Allow pass column to plcontainer_apply (#229)

This PR allows to pass specific columns when using
plcontainer_apply.

Author: ruxuez

greenplumpython/func.py

@@ -117,10 +117,18 @@ def apply(
         ):
             return_annotation = inspect.signature(self._function._wrapped_func).return_annotation  # type: ignore reportUnknownArgumentType
             _serialize_to_type_name(return_annotation, db=db, for_return=True)
+            input_args = self._args
+            if len(input_args) == 0:
+                raise Exception("No input data specified, please specify a DataFrame or Columns")
+            input_clause = (
+                "*"
+                if (len(input_args) == 1 and isinstance(input_args[0], DataFrame))
+                else ",".join([arg._serialize(db=db) for arg in input_args])
+            )
             return DataFrame(
                 f"""
                 SELECT * FROM plcontainer_apply(TABLE(
-                    SELECT * {from_clause}), '{self._function._qualified_name_str}', 4096) AS
+                    SELECT {input_clause} {from_clause}), '{self._function._qualified_name_str}', 4096) AS
                     {_defined_types[return_annotation.__args__[0]]._serialize(db=db)}
                 """,
                 db=db,
@@ -370,6 +378,7 @@ def _serialize(self, db: Database) -> str:
             f"        import sys as {sys_lib_name}\n"
             f"        if {sysconfig_lib_name}.get_python_version() != '{python_version}':\n"
             f"            raise ModuleNotFoundError\n"
+            f"        {sys_lib_name}.modules['plpy']=plpy\n"
             f"        setattr({sys_lib_name}.modules['plpy'], '_SD', SD)\n"
             f"        GD['{func_ast.name}'] = {pickle_lib_name}.loads({func_pickled})\n"
             f"    except ModuleNotFoundError:\n"

tests/test_plcontainer.py

@@ -1,25 +1,56 @@
 from dataclasses import dataclass
 
+import pytest
+
 import greenplumpython as gp
 from tests import db
 
 
-def test_simple_func(db: gp.Database):
-    @dataclass
-    class Int:
-        i: int
+@dataclass
+class Int:
+    i: int
+
+
+@dataclass
+class Pair:
+    i: int
+    j: int
+
+
+@pytest.fixture
+def t(db: gp.Database):
+    rows = [(i, i) for i in range(10)]
+    return db.create_dataframe(rows=rows, column_names=["a", "b"])
+
+
+@gp.create_function(language_handler="plcontainer", runtime="plc_python_example")
+def add_one(x: list[Int]) -> list[Int]:
+    return [{"i": arg["i"] + 1} for arg in x]
 
-    @gp.create_function(language_handler="plcontainer", runtime="plc_python_example")
-    def add_one(x: list[Int]) -> list[Int]:
-        return [{"i": arg["i"] + 1} for arg in x]
 
+def test_simple_func(db: gp.Database):
     assert (
         len(
             list(
                 db.create_dataframe(columns={"i": range(10)}).apply(
-                    lambda _: add_one(), expand=True
+                    lambda t: add_one(t), expand=True
                 )
             )
         )
         == 10
     )
+
+
+def test_func_no_input(db: gp.Database):
+
+    with pytest.raises(Exception) as exc_info:  # no input data for func raises Exception
+        db.create_dataframe(columns={"i": range(10)}).apply(lambda _: add_one(), expand=True)
+    assert "No input data specified, please specify a DataFrame or Columns" in str(exc_info.value)
+
+
+def test_func_column(db: gp.Database, t: gp.DataFrame):
+    @gp.create_function(language_handler="plcontainer", runtime="plc_python_example")
+    def add(x: list[Pair]) -> list[Int]:
+        return [{"i": arg["i"] + arg["j"]} for arg in x]
+
+    assert len(list(t.apply(lambda t: add(t["a"], t["b"]), expand=True))) == 10