Using Rust 1.37 Toolset

Red Hat Developer Tools 1

Installing and using the Rust 1.37 toolset

Supriya Takkhi

Olga Tikhomirova

Peter Macko

Kevin Owen

Vladimir Slavik

Red Hat Developer Group Documentation Team

Abstract

Rust is a Red Hat offering for developers on the Red Hat Enterprise Linux platform. The Rust User Guide provides an overview of this product, explains how to invoke and use the Rust versions of the tools, and links to resources with more in-depth information.

Chapter 1. Rust

1.1. About the Rust toolset

The Rust toolset is a Red Hat offering for developers on the Red Hat Enterprise Linux platform. It provides the Rust programming language compiler rustc, the cargo build tool and dependency manager, the rustfmt tool, and required libraries. The cargo-vendor package is now built into the cargo command, but its usage remains the same.

The Rust toolset is distributed as a part of Red Hat Developer Tools for Red Hat Enterprise Linux 7 and is available as a module in Red Hat Enterprise Linux 8.

The following components are available as a part of the Rust toolset:

Table 1.1. Rust Components

NameVersionDescription

rust

1.37

A Rust compiler front-end for LLVM.

cargo

1.37

A build system and dependency manager for Rust.

rustfmt

1.37

A tool for automatic formatting of Rust code.

1.2. Compatibility

The Rust toolset is available for Red Hat Enterprise Linux 7 and Red Hat Enterprise Linux 8 on the following architectures:

  • The 64-bit Intel and AMD architectures
  • The 64-bit ARM architecture
  • The IBM Power Systems architecture
  • The little-endian variant of IBM Power Systems architecture
  • The IBM Z Systems architecture

1.3. Getting access to the Rust toolset on Red Hat Enterprise Linux 7

The Rust toolset is an offering that is distributed as a part of the Red Hat Developer Tools content set, which is available to customers with deployments of Red Hat Enterprise Linux 7. To install the Rust toolset, enable the Red Hat Developer Tools and Red Hat Software Collections repositories by using the Red Hat Subscription Management and add the Red Hat Developer Tools GPG key to your system.

  1. Enable the rhel-7-variant-devtools-rpms repository:

    # subscription-manager repos --enable rhel-7-variant-devtools-rpms

    Replace variant with the Red Hat Enterprise Linux system variant (server or workstation).

    Note

    Consider using Red Hat Enterprise Linux Server to access the widest range of the development tools.

  2. Enable the rhel-variant-rhscl-7-rpms repository:

    # subscription-manager repos --enable rhel-variant-rhscl-7-rpms

    Replace variant with the Red Hat Enterprise Linux system variant (server or workstation).

  3. Add the Red Hat Developer Tools key to your system:

    # cd /etc/pki/rpm-gpg
    # wget -O RPM-GPG-KEY-redhat-devel https://www.redhat.com/security/data/a5787476.txt
    # rpm --import RPM-GPG-KEY-redhat-devel

Once the subscription is attached to the system and the repositories are enabled, install the Rust toolset as described in Section 1.4, “Installing the Rust toolset”.

Additional Resources

1.4. Installing the Rust toolset

The Rust toolset is distributed as a collection of RPM packages that can be installed, updated, uninstalled, and inspected by using the standard package management tools that are included in Red Hat Enterprise Linux. Note that a valid subscription that provides access to the Red Hat Developer Tools content set is required to install the Rust toolset on a Red Hat Enterprise Linux 7 system. For detailed instructions on how to associate your Red Hat Enterprise Linux 7 system with an appropriate subscription and get access to the Rust toolset, see Section 1.3, “Getting access to the Rust toolset on Red Hat Enterprise Linux 7”.

Important

Before installing the Rust toolset, install all available Red Hat Enterprise Linux updates.

  1. Install all of the components included in the Rust toolset for your operating system:

    • On Red Hat Enterprise Linux 7, install the rust-toolset-1.37 package:

      # yum install rust-toolset-1.37
    • On Red Hat Enterprise Linux 8, install the rust-toolset module:

      # yum module install rust-toolset

      This installs all development and debugging tools, and other dependent packages to the system. Notably, the Rust toolset has a dependency on Clang and LLVM Toolset.

Installable documentation

  • Install The Rust Programming Language book and API documentation in HTML format:

    • On Red Hat Enterprise Linux 7, install the rust-toolset-1.37-rust-doc package:

      # yum install rust-toolset-1.37-rust-doc

      The book is available in /opt/rh/rust-toolset-1.37/usr/share/doc/rust/html/index.html

      The API documentation for all crates is available in HTML format in /opt/rh/rust-toolset-1.37/usr/share/doc/rust/html/std/index.html.

