Add functions for finding and running muse2

Author: alexdewar

muse2_data_analysis/__init__.py

@@ -3,5 +3,7 @@
 from contextlib import suppress
 from importlib.metadata import PackageNotFoundError, version
 
+from .muse2 import find_muse2, run_muse2  # noqa: F401
+
 with suppress(PackageNotFoundError):
     __version__ = version(__name__)

muse2_data_analysis/muse2.py

@@ -0,0 +1,47 @@
+"""Tools for running the muse2 command-line program.
+
+If the MUSE2_PATH environment variable is set, this will be used, otherwise muse2 will
+be searched for on the PATH.
+"""
+
+import os
+import shutil
+import subprocess as sp
+from pathlib import Path
+
+_muse2_path: Path | None = None
+
+
+def find_muse2() -> Path:
+    """Get the path to muse2, if any.
+
+    Raises an exception if muse2 is not found.
+    """
+    # Cache path
+    global _muse2_path
+    if _muse2_path:
+        return _muse2_path
+
+    path = os.getenv("MUSE2_PATH") or shutil.which("muse2")
+    if not path:
+        raise RuntimeError(
+            "Could not find path to muse2. Either set the MUSE2_PATH environment "
+            "variable or installing muse2 to your PATH (e.g. by running 'cargo "
+            "install muse2')"
+        )
+
+    _muse2_path = Path(path)
+    return _muse2_path
+
+
+def run_muse2(*args: str) -> str:
+    """Run muse2 with the specified arguments, returning combined stdout and stderr.
+
+    Raises an exception if muse2 is not found.
+    """
+    muse2 = find_muse2()
+    output = sp.run((muse2, *args), text=True, stdout=sp.PIPE, stderr=sp.STDOUT)
+    if output.returncode != 0:
+        raise RuntimeError(f"Error running muse2: {output.stdout}")
+
+    return output.stdout