# Cargo
* [cargo_bootstrap_repository](#cargo_bootstrap_repository)
* [cargo_build_script](#cargo_build_script)
* [cargo_dep_env](#cargo_dep_env)
* [cargo_env](#cargo_env)
## cargo_bootstrap_repository
cargo_bootstrap_repository(name, binary, build_mode, cargo_lockfile, cargo_toml, env, env_label,
iso_date, repo_mapping, rust_toolchain_cargo_template,
rust_toolchain_rustc_template, srcs, timeout, version)
A rule for bootstrapping a Rust binary using [Cargo](https://doc.rust-lang.org/cargo/)
**ATTRIBUTES**
| Name | Description | Type | Mandatory | Default |
| :------------- | :------------- | :------------- | :------------- | :------------- |
| name | A unique name for this repository. | Name | required | |
| binary | The binary to build (the --bin parameter for Cargo). If left empty, the repository name will be used. | String | optional | "" |
| build_mode | The build mode the binary should be built with | String | optional | "release" |
| cargo_lockfile | The lockfile of the crate_universe resolver | Label | required | |
| cargo_toml | The path of the crate_universe resolver manifest (Cargo.toml file) | Label | required | |
| env | A mapping of platform triple to a set of environment variables. See [cargo_env](#cargo_env) for usage details. Additionally, the platform triple * applies to all platforms. | Dictionary: String -> String | optional | {} |
| env_label | A mapping of platform triple to a set of environment variables. This attribute differs from env in that all variables passed here must be fully qualified labels of files. See [cargo_env](#cargo_env) for usage details. Additionally, the platform triple * applies to all platforms. | Dictionary: String -> String | optional | {} |
| iso_date | The iso_date of cargo binary the resolver should use. Note: This can only be set if version is beta or nightly | String | optional | "" |
| repo_mapping | A dictionary from local repository name to global repository name. This allows controls over workspace dependency resolution for dependencies of this repository.<p>For example, an entry "@foo": "@bar" declares that, for any time this repository depends on @foo (such as a dependency on @foo//some:target, it should actually resolve that dependency within globally-declared @bar (@bar//some:target). | Dictionary: String -> String | required | |
| rust_toolchain_cargo_template | The template to use for finding the host cargo binary. {version} (eg. '1.53.0'), {triple} (eg. 'x86_64-unknown-linux-gnu'), {arch} (eg. 'aarch64'), {vendor} (eg. 'unknown'), {system} (eg. 'darwin'), {channel} (eg. 'stable'), and {tool} (eg. 'rustc.exe') will be replaced in the string if present. | String | optional | "@rust_{system}_{arch}__{triple}__{channel}_tools//:bin/{tool}" |
| rust_toolchain_rustc_template | The template to use for finding the host rustc binary. {version} (eg. '1.53.0'), {triple} (eg. 'x86_64-unknown-linux-gnu'), {arch} (eg. 'aarch64'), {vendor} (eg. 'unknown'), {system} (eg. 'darwin'), {channel} (eg. 'stable'), and {tool} (eg. 'rustc.exe') will be replaced in the string if present. | String | optional | "@rust_{system}_{arch}__{triple}__{channel}_tools//:bin/{tool}" |
| srcs | Souce files of the crate to build. Passing source files here can be used to trigger rebuilds when changes are made | List of labels | optional | [] |
| timeout | Maximum duration of the Cargo build command in seconds | Integer | optional | 600 |
| version | The version of cargo the resolver should use | String | optional | "1.76.0" |
## cargo_dep_env
cargo_dep_env(name, out_dir, src)
A rule for generating variables for dependent `cargo_build_script`s without a build script. This is useful for using Bazel rules instead of a build script, while also generating configuration information for build scripts which depend on this crate.
**ATTRIBUTES**
| Name | Description | Type | Mandatory | Default |
| :------------- | :------------- | :------------- | :------------- | :------------- |
| name | A unique name for this target. | Name | required | |
| out_dir | Folder containing additional inputs when building all direct dependencies.
This has the same effect as a cargo_build_script which prints puts files into $OUT_DIR, but without requiring a build script. | Label | optional | None |
| src | File containing additional environment variables to set for build scripts of direct dependencies.
This has the same effect as a cargo_build_script which prints cargo:VAR=VALUE lines, but without requiring a build script.