    • On Red Hat Enterprise Linux 8, install the rust-doc package:

      # yum install rust-doc

      The book is available in /usr/share/doc/rust/html/index.html

      The API documentation for all crates is available in HTML format in /usr/share/doc/rust/html/std/index.html.

Online Documentation

Chapter 2. cargo

cargo is a tool for development using the Rust programming language. cargo fulfills the following roles:

  • Build tool and frontend for the Rust compiler rustc.

    Note

    Consider using cargo over rustc.

  • Package and dependency manager.

    cargo allows Rust projects to declare dependencies with specific version requirement. cargo will resolve the full dependency graph, download packages as needed, and build and test the entire project.

The Rust toolset is distributed with cargo 1.37.

2.1. Installing cargo

  • Install the Rust toolset. For details, see Section 1.4, “Installing the Rust toolset”.

    Note

    cargo is installed as a part of the Rust toolset.

    On Red Hat Enterprise Linux 7, cargo is provided by the rust-toolset-1.37-cargo package.

    On Red Hat Enterprise Linux 8, cargo is provided by the rust-toolset module.

2.2. Creating a new project

To create a Rust program on the command line, run the cargo tool as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo new --bin project_name'
  • For Red Hat Enterprise Linux 8:

    $ cargo new --bin project_name

This creates a directory project_name containing a text file named Cargo.toml and a subdirectory src containing a text file named main.rs.

To configure the project and add dependencies, edit the file Cargo.toml. See Section 2.7, “Configuring project dependencies”.

To edit the project code, edit the file main.rs and add new source files in the src subdirectory as needed.

To create a project for a cargo package instead of a program, run the cargo tool on the command line as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo new --lib project_name'
  • For Red Hat Enterprise Linux 8:

    $ cargo new --lib project_name

Note that you can execute any command using the scl utility on Red Hat Enterprise Linux 7, causing it to be run with the Rust binaries available. This allows you to run a shell session with the Rust cargo command directly available:

$ scl enable rust-toolset-1.37 'bash'

Example 2.1. Creating a project using cargo

Create a new Rust project called helloworld:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo new --bin helloworld'
         Created binary (application) helloworld project
  • For Red Hat Enterprise Linux 8:

    $ cargo new --bin helloworld
         Created binary (application) helloworld project

Examine the result:

$ cd helloworld
$ tree
.
├── Cargo.toml
└── src
    └── main.rs

1 directory, 2 files
$ cat src/main.rs
fn main() {
    println!("Hello, world!");
}

A directory helloworld is created for the project, with a file Cargo.toml for tracking project metadata, and a subdirectory src containing the main source code file main.rs.

The source code file main.rs has been initialized by cargo to a sample hello world program.

Note

The tree tool is available from the default Red Hat Enterprise Linux repositories. To install it:

# yum install tree

2.3. Building a project

To build a Rust project on the command line, change to the project directory and run the cargo tool as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo build'
  • For Red Hat Enterprise Linux 8:

    $ cargo build

This resolves all dependencies of the project, downloads the missing dependencies, and compiles the project using the rustc compiler.

By default, the project is built and compiled in debug mode. To build the project in release mode, run the cargo tool with the --release option as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo build --release'
  • For Red Hat Enterprise Linux 8:

    $ cargo build --release

Example 2.2. Building a project using cargo

This example assumes that you have successfully created the Rust project helloworld according to Example 2.1, “Creating a project using cargo”.

Change to the directory helloworld and build the project:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo build'
       Compiling helloworld v0.1.0 (file:///home/vslavik/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 0.51 secs
  • For Red Hat Enterprise Linux 8:

    $ cargo build
       Compiling helloworld v0.1.0 (file:///home/vslavik/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 0.51 secs

Examine the result:

$ tree
.
├── Cargo.lock
├── Cargo.toml
├── src
│   └── main.rs
└── target
    └── debug
        ├── build
        ├── deps
        │   └── helloworld-b7c6fab39c2d17a7
        ├── examples
        ├── helloworld
        ├── helloworld.d
        ├── incremental
        └── native

8 directories, 6 files

A subdirectory structure has been created, starting with the directory target. Since the project was built in debug mode, the actual build output is contained in a further subdirectory debug. The actual resulting executable file is target/debug/helloworld.

