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fix(rust-bindings): detect NIXL availability and fallback to stubs #1120

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fix(rust-bindings): detect NIXL availability and fallback to stubs #1120

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74 changes: 57 additions & 17 deletions src/bindings/rust/build.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -84,6 +84,34 @@ fn get_nixl_libs() -> Option<Vec<pkg_config::Library>> {
}
}

/// Check if NIXL library is available on the system
fn check_nixl_available() -> bool {
// First try pkg-config
if pkg_config::probe_library("nixl").is_ok() {
return true;
}

// Fall back to checking common library paths
let nixl_root_path =
env::var("NIXL_PREFIX").unwrap_or_else(|_| "/opt/nvidia/nvda_nixl".to_string());
let arch = get_arch();

// Check various possible library locations
let possible_paths = [
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@milesial milesial Dec 16, 2025

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Can the check for availability use the same set of paths that would be sent to the linker? We're missing 2 of the 5 right now. And maybe use the same function for both so they are always aligned

    // Add all possible library paths
    println!("cargo:rustc-link-search=native={}", nixl_lib_path);
    println!("cargo:rustc-link-search=native={}", nixl_root_path);
    println!("cargo:rustc-link-search=native={}/lib", nixl_root_path);
    println!("cargo:rustc-link-search=native={}/lib64", nixl_root_path);
    println!("cargo:rustc-link-search=native={}/lib/x86_64-linux-gnu", nixl_root_path);

format!("{}/lib/{}-linux-gnu/libnixl.so", nixl_root_path, arch),
format!("{}/lib64/libnixl.so", nixl_root_path),
format!("{}/lib/libnixl.so", nixl_root_path),
];

for path in &possible_paths {
if std::path::Path::new(path).exists() {
return true;
}
}

false
}

fn build_nixl(cc_builder: &mut cc::Build) -> anyhow::Result<()> {
let nixl_root_path =
env::var("NIXL_PREFIX").unwrap_or_else(|_| "/opt/nvidia/nvda_nixl".to_string());
Expand Down Expand Up @@ -233,25 +261,37 @@ fn create_builder() -> cc::Build {
fn run_build(use_stub_api: bool) {
let mut cc_builder = create_builder();

if !use_stub_api {
let no_fallback = env::var("NIXL_NO_STUBS_FALLBACK")
.map(|v| v == "1")
.unwrap_or(false);

if let Err(e) = build_nixl(&mut cc_builder) {
if !no_fallback {
println!(
"cargo:warning=NIXL build failed: {}, falling back to stub API",
e
);
let mut stub_builder = create_builder();
build_stubs(&mut stub_builder);
} else {
panic!("Failed to build NIXL: {}", e);
}
if use_stub_api {
build_stubs(&mut cc_builder);
return;
}

let no_fallback = env::var("NIXL_NO_STUBS_FALLBACK")
.map(|v| v == "1")
.unwrap_or(false);

// Check if NIXL is available before attempting to build
if !check_nixl_available() {
if no_fallback {
panic!("NIXL library not found and NIXL_NO_STUBS_FALLBACK is set");
}
} else {
println!("cargo:warning=NIXL library not found, building with stub API");
build_stubs(&mut cc_builder);
return;
}

// Try to build with NIXL
if let Err(e) = build_nixl(&mut cc_builder) {
if !no_fallback {
println!(
"cargo:warning=NIXL build failed: {}, falling back to stub API",
e
);
let mut stub_builder = create_builder();
build_stubs(&mut stub_builder);
} else {
panic!("Failed to build NIXL: {}", e);
}
}
}

Expand Down
15 changes: 12 additions & 3 deletions src/bindings/rust/wrapper.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,9 +16,18 @@
*/
#pragma once

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
// Use built-in compiler types to avoid system header dependencies
typedef __SIZE_TYPE__ size_t;
typedef __UINT64_TYPE__ uint64_t;
typedef __INT64_TYPE__ int64_t;
typedef __UINT16_TYPE__ uint16_t;
typedef __UINTPTR_TYPE__ uintptr_t;

#ifndef __cplusplus
typedef _Bool bool;
#define true 1
#define false 0
#endif

#ifdef __cplusplus
extern "C" {
Expand Down