How do I share common code between Rust projects without publishing to crates.io?

Question

There may not be a good answer for this question, but I have code that I would like to share between two different Rust projects WITHOUT publishing the crate to crates.io.

The code is proprietary and I don't want to put it out into the wild.

Answer 1

but it's proprietary code and I don't want to put it out into the wild.

You don't have to publish a crate. Specifically, just create the crate (cargo new shared_stuff) then specify the path to the common crate(s) in the dependent project's Cargo.toml:

[dependency.shared_stuff]
path = "path/to/shared/crate"

The Cargo documentation has an entire section on types of dependencies:

• Specifying dependencies from crates.io
• Specifying dependencies from git repositories
• Specifying path dependencies

I believe that Cargo will allow you to fetch from a private git repository (such as on Github or another privately hosted service, such as GitLab), but I haven't tried that personally. Based on my searching, you will need to have previously authenticated or otherwise configured git to not require an interactive password entry.

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It's theoretically possible to create your own crate registry. I've not even attempted to do this, but the machinery is present in Cargo to handle it.