Rust rules

bazel_version
cargo_build_script
rust_benchmark
rust_binary
rust_bindgen
rust_bindgen_library
rust_bindgen_toolchain
rust_doc
rust_doc_test
rust_grpc_library
rust_library
rust_proto_library
rust_proto_toolchain
rust_repositories
rust_repository_set
rust_test
rust_toolchain
rust_toolchain_repository
rust_toolchain_repository_proxy
rust_wasm_bindgen
rust_wasm_bindgen_toolchain
rust_workspace

rust_benchmark

Builds a Rust benchmark test.

Warning: This rule is currently experimental. Rust Benchmark tests require the Bencher interface in the unstable libtest crate, which is behind the test unstable feature gate. As a result, using this rule would require using a nightly binary release of Rust.

Example:

Suppose you have the following directory structure for a Rust project with a library crate, fibonacci with benchmarks under the benches/ directory:

[workspace]/
  WORKSPACE
  fibonacci/
      BUILD
      src/
          lib.rs
      benches/
          fibonacci_bench.rs

fibonacci/src/lib.rs:

pub fn fibonacci(n: u64) -> u64 {
    if n < 2 {
        return n;
    }
    let mut n1: u64 = 0;
    let mut n2: u64 = 1;
    for _ in 1..n {
        let sum = n1 + n2;
        n1 = n2;
        n2 = sum;
    }
    n2
}

fibonacci/benches/fibonacci_bench.rs:

#![feature(test)]

extern crate test;
extern crate fibonacci;

use test::Bencher;

#[bench]
fn bench_fibonacci(b: &mut Bencher) {
    b.iter(|| fibonacci::fibonacci(40));
}

To build the benchmark test, add a rust_benchmark target:

fibonacci/BUILD:

package(default_visibility = ["//visibility:public"])

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_library", "rust_benchmark")

rust_library(
  name = "fibonacci",
  srcs = ["src/lib.rs"],
)

rust_benchmark(
  name = "fibonacci_bench",
  srcs = ["benches/fibonacci_bench.rs"],
  deps = [":fibonacci"],
)

Run the benchmark test using: bazel run //fibonacci:fibonacci_bench.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
aliases	Remap crates to a new name or moniker for linkage to this target These are other rust_library targets and will be presented as the new name given.	Dictionary: Label -> String	optional	{}
crate_features	List of features to enable for this crate. Features are defined in the code using the #[cfg(feature = “foo”)] configuration option. The features listed here will be passed to rustc with --cfg feature=“${feature_name}” flags.	List of strings	optional	[]
crate_root	The file that will be passed to rustc to be used for building this crate. If crate_root is not set, then this rule will look for a lib.rs file (or main.rs for rust_binary) or the single file in srcs if srcs contains only one file.	Label	optional	None
data	List of files used by this rule at runtime. This attribute can be used to specify any data files that are embedded into the library, such as via the include_str! macro.	List of labels	optional	[]
deps	List of other libraries to be linked to this library target. These can be either other rust_library targets or cc_library targets if linking a native library.	List of labels	optional	[]
edition	The rust edition to use for this crate. Defaults to the edition specified in the rust_toolchain.	String	optional	""
out_dir_tar	Deprecated, do not use, see [#cargo_build_script] instead.	Label	optional	None
proc_macro_deps	List of rust_library targets with kind proc-macro used to help build this library target.	List of labels	optional	[]
rustc_env	Dictionary of additional “key”: “value” environment variables to set for rustc.	Dictionary: String -> String	optional	{}
rustc_flags	List of compiler flags passed to rustc.	List of strings	optional	[]
srcs	List of Rust .rs source files used to build the library. If srcs contains more than one file, then there must be a file either named lib.rs. Otherwise, crate_root must be set to the source file that is the root of the crate to be passed to rustc to build this crate.	List of labels	optional	[]
version	A version to inject in the cargo environment variable.	String	optional	“0.0.0”

rust_binary

Builds a Rust binary crate.

