Added rustfmt rules and aspects.

.bazelci/presubmit.yml

@@ -100,6 +100,20 @@ tasks:
     platform: ubuntu1804
     shell_commands:
       - ./test/clippy/clippy_failure_test.sh
+  rustfmt_examples:
+    name: Rustfmt on Examples
+    platform: ubuntu2004
+    working_directory: examples
+    build_flags:
+      - "--aspects=@rules_rust//rust:defs.bzl%rustfmt_aspect"
+      - "--output_groups=rustfmt_checks"
+    build_targets:
+      - //...
+  rustfmt_failure:
+    name: Negative Rustfmt Tests
+    platform: ubuntu2004
+    run_targets:
+      - "//test/rustfmt:test_runner"
   ubuntu2004_clang:
     name: Ubuntu 20.04 with Clang
     platform: ubuntu2004

BUILD.bazel

@@ -17,3 +17,10 @@ error_format(
     build_setting_default = "human",
     visibility = ["//visibility:public"],
 )
+
+# This setting is used by the rustfmt rules. See https://bazelbuild.github.io/rules_rust/rust_fmt.html
+label_flag(
+    name = "rustfmt.toml",
+    build_setting_default = "//tools/rustfmt:rustfmt.toml",
+    visibility = ["//visibility:public"],
+)

docs/BUILD.bazel

@@ -88,6 +88,14 @@ PAGES = dict([
             "rust_doc_test",
         ],
     ),
+    page(
+        name = "rust_fmt",
+        header_template = ":rust_fmt.vm",
+        symbols = [
+            "rustfmt_aspect",
+            "rustfmt_test",
+        ],
+    ),
     page(
         name = "rust_proto",
         symbols = [

docs/flatten.md

@@ -33,6 +33,8 @@
 * [rust_wasm_bindgen](#rust_wasm_bindgen)
 * [rust_wasm_bindgen_repositories](#rust_wasm_bindgen_repositories)
 * [rust_wasm_bindgen_toolchain](#rust_wasm_bindgen_toolchain)
+* [rustfmt_aspect](#rustfmt_aspect)
+* [rustfmt_test](#rustfmt_test)
 
 
 <a id="#crate_universe"></a>
@@ -1281,6 +1283,25 @@ For additional information, see the [Bazel toolchains documentation][toolchains]
 | <a id="rust_wasm_bindgen_toolchain-bindgen"></a>bindgen |  The label of a <code>wasm-bindgen-cli</code> executable.   | <a href="https://bazel.build/docs/build-ref.html#labels">Label</a> | optional | None |
 
 
+<a id="#rustfmt_test"></a>
+
+## rustfmt_test
+
+<pre>
+rustfmt_test(<a href="#rustfmt_test-name">name</a>, <a href="#rustfmt_test-targets">targets</a>)
+</pre>
+
+A test rule for performing `rustfmt --check` on a set of targets
+
+**ATTRIBUTES**
+
+
+| Name  | Description | Type | Mandatory | Default |
+| :------------- | :------------- | :------------- | :------------- | :------------- |
+| <a id="rustfmt_test-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/docs/build-ref.html#name">Name</a> | required |  |
+| <a id="rustfmt_test-targets"></a>targets |  Rust targets to run <code>rustfmt --check</code> on.   | <a href="https://bazel.build/docs/build-ref.html#labels">List of labels</a> | optional | [] |
+
+
 <a id="#cargo_build_script"></a>
 
 ## cargo_build_script
@@ -1757,3 +1778,40 @@ $ bazel build --aspects=@rules_rust//rust:defs.bzl%rust_clippy_aspect
 | <a id="rust_clippy_aspect-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/docs/build-ref.html#name">Name</a> | required |   |
 
 
+<a id="#rustfmt_aspect"></a>
+
+## rustfmt_aspect
+
+<pre>
+rustfmt_aspect(<a href="#rustfmt_aspect-name">name</a>)
+</pre>
+
+This aspect is used to gather information about a crate for use in rustfmt and perform rustfmt checks
+
+Output Groups:
+
+- `rustfmt_manifest`: A manifest used by rustfmt binaries to provide crate specific settings.
+- `rustfmt_checks`: Executes `rustfmt --check` on the specified target.
+
+The build setting `@rules_rust//:rustfmt.toml` is used to control the Rustfmt [configuration settings][cs]
+used at runtime.
+
+[cs]: https://rust-lang.github.io/rustfmt/
+
+This aspect is executed on any target which provides the `CrateInfo` provider. However
+users may tag a target with `norustfmt` to have it skipped. Additionally, generated
+source files are also ignored by this aspect.
+
+
+**ASPECT ATTRIBUTES**
+
+
+
+**ATTRIBUTES**
+
+
+| Name  | Description | Type | Mandatory | Default |
+| :------------- | :------------- | :------------- | :------------- | :------------- |
+| <a id="rustfmt_aspect-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/docs/build-ref.html#name">Name</a> | required |   |
+
+

