Cargo is the package manager for Rust programming language. The cargo package command is used to assemble a local package into a distributable tarball (a .crate file). It is similar to the cargo publish --dry-run command, but provides more options.

Use case 1: Perform checks and create a .crate file (equivalent of cargo publish --dry-run)

Code:

cargo package

Motivation: This use case is helpful when you want to perform checks and verify that your package is ready to be published to the crate registry. By running cargo package, you can get a dry-run of the publish process without actually publishing anything.

Explanation: The cargo package command performs the following actions:

• Verifies the package’s metadata and structure.
• Checks if all the required dependencies are available.
• Builds the package and its dependencies.
• Creates a distributable tarball (a .crate file) containing the compiled package and its dependencies.

Example Output:

   Compiling my_package v0.1.0 (...)
    Finished release [optimized] target(s) in 0.50s
 Exporting my_package v0.1.0 (...)
Package my_package has been successfully generated in ./my_package-0.1.0.crate

Use case 2: Display what files would be included in the tarball without actually creating it

Code:

cargo package --list

Motivation: Sometimes, you may want to review the files that would be included in the tarball before actually generating it. This use case allows you to inspect the contents without creating the .crate file.

Explanation: The --list option enables the display of all the files that would be included in the tarball. It provides a preview of the package’s content without performing the actual packing process.

Example Output:

Files to be included in the tarball:
- Cargo.toml
- src/main.rs
- src/lib.rs
- README.md
- LICENSE
- ...

Conclusion:

The cargo package command is a powerful tool for packaging Rust projects into distributable tarballs. It allows you to perform checks, inspect the package contents, and create the necessary files for distribution. Whether you want to verify the readiness of your package or want to review its contents, cargo package has got you covered.