Example:

Suppose you have the following directory structure for a Rust project with a library crate, hello_lib, and a binary crate, hello_world that uses the hello_lib library:

[workspace]/
    WORKSPACE
    hello_lib/
        BUILD
        src/
            lib.rs
    hello_world/
        BUILD
        src/
            main.rs

hello_lib/src/lib.rs:

pub struct Greeter {
    greeting: String,
}

impl Greeter {
    pub fn new(greeting: &str) -> Greeter {
        Greeter { greeting: greeting.to_string(), }
    }

    pub fn greet(&self, thing: &str) {
        println!("{} {}", &self.greeting, thing);
    }
}

hello_lib/BUILD:

package(default_visibility = ["//visibility:public"])

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_library")

rust_library(
    name = "hello_lib",
    srcs = ["src/lib.rs"],
)

hello_world/src/main.rs:

extern crate hello_lib;

fn main() {
    let hello = hello_lib::Greeter::new("Hello");
    hello.greet("world");
}

hello_world/BUILD:

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_binary")

rust_binary(
    name = "hello_world",
    srcs = ["src/main.rs"],
    deps = ["//hello_lib"],
)

Build and run hello_world:

$ bazel run //hello_world
INFO: Found 1 target...
Target //examples/rust/hello_world:hello_world up-to-date:
  bazel-bin/examples/rust/hello_world/hello_world
INFO: Elapsed time: 1.308s, Critical Path: 1.22s

INFO: Running command line: bazel-bin/examples/rust/hello_world/hello_world
Hello world

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
aliases	Remap crates to a new name or moniker for linkage to this target These are other rust_library targets and will be presented as the new name given.	Dictionary: Label -> String	optional	{}
crate_features	List of features to enable for this crate. Features are defined in the code using the #[cfg(feature = “foo”)] configuration option. The features listed here will be passed to rustc with --cfg feature=“${feature_name}” flags.	List of strings	optional	[]
crate_root	The file that will be passed to rustc to be used for building this crate. If crate_root is not set, then this rule will look for a lib.rs file (or main.rs for rust_binary) or the single file in srcs if srcs contains only one file.	Label	optional	None
crate_type	-	String	optional	“bin”
data	List of files used by this rule at runtime. This attribute can be used to specify any data files that are embedded into the library, such as via the include_str! macro.	List of labels	optional	[]
deps	List of other libraries to be linked to this library target. These can be either other rust_library targets or cc_library targets if linking a native library.	List of labels	optional	[]
edition	The rust edition to use for this crate. Defaults to the edition specified in the rust_toolchain.	String	optional	""
linker_script	Link script to forward into linker via rustc options.	Label	optional	None
out_binary	-	Boolean	optional	False
out_dir_tar	Deprecated, do not use, see [#cargo_build_script] instead.	Label	optional	None
proc_macro_deps	List of rust_library targets with kind proc-macro used to help build this library target.	List of labels	optional	[]
rustc_env	Dictionary of additional “key”: “value” environment variables to set for rustc.	Dictionary: String -> String	optional	{}
rustc_flags	List of compiler flags passed to rustc.	List of strings	optional	[]
srcs	List of Rust .rs source files used to build the library. If srcs contains more than one file, then there must be a file either named lib.rs. Otherwise, crate_root must be set to the source file that is the root of the crate to be passed to rustc to build this crate.	List of labels	optional	[]
version	A version to inject in the cargo environment variable.	String	optional	“0.0.0”

rust_bindgen

Generates a rust source file from a cc_library and a header.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
bindgen_flags	Flags to pass directly to the bindgen executable. See https://rust-lang.github.io/rust-bindgen/ for details.	List of strings	optional	[]
cc_lib	The cc_library that contains the .h file. This is used to find the transitive includes.	Label	optional	None
clang_flags	Flags to pass directly to the clang executable.	List of strings	optional	[]
header	The .h file to generate bindings for.	Label	optional	None

rust_bindgen_toolchain

The tools required for the rust_bindgen rule.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
bindgen	The label of a bindgen executable.	Label	optional	None
clang	The label of a clang executable.	Label	optional	None
libclang	A cc_library that provides bindgen's runtime dependency on libclang.	Label	optional	None
libstdcxx	A cc_library that satisfies libclang's libstdc++ dependency.	Label	optional	None
rustfmt	The label of a rustfmt executable. If this is provided, generated sources will be formatted.	Label	optional	None

rust_doc

Generates code documentation.