Note

The tree tool is available from the default Red Hat Enterprise Linux repositories. To install it:

# yum install tree

2.4. Checking a program

To verify that a Rust program managed by cargo can be built, on the command line change to the project directory and run the cargo tool as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo check'
  • For Red Hat Enterprise Linux 8:

    $ cargo check
Note

Consider using the cargo check command over the cargo build command for verification of a Rust program validity when you do not need the executable code. The cargo check command is faster than a full project build using the cargo build command, because it does not generate the executable code.

By default, the project is checked in debug mode. To check the project in release mode, run the cargo tool with the --release option as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo check --release'
  • For Red Hat Enterprise Linux 8:

    $ cargo check --release

Example 2.3. Checking a program with cargo

This example assumes that you have successfully built the Rust project helloworld according to Example 2.2, “Building a project using cargo”.

Change to the directory helloworld and check the project:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo check'
       Compiling helloworld v0.1.0 (file:///home/vslavik/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 0.5 secs
  • For Red Hat Enterprise Linux 8:

    $ cargo check
       Compiling helloworld v0.1.0 (file:///home/vslavik/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 0.5 secs

The project is checked, with output similar to that of the cargo build command. However, the executable file is not generated. You can verify this by comparing the current time with the time stamp of the executable file:

$ date
Fri Oct 13 08:53:21 CEST 2017
$ ls -l target/debug/helloworld
-rwxrwxr-x. 2 vslavik vslavik 252624 Oct 13 08:48 target/debug/helloworld

2.5. Running a program

To run a Rust program managed as a project by cargo on the command line, change to the project directory and run the cargo tool as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo run'
  • For Red Hat Enterprise Linux 8:

    $ cargo run

If the program has not been built yet, cargo will run a build before running the program.

Note

Consider using cargo to run a Rust program during development. It will correctly resolve the output path independently of the build mode.

By default, the project is built in debug mode. To build the project in release mode before running, run the cargo tool with the --release option as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo run --release'
  • For Red Hat Enterprise Linux 8:

    $ cargo run --release

Example 2.4. Running a program with cargo

This example assumes that you have successfully built the Rust project helloworld according to Example 2.2, “Building a project using cargo”.

Change to the directory helloworld and run the project:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo run'
        Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
         Running target/debug/helloworld
    Hello, world!
  • For Red Hat Enterprise Linux 8:

    $ cargo run
        Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
         Running target/debug/helloworld
    Hello, world!

cargo first rebuilds the project, and then runs the resulting executable file.

In this example, there were no changes to the source code since last build. As a result, cargo did not have to rebuild the executable file, but merely accepted it as current.

2.6. Running project tests

To run tests for a cargo project on the command line, change to the project directory and run the cargo tool as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo test'
  • For Red Hat Enterprise Linux 8:

    $ cargo test

By default, the project is tested in debug mode. To test the project in release mode, run the cargo tool with the --release option as follows:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo test --release'
  • For Red Hat Enterprise Linux 8:

    $ cargo test --release

Example 2.5. Testing a project with cargo

This example assumes that you have successfully built the Rust project helloworld according to Example 2.2, “Building a project using cargo”.

Change to the directory helloworld, and edit the file src/main.rs so that it contains the following source code:

fn main() {
    println!("Hello, world!");
}

#[test]
fn my_test() {
    assert_eq!(21+21, 42);
}

The function my_test marked as a test has been added.

Save the file, and run the test:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo test'
       Compiling helloworld v0.1.0 (file:///home/vslavik/Documentation/rusttest/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 0.26 secs
         Running target/debug/deps/helloworld-9dd6b83647b49aec
    
    running 1 test
    test my_test ... ok
    
    test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured
  • For Red Hat Enterprise Linux 8:

    $ cargo test
       Compiling helloworld v0.1.0 (file:///home/vslavik/Documentation/rusttest/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 0.26 secs
         Running target/debug/deps/helloworld-9dd6b83647b49aec
    
    running 1 test
    test my_test ... ok
    
    test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured

cargo first rebuilds the project, and then runs the tests found in the project. The test my_test has been succesfully passed.

2.7. Configuring project dependencies

To specify dependencies for a cargo project, edit the file Cargo.toml in the project directory. The section [dependencies] contains a list of the project dependencies. Each dependency is listed on a new line in the following format:

crate_name = version

Rust code packages are called crates.

