Update build script to use export-config from pyo3-build-config.

src/rust/Cargo.toml

@@ -19,8 +19,8 @@ openssl-sys = "0.9.72"
 
 [build-dependencies]
 cc = "1.0.72"
-# TODO: update after merge/release in pyo3
 
+# TODO: update after merge/release in pyo3
 [build-dependencies.pyo3-build-config]
 git = "https://github.com/aganders3/pyo3"
 branch = "export-conf"

src/rust/build.rs

@@ -1,7 +1,9 @@
 use std::env;
-use std::io::Write;
+use std::fs;
 use std::path::{Path, MAIN_SEPARATOR};
-use std::process::{Command, Stdio};
+use std::process::Command;
+
+use pyo3_build_config::InterpreterConfig;
 
 fn main() {
     let target = env::var("TARGET").unwrap();
@@ -19,10 +21,11 @@ fn main() {
         }
     }
 
+    let pyo3_interpreter =
+        InterpreterConfig::from_pyo3_export_config().expect("could not find pyo3 interpreter");
+
     let out_dir = env::var("OUT_DIR").unwrap();
-    // FIXME: maybe pyo3-build-config should provide a way to do this?
-    let python = env::var("PYO3_PYTHON").unwrap_or_else(|_| "python3".to_string());
-    println!("cargo:rerun-if-changed=../_cffi_src/");
+
     let python_path = match env::var("PYTHONPATH") {
         Ok(mut val) => {
             if cfg!(target_os = "windows") {
@@ -35,30 +38,20 @@ fn main() {
         }
         Err(_) => format!("..{}", MAIN_SEPARATOR),
     };
-    let output = Command::new(&python)
-        .env("PYTHONPATH", python_path)
-        .env("OUT_DIR", &out_dir)
-        .arg("../_cffi_src/build_openssl.py")
-        .output()
+
+    println!("cargo:rerun-if-changed=../_cffi_src/");
+    pyo3_interpreter
+        .run_python_script_with_envs(
+            &fs::read_to_string("../_cffi_src/build_openssl.py")
+                .expect("failed to read build_openssl.py"),
+            vec![("PYTHONPATH", python_path), ("OUT_DIR", out_dir.clone())],
+        )
         .expect("failed to execute build_openssl.py");
-    if !output.status.success() {
-        panic!(
-            "failed to run build_openssl.py, stdout: \n{}\nstderr: \n{}\n",
-            String::from_utf8(output.stdout).unwrap(),
-            String::from_utf8(output.stderr).unwrap()
-        );
-    }
 
-    let python_impl = run_python_script(
-        &python,
-        "import platform; print(platform.python_implementation(), end='')",
-    )
-    .unwrap();
-    let python_include = run_python_script(
-        &python,
-        "import sysconfig; print(sysconfig.get_path('include'), end='')",
-    )
-    .unwrap();
+    let python_impl = pyo3_interpreter.implementation.to_string();
+    let python_include = pyo3_interpreter
+        .run_python_script("import sysconfig; print(sysconfig.get_path('include'), end='')")
+        .unwrap();
     let openssl_include =
         std::env::var_os("DEP_OPENSSL_INCLUDE").expect("unable to find openssl include path");
     let openssl_c = Path::new(&out_dir).join("_openssl.c");
@@ -84,40 +77,6 @@ fn main() {
     build.compile("_openssl.a");
 }
 
-/// Run a python script using the specified interpreter binary.
-fn run_python_script(interpreter: impl AsRef<Path>, script: &str) -> Result<String, String> {
-    let interpreter = interpreter.as_ref();
-    let out = Command::new(interpreter)
-        .env("PYTHONIOENCODING", "utf-8")
-        .stdin(Stdio::piped())
-        .stdout(Stdio::piped())
-        .stderr(Stdio::inherit())
-        .spawn()
-        .and_then(|mut child| {
-            child
-                .stdin
-                .as_mut()
-                .expect("piped stdin")
-                .write_all(script.as_bytes())?;
-            child.wait_with_output()
-        });
-
-    match out {
-        Err(err) => Err(format!(
-            "failed to run the Python interpreter at {}: {}",
-            interpreter.display(),
-            err
-        )),
-        Ok(ok) if !ok.status.success() => Err(format!(
-            "Python script failed: {}",
-            String::from_utf8(ok.stderr).expect("failed to parse Python script output as utf-8")
-        )),
-        Ok(ok) => Ok(
-            String::from_utf8(ok.stdout).expect("failed to parse Python script output as utf-8")
-        ),
-    }
-}
-
 fn macos_link_search_path() -> Option<String> {
     let output = Command::new("clang")
         .arg("--print-search-dirs")