Example: Suppose you have the following directory structure for a Rust library crate:

[workspace]/
    WORKSPACE
    hello_lib/
        BUILD
        src/
            lib.rs

To build rustdoc documentation for the hello_lib crate, define a rust_doc rule that depends on the the hello_lib rust_library target:

package(default_visibility = ["//visibility:public"])

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_library", "rust_doc")

rust_library(
    name = "hello_lib",
    srcs = ["src/lib.rs"],
)

rust_doc(
    name = "hello_lib_doc",
    dep = ":hello_lib",
)

Running bazel build //hello_lib:hello_lib_doc will build a zip file containing the documentation for the hello_lib library crate generated by rustdoc.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
dep	The label of the target to generate code documentation for. rust_doc can generate HTML code documentation for the source files of rust_library or rust_binary targets.	Label	required
html_after_content	File to add in <body>, after content.	Label	optional	None
html_before_content	File to add in <body>, before content.	Label	optional	None
html_in_header	File to add to <head>.	Label	optional	None
markdown_css	CSS files to include via <link> in a rendered Markdown file.	List of labels	optional	[]

rust_doc_test

Runs Rust documentation tests.

Example:

Suppose you have the following directory structure for a Rust library crate:

[workspace]/
  WORKSPACE
  hello_lib/
      BUILD
      src/
          lib.rs

To run documentation tests for the hello_lib crate, define a rust_doc_test target that depends on the hello_lib rust_library target:

package(default_visibility = ["//visibility:public"])

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_library", "rust_doc_test")

rust_library(
    name = "hello_lib",
    srcs = ["src/lib.rs"],
)

rust_doc_test(
    name = "hello_lib_doc_test",
    dep = ":hello_lib",
)

Running bazel test //hello_lib:hello_lib_doc_test will run all documentation tests for the hello_lib library crate.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
dep	The label of the target to run documentation tests for. rust_doc_test can run documentation tests for the source files of rust_library or rust_binary targets.	Label	required

rust_grpc_library

Builds a Rust library crate from a set of proto_librarys suitable for gRPC.

Example:

load("@io_bazel_rules_rust//proto:proto.bzl", "rust_grpc_library")
load("@io_bazel_rules_rust//proto:toolchain.bzl", "GRPC_COMPILE_DEPS")

proto_library(
    name = "my_proto",
    srcs = ["my.proto"]
)

rust_grpc_library(
    name = "rust",
    deps = [":my_proto"],
)

rust_binary(
    name = "my_service",
    srcs = ["my_service.rs"],
    deps = [":rust"] + GRPC_COMPILE_DEPS,
)

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
deps	List of proto_library dependencies that will be built. One crate for each proto_library will be created with the corresponding gRPC stubs.	List of labels	required
rust_deps	The crates the generated library depends on.	List of labels	optional	[“@io_bazel_rules_rust//proto/raze:protobuf”, “@io_bazel_rules_rust//proto/raze:grpc”, “@io_bazel_rules_rust//proto/raze:tls_api”, “@io_bazel_rules_rust//proto/raze:tls_api_stub”]

rust_library

Builds a Rust library crate.

Example:

Suppose you have the following directory structure for a simple Rust library crate:

[workspace]/
    WORKSPACE
    hello_lib/
        BUILD
        src/
            greeter.rs
            lib.rs

hello_lib/src/greeter.rs:

pub struct Greeter {
    greeting: String,
}

impl Greeter {
    pub fn new(greeting: &str) -> Greeter {
        Greeter { greeting: greeting.to_string(), }
    }

    pub fn greet(&self, thing: &str) {
        println!("{} {}", &self.greeting, thing);
    }
}

hello_lib/src/lib.rs:

pub mod greeter;

hello_lib/BUILD:

package(default_visibility = ["//visibility:public"])

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_library")

rust_library(
    name = "hello_lib",
    srcs = [
        "src/greeter.rs",
        "src/lib.rs",
    ],
)

