[components] Better error message for failing entry points

python_modules/libraries/dagster-components/dagster_components/core/component.py

@@ -5,6 +5,7 @@
 import inspect
 import sys
 import textwrap
+import warnings
 from abc import ABC, abstractmethod
 from collections.abc import Iterable, Mapping, Sequence
 from dataclasses import dataclass
@@ -30,7 +31,11 @@
 )
 from dagster_components.core.schema.base import ResolvableSchema
 from dagster_components.core.schema.context import ResolutionContext
-from dagster_components.utils import load_module_from_path
+from dagster_components.utils import format_error_message, load_module_from_path
+
+
+class ComponentsEntryPointLoadError(DagsterError):
+    pass
 
 
 class ComponentDeclNode(ABC):
@@ -158,7 +163,19 @@ def from_entry_point_discovery(
             ):
                 continue
 
-            root_module = entry_point.load()
+            try:
+                root_module = entry_point.load()
+            except Exception as e:
+                warnings.warn(
+                    format_error_message(f"""
+                        Error loading entry point {entry_point.name} in group
+                        {COMPONENTS_ENTRY_POINT_GROUP}. Any components defined by this entry point
+                        will note be available. Error:
+                    """)
+                    + "\n"
+                    + f"  {(e)}"
+                )
+
             if not isinstance(root_module, ModuleType):
                 raise DagsterError(
                     f"Invalid entry point {entry_point.name} in group {COMPONENTS_ENTRY_POINT_GROUP}. "

python_modules/libraries/dagster-components/dagster_components/utils.py

@@ -1,5 +1,6 @@
 import importlib.util
 import sys
+import textwrap
 from collections.abc import Iterator, Mapping
 from contextlib import contextmanager
 from dataclasses import dataclass
@@ -36,6 +37,11 @@ def exit_with_error(error_message: str) -> None:
     sys.exit(1)
 
 
+def format_error_message(message: str) -> str:
+    # width=10000 unwraps any hardwrapping
+    return textwrap.dedent(textwrap.fill(message, width=10000))
+
+
 # Temporarily places a path at the front of sys.path, ensuring that any modules in that path are
 # importable.
 @contextmanager

python_modules/libraries/dagster-components/dagster_components_tests/registry_tests/test_registry.py

@@ -6,6 +6,11 @@
 from collections.abc import Iterator, Sequence
 from contextlib import contextmanager
 from pathlib import Path
+from typing import Any, Callable, Optional
+
+import tomli
+import tomli_w
+from dagster._utils import pushd
 
 from dagster_dg.component import GlobalComponentKey
 
@@ -36,14 +41,18 @@ def _temp_venv(install_args: Sequence[str]) -> Iterator[Path]:
 """
 
 
-def _get_component_types_in_python_environment(python_executable: Path) -> Sequence[str]:
+def _get_component_print_script_output(python_executable: Path) -> str:
     with tempfile.NamedTemporaryFile(mode="w") as f:
         f.write(COMPONENT_PRINT_SCRIPT)
         f.flush()
         result = subprocess.run(
-            [str(python_executable), f.name], capture_output=True, text=True, check=False
+            [str(python_executable), f.name], capture_output=True, text=True, check=True
         )
-        return result.stdout.strip().split("\n")
+        return result.stdout.strip()
+
+
+def _get_component_types_in_python_environment(python_executable: Path) -> Sequence[str]:
+    return _get_component_print_script_output(python_executable).split("\n")
 
 
 def _find_repo_root():
@@ -151,40 +160,77 @@ def test_all_dagster_components_have_defined_summary():
 """
 