docs/index.md

@@ -42,6 +42,7 @@ supported in certain environments.
 - [defs](defs.md): standard rust rules for building and testing libraries and binaries.
 - [rust_doc](rust_doc.md): rules for generating and testing rust documentation.
 - [rust_clippy](rust_clippy.md): rules for running [clippy](https://github.com/rust-lang/rust-clippy#readme).
+- [rust_fmt](rust_fmt.md): rules for running [rustfmt](https://github.com/rust-lang/rustfmt#readme).
 - [rust_proto](rust_proto.md): rules for generating [protobuf](https://developers.google.com/protocol-buffers).
   and [gRPC](https://grpc.io) stubs.
 - [rust_bindgen](rust_bindgen.md): rules for generating C++ bindings.

docs/rust_fmt.md

@@ -0,0 +1,104 @@
+<!-- Generated with Stardoc: http://skydoc.bazel.build -->
+# Rust Fmt
+
+* [rustfmt_aspect](#rustfmt_aspect)
+* [rustfmt_test](#rustfmt_test)
+
+
+## Overview
+
+
+[Rustfmt][rustfmt] is a tool for formatting Rust code according to style guidelines. 
+By default, Rustfmt uses a style which conforms to the [Rust style guide][rsg] that
+has been formalized through the [style RFC process][rfcp]. A complete list of all
+configuration options can be found in the [Rustfmt GitHub Pages][rgp].
+
+
+
+### Setup
+
+
+Formatting your Rust targets' source code requires no setup outside of loading `rules_rust`
+in your workspace. Simply run `bazel run @rules_rust//tools/rustfmt` to format source code.
+
+In addition to this formatter, a check can be added to your build phase using the [rustfmt_aspect](#rustfmt-aspect)
+aspect. Simply add the following to a `.bazelrc` file to enable this check.
+
+```text
+build --aspects=@rules_rust//rust:defs.bzl%rustfmt_aspect
+build --output_groups=+rustfmt_checks
+```
+
+It's recommended to only enable this aspect in your CI environment so formatting issues do not
+impact user's ability to rapidly iterate on changes.
+
+The `rustfmt_aspect` also uses a `--@rules_rust//:rustfmt.toml` setting which determines the
+[configuration file][rgp] used by the formatter (`@rules_rust//tools/rustfmt`) and the aspect
+(`rustfmt_aspect`). This flag can be added to your `.bazelrc` file to ensure a consistent config
+file is used whenever `rustfmt` is run:
+
+```text
+build --@rules_rust//:rustfmt.toml=//:rustfmt.toml
+```
+
+[rustfmt]: https://github.com/rust-lang/rustfmt#readme
+[rsg]: https://github.com/rust-lang-nursery/fmt-rfcs/blob/master/guide/guide.md
+[rfcp]: https://github.com/rust-lang-nursery/fmt-rfcs
+[rgp]: https://rust-lang.github.io/rustfmt/
+
+<a id="#rustfmt_test"></a>
+
+## rustfmt_test
+
+<pre>
+rustfmt_test(<a href="#rustfmt_test-name">name</a>, <a href="#rustfmt_test-targets">targets</a>)
+</pre>
+
+A test rule for performing `rustfmt --check` on a set of targets
+
+**ATTRIBUTES**
+
+
+| Name  | Description | Type | Mandatory | Default |
+| :------------- | :------------- | :------------- | :------------- | :------------- |
+| <a id="rustfmt_test-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/docs/build-ref.html#name">Name</a> | required |  |
+| <a id="rustfmt_test-targets"></a>targets |  Rust targets to run <code>rustfmt --check</code> on.   | <a href="https://bazel.build/docs/build-ref.html#labels">List of labels</a> | optional | [] |
+
+
+<a id="#rustfmt_aspect"></a>
+
+## rustfmt_aspect
+
+<pre>
+rustfmt_aspect(<a href="#rustfmt_aspect-name">name</a>)
+</pre>
+
+This aspect is used to gather information about a crate for use in rustfmt and perform rustfmt checks
+
+Output Groups:
+
+- `rustfmt_manifest`: A manifest used by rustfmt binaries to provide crate specific settings.
+- `rustfmt_checks`: Executes `rustfmt --check` on the specified target.
+
+The build setting `@rules_rust//:rustfmt.toml` is used to control the Rustfmt [configuration settings][cs]
+used at runtime.
+
+[cs]: https://rust-lang.github.io/rustfmt/
+
+This aspect is executed on any target which provides the `CrateInfo` provider. However
+users may tag a target with `norustfmt` to have it skipped. Additionally, generated
+source files are also ignored by this aspect.
+
+
+**ASPECT ATTRIBUTES**
+
+
+
+**ATTRIBUTES**
+
+
+| Name  | Description | Type | Mandatory | Default |
+| :------------- | :------------- | :------------- | :------------- | :------------- |
+| <a id="rustfmt_aspect-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/docs/build-ref.html#name">Name</a> | required |   |
+
+