Build the library:

$ bazel build //hello_lib
INFO: Found 1 target...
Target //examples/rust/hello_lib:hello_lib up-to-date:
  bazel-bin/examples/rust/hello_lib/libhello_lib.rlib
INFO: Elapsed time: 1.245s, Critical Path: 1.01s

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
aliases	Remap crates to a new name or moniker for linkage to this target These are other rust_library targets and will be presented as the new name given.	Dictionary: Label -> String	optional	{}
crate_features	List of features to enable for this crate. Features are defined in the code using the #[cfg(feature = “foo”)] configuration option. The features listed here will be passed to rustc with --cfg feature=“${feature_name}” flags.	List of strings	optional	[]
crate_root	The file that will be passed to rustc to be used for building this crate. If crate_root is not set, then this rule will look for a lib.rs file (or main.rs for rust_binary) or the single file in srcs if srcs contains only one file.	Label	optional	None
crate_type	The type of linkage to use for building this library. Options include “lib”, “rlib”, “dylib”, “cdylib”, “staticlib”, and “proc-macro”. The exact output file will depend on the toolchain used.	String	optional	“rlib”
data	List of files used by this rule at runtime. This attribute can be used to specify any data files that are embedded into the library, such as via the include_str! macro.	List of labels	optional	[]
deps	List of other libraries to be linked to this library target. These can be either other rust_library targets or cc_library targets if linking a native library.	List of labels	optional	[]
edition	The rust edition to use for this crate. Defaults to the edition specified in the rust_toolchain.	String	optional	""
out_dir_tar	Deprecated, do not use, see [#cargo_build_script] instead.	Label	optional	None
proc_macro_deps	List of rust_library targets with kind proc-macro used to help build this library target.	List of labels	optional	[]
rustc_env	Dictionary of additional “key”: “value” environment variables to set for rustc.	Dictionary: String -> String	optional	{}
rustc_flags	List of compiler flags passed to rustc.	List of strings	optional	[]
srcs	List of Rust .rs source files used to build the library. If srcs contains more than one file, then there must be a file either named lib.rs. Otherwise, crate_root must be set to the source file that is the root of the crate to be passed to rustc to build this crate.	List of labels	optional	[]
version	A version to inject in the cargo environment variable.	String	optional	“0.0.0”

rust_proto_library

Builds a Rust library crate from a set of proto_librarys.

Example:

load("@io_bazel_rules_rust//proto:proto.bzl", "rust_proto_library")
load("@io_bazel_rules_rust//proto:toolchain.bzl", "PROTO_COMPILE_DEPS")

proto_library(
    name = "my_proto",
    srcs = ["my.proto"]
)

proto_rust_library(
    name = "rust",
    deps = [":my_proto"],
)

rust_binary(
    name = "my_proto_binary",
    srcs = ["my_proto_binary.rs"],
    deps = [":rust"] + PROTO_COMPILE_DEPS,
)

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
deps	List of proto_library dependencies that will be built. One crate for each proto_library will be created with the corresponding stubs.	List of labels	required
rust_deps	The crates the generated library depends on.	List of labels	optional	[“@io_bazel_rules_rust//proto/raze:protobuf”]

rust_proto_toolchain

Declares a Rust Proto toolchain for use.

This is used to configure proto compilation and can be used to set different protobuf compiler plugin.

Example:

Suppose a new nicer gRPC plugin has came out. The new plugin can be used in Bazel by defining a new toolchain definition and declaration:

load('@io_bazel_rules_rust//proto:toolchain.bzl', 'rust_proto_toolchain')

rust_proto_toolchain(
   name="rust_proto_impl",
   grpc_plugin="@rust_grpc//:grpc_plugin",
   grpc_compile_deps=["@rust_grpc//:grpc_deps"],
)

toolchain(
    name="rust_proto",
    exec_compatible_with = [
        "@platforms//cpu:cpuX",
    ],
    target_compatible_with = [
        "@platforms//cpu:cpuX",
    ],
    toolchain = ":rust_proto_impl",
)

Then, either add the label of the toolchain rule to register_toolchains in the WORKSPACE, or pass it to the “--extra_toolchains” flag for Bazel, and it will be used.

