Fix issue with parsers not being compatible with extensions (#2320)

metaflow/__init__.py

@@ -119,12 +119,11 @@ class and related decorators.
 # Decorators
 from .decorators import step, _import_plugin_decorators
 
-# Config parsers
-from .plugins.pypi.parsers import (
-    requirements_txt_parser,
-    pyproject_toml_parser,
-    conda_environment_yml_parser,
-)
+
+# Parsers (for configs) for now
+from .plugins import _import_tl_plugins
+
+_import_tl_plugins(globals())
 
 # this auto-generates decorator functions from Decorator objects
 # in the top-level metaflow namespace

metaflow/extension_support/plugins.py

@@ -198,6 +198,7 @@ def resolve_plugins(category, path_only=False):
         list(x.commands)[0] if len(x.commands) == 1 else "too many commands"
     ),
     "runner_cli": lambda x: x.name,
+    "tl_plugin": None,
 }
 
 

metaflow/plugins/__init__.py

@@ -167,6 +167,12 @@
     ),
 ]
 
+TL_PLUGINS_DESC = [
+    ("requirements_txt_parser", ".pypi.parsers.requirements_txt_parser"),
+    ("pyproject_toml_parser", ".pypi.parsers.pyproject_toml_parser"),
+    ("conda_environment_yml_parser", ".pypi.parsers.conda_environment_yml_parser"),
+]
+
 process_plugins(globals())
 
 
@@ -207,6 +213,8 @@ def get_runner_cli_path():
 if sys.version_info >= (3, 7):
     DEPLOYER_IMPL_PROVIDERS = resolve_plugins("deployer_impl_provider")
 
+TL_PLUGINS = resolve_plugins("tl_plugin")
+
 from .cards.card_modules import MF_EXTERNAL_CARDS
 
 # Cards; due to the way cards were designed, it is harder to make them fit
@@ -251,3 +259,9 @@ def get_runner_cli_path():
     TestRefreshComponentCard,
 ]
 merge_lists(CARDS, MF_EXTERNAL_CARDS, "type")
+
+
+def _import_tl_plugins(globals_dict):
+
+    for name, p in TL_PLUGINS.items():
+        globals_dict[name] = p