 
-def test_components_from_third_party_lib(tmpdir):
-    with tmpdir.as_cwd():
-        # Create test package that defines some components
-        os.makedirs("dagster-foo")
-        with open("dagster-foo/pyproject.toml", "w") as f:
-            f.write(DAGSTER_FOO_PYPROJECT_TOML)
-
-        os.makedirs("dagster-foo/dagster_foo/lib/sub")
-
-        with open("dagster-foo/dagster_foo/lib/__init__.py", "w") as f:
-            f.write(DAGSTER_FOO_LIB_ROOT)
-
-        with open("dagster-foo/dagster_foo/lib/sub/__init__.py", "w") as f:
-            f.write(_generate_test_component_source(2))
-
-        # Need pipes because dependency of dagster
-        deps = [
-            "-e",
-            _get_editable_package_root("dagster"),
-            "-e",
-            _get_editable_package_root("dagster-components"),
-            "-e",
-            _get_editable_package_root("dagster-pipes"),
-            "-e",
-            "dagster-foo",
-        ]
-
-        with _temp_venv(deps) as python_executable:
-            component_types = _get_component_types_in_python_environment(python_executable)
-            assert (
-                GlobalComponentKey(name="test_component_1", namespace="dagster_foo").to_typename()
-                in component_types
-            )
-            assert (
-                GlobalComponentKey(name="test_component_2", namespace="dagster_foo").to_typename()
-                in component_types
-            )
+@contextmanager
+def isolated_venv_with_component_lib_dagster_foo(
+    pre_install_hook: Optional[Callable[[], None]] = None,
+):
+    with tempfile.TemporaryDirectory() as tmpdir:
+        with pushd(tmpdir):
+            # Create test package that defines some components
+            os.makedirs("dagster-foo")
+            with open("dagster-foo/pyproject.toml", "w") as f:
+                f.write(DAGSTER_FOO_PYPROJECT_TOML)
+
+            os.makedirs("dagster-foo/dagster_foo/lib/sub")
+
+            with open("dagster-foo/dagster_foo/lib/__init__.py", "w") as f:
+                f.write(DAGSTER_FOO_LIB_ROOT)
+
+            with open("dagster-foo/dagster_foo/lib/sub/__init__.py", "w") as f:
+                f.write(_generate_test_component_source(2))
+
+            if pre_install_hook:
+                pre_install_hook()
+
+            # Need pipes because dependency of dagster
+            deps = [
+                "-e",
+                _get_editable_package_root("dagster"),
+                "-e",
+                _get_editable_package_root("dagster-components"),
+                "-e",
+                _get_editable_package_root("dagster-pipes"),
+                "-e",
+                "dagster-foo",
+            ]
+
+            with _temp_venv(deps) as python_executable:
+                component_types = _get_component_types_in_python_environment(python_executable)
+                assert (
+                    GlobalComponentKey(name="test_component_1", namespace="dagster_foo").to_typename()
+                    in component_types
+                )
+                assert (
+                    GlobalComponentKey(name="test_component_2", namespace="dagster_foo").to_typename()
+                    in component_types
+                )
+                yield python_executable
+
+
+@contextmanager
+def modify_toml(path: Path) -> Iterator[dict[str, Any]]:
+    toml = tomli.loads(path.read_text())
+    yield toml
+    path.write_text(tomli_w.dumps(toml))
+
+
+def test_components_from_third_party_lib():
+    with isolated_venv_with_component_lib_dagster_foo() as python_executable:
+        component_types = _get_component_types_in_python_environment(python_executable)
+        assert "dagster_foo.test_component_1" in component_types
+        assert "dagster_foo.test_component_2" in component_types
+
+
+# def test_entry_point_null_reference():
+#
+#     # Modify the entry point to point to a non-existent module
+#     def pre_install_hook():
+#         with modify_toml(Path("dagster-foo/pyproject.toml")) as toml:
+#             toml["project"]["entry-points"]["dagster.components"]["dagster_foo"] = "fake.module"
+#
+#     with isolated_venv_with_component_lib_dagster_foo(pre_install_hook) as python_executable:
+#         script_output = _get_component_print_script_output(python_executable)
+#         # assert
+#         component_types = _get_component_types_in_python_environment(python_executable)
+#         assert "dagster_foo.test_component_1" in component_types
+#         assert "dagster_foo.test_component_2" in component_types

python_modules/libraries/dagster-components/setup.py

@@ -48,6 +48,6 @@ def get_version() -> str:
     extras_require={
         "sling": ["dagster-sling"],
         "dbt": ["dagster-dbt"],
-        "test": ["dbt-duckdb", "dagster-dg"],
+        "test": ["dbt-duckdb", "dagster-dg", "tomli", "tomli_w"],
     },
 )