nginx-sys

The nginx-sys crate provides low-level bindings for the nginx C API, allowing Rust applications to interact with nginx servers and modules.

Usage

Add nginx-sys as a dependency in your Cargo.toml:

[dependencies]
nginx-sys = "0.5.0"

Set the path to your nginx sources and build directory using the environment variables, or enable the nginx-sys/vendored feature to use a downloaded copy of the nginx sources.

Note that it is recommended to use the exact source and configure arguments of the nginx build you are planning to use in production. configure arguments alter the APIs and the symbols visible to the Rust code, and some OS distributions are known to ship nginx packages with API-breaking patches applied.

Features

• vendored: Enables the build scripts to download and build a copy of nginx source and link against it.

Input variables

NGINX_SOURCE_DIR, NGINX_BUILD_DIR control paths to an external nginx source tree and a configured build directory. Normally, specifying either of these is sufficient, as the build directory defaults to objs under the source dir.

However, it's possible to set the latter to any valid path with configure --builddir=<...>, and we need both paths to support such configuration.

The variables above are optional, but take preference when the vendored crate feature is enabled.

Output variables

Following metadata variables are passed to the build scripts of any direct dependents of the package.

Check the using another sys crate and the links manifest key sections of the Cargo Book for more details about passing metadata between packages.

DEP_NGINX_FEATURES

nginx has various configuration options that may affect the availability of functions, constants and structure fields. This is not something that can be detected at runtime, as an attempt to use a symbol unavailable in the bindings would result in compilation error.

DEP_NGINX_FEATURES_CHECK contains the full list of feature flags supported by nginx-sys, i.e. everything that can be used for feature checks. The most common use for this variable is to specify cargo::rustc-check-cfg.

DEP_NGINX_FEATURES contains the list of features enabled in the version of nginx being built against.

An example of a build script with these variables:

// Specify acceptable values for `ngx_feature`.
println!("cargo::rerun-if-env-changed=DEP_NGINX_FEATURES_CHECK");
println!(
    "cargo::rustc-check-cfg=cfg(ngx_feature, values({}))",
    std::env::var("DEP_NGINX_FEATURES_CHECK").unwrap_or("any()".to_string())
);
// Read feature flags detected by nginx-sys and pass to the compiler.
println!("cargo::rerun-if-env-changed=DEP_NGINX_FEATURES");
if let Ok(features) = std::env::var("DEP_NGINX_FEATURES") {
    for feature in features.split(',').map(str::trim) {
        println!("cargo::rustc-cfg=ngx_feature=\"{}\"", feature);
    }
}

And an usage example:

#[cfg(ngx_feature = "debug")]
println!("this nginx binary was built with debug logging enabled");

DEP_NGINX_OS

Version, as detected by the nginx configuration script.

DEP_NGINX_OS_CHECK contains the full list of supported values, and DEP_NGINX_OS the currently detected one.

Usage examples:

// Specify acceptable values for `ngx_os`
println!("cargo::rerun-if-env-changed=DEP_NGINX_OS_CHECK");
println!(
    "cargo::rustc-check-cfg=cfg(ngx_os, values({}))",
    std::env::var("DEP_NGINX_OS_CHECK").unwrap_or("any()".to_string())
);
// Read operating system detected by nginx-sys and pass to the compiler.
println!("cargo::rerun-if-env-changed=DEP_NGINX_OS");
if let Ok(os) = std::env::var("DEP_NGINX_OS") {
    println!("cargo::rustc-cfg=ngx_os=\"{}\"", os);
}

#[cfg(ngx_os = "freebsd")]
println!("this nginx binary was built on FreeBSD");

Version and build information

• DEP_NGINX_VERSION_NUMBER: a numeric representation with 3 digits for each component: 1026002
• DEP_NGINX_VERSION: human-readable string in a product/version format: nginx/1.26.2
• DEP_NGINX_BUILD: version string with the optional build name (--build=) included: nginx/1.25.5 (nginx-plus-r32)

Usage example:

println!("cargo::rustc-check-cfg=cfg(nginx1_27_0)");
println!("cargo::rerun-if-env-changed=DEP_NGINX_VERSION_NUMBER");
if let Ok(version) = std::env::var("DEP_NGINX_VERSION_NUMBER") {
    let version: u64 = version.parse().unwrap();

    if version >= 1_027_000 {
        println!("cargo::rustc-cfg=nginx1_27_0");
    }
}

Examples

Get nginx Version

This example demonstrates how to retrieve the version of the nginx server.

use nginx_sys::nginx_version;

println!("nginx version: {}", nginx_version);