cargo/issues for adding tools to the runtime, we can certainly take a look.