1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
//! ONNX Runtime global environment: single init per process, runtime dylib loading.
//!
//! With the `load-dynamic` Cargo feature (always enabled in lean-ctx's `ort`
//! dependency), `libonnxruntime` is loaded at runtime via [`ort::init_from`].
//! This module resolves the library path across platforms, including NixOS.
//!
//! # Search order
//!
//! 1. `ORT_DYLIB_PATH` env var (resolved relative to the executable directory)
//! 2. Nix profile paths — `/run/current-system/sw/lib/`, `~/.nix-profile/lib/` (Linux)
//! 3. Well-known system directories per platform, including the active
//! `HOMEBREW_PREFIX` and the standard Homebrew/Linuxbrew lib dirs
//! 4. `LD_LIBRARY_PATH` / `DYLD_LIBRARY_PATH`
//!
//! If no copy is found, [`ensure_ort_env`] returns an eager error — session
//! creation hangs rather than failing, so we fail fast.
use std::path::{Path, PathBuf};
use std::sync::OnceLock;
use ort::ep::ExecutionProviderDispatch;
/// Ensure the global ONNX Runtime environment is initialized.
///
/// On first call: resolves `libonnxruntime` via the search chain defined in
/// `resolve_ort_dylib`, loads it with [`ort::init_from`], and registers GPU
/// execution providers. Subsequent calls are no-ops.
///
/// Returns an eager error when the shared library cannot be found (session
/// creation would otherwise hang).
pub fn ensure_ort_env(eps: &[ExecutionProviderDispatch]) -> anyhow::Result<()> {
static INIT: OnceLock<anyhow::Result<()>> = OnceLock::new();
// get_or_init runs the closure at most once; all subsequent calls return
// a reference to the stored Result.
match INIT.get_or_init(|| {
tracing::debug!("Initializing ONNX Runtime environment");
init_ort(eps)
}) {
Ok(()) => Ok(()),
// anyhow::Error is !Clone so we reconstitute from Display.
Err(e) => Err(anyhow::anyhow!("{e}")),
}
}
// ---------------------------------------------------------------------------
// Initialisation
// ---------------------------------------------------------------------------
/// Load `libonnxruntime` at runtime via [`ort::init_from`].
///
/// The library path is resolved by [`resolve_ort_dylib`]; errors are
/// propagated eagerly to avoid hanging on first session creation.
fn init_ort(eps: &[ExecutionProviderDispatch]) -> anyhow::Result<()> {
let path = resolve_ort_dylib()?;
tracing::debug!("Loading libonnxruntime from {}", path.display());
ort::init_from(&path)
.map_err(|e| anyhow::anyhow!("ort::init_from({}) failed: {e}", path.display()))?
.with_name("lean-ctx")
.with_execution_providers(eps)
.commit();
tracing::info!("ONNX Runtime initialised ({})", path.display());
Ok(())
}
// ---------------------------------------------------------------------------
// Library resolution
// ---------------------------------------------------------------------------
fn dylib_filename() -> &'static str {
if cfg!(target_os = "windows") {
"onnxruntime.dll"
} else if cfg!(target_os = "macos") {
"libonnxruntime.dylib"
} else {
"libonnxruntime.so"
}
}
/// Search for `libonnxruntime` across platform-specific locations.
///
/// Returns the first path found, or a descriptive error.
fn resolve_ort_dylib() -> anyhow::Result<PathBuf> {
let name = dylib_filename();
// 1. ORT_DYLIB_PATH env var (resolved relative to exe dir)
if let Ok(p) = std::env::var("ORT_DYLIB_PATH") {
let path = PathBuf::from(&p);
if path.is_relative() {
let rel_to_exe = || -> Option<PathBuf> {
let exe = std::env::current_exe().ok()?;
let dir = exe.parent()?;
let abs = dir.join(&path);
abs.is_file().then_some(abs)
};
if let Some(abs) = rel_to_exe() {
return Ok(abs);
}
}
if path.is_file() {
return Ok(path);
}
anyhow::bail!("ORT_DYLIB_PATH={p} set but file does not exist");
}
// 2. Nix profile paths (Linux) — system & user profiles always point to
// the currently activated version.
#[cfg(target_os = "linux")]
if let Some(found) = nix_profile_search(name) {
return Ok(found);
}
// 3. Well-known system paths (per platform)
if let Some(found) = well_known_paths(name) {
return Ok(found);
}
// 4. LD_LIBRARY_PATH / DYLD_LIBRARY_PATH
if let Some(found) = lib_path_search(name) {
return Ok(found);
}
anyhow::bail!(
"libonnxruntime not found.\n\
Set ORT_DYLIB_PATH=<path> to point to the shared library.\n\
Install: pip install onnxruntime (Python bundles the .so)\n\
NixOS: nix-shell -p onnxruntime\n\
Homebrew: brew install onnxruntime\n\
Searched: ORT_DYLIB_PATH, Nix store, well-known system dirs, \
LD_LIBRARY_PATH/DYLD_LIBRARY_PATH"
)
}
// ---------------------------------------------------------------------------
// Platform-specific searches
// ---------------------------------------------------------------------------
/// Check Nix profile symlinks for `libonnxruntime`.
///
/// Nix maintains `/run/current-system/sw/lib/` (system profile) and
/// `~/.nix-profile/lib/` (user profile) as symlinks to the currently
/// activated package versions — these are always authoritative.