Example 2.6. Adding Dependency to a Project and Building it with cargo

This example assumes that you have successfully built the Rust project helloworld according to Example 2.2, “Building a project using cargo”.

Change to the directory helloworld and edit the file src/main.rs so that it contains the following source code:

extern crate time;

fn main() {
    println!("Hello, world!");
    println!("Time is: {}", time::now().rfc822());
}

The code now requires an external crate time. Add this dependency to project configuration by editing the file Cargo.toml so that it contains the following code:

[package]
name = "helloworld"
version = "0.1.0"
authors = ["Your Name <yourname@example.com>"]

[dependencies]
time = "0.1"

Run the cargo run command to build the project and run the resulting executable file:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo run'
        Updating registry `https://github.com/rust-lang/crates.io-index`
     Downloading time v0.1.38
     Downloading libc v0.2.32
        Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
         Running `target/debug/helloworld`
    Hello, world!
    Time is: Fri, 13 Oct 2017 11:08:57
  • For Red Hat Enterprise Linux 8:

    $ cargo run
        Updating registry `https://github.com/rust-lang/crates.io-index`
     Downloading time v0.1.38
     Downloading libc v0.2.32
        Finished dev [unoptimized + debuginfo] target(s) in 0.0 secs
         Running `target/debug/helloworld`
    Hello, world!
    Time is: Fri, 13 Oct 2017 11:08:57

cargo downloads the time crate and its dependencies (crate libc), stores them locally, builds all of the project source code including the dependency crates, and finally runs the resulting executable.

Additional Resources

2.8. Building project documentation

Note

Consider using the cargo doc command over rustdoc. The command cargo doc utilizes the rustdoc utility.

Note

cargo doc extracts documentation comments only for public functions, variables, and members.

Rust code can contain comments marked for extraction into documentation. The comments support the Markdown language.

To build project documentation using the cargo tool, change to the project directory and run cargo tool:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo doc --no-deps'
  • For Red Hat Enterprise Linux 8:

    $ cargo doc --no-deps

This extracts documentation stored from the special comments in the source code of your project and writes the documentation in the HTML format.

  • Omit the --no-deps option to include dependencies in the generated documentation, including third-party libraries.
  • Add the --open option to open the generated documentation in your browser.

Example 2.7. Building project documentation

This example assumes that you have successfully built the Rust project helloworld with dependencies, according to Example 2.6, “Adding Dependency to a Project and Building it with cargo”.

Change to the directory helloworld and edit the file src/main.rs so that it contains the following source code:

//! This is a hello-world program.
extern crate time;

/// Prints a greeting to `stdout`.
pub fn print_output() {
    println!("Hello, world!");
    println!("Time is: {}", time::now().rfc822());
}

/// The program entry point.
fn main() {
    print_output();
}

The code now contains a public function print_output(). The whole helloworld program, the print_output() function, and the main() function have documentation comments.

Run the cargo doc command to build the project documentation:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo doc --no-deps'
     Documenting helloworld v0.1.0 (file:///home/vslavik/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 0.31 secs
  • For Red Hat Enterprise Linux 8:

    $ cargo doc --no-deps
     Documenting helloworld v0.1.0 (file:///home/vslavik/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 0.31 secs

Install the tree tool that is available in the default Red Hat Enterprise Linux repositories, if not already installed:

# yum install tree

Examine the result:

$ tree
.
├── Cargo.lock
├── Cargo.toml
├── src
│   └── main.rs
└── target
...
    └── doc
...
        ├── helloworld
        │   ├── fn.print_output.html
        │   ├── index.html
        │   ├── print_output.v.html
        │   └── sidebar-items.js
...
        └── src
            └── helloworld
                └── main.rs.html

12 directories, 32 files

cargo builds the project documentation. To view the documentation, open the file target/doc/helloworld/index.html in your browser. The generated documentation does not contain any mention of the main() function, because it is not public.

Run the cargo doc command without the --no-deps option to build the project documentation, including the dependency libraries time and libc:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo doc'
     Documenting libc v0.2.32
     Documenting time v0.1.38
     Documenting helloworld v0.1.0 (file:///home/vslavik/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 3.41 secs
  • For Red Hat Enterprise Linux 8:

    $ cargo doc
     Documenting libc v0.2.32
     Documenting time v0.1.38
     Documenting helloworld v0.1.0 (file:///home/vslavik/helloworld)
        Finished dev [unoptimized + debuginfo] target(s) in 3.41 secs

Examine the resulting directory structure with tree command:

$ tree
...
92 directories, 11804 files
$ ls -d target/doc/*/
target/doc/helloworld/  target/doc/implementors/  target/doc/libc/  target/doc/src/  target/doc/time/

The resulting documentation now covers the dependency libraries time and libc, with each present as another subdirectory in the target/doc/ directory.