See @io_bazel_rules_rust//proto:BUILD for examples of defining the toolchain.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
edition	The edition used by the generated rust source.	String	optional	“2015”
grpc_plugin	The location of the Rust protobuf compiler plugin to generate rust gRPC stubs.	Label	optional	@io_bazel_rules_rust//proto:protoc_gen_rust_grpc
proto_plugin	The location of the Rust protobuf compiler plugin used to generate rust sources.	Label	optional	@io_bazel_rules_rust//proto:protoc_gen_rust
protoc	The location of the protoc binary. It should be an executable target.	Label	optional	@com_google_protobuf//:protoc

rust_test

Builds a Rust test crate.

Examples:

Suppose you have the following directory structure for a Rust library crate with unit test code in the library sources:

[workspace]/
    WORKSPACE
    hello_lib/
        BUILD
        src/
            lib.rs

hello_lib/src/lib.rs:

pub struct Greeter {
    greeting: String,
}

impl Greeter {
    pub fn new(greeting: &str) -> Greeter {
        Greeter { greeting: greeting.to_string(), }
    }

    pub fn greet(&self, thing: &str) {
        println!("{} {}", &self.greeting, thing);
    }
}

#[cfg(test)]
mod test {
    use super::Greeter;

    #[test]
    fn test_greeting() {
        let hello = Greeter::new("Hi");
        assert_eq!("Hi Rust", hello.greeting("Rust"));
    }
}

To build and run the tests, simply add a rust_test rule with no srcs and only depends on the hello_lib rust_library target:

hello_lib/BUILD:

package(default_visibility = ["//visibility:public"])

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_library", "rust_test")

rust_library(
    name = "hello_lib",
    srcs = ["src/lib.rs"],
)

rust_test(
    name = "hello_lib_test",
    deps = [":hello_lib"],
)

Run the test with bazel build //hello_lib:hello_lib_test.

To run a crate or lib with the #[cfg(test)] configuration, handling inline tests, you should specify the crate directly like so.

rust_test(
    name = "hello_lib_test",
    crate = ":hello_lib",
    # You may add other deps that are specific to the test configuration
    deps = ["//some/dev/dep"],
)

Example: `test` directory

Integration tests that live in the tests directory, they are essentially built as separate crates. Suppose you have the following directory structure where greeting.rs is an integration test for the hello_lib library crate:

[workspace]/
    WORKSPACE
    hello_lib/
        BUILD
        src/
            lib.rs
        tests/
            greeting.rs

hello_lib/tests/greeting.rs:

extern crate hello_lib;

use hello_lib;

#[test]
fn test_greeting() {
    let hello = greeter::Greeter::new("Hello");
    assert_eq!("Hello world", hello.greeting("world"));
}

To build the greeting.rs integration test, simply add a rust_test target with greeting.rs in srcs and a dependency on the hello_lib target:

hello_lib/BUILD:

package(default_visibility = ["//visibility:public"])

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_library", "rust_test")

rust_library(
    name = "hello_lib",
    srcs = ["src/lib.rs"],
)

rust_test(
    name = "greeting_test",
    srcs = ["tests/greeting.rs"],
    deps = [":hello_lib"],
)