This files should contain a single variable per line, of format NAME=value, and newlines may be included in a value by ending a line with a trailing back-slash (\\). | Label | required | |
## cargo_build_script
cargo_build_script(name, edition, crate_name, crate_root, srcs, crate_features, version, deps,
link_deps, proc_macro_deps, build_script_env, data, compile_data, tools, links,
rundir, rustc_env, rustc_env_files, rustc_flags, visibility, tags, aliases, kwargs)
Compile and execute a rust build script to generate build attributes
This rules take the same arguments as rust_binary.
Example:
Suppose you have a crate with a cargo build script `build.rs`:
```output
[workspace]/
hello_lib/
BUILD
build.rs
src/
lib.rs
```
Then you want to use the build script in the following:
`hello_lib/BUILD`:
```python
package(default_visibility = ["//visibility:public"])
load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_library")
load("@rules_rust//cargo:defs.bzl", "cargo_build_script")
# This will run the build script from the root of the workspace, and
# collect the outputs.
cargo_build_script(
name = "build_script",
srcs = ["build.rs"],
# Optional environment variables passed during build.rs compilation
rustc_env = {
"CARGO_PKG_VERSION": "0.1.2",
},
# Optional environment variables passed during build.rs execution.
# Note that as the build script's working directory is not execroot,
# execpath/location will return an absolute path, instead of a relative
# one.
build_script_env = {
"SOME_TOOL_OR_FILE": "$(execpath @tool//:binary)"
},
# Optional data/tool dependencies
data = ["@tool//:binary"],
)
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 name for the underlying rule. This should be the name of the package being compiled, optionally with a suffix of _build_script. | none |
| edition | The rust edition to use for the internal binary crate. | `None` |
| crate_name | Crate name to use for build script. | `None` |
| crate_root | The file that will be passed to rustc to be used for building this crate. | `None` |
| srcs | Souce files of the crate to build. Passing source files here can be used to trigger rebuilds when changes are made. | `[]` |
| crate_features | A list of features to enable for the build script. | `[]` |
| version | The semantic version (semver) of the crate. | `None` |
| deps | The build-dependencies of the crate. | `[]` |
| link_deps | The subset of the (normal) dependencies of the crate that have the links attribute and therefore provide environment variables to this build script. | `[]` |
| proc_macro_deps | List of rust_proc_macro targets used to build the script. | `[]` |
| build_script_env | Environment variables for build scripts. | `{}` |
| data | Files needed by the build script. | `[]` |
| compile_data | Files needed for the compilation of the build script. | `[]` |
| tools | Tools (executables) needed by the build script. | `[]` |
| links | Name of the native library this crate links against. | `None` |
| rundir | A directory to cd to before the cargo_build_script is run. This should be a path relative to the exec root.
The default behaviour (and the behaviour if rundir is set to the empty string) is to change to the relative path corresponding to the cargo manifest directory, which replicates the normal behaviour of cargo so it is easy to write compatible build scripts.
If set to ., the cargo build script will run in the exec root. | `None` |
| rustc_env | Environment variables to set in rustc when compiling the build script. | `{}` |
| rustc_env_files | Files containing additional environment variables to set for rustc when building the build script. | `[]` |
| rustc_flags | List of compiler flags passed to rustc. | `[]` |
| visibility | Visibility to apply to the generated build script output. | `None` |
| tags | (list of str, optional): Tags to apply to the generated build script output. | `None` |
| 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. | `None` |
| kwargs | Forwards to the underlying rust_binary rule. An exception is the compatible_with attribute, which shouldn't be forwarded to the rust_binary, as the rust_binary is only built and used in exec mode. We propagate the compatible_with attribute to the _build_scirpt_run target. | none |
## cargo_env
cargo_env(env)
A helper for generating platform specific environment variables
```python
load("@rules_rust//rust:defs.bzl", "rust_common")
load("@rules_rust//cargo:defs.bzl", "cargo_bootstrap_repository", "cargo_env")
cargo_bootstrap_repository(
name = "bootstrapped_bin",
cargo_lockfile = "//:Cargo.lock",
cargo_toml = "//:Cargo.toml",
srcs = ["//:resolver_srcs"],
version = rust_common.default_version,
binary = "my-crate-binary",
env = {
"x86_64-unknown-linux-gnu": cargo_env({
"FOO": "BAR",
}),
},
env_label = {
"aarch64-unknown-linux-musl": cargo_env({
"DOC": "//:README.md",
}),
}
)
```
**PARAMETERS**
| Name | Description | Default Value |
| :------------- | :------------- | :------------- |
| env | A map of environment variables | none |
**RETURNS**
str: A json encoded string of the environment variables