Additional Resources

A detailed description of the cargo doc tool and its features is beyond the scope of this document. For more information, see the resources listed below.

2.9. Vendoring project dependencies

Vendoring project dependencies means creating a local copy of the dependencies for offline redistribution and reuse. Vendored dependencies can be used by the cargo build tool without any connection to the internet.

Note that starting with this release the cargo-vendor package is included in cargo, but there has been no change in the way it works.

Example 2.8. Vendoring project dependencies

This example assumes that you have successfully built the Rust project helloworld with dependencies, according to Example 2.6, “Adding Dependency to a Project and Building it with cargo”.

Change to the directory helloworld and run the cargo vendor command to vendor the project with dependencies:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo vendor'
     Downloading kernel32-sys v0.2.2
     Downloading redox_syscall v0.1.31
     Downloading winapi-build v0.1.1
     Downloading winapi v0.2.8
       Vendoring kernel32-sys v0.2.2 (/home/vslavik/.cargo/registry/src/github.com-1ecc6299db9ec823/kernel32-sys-0.2.2) to vendor/kernel32-sys
       Vendoring libc v0.2.32 (/home/vslavik/.cargo/registry/src/github.com-1ecc6299db9ec823/libc-0.2.32) to vendor/libc
       Vendoring redox_syscall v0.1.31 (/home/vslavik/.cargo/registry/src/github.com-1ecc6299db9ec823/redox_syscall-0.1.31) to vendor/redox_syscall
       Vendoring time v0.1.38 (/home/vslavik/.cargo/registry/src/github.com-1ecc6299db9ec823/time-0.1.38) to vendor/time
       Vendoring winapi v0.2.8 (/home/vslavik/.cargo/registry/src/github.com-1ecc6299db9ec823/winapi-0.2.8) to vendor/winapi
       Vendoring winapi-build v0.1.1 (/home/vslavik/.cargo/registry/src/github.com-1ecc6299db9ec823/winapi-build-0.1.1) to vendor/winapi-build
    To use vendored sources, add this to your .cargo/config for this project:
    
        [source.crates-io]
        replace-with = "vendored-sources"
    
        [source.vendored-sources]
        directory = "/home/vslavik/helloworld/vendor"
  • For Red Hat Enterprise Linux 8:

    $ cargo vendor

Examine the result:

$ ls
Cargo.lock  Cargo.toml  src  target  vendor
$ tree vendor
vendor
├── kernel32-sys
│   ├── build.rs
│   ├── Cargo.toml
│   ├── README.md
│   └── src
│       └── lib.rs
├── libc
│   ├── appveyor.yml
│   ├── Cargo.toml
...
75 directories, 319 files

The vendor directory contains copies of all the dependency crates needed to build the helloworld program. Note that the crates for building the project on the Windows operating system have been vendored, too, despite running this command on Red Hat Enterprise Linux.

Note

The tree tool is available from the default Red Hat Enterprise Linux repositories. To install it:

# yum install tree

2.10. Additional Resources

A detailed description of the cargo tool and its features is beyond the scope of this document. For more information, see the resources listed below.

Cargo documentation

  • cargo(1) — The manual page for the cargo tool provides detailed information on its usage. To display the manual page for the version included in the Rust toolset:

    • For Red Hat Enterprise Linux 7:

      $ scl enable rust-toolset-1.37 'man cargo'
    • For Red Hat Enterprise Linux 8:

      $ man cargo
  • Cargo, Rust’s Package Manager HTML book is provided as a package:

    • On Red Hat Enterprise Linux 7:

      # yum install rust-toolset-1.37-cargo-doc

      The HTML is available at /opt/rh/rust-toolset-1.37/usr/share/doc/cargo/html/index.html

    • On Red Hat Enterprise Linux 8:

      # yum install cargo-doc

      The HTML is available at /usr/share/doc/cargo/html/index.html

Online Cargo Documentation

See also

  • Chapter 1, Rust — An overview of the Rust toolset and more information on how to install it on your system.

Chapter 3. rustfmt

The rustfmt tool provides automatic formatting of Rust source code.

Rust is distributed with rustfmt 1.37.

