fix python interpreter (#456)

* fix python interpreter

* fix tests

* lint

tests/integration_tests/function_wrapper/test_single_function.py

@@ -37,7 +37,7 @@ def test_example_func_dry_run(proj_path):
             "--outs",
             "test.txt",
             (
-                f'{utils.get_python_interpreter()} -c "from test_single_function import '
+                f'{utils.config.interpreter} -c "from test_single_function import '
                 'example_func; example_func(exec_func=True)" '
             ),
         ]

tests/unit_tests/core/test_core_base.py

@@ -339,8 +339,9 @@ def test_write_graph():
         "--outs",
         "example.dat",
         (
-            'python3 -c "from test_core_base import ExampleDVCOutsNode; '
-            "ExampleDVCOutsNode.load(name='ExampleDVCOutsNode').run_and_save()\" "
+            f'{utils.config.interpreter} -c "from test_core_base import'
+            " ExampleDVCOutsNode;"
+            " ExampleDVCOutsNode.load(name='ExampleDVCOutsNode').run_and_save()\" "
         ),
     ]
 

tests/unit_tests/core/test_dvcgraph.py

@@ -185,7 +185,7 @@ def test_prepare_dvc_script():
         "--deps",
         "file.txt",
         (
-            f'{utils.get_python_interpreter()} -c "from src.file import MyNode;'
+            f'{utils.config.interpreter} -c "from src.file import MyNode;'
             ' MyNode.load().run_and_save()" '
         ),
     ]
@@ -214,7 +214,7 @@ def test_prepare_dvc_script():
         "--deps",
         "src/file.py",
         (
-            f'{utils.get_python_interpreter()} -c "from src.file import MyNode;'
+            f'{utils.config.interpreter} -c "from src.file import MyNode;'
             ' MyNode.load().run_and_save()" '
         ),
     ]

tests/unit_tests/utils/test_utils.py

@@ -68,9 +68,16 @@ def test_check_type():
     assert utils.check_type({"a": {"b": "c"}}, str, allow_dict=True)
 
 
-def test_python_interpreter():
-    assert utils.get_python_interpreter() in ["python", "python3"]
+def test_config_interpreter():
+    assert utils.config.interpreter in ["python", "python3"]
 
 
 def test_module_to_path():
     assert utils.module_to_path("src.module") == pathlib.Path("src", "module.py")
+
+
+def test_config_change():
+    assert utils.config.lazy
+    with utils.config.updated_config(lazy=False):
+        assert not utils.config.lazy
+    assert utils.config.lazy

zntrack/core/dvcgraph.py

@@ -172,7 +172,7 @@ def prepare_dvc_script(
     if nb_name is not None:
         script += ["--deps", utils.module_to_path(module).as_posix()]
 
-    import_str = f"""{utils.get_python_interpreter()} -c "from {module} import """
+    import_str = f"""{utils.config.interpreter} -c "from {module} import """
     import_str += f"""{func_or_cls}; {func_or_cls}{call_args}" """
     script += [import_str]
     log.debug(f"dvc script: {' '.join([str(x) for x in script])}")

zntrack/utils/__init__.py

@@ -17,7 +17,6 @@
     decode_dict,
     deprecated,
     encode_dict,
-    get_python_interpreter,
     module_handler,
     module_to_path,
     run_dvc_cmd,
@@ -38,7 +37,6 @@
     "exceptions",
     Files.__name__,
     "check_type",
-    "get_python_interpreter",
     "run_dvc_cmd",
     "FILE_DVC_TRACKED",
     "VALUE_DVC_TRACKED",

zntrack/utils/config.py

@@ -1,6 +1,9 @@
 """Description: Configuration File for ZnTrack."""
+import contextlib
 import dataclasses
 import logging
+import sys
+import typing
 from pathlib import Path
 
 
@@ -27,12 +30,19 @@ class Config:
         runs. If you encounter any issues you can set it to logging.INFO for more in-depth
         information. DEBUG level can produce a lot of useful information for more complex
         issues.
+    interpreter: str|Path, default = None
+        Set the Python interpreter to be used for the 'dvc cmd'.
+        If None, ZnTrack will try to automatically determine the interpreter.
+        Use e.g. `config.interpreter=sys.executable` to use a specific version.
+        Note, that changing the command will also affect your graph, and you might
+        not be able to use the existing cache.
     """
 
     nb_name: str = None
     nb_class_path: Path = Path("src")
     lazy: bool = True
     allow_empty_loading: bool = False
+    interpreter: typing.Union[str, Path] = Path(sys.executable).name
     _log_level: int = dataclasses.field(default=logging.INFO, init=False, repr=True)
 
     @property
@@ -47,6 +57,24 @@ def log_level(self, value):
         logger = logging.getLogger("zntrack")
         logger.setLevel(self._log_level)
 
+    @contextlib.contextmanager
+    def updated_config(self, **kwargs) -> None:
+        """Temporarily update the config.
+
+        Yields
+        ------
+            Environment with temporarily changed config.
+        """
+        state = {}
+        for key, value in kwargs.items():
+            state[key] = getattr(self, key)
+            setattr(self, key, value)
+        try:
+            yield
+        finally:
+            for key, value in state.items():
+                setattr(self, key, value)
+
 
 @dataclasses.dataclass(frozen=True)
 class Files:

zntrack/utils/utils.py

@@ -150,36 +150,6 @@ def module_to_path(module: str, suffix=".py") -> pathlib.Path:
     return pathlib.Path(*module.split(".")).with_suffix(suffix)
 
 
-def get_python_interpreter() -> str:
-    """Find the most suitable python interpreter.
-
-    Try to run subprocess check calls to see, which python interpreter
-    should be selected
-
-    Returns
-    -------
-    interpreter: str
-        Name of the python interpreter that works with subprocess calls
-    """
-    for interpreter in ["python3", "python"]:
-        try:
-            subprocess.check_call(
-                [interpreter, "--version"],
-                stdout=subprocess.DEVNULL,
-                stderr=subprocess.DEVNULL,
-            )
-            log.debug(f"Using command {interpreter} for dvc!")
-            return interpreter
-
-        except subprocess.CalledProcessError:
-            log.debug(f"{interpreter} is not working!")
-        except FileNotFoundError as err:
-            log.debug(err)
-    raise ValueError(
-        "Could not find a working python interpreter to work with subprocesses!"
-    )
-
-
 def run_dvc_cmd(script):
     """Run the DVC script via subprocess calls.