Run the test with bazel build //hello_lib:hello_lib_test.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
aliases	Remap crates to a new name or moniker for linkage to this target These are other rust_library targets and will be presented as the new name given.	Dictionary: Label -> String	optional	{}
crate	Target inline tests declared in the given crate These tests are typically those that would be held out under #[cfg(test)] declarations.	Label	optional	None
crate_features	List of features to enable for this crate. Features are defined in the code using the #[cfg(feature = “foo”)] configuration option. The features listed here will be passed to rustc with --cfg feature=“${feature_name}” flags.	List of strings	optional	[]
crate_root	The file that will be passed to rustc to be used for building this crate. If crate_root is not set, then this rule will look for a lib.rs file (or main.rs for rust_binary) or the single file in srcs if srcs contains only one file.	Label	optional	None
data	List of files used by this rule at runtime. This attribute can be used to specify any data files that are embedded into the library, such as via the include_str! macro.	List of labels	optional	[]
deps	List of other libraries to be linked to this library target. These can be either other rust_library targets or cc_library targets if linking a native library.	List of labels	optional	[]
edition	The rust edition to use for this crate. Defaults to the edition specified in the rust_toolchain.	String	optional	""
out_dir_tar	Deprecated, do not use, see [#cargo_build_script] instead.	Label	optional	None
proc_macro_deps	List of rust_library targets with kind proc-macro used to help build this library target.	List of labels	optional	[]
rustc_env	Dictionary of additional “key”: “value” environment variables to set for rustc.	Dictionary: String -> String	optional	{}
rustc_flags	List of compiler flags passed to rustc.	List of strings	optional	[]
srcs	List of Rust .rs source files used to build the library. If srcs contains more than one file, then there must be a file either named lib.rs. Otherwise, crate_root must be set to the source file that is the root of the crate to be passed to rustc to build this crate.	List of labels	optional	[]
version	A version to inject in the cargo environment variable.	String	optional	“0.0.0”

rust_toolchain

Declares a Rust toolchain for use.

This is for declaring a custom toolchain, eg. for configuring a particular version of rust or supporting a new platform.

Example:

Suppose the core rust team has ported the compiler to a new target CPU, called cpuX. This support can be used in Bazel by defining a new toolchain definition and declaration:

load('@io_bazel_rules_rust//rust:toolchain.bzl', 'rust_toolchain')

rust_toolchain(
    name = "rust_cpuX_impl",
    rustc = "@rust_cpuX//:rustc",
    rustc_lib = "@rust_cpuX//:rustc_lib",
    rust_lib = "@rust_cpuX//:rust_lib",
    rust_doc = "@rust_cpuX//:rustdoc",
    binary_ext = "",
    staticlib_ext = ".a",
    dylib_ext = ".so",
    stdlib_linkflags = ["-lpthread", "-ldl"],
    os = "linux",
)

toolchain(
    name = "rust_cpuX",
    exec_compatible_with = [
        "@platforms//cpu:cpuX",
    ],
    target_compatible_with = [
        "@platforms//cpu:cpuX",
    ],
    toolchain = ":rust_cpuX_impl",
)

Then, either add the label of the toolchain rule to register_toolchains in the WORKSPACE, or pass it to the "--extra_toolchains" flag for Bazel, and it will be used.

See @io_bazel_rules_rust//rust:repositories.bzl for examples of defining the @rust_cpuX repository with the actual binaries and libraries.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
binary_ext	The extension for binaries created from rustc.	String	required
cargo	The location of the cargo binary. Can be a direct source or a filegroup containing one item.	Label	optional	None
clippy_driver	The location of the clippy-driver binary. Can be a direct source or a filegroup containing one item.	Label	optional	None
debug_info	Rustc debug info levels per opt level	Dictionary: String -> String	optional	{“opt”: “0”, “dbg”: “2”, “fastbuild”: “0”}
default_edition	The edition to use for rust_* rules that don't specify an edition.	String	optional	“2015”
dylib_ext	The extension for dynamic libraries created from rustc.	String	required
exec_triple	The platform triple for the toolchains execution environment. For more details see: https://docs.bazel.build/versions/master/skylark/rules.html#configurations	String	optional	""
opt_level	Rustc optimization levels.	Dictionary: String -> String	optional	{“opt”: “3”, “dbg”: “0”, “fastbuild”: “0”}
os	The operating system for the current toolchain	String	required
rust_doc	The location of the rustdoc binary. Can be a direct source or a filegroup containing one item.	Label	optional	None
rust_lib	The rust standard library.	Label	optional	None
rustc	The location of the rustc binary. Can be a direct source or a filegroup containing one item.	Label	optional	None
rustc_lib	The libraries used by rustc during compilation.	Label	optional	None
rustfmt	The location of the rustfmt binary. Can be a direct source or a filegroup containing one item.	Label	optional	None
staticlib_ext	The extension for static libraries created from rustc.	String	required
stdlib_linkflags	Additional linker libs used when std lib is linked, see https://github.com/rust-lang/rust/blob/master/src/libstd/build.rs	List of strings	required
target_triple	The platform triple for the toolchains target environment. For more details see: https://docs.bazel.build/versions/master/skylark/rules.html#configurations	String	optional	""

