How to use the command 'cargo tree' (with examples)

Cargo is a package manager for the Rust programming language. The cargo tree command is used to display a tree visualization of the dependency graph of a Rust project. It shows the dependencies of the project and their relationship to each other.

Use case 1: Show a dependency tree of the current project

Code:

cargo tree

Motivation: It is important to understand the dependencies of a project in order to manage them effectively. By using the cargo tree command, we can get a clear visualization of the dependency tree for the current project.

Explanation: This command displays a tree visualization of the dependency graph of the current project. It shows the direct and indirect dependencies of the project, including the versions of each dependency.

Example output:

project 0.1.0
├── rand 0.6.5
│   └── rand_core 0.5.1
├── serde 1.0.130
└── tokio 1.0.0
    ├── bytes 0.5.6
    ├── futures 0.3.17
    └── io_uring 0.3.5

(*) denotes that a package has already been shown elsewhere in the graph

Use case 2: Only show dependencies up to the specified depth

Code:

cargo tree --depth 1

Motivation: Sometimes, we only need to see the direct dependencies of a project instead of the entire tree. By specifying the depth, we can limit the output to a specific level in the dependency tree.

Explanation: The --depth option is used to specify the maximum depth of the dependency tree to display. When n is set to 1, only the direct dependencies are shown in the tree visualization.

Example output:

project 0.1.0
├── rand 0.6.5
├── serde 1.0.130
└── tokio 1.0.0

(*) denotes that a package has already been shown elsewhere in the graph

Use case 3: Do not display a specific package in the tree

Code:

cargo tree --prune package_spec

Motivation: In some cases, we may want to exclude a specific package (and its dependencies) from the dependency tree, especially if the package is not relevant to the current analysis or if it causes clutter in the visualization.

Explanation: The --prune option is used to exclude a specific package (and its dependencies) from the dependency tree. The package_spec argument is the name or identifier of the package to be pruned from the tree.

Example output:

project 0.1.0
├── rand 0.6.5
│   └── rand_core 0.5.1
└── tokio 1.0.0
    ├── bytes 0.5.6
    └── io_uring 0.3.5

(*) denotes that a package has already been shown elsewhere in the graph

Use case 4: Show all occurrences of repeated dependencies

Code:

cargo tree --no-dedupe

Motivation: By default, the cargo tree command deduplicates dependencies to reduce clutter in the visualization. However, in some cases, it is useful to see all occurrences of repeated dependencies in order to understand their impact on the project.

Explanation: The --no-dedupe option is used to show all occurrences of repeated dependencies. By enabling this option, the dependency tree will display each instance of a repeated dependency separately.

Example output:

project 0.1.0
├── rand 0.6.5
│   └── rand_core 0.5.1
├── rand 0.7.0
│   └── rand_core 0.6.1
├── serde 1.0.130
└── tokio 1.0.0
    ├── bytes 0.5.6
    ├── futures 0.3.17
    └── io_uring 0.3.5

(*) denotes that a package has already been shown elsewhere in the graph

Use case 5: Only show specific types of dependencies

Code:

cargo tree --edges normal|build|dev

Motivation: There are different types of dependencies in a Rust project, such as normal dependencies, build dependencies, and development dependencies. By filtering the tree based on the types of dependencies, we can focus on specific aspects of the project.

Explanation: The --edges option is used to specify the types of dependencies to show in the tree visualization. It accepts three arguments: normal (for normal dependencies), build (for build dependencies), and dev (for development dependencies). Multiple options can be used in combination.

Example output:

project 0.1.0
├── rand 0.6.5
├── serde 1.0.130
└── tokio 1.0.0

(*) denotes that a package has already been shown elsewhere in the graph

Conclusion:

The cargo tree command is a powerful tool for understanding and managing dependencies in Rust projects. By visualizing the project’s dependency tree, we can easily identify and analyze the dependencies, their relationships, and their impact on the project. The various options provided by the command allow us to customize the output based on our specific needs.