3.1. Installing rustfmt

  • For Red Hat Enterprise Linux 7:

    # yum install rust-toolset-1.37-rustfmt
  • For Red Hat Enterprise Linux 8:

    # dnf install rustfmt

3.2. Using rustfmt as a standalone tool

To format a rust source file and all its dependencies with the rustfmt tool:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'rustfmt source-file'
  • For Red Hat Enterprise Linux 8:

    $ rustfmt source-file

Replace source-file with path to the source file.

By default, rustfmt modifies the affected files in place without displaying details or creating backups. To change the behavior, use the --write-mode value option. For further details see the help mesage of rustfmt:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'rustfmt --help'
  • For Red Hat Enterprise Linux 8:

    $ rustfmt --help

Additionally, rustfmt accepts standard input instead of a file and provides its output in standard output.

3.3. Using rustfmt with cargo

To format all source files in a cargo crate:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'cargo fmt'
  • For Red Hat Enterprise Linux 8:

    $ cargo fmt

To change the rustfmt formatting options, create the configuration file rustfmt.toml in the project directory and supply the configuration there. For further details see the help message of rustfmt:

  • For Red Hat Enterprise Linux 7:

    $ scl enable rust-toolset-1.37 'rustfmt --config-help'
  • For Red Hat Enterprise Linux 8:

    $ rustfmt --config-help

3.4. Additional Resources

  • Help messages of rustfmt:

    • For Red Hat Enterprise Linux 7:

      $ scl enable rust-toolset-1.37 'rustfmt --help'
      $ scl enable rust-toolset-1.37 'rustfmt --config-help'
    • For Red Hat Enterprise Linux 8:

      $ rustfmt --help
      $ rustfmt --config-help
  • Configuring Rustfmt in Configurations.md:

    • Location in Red Hat Enterprise Linux 7:

      /opt/rh/rust-toolset-1.37/usr/share/doc/rust-toolset-1.37-rustfmt-1.37.0/Configurations.md

    • Location in Red Hat Enterprise Linux 8:

      /usr/share/doc/rustfmt/Configurations.md

Chapter 4. Container image with the Rust toolset for RHEL 7

The Rust toolset is available as a container image which can be downloaded from Red Hat Container Registry.

4.1. Image contents

The devtools/rust-toolset-1.37-rhel7 image provides content corresponding to the following packages:

ComponentVersionPackage

Rust

1.37

rust-toolset-1.37-rust

Cargo

1.37

rust-toolset-1.37-cargo

4.2. Accessing the image

To pull the image, run the required command as root:

# podman pull registry.access.redhat.com/devtools/rust-toolset-rhel7:1.37.0
# podman pull registry.access.redhat.com/devtools/rust-toolset-rhel7:1.35.0
# podman pull registry.access.redhat.com/devtools/rust-toolset-rhel7:1.31.1

4.3. Additional Resources

Chapter 5. Changes in the Rust 1.37 toolset

This chapter lists some notable changes in the Rust 1.37 toolset since its previous release.

5.1. Rust

Rust has been updated from version 1.35 to 1.37. Notable changes include:

  • Changes in Rust 1.37

    • You can now access enum variants through the name of a type alias.
    • Constant items can now be defined unnamed as _, which is sometimes useful for generated code to define new items in an implicit scope, without conflicting with the original scope.
    • The compiler now has options -C profile-generate and -C profile-use in support of profile-guided optimization.
    • Enums may now specify a manual alignment to increase the natural one.
    • Support for vendoring dependencies (cargo vendor) is now built into the main cargo tool, and the separate cargo-vendor rpm is obsolete.
    • Cargo now supports specifying a default binary for cargo run.
  • Changes in Rust 1.36

    • The Future trait provides the foundation for async/await processing.
    • The alloc crate provides types that need a global allocator, but do not need the entire std system interface, especially like Vec<T>.
    • The MaybeUninit<T> type provides a proper way for unsafe code to deal with uninitialized memory, without running into issues with undefined behavior.
    • NLL (non-lexical lifetimes) is now enabled for 2015 edition crates, which is generally more permissive in borrow checking. The old AST checker is still used in some cases where NLL is more restrictive, but those are soundness holes that will become errors in a future version.
    • A new HashMap<K, V> implementation is now used, based on the SwissTable design, which is generally faster with lower memory overhead.
    • Cargo now supports an --offline mode that only resolves using locally cached dependencies. Use the cargo fetch command to download in advance.

5.2. cargo

The cargo tool has been updated from version 1.31.0 to 1.37.

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