# cargo-modules
[](https://travis-ci.org/regexident/cargo-modules)
[](https://crates.io/crates/cargo-modules/)
[](https://crates.io/crates/cargo-modules/)
[](https://crates.io/crates/cargo-modules/)
## Synopsis
A cargo plugin for visualizing/analyzing a crate's internal structure.
## Motivation
With time, as your Rust projects grow bigger and bigger, it gets more and more important to properly structure your code.
Fortunately Rust provides us with a quite sophisticated module system, allowing us to neatly split up our crates into arbitrarily small sub-modules of types and functions.
While this helps to avoid monolithic and unstructured chunks of code, it can also make it hard at times to still mentally stay on top of the over-all high-level structure of the project at hand.
This is where `cargo-modules` comes into play:
## Installation
Install `cargo-modules` via:
```bash
cargo install cargo-modules
```
## Usage
The `cargo-modules` tool comes with a couple of commands:
```bash
# Print a crate's hierarchical structure as a tree:
cargo modules structure <OPTIONS>
# Print a crate's internal dependencies as a graph:
cargo modules dependencies <OPTIONS>
# Detect unlinked source files within a crate's directory:
cargo modules orphans <OPTIONS>
```
<details>
<summary>Command help</summary>
```terminal
$ cargo modules --help
Visualize/analyze a crate's internal structure.
Usage: cargo-modules <COMMAND>
Commands:
structure Prints a crate's hierarchical structure as a tree.
dependencies Prints a crate's internal dependencies as a graph.
orphans Detects unlinked source files within a crate's directory.
help Print this message or the help of the given subcommand(s)
Options:
-h, --help Print help
```
</details>
### cargo modules structure
Print a crate's hierarchical structure as a tree:
```bash
cargo modules structure <OPTIONS>
```
<details>
<summary>Command help</summary>
```terminal
$ cargo modules structure --help
Prints a crate's hierarchical structure as a tree.
Usage: cargo-modules structure [OPTIONS]
Options:
--verbose Use verbose output
--lib Process only this package's library
--bin <BIN> Process only the specified binary
-p, --package <PACKAGE> Package to process (see `cargo help pkgid`)
--no-default-features Do not activate the `default` feature
--all-features Activate all available features
--features <FEATURES> List of features to activate. This will be ignored if `--cargo-all-features` is provided
--target <TARGET> Analyze for target triple
--manifest-path <MANIFEST_PATH> Path to Cargo.toml [default: .]
--no-fns Filter out functions (e.g. fns, async fns, const fns) from tree
--no-traits Filter out traits (e.g. trait, unsafe trait) from tree
--no-types Filter out types (e.g. structs, unions, enums) from tree
--sort-by <SORT_BY> The sorting order to use (e.g. name, visibility, kind) [default: name]
--sort-reversed Reverses the sorting order
--focus-on <FOCUS_ON> Focus the graph on a particular path or use-tree's environment, e.g. "foo::bar::{self, baz, blee::*}"
--max-depth <MAX_DEPTH> The maximum depth of the generated graph relative to the crate's root node, or nodes selected by '--focus-on'
--cfg-test Analyze with `#[cfg(test)]` enabled (i.e as if built via `cargo test`)
-h, --help Print help
```
</details>
#### Example
```bash
cd ./tests/projects/readme_tree_example
cargo-modules structure --cfg-test
```
Output:
```rust
crate readme_tree_example
├── trait Lorem: pub
├── mod amet: pub(crate)
│ └── mod consectetur: pub(self)
│ └── mod adipiscing: pub(self)
│ └── union Elit: pub(in crate::amet)
├── mod dolor: pub(crate)
│ └── enum Sit: pub(crate)
└── mod tests: pub(crate) #[cfg(test)]
└── fn it_works: pub(self) #[test]
```
(Project source code: [readme_tree_example/src/lib.rs](./tests/projects/readme_tree_example/src/lib.rs))
#### Terminal Colors
If you are running the command on a terminal with color support and don't have `NO_COLOR` defined in your environment, then the output will be colored for easier visual parsing:
```plain
└── <visibility> <keyword> <name> [<test-attributes>]
```
The `<visibility>` ([more info](https://doc.rust-lang.org/reference/visibility-and-privacy.html)) is further more highlighted by the following colors:
| 🟢 green | Items visible to all and everything (i.e. `pub`) |
| 🟡 yellow | Items visible to the current crate (i.e. `pub(crate)`) |
| 🟠 orange | Items visible to a certain parent module (i.e. `pub(in path)`) |
| 🔴 red | Items visible to the current module (i.e. `pub(self)`, implied by lack of `pub …`) |
The `<keyword>` is highlighted in 🔵 blue to visually separate it from the name.
Test-guarded items (i.e. `#[cfg(test)] …`) and test functions (i.e. `#[test] fn …`) have their corresponding `<test-attributes>` printed next to them in gray and cyan.
### cargo modules dependencies
Print a crate's internal dependencies as a graph:
```bash
cargo modules dependencies <OPTIONS>
```
<details>
<summary>Command help</summary>
```terminal
$ cargo modules dependencies --help
Prints a crate's internal dependencies as a graph.
Usage: cargo-modules dependencies [OPTIONS]
Options:
--verbose Use verbose output
--lib Process only this package's library
--bin <BIN> Process only the specified binary
-p, --package <PACKAGE> Package to process (see `cargo help pkgid`)
--no-default-features Do not activate the `default` feature
--all-features Activate all available features
--features <FEATURES> List of features to activate. This will be ignored if `--cargo-all-features` is provided
--target <TARGET> Analyze for target triple
--manifest-path <MANIFEST_PATH> Path to Cargo.toml [default: .]