#[cfg(target_os = "linux")]
fn nix_profile_search(name: &str) -> Option<PathBuf> {
let home = dirs::home_dir();
let user_profile = home
.as_ref()
.map(|h| h.join(".nix-profile").join("lib").join(name));
let candidates = [
Some(Path::new("/run/current-system/sw/lib").join(name)),
user_profile,
];
candidates.into_iter().flatten().find(|c| c.is_file())
}
/// Check well-known system directories for `libonnxruntime`.
fn well_known_paths(name: &str) -> Option<PathBuf> {
// Platform-specific hints.
let dirs: &[&str] = if cfg!(target_os = "linux") {
&[
"/usr/lib",
"/usr/lib64",
"/usr/local/lib",
// Linuxbrew default prefix (the `onnxruntime` formula symlinks its
// dylib here). A custom prefix is covered by HOMEBREW_PREFIX below.
"/home/linuxbrew/.linuxbrew/lib",
]
} else if cfg!(target_os = "macos") {
&["/usr/local/lib", "/opt/homebrew/lib", "/opt/local/lib"]
} else if cfg!(target_os = "windows") {
// On Windows, check next to the executable and common install paths.
&[]
} else {
&["/usr/lib", "/usr/local/lib"]
};
// Also check next to the executable (common for portable installs, macOS
// Frameworks, Windows sibling layout, and Linux $ORIGIN setups).
let exe_relative = || -> Option<PathBuf> {
let exe = std::env::current_exe().ok()?;
let dir = exe.parent()?;
let sibling = dir.join(name);
if sibling.is_file() {
return Some(sibling);
}
// macOS app bundle: executable in MyApp.app/Contents/MacOS/,
// library in MyApp.app/Contents/Frameworks/
#[cfg(target_os = "macos")]
{
let parent = dir.parent()?;
let fw = parent.join("Frameworks").join(name);
if fw.is_file() {
return Some(fw);
}
}
None
};
if let Some(path) = exe_relative() {
return Some(path);
}
// Honor an active Homebrew environment. `brew shellenv` exports
// HOMEBREW_PREFIX, so a binary launched from a brew-configured shell can
// locate the dylib regardless of platform or custom prefix — Apple Silicon
// (/opt/homebrew), Intel (/usr/local) and Linuxbrew
// (/home/linuxbrew/.linuxbrew) all symlink `onnxruntime` into <prefix>/lib.
if let Ok(prefix) = std::env::var("HOMEBREW_PREFIX") {
let candidate = Path::new(&prefix).join("lib").join(name);
if candidate.is_file() {
return Some(candidate);
}
}
for dir in dirs {
let candidate = Path::new(dir).join(name);
if candidate.is_file() {
return Some(candidate);
}
}
None
}
/// Scan `LD_LIBRARY_PATH` (Linux) or `DYLD_LIBRARY_PATH` (macOS) directories.
fn lib_path_search(name: &str) -> Option<PathBuf> {
let var = if cfg!(target_os = "macos") {
"DYLD_LIBRARY_PATH"
} else {
"LD_LIBRARY_PATH"
};
let path = std::env::var(var).ok()?;
for segment in std::env::split_paths(&path) {
let candidate = segment.join(name);
if candidate.is_file() {
return Some(candidate);
}
}
None
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn dylib_filename_known_platform() {
let name = dylib_filename();
if cfg!(target_os = "linux") {
assert_eq!(name, "libonnxruntime.so");
} else if cfg!(target_os = "macos") {
assert_eq!(name, "libonnxruntime.dylib");
} else if cfg!(target_os = "windows") {
assert_eq!(name, "onnxruntime.dll");
}
}
#[test]
fn resolve_dylib_env_var_takes_precedence() {
// Set ORT_DYLIB_PATH to a known file (/tmp is guaranteed to exist,
// but the file itself won't — this should still error with a clear
// message about the file not existing).
crate::test_env::set_var("ORT_DYLIB_PATH", "/nonexistent/foo.so");
let err = resolve_ort_dylib().unwrap_err();
assert!(err.to_string().contains("ORT_DYLIB_PATH"));
crate::test_env::remove_var("ORT_DYLIB_PATH");
}
#[test]
fn lib_path_search_no_library() {
// Should not crash when the env var is unset.
assert!(lib_path_search("nonexistent.so.42").is_none());
}
#[test]
fn well_known_paths_returns_none_for_nonsense() {
assert!(well_known_paths("this-library-surely-does-not-exist.so").is_none());
}
#[test]
fn homebrew_prefix_lib_is_searched() {
// A dylib under $HOMEBREW_PREFIX/lib is discovered (covers Homebrew on
// any platform / custom prefix, incl. Linuxbrew). See issue #544.
let tmp = std::env::temp_dir().join(format!("lc-ort-hb-{}", std::process::id()));
let libdir = tmp.join("lib");
std::fs::create_dir_all(&libdir).unwrap();
let name = "libonnxruntime-test-marker.dylib";
std::fs::write(libdir.join(name), b"marker").unwrap();
crate::test_env::set_var("HOMEBREW_PREFIX", tmp.to_str().unwrap());
let found = well_known_paths(name);
crate::test_env::remove_var("HOMEBREW_PREFIX");
std::fs::remove_dir_all(&tmp).ok();
assert_eq!(found, Some(libdir.join(name)));
}
#[cfg(target_os = "linux")]
#[test]
fn nix_profile_search_no_panic() {
// When no Nix profile is present, returns None without crashing.
assert!(nix_profile_search("nonexistent.so").is_none());
}
}