rust_toolchain_repository

Composes a single workspace containing the toolchain components for compiling on a given platform to a series of target platforms. A given instance of this rule should be accompanied by a rust_toolchain_repository_proxy invocation to declare its toolchains to Bazel; the indirection allows separating toolchain selection from toolchain fetching.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this repository.	Name	required
dev_components	Whether to download the rustc-dev components (defaults to False). Requires version to be “nightly”.	Boolean	optional	False
edition	The rust edition to be used by default.	String	optional	“2015”
exec_triple	The Rust-style target that this compiler runs on	String	required
extra_target_triples	Additional rust-style targets that this set of toolchains should support.	List of strings	optional	[]
iso_date	The date of the tool (or None, if the version is a specific version).	String	optional	""
rustfmt_version	The version of the tool among “nightly”, “beta”, or an exact version.	String	optional	""
sha256s	A dict associating tool subdirectories to sha256 hashes. See rust_repositories for more details.	Dictionary: String -> String	optional	{}
toolchain_name_prefix	The per-target prefix expected for the rust_toolchain declarations in the parent workspace.	String	optional	""
version	The version of the tool among “nightly”, “beta”, or an exact version.	String	required

rust_toolchain_repository_proxy

Generates a toolchain-bearing repository that declares the toolchains from some other rust_toolchain_repository.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this repository.	Name	required
exec_triple	The Rust-style target triple for the compilation platform	String	required
extra_target_triples	The Rust-style triples for extra compilation targets	List of strings	optional	[]
parent_workspace_name	The name of the other rust_toolchain_repository	String	required
toolchain_name_prefix	The per-target prefix expected for the rust_toolchain declarations in the parent workspace.	String	optional	""

rust_wasm_bindgen

Generates javascript and typescript bindings for a webassembly module.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
bindgen_flags	Flags to pass directly to the bindgen executable. See https://github.com/rustwasm/wasm-bindgen/ for details.	List of strings	optional	[]
wasm_file	The .wasm file to generate bindings for.	Label	optional	None

rust_wasm_bindgen_toolchain

The tools required for the rust_wasm_bindgen rule.

ATTRIBUTES

Name	Description	Type	Mandatory	Default
name	A unique name for this target.	Name	required
bindgen	The label of a bindgen executable.	Label	optional	None

cargo_build_script

Compile and execute a rust build script to generate build attributes

This rules take the same arguments as rust_binary.

Example:

Suppose you have a crate with a cargo build script build.rs:

[workspace]/
    hello_lib/
        BUILD
        build.rs
        src/
            lib.rs

Then you want to use the build script in the following:

hello_lib/BUILD:

package(default_visibility = ["//visibility:public"])

load("@io_bazel_rules_rust//rust:rust.bzl", "rust_binary", "rust_library")
load("@io_bazel_rules_rust//cargo:cargo_build_script.bzl", "cargo_build_script")

# This will run the build script from the root of the workspace, and
# collect the outputs.
cargo_build_script(
    name = "build_script",
    srcs = ["build.rs"],
    # Data are shipped during execution.
    data = ["src/lib.rs"],
    # Environment variables passed during build.rs execution
    build_script_env = {"CARGO_PKG_VERSION": "0.1.2"},
)

rust_library(
    name = "hello_lib",
    srcs = [
        "src/lib.rs",
    ],
    deps = [":build_script"],
)

The hello_lib target will be build with the flags and the environment variables declared by the build script in addition to the file generated by it.

PARAMETERS

Name	Description	Default Value
name	The target name for the underlying rule	none
crate_name	Name of the crate associated with this build script target.	""
crate_features	A list of features to enable for the build script.	[]
version	The semantic version (semver) of the crate.	None
deps	The dependencies of the crate defined by crate_name.	[]
build_script_env	Environment variables for build scripts.	{}
kwargs	Forwards to the underlying rust_binary rule.	none

rust_bindgen_library

Generates a rust source file for header, and builds a rust_library.

