Merge pull request #97 from SFDO-Tooling/feature/nicer-plugin-exceptions

Throw plugin exceptions while line# is available

snowfakery/data_gen_exceptions.py

@@ -46,6 +46,14 @@ class DataGenValueError(DataGenError):
     pass
 
 
+class DataGenImportError(DataGenError):
+    pass
+
+
+class DataGenTypeError(DataGenError):
+    pass
+
+
 def fix_exception(message, parentobj, e):
     """Add filename and linenumber to an exception if needed"""
     filename, line_num = parentobj.filename, parentobj.line_num

snowfakery/data_generator.py

@@ -1,17 +1,16 @@
 import warnings
 from typing import IO, Tuple, Mapping, List, Dict, TextIO, Union
-from importlib import import_module
 from click.utils import LazyFile
 
 from yaml import safe_dump, safe_load
-from faker.providers import BaseProvider as FakerProvider
 
 from .data_gen_exceptions import DataGenNameError
 from .output_streams import DebugOutputStream, OutputStream
 from .parse_recipe_yaml import parse_recipe
 from .data_generator_runtime import output_batches, StoppingCriteria, Globals
 from .data_gen_exceptions import DataGenError
 from . import SnowfakeryPlugin
+from faker.providers import BaseProvider as FakerProvider
 
 
 # This tool is essentially a three stage interpreter.
@@ -83,32 +82,18 @@ def save_continuation_yaml(continuation_data: Globals, continuation_file: TextIO
     safe_dump(continuation_data, continuation_file)
 
 
-def resolve_plugin(plugin: str) -> object:
-    "Resolve a plugin to a class"
-    module_name, class_name = plugin.rsplit(".", 1)
-    module = import_module(module_name)
-    cls = getattr(module, class_name)
-    if issubclass(cls, FakerProvider):
-        return (FakerProvider, cls)
-    elif issubclass(cls, SnowfakeryPlugin):
-        return (SnowfakeryPlugin, cls)
-    else:
-        raise TypeError(f"{cls} is not a Faker Provider nor Snowfakery Plugin")
-
-
-def process_plugins(plugins: List[str]) -> Tuple[List[object], Mapping[str, object]]:
+def process_plugins(plugins: List) -> Tuple[List[object], Mapping[str, object]]:
     """Resolve a list of names for SnowfakeryPlugins and Faker Providers to objects
 
     The Providers are returned as a list of objects.
     The Plugins are a mapping of ClassName:object so they can be namespaced.
     """
-    plugin_classes = [resolve_plugin(plugin) for plugin in plugins]
     faker_providers = [
-        provider for baseclass, provider in plugin_classes if baseclass == FakerProvider
+        provider for baseclass, provider in plugins if baseclass == FakerProvider
     ]
     snowfakery_plugins = {
         plugin.__name__: plugin
-        for baseclass, plugin in plugin_classes
+        for baseclass, plugin in plugins
         if baseclass == SnowfakeryPlugin
     }
     return (faker_providers, snowfakery_plugins)

snowfakery/parse_recipe_yaml.py

@@ -19,6 +19,7 @@
     ReferenceValue,
 )
 
+from snowfakery.plugins import resolve_plugin
 import snowfakery.data_gen_exceptions as exc
 
 SHARED_OBJECT = "#SHARED_OBJECT"
@@ -32,9 +33,7 @@
 
 
 class ParseResult:
-    def __init__(
-        self, options, tables: Mapping, templates, plugins: Sequence[str] = ()
-    ):
+    def __init__(self, options, tables: Mapping, templates, plugins: Sequence = ()):
         self.options = options
         self.tables = tables
         self.templates = templates
@@ -485,7 +484,12 @@ def parse_top_level_elements(path: Path, data: List, context: ParseContext):
     templates.extend(parse_included_files(path, data, context))
     context.options.extend(top_level_objects["option"])
     context.macros.update({obj["macro"]: obj for obj in top_level_objects["macro"]})
-    context.plugins.extend([obj["plugin"] for obj in top_level_objects["plugin"]])
+    context.plugins.extend(
+        [
+            resolve_plugin(obj["plugin"], obj["__line__"])
+            for obj in top_level_objects["plugin"]
+        ]
+    )
     templates.extend(top_level_objects["object"])
     return templates
 

snowfakery/plugins.py

@@ -1,7 +1,11 @@
 from typing import Any, Callable, Mapping
+from importlib import import_module
 
 import yaml
 from yaml.representer import Representer
+from faker.providers import BaseProvider as FakerProvider
+
+import snowfakery.data_gen_exceptions as exc
 
 
 class SnowfakeryPlugin:
@@ -80,6 +84,29 @@ def lazy(func: Any) -> Callable:
     return func
 
 
+def resolve_plugin(plugin: str, lineinfo) -> object:
+    "Resolve a plugin to a class"
+    module_name, class_name = plugin.rsplit(".", 1)
+
+    try:
+        module = import_module(module_name)
+    except ModuleNotFoundError as e:
+        raise exc.DataGenImportError(
+            f"Cannot find plugin: {e}", lineinfo.filename, lineinfo.line_num
+        )
+    cls = getattr(module, class_name)
+    if issubclass(cls, FakerProvider):
+        return (FakerProvider, cls)
+    elif issubclass(cls, SnowfakeryPlugin):
+        return (SnowfakeryPlugin, cls)
+    else:
+        raise exc.DataGenTypeError(
+            f"{cls} is not a Faker Provider nor Snowfakery Plugin",
+            lineinfo.filename,
+            lineinfo.line_num,
+        )
+
+
 class PluginResult:
     """`PluginResult` objects expose a namespace that other code can access through dot-notation.
 

tests/test_custom_plugins_and_providers.py

@@ -3,7 +3,11 @@
 
 from snowfakery.data_generator import generate
 from snowfakery import SnowfakeryPlugin, lazy
-from snowfakery.data_gen_exceptions import DataGenError
+from snowfakery.data_gen_exceptions import (
+    DataGenError,
+    DataGenTypeError,
+    DataGenImportError,
+)
 
 from unittest import mock
 import pytest
@@ -61,9 +65,10 @@ def test_bogus_plugin(self):
           fields:
             service_name: saascrmlightning
         """
-        with pytest.raises(TypeError) as e:
+        with pytest.raises(DataGenTypeError) as e:
             generate(StringIO(yaml), {})
         assert "TestCustomPlugin" in str(e.value)
+        assert ":2" in str(e.value)
 
     def test_missing_plugin(self):
         yaml = """
@@ -72,7 +77,7 @@ def test_missing_plugin(self):
           fields:
             service_name: saascrmlightning
         """
-        with pytest.raises(ImportError) as e:
+        with pytest.raises(DataGenImportError) as e:
             generate(StringIO(yaml), {})
         assert "xyzzy" in str(e.value)