Add support library helper function that puts output files under Cond…

…uctor's task outputs when relevant (#88)

* Add library function to deal with output paths

* Handle string paths, update docs

* Fix compatibility with Python 3.8

src/conductor/lib/path.py

@@ -1,6 +1,6 @@
 import os
 import pathlib
-from typing import List
+from typing import List, Union
 
 from conductor.config import (
     DEPS_ENV_VARIABLE_NAME,
@@ -36,3 +36,20 @@ def get_output_path() -> pathlib.Path:
             "being executed by Conductor.".format(OUTPUT_ENV_VARIABLE_NAME)
         )
     return pathlib.Path(os.environ[OUTPUT_ENV_VARIABLE_NAME])
+
+
+def in_output_dir(file_path: Union[pathlib.Path, str]) -> pathlib.Path:
+    """
+    If the current script is being run by Conductor, this function amends
+    `file_path` to make it fall under where Conductor's task outputs should be
+    stored. Otherwise, this function returns `file_path` unchanged.
+
+    This is meant to be useful for scripts that may be run independently of
+    Conductor. Note that `file_path` should be a relative path.
+    """
+    if OUTPUT_ENV_VARIABLE_NAME in os.environ:
+        return get_output_path() / file_path
+    elif not isinstance(file_path, pathlib.Path):
+        return pathlib.Path(file_path)
+    else:
+        return file_path

tests/fixture-projects/lib-test/path/COND

@@ -21,3 +21,8 @@ run_command(
   name="output_path",
   run="python3 output_path.py",
 )
+
+run_command(
+  name="in_output_dir",
+  run="python3 in_output_dir.py",
+)

tests/fixture-projects/lib-test/path/in_output_dir.py

@@ -0,0 +1,17 @@
+import os
+import pathlib
+import conductor.lib as cond
+
+
+def main():
+    my_file = pathlib.Path("./test.csv")
+    file_in_output_dir = cond.in_output_dir(my_file)
+    assert file_in_output_dir != my_file
+
+    output_dir = cond.get_output_path()
+    # Or use pathlib.Path.is_relative_to() on Python 3.9+.
+    assert os.path.commonpath([file_in_output_dir, output_dir]) == str(output_dir)
+
+
+if __name__ == "__main__":
+    main()

tests/lib_path_test.py

@@ -27,3 +27,16 @@ def test_get_output_path(tmp_path: pathlib.Path):
     result = cond.run("//path:output_path")
     # The output_path.py script in lib-test/path/ does the correctness assertions.
     assert result.returncode == 0
+
+
+def test_in_output_dir_non_cond():
+    file_path = pathlib.Path("./test.csv")
+    out = condlib.in_output_dir(file_path)
+    assert out == file_path
+
+
+def test_in_output_dir(tmp_path: pathlib.Path):
+    cond = ConductorRunner.from_template(tmp_path, FIXTURE_TEMPLATES["lib-test"])
+    result = cond.run("//path:in_output_dir")
+    # The in_output_dir.py script in lib-test/path/ does the correctness assertions.
+    assert result.returncode == 0

website/docs/python-support-library.md

@@ -90,3 +90,18 @@ def main():
 if __name__ == "__main__":
     main()
 ```
+
+### `in_output_dir()`
+
+```python
+def in_output_dir(file_path: path.Path | str) -> pathlib.Path
+```
+
+If the current script is being run by Conductor, this function amends
+`file_path` to make it fall under where Conductor's task outputs should be
+stored. Otherwise, this function returns `file_path` unchanged (but as a
+`pathlib.Path`).
+
+This is meant to be useful for scripts that may be run independently of
+Conductor. Note that `file_path` should be a relative path.
+