Arguments are the same as rust_bindgen, and kwargs are passed directly to rust_library.

PARAMETERS

Name	Description	Default Value
name	A unique name for this target.	none
header	The label of the .h file to generate bindings for.	none
cc_lib	The label of the cc_library that contains the .h file. This is used to find the transitive includes.	none
bindgen_flags	Flags to pass directly to the bindgen executable. See https://rust-lang.github.io/rust-bindgen/ for details.	None
clang_flags	Flags to pass directly to the clang executable.	None
kwargs	Arguments to forward to the underlying rust_library rule.	none

rust_repositories

Emits a default set of toolchains for Linux, OSX, and Freebsd

Skip this macro and call the rust_repository_set macros directly if you need a compiler for other hosts or for additional target triples.

The sha256 attribute represents a dict associating tool subdirectories to sha256 hashes. As an example:

{
    "rust-1.46.0-x86_64-unknown-linux-gnu": "e3b98bc3440fe92817881933f9564389eccb396f5f431f33d48b979fa2fbdcf5",
    "rustfmt-1.4.12-x86_64-unknown-linux-gnu": "1894e76913303d66bf40885a601462844eec15fca9e76a6d13c390d7000d64b0",
    "rust-std-1.46.0-x86_64-unknown-linux-gnu": "ac04aef80423f612c0079829b504902de27a6997214eb58ab0765d02f7ec1dbc",
}

This would match for exec_triple = "x86_64-unknown-linux-gnu". If not specified, rules_rust pulls from a non-exhaustive list of known checksums..

See load_arbitrary_tool in @io_bazel_rules_rust//rust:repositories.bzl for more details.

PARAMETERS

Name	Description	Default Value
version	The version of Rust. Either “nightly”, “beta”, or an exact version.	“1.44.0”
iso_date	The date of the nightly or beta release (or None, if the version is a specific version).	None
rustfmt_version	The version of rustfmt. Either “nightly”, “beta”, or an exact version.	“1.4.18”
edition	The rust edition to be used by default (2015 (default) or 2018)	None
dev_components	Whether to download the rustc-dev components (defaults to False). Requires version to be “nightly”.	False
sha256s	A dict associating tool subdirectories to sha256 hashes.	None

rust_repository_set

Assembles a remote repository for the given toolchain params, produces a proxy repository to contain the toolchain declaration, and registers the toolchains.

N.B. A “proxy repository” is needed to allow for registering the toolchain (with constraints) without actually downloading the toolchain.

PARAMETERS

Name	Description	Default Value
name	The name of the generated repository	none
version	The version of the tool among “nightly”, "beta', or an exact version.	none
exec_triple	The Rust-style target that this compiler runs on	none
extra_target_triples	Additional rust-style targets that this set of toolchains should support. Defaults to [].	[]
iso_date	The date of the tool. Defaults to None.	None
rustfmt_version	The version of rustfmt to be associated with the toolchain. Defaults to None.	None
edition	The rust edition to be used by default (2015 (if None) or 2018).	None
dev_components	Whether to download the rustc-dev components. Requires version to be “nightly”. Defaults to False.	False
sha256s	A dict associating tool subdirectories to sha256 hashes. See rust_repositories for more details.	None

rust_workspace

A helper macro for setting up requirements for rules_rust within a given workspace.

This macro should always loaded and invoked after rust_repositories within a WORKSPACE file.

PARAMETERS

Rust rules

rust_benchmark

rust_binary

rust_bindgen

rust_bindgen_toolchain

rust_doc

rust_doc_test

rust_grpc_library

rust_library

rust_proto_library

rust_proto_toolchain

rust_test

Example: test directory

rust_toolchain

rust_toolchain_repository

rust_toolchain_repository_proxy

rust_wasm_bindgen

rust_wasm_bindgen_toolchain

cargo_build_script

rust_bindgen_library

rust_repositories

rust_repository_set

rust_workspace

Example: `test` directory