docs/rust_fmt.vm

@@ -0,0 +1,41 @@
+#[[
+## Overview
+]]#
+
+[Rustfmt][rustfmt] is a tool for formatting Rust code according to style guidelines. 
+By default, Rustfmt uses a style which conforms to the [Rust style guide][rsg] that
+has been formalized through the [style RFC process][rfcp]. A complete list of all
+configuration options can be found in the [Rustfmt GitHub Pages][rgp].
+
+
+#[[
+### Setup
+]]#
+
+Formatting your Rust targets' source code requires no setup outside of loading `rules_rust`
+in your workspace. Simply run `bazel run @rules_rust//tools/rustfmt` to format source code.
+
+In addition to this formatter, a check can be added to your build phase using the [rustfmt_aspect](#rustfmt-aspect)
+aspect. Simply add the following to a `.bazelrc` file to enable this check.
+
+```text
+build --aspects=@rules_rust//rust:defs.bzl%rustfmt_aspect
+build --output_groups=+rustfmt_checks
+```
+
+It's recommended to only enable this aspect in your CI environment so formatting issues do not
+impact user's ability to rapidly iterate on changes.
+
+The `rustfmt_aspect` also uses a `--@rules_rust//:rustfmt.toml` setting which determines the
+[configuration file][rgp] used by the formatter (`@rules_rust//tools/rustfmt`) and the aspect
+(`rustfmt_aspect`). This flag can be added to your `.bazelrc` file to ensure a consistent config
+file is used whenever `rustfmt` is run:
+
+```text
+build --@rules_rust//:rustfmt.toml=//:rustfmt.toml
+```
+
+[rustfmt]: https://github.com/rust-lang/rustfmt#readme
+[rsg]: https://github.com/rust-lang-nursery/fmt-rfcs/blob/master/guide/guide.md
+[rfcp]: https://github.com/rust-lang-nursery/fmt-rfcs
+[rgp]: https://rust-lang.github.io/rustfmt/

docs/symbols.bzl

@@ -50,6 +50,8 @@ load(
     _rust_static_library = "rust_static_library",
     _rust_test = "rust_test",
     _rust_test_suite = "rust_test_suite",
+    _rustfmt_aspect = "rustfmt_aspect",
+    _rustfmt_test = "rustfmt_test",
 )
 load(
     "@rules_rust//rust:repositories.bzl",
@@ -113,3 +115,6 @@ rust_analyzer_aspect = _rust_analyzer_aspect
 
 crate_universe = _crate_universe
 crate = _crate
+
+rustfmt_aspect = _rustfmt_aspect
+rustfmt_test = _rustfmt_test

rust/defs.bzl

@@ -49,6 +49,11 @@ load(
     "//rust/private:rustdoc_test.bzl",
     _rust_doc_test = "rust_doc_test",
 )
+load(
+    "//rust/private:rustfmt.bzl",
+    _rustfmt_aspect = "rustfmt_aspect",
+    _rustfmt_test = "rustfmt_test",
+)
 
 rust_library = _rust_library
 # See @rules_rust//rust/private:rust.bzl for a complete description.
@@ -96,7 +101,13 @@ rust_common = _rust_common
 # See @rules_rust//rust/private:common.bzl for a complete description.
 
 rust_analyzer_aspect = _rust_analyzer_aspect
-# See @rules_rust//rust:private/rust_analyzer.bzl for a complete description.
+# See @rules_rust//rust/private:rust_analyzer.bzl for a complete description.
 
 rust_analyzer = _rust_analyzer
-# See @rules_rust//rust:private/rust_analyzer.bzl for a complete description.
+# See @rules_rust//rust/private:rust_analyzer.bzl for a complete description.
+
+rustfmt_aspect = _rustfmt_aspect
+# See @rules_rust//rust/private:rustfmt.bzl for a complete description.
+
+rustfmt_test = _rustfmt_test
+# See @rules_rust//rust/private:rustfmt.bzl for a complete description.