Add buildinfo() Python method

This currently returns a dict with a single entry for the rustc version.

We do this because the Rust compiler doesn't embed its own version into
the resulting library on macOS (not sure about Windows), so we can't
reliably extract the compiler version that was used to build reclass-rs
from the library `.so`.

The implementation uses a Rust build script (`build.rs`) which uses the
`rustc_version` crate to get the Rust compiler's version. For now, the
crate just provides a convenience wrapper for calling `rustc --version`,
but would allow us to access more structured compiler info in the
future.

Author: simu

Cargo.toml

@@ -31,6 +31,9 @@ serde_yaml = "0.9.34"
 walkdir = "2.5.0"
 yaml-merge-keys = { version = "0.8.1", features = ["serde_yaml"] }
 
+[build-dependencies]
+rustc_version = "0.4.1"
+
 [dev-dependencies]
 criterion = "0.6.0"
 paste = "1.0.14"

build.rs

@@ -0,0 +1,16 @@
+use std::env;
+use std::fs;
+use std::path::Path;
+
+use rustc_version::version_meta;
+
+fn main() {
+    let rustc_version = version_meta().unwrap().short_version_string;
+    let out_dir = env::var("OUT_DIR").unwrap();
+    let dest_path = Path::new(&out_dir).join("rustc_version.rs");
+    fs::write(
+        &dest_path,
+        format!(r#"static RUSTC_VERSION: &str = "{rustc_version}";"#,),
+    )
+    .unwrap();
+}

src/lib.rs

@@ -7,6 +7,9 @@
 #![allow(clippy::module_name_repetitions)]
 #![allow(clippy::similar_names)]
 
+// embed RUSTC_VERSION definition which is generated by `build.rs` using the `rustc_version` crate
+include!(concat!(env!("OUT_DIR"), "/rustc_version.rs"));
+
 mod config;
 mod fsutil;
 mod inventory;
@@ -405,6 +408,13 @@ impl Default for Reclass {
     }
 }
 
+#[pyfunction]
+fn buildinfo() -> HashMap<&'static str, &'static str> {
+    let mut res = HashMap::new();
+    res.insert("rustc_version", RUSTC_VERSION);
+    res
+}
+
 #[pymodule]
 fn reclass_rs(_py: Python, m: &Bound<'_, PyModule>) -> PyResult<()> {
     // Register the top-level `Reclass` Python class which is used to configure the library
@@ -417,6 +427,8 @@ fn reclass_rs(_py: Python, m: &Bound<'_, PyModule>) -> PyResult<()> {
     m.add_class::<NodeInfo>()?;
     // Register the Inventory class
     m.add_class::<Inventory>()?;
+    // Register the buildinfo method
+    m.add_function(wrap_pyfunction!(buildinfo, m)?)?;
     Ok(())
 }
 

tests/test_buildinfo.py

@@ -0,0 +1,20 @@
+import subprocess
+import pytest
+
+import reclass_rs
+
+
+def test_buildinfo():
+    buildinfo = reclass_rs.buildinfo()
+
+    try:
+        rustc_version = (
+            subprocess.run(
+                ["rustc", "--version"], stderr=subprocess.STDOUT, stdout=subprocess.PIPE
+            )
+            .stdout.decode("utf-8")
+            .strip()
+        )
+    except FileNotFoundError:
+        pytest.skip("No rustc compiler available in test environment")
+    assert buildinfo == {"rustc_version": rustc_version}