Project Structure

In Java, a standard Maven project would have the following structure:

project directory/
.
+-- src/
|  +-- main/
|    +-- java/
|     +-- Application.java
|    +-- resources
|     +-- application.properties
|  +-- test/
|    +-- java/
|     +-- ApplicationTests.java
+-- target/
|   +-- build output files
+-- mvnw
+-- mvnw.cmd
+-- pom.xml
  • Both Java source code and the corresponding test files are contained in the src/ directory.
  • The pom.xml file and the Maven wrappers are stored at the root of the project.
  • The target directory contains all the build output files.

Cargo uses the following conventions for the package layout to make it easy to dive into a new Cargo package:

project directory/
.
+-- Cargo.lock
+-- Cargo.toml
+-- src/
|   +-- lib.rs
|   +-- main.rs
+-- benches/
|   +-- some-bench.rs
+-- examples/
|   +-- some-example.rs
+-- tests/
    +-- some-integration-test.rs
+-- target/
|   +-- build output files
  • Cargo.toml and Cargo.lock are stored in the root of the package.
  • src/lib.rs is the default library file, and src/main.rs is the default executable file (see target auto-discovery).
  • Benchmarks go in the benches directory, integration tests go in the tests directory (see testing, benchmarking).
  • Examples go in the examples directory.
  • There is no separate crate for unit tests, unit tests live in the same file as the code (see testing).

Managing large projects

For very large projects in Rust, Cargo offers workspaces to organize the project. A workspace can help manage multiple related packages that are developed in tandem. Some projects use virtual manifests, especially when there is no primary package.