--no-externs Filter out extern items from extern crates from graph
--no-fns Filter out functions (e.g. fns, async fns, const fns) from graph
--no-modules Filter out modules (e.g. `mod foo`, `mod foo {}`) from graph
--no-sysroot Filter out sysroot crates (`std`, `core` & friends) from graph
--no-traits Filter out traits (e.g. trait, unsafe trait) from graph
--no-types Filter out types (e.g. structs, unions, enums) from graph
--no-uses Filter out "use" edges from graph
--acyclic Require graph to be acyclic
--layout <LAYOUT> The graph layout algorithm to use (e.g. none, dot, neato, twopi, circo, fdp, sfdp) [default: neato]
--focus-on <FOCUS_ON> Focus the graph on a particular path or use-tree's environment, e.g. "foo::bar::{self, baz, blee::*}"
--max-depth <MAX_DEPTH> The maximum depth of the generated graph relative to the crate's root node, or nodes selected by '--focus-on'
--cfg-test Analyze with `#[cfg(test)]` enabled (i.e as if built via `cargo test`)
-h, --help Print help
If you have xdot installed on your system, you can run this using:
`cargo modules dependencies | xdot -`
```
</details>
#### Example
```bash
cd ./tests/projects/smoke
```plain
See "./docs/dependencies_output.dot" for the corresponding raw dot file.
```
(Project source code: [readme_graph_example/src/lib.rs](./tests/projects/readme_graph_example/src/lib.rs))
#### Node Structure
The individual nodes are structured as follows:
```plain
┌────────────────────────┐
│ <visibility> <keyword> │
├────────────────────────┤
│ <path> │
└────────────────────────┘
```
#### Node Colors
The `<visibility>` ([more info](https://doc.rust-lang.org/reference/visibility-and-privacy.html)) is further more highlighted by the following colors:
| 🔵 blue | Crates (i.e. their implicit root module) |
| 🟢 green | Items visible to all and everything (i.e. `pub`) |
| 🟡 yellow | Items visible to the current crate (i.e. `pub(crate)`) |
| 🟠 orange | Items visible to a certain parent module (i.e. `pub(in path)`) |
| 🔴 red | Items visible to the current module (i.e. `pub(self)`, implied by lack of `pub …`) |
#### Acyclic Mode
cargo-modules's `dependencies` command checks for the presence of a `--acyclic` flag. If found it will search for cycles in the directed graph and return an error for any cycles it found.
Running `cargo modules dependencies --lib --acyclic` on the source of the tool itself emits the following cycle error:
```plain
Error: Circular dependency between `cargo_modules::options::general` and `cargo_modules::options::generate`.
┌> cargo_modules::options::general
│ └─> cargo_modules::options::generate::graph
│ └─> cargo_modules::options::generate
└──────────┘
```
### cargo modules orphans
Detect unlinked source files within a crate's directory:
```bash
cargo modules orphans <OPTIONS>
```
<details>
<summary>Command help</summary>
```terminal
$ cargo modules orphans --help
Detects unlinked source files within a crate's directory.
Usage: cargo-modules orphans [OPTIONS]
Options:
--verbose Use verbose output
--lib Process only this package's library
--bin <BIN> Process only the specified binary
-p, --package <PACKAGE> Package to process (see `cargo help pkgid`)
--no-default-features Do not activate the `default` feature
--all-features Activate all available features
--features <FEATURES> List of features to activate. This will be ignored if `--cargo-all-features` is provided
--target <TARGET> Analyze for target triple
--manifest-path <MANIFEST_PATH> Path to Cargo.toml [default: .]
--deny Returns a failure code if one or more orphans are found
--cfg-test Analyze with `#[cfg(test)]` enabled (i.e as if built via `cargo test`)
-h, --help Print help
```
</details>
#### Example
```bash
cd ./tests/projects/readme_tree_example
cargo-modules structure --types --traits --fns --tests
```
Output:
```plain
2 orphans found:
warning: orphaned module `foo` at src/orphans/foo/mod.rs
--> src/orphans.rs
| ^^^^^^^^^^^^^^ orphan module not loaded from file
|
help: consider loading `foo` from module `orphans::orphans`
|
| mod foo;
| ++++++++
|
warning: orphaned module `bar` at src/orphans/bar.rs
--> src/orphans.rs
| ^^^^^^^^^^^^^^ orphan module not loaded from file
|
help: consider loading `bar` from module `orphans::orphans`
|
| mod bar;
| ++++++++
|
Error: Found 2 orphans in crate 'orphans'
```
(Project source code: [readme_tree_example/src/lib.rs](./tests/projects/readme_orphans_example/src/lib.rs))
### No-Color Mode
cargo-modules checks for the presence of a `NO_COLOR` environment variable that, when present (regardless of its value), prevents the addition of color to the console output (and only the console output!).
## Contributing
Please read [CONTRIBUTING.md](CONTRIBUTING.md) for details on our [code of conduct](https://www.rust-lang.org/conduct.html),
and the process for submitting pull requests to us.
## Versioning
We use [SemVer](http://semver.org/) for versioning. For the versions available, see the [tags on this repository](https://github.com/regexident/cargo-modules/tags).
## License
This project is licensed under the [**MPL-2.0**](https://www.tldrlegal.com/l/mpl-2.0) – see the [LICENSE.md](LICENSE.md) file for details.