deployer inheritance (#2135)

* Move DeployedFlow and Triggered run to a more inheritance model.

The _enrich_* methods were making it very hard to generate proper stubs.
This will hopefully improve that.

* Fix circular dependency and address comments

Some doc cleanup as well.

* Removed extraneous code

* Forgot file

* Update NBDeployer to forward to underlying deployer

* Fix circular deps and other crap

* Added stub-gen for deployer (try 2)

* Fix stub test

* Fix dataclients

* fix docstrings for deployer (#2119)

* Renamed metadata directory to metadata_provider (and related changes)

There was a clash between the `metadata` function and the `metadata` module
which caused issues with stubs (at least the new way of generating)

* Forgot one

* Typo

* Make nbdocs happy

* add docstrings for injected methods

---------

Co-authored-by: Romain Cledat <[email protected]>

metaflow/__init__.py

@@ -101,9 +101,7 @@ class and related decorators.
 # Flow spec
 from .flowspec import FlowSpec
 
-from .parameters import Parameter, JSONTypeClass
-
-JSONType = JSONTypeClass()
+from .parameters import Parameter, JSONTypeClass, JSONType
 
 # data layer
 # For historical reasons, we make metaflow.plugins.datatools accessible as
@@ -149,6 +147,7 @@ class and related decorators.
     from .runner.metaflow_runner import Runner
     from .runner.nbrun import NBRunner
     from .runner.deployer import Deployer
+    from .runner.deployer import DeployedFlow
     from .runner.nbdeploy import NBDeployer
 
 __ext_tl_modules__ = []

metaflow/client/core.py

@@ -39,7 +39,7 @@
 from .filecache import FileCache
 
 if TYPE_CHECKING:
-    from metaflow.metadata import MetadataProvider
+    from metaflow.metadata_provider import MetadataProvider
 
 try:
     # python2
@@ -143,7 +143,7 @@ def default_metadata() -> str:
     if default:
         current_metadata = default[0]
     else:
-        from metaflow.plugins.metadata import LocalMetadataProvider
+        from metaflow.plugins.metadata_providers import LocalMetadataProvider
 
         current_metadata = LocalMetadataProvider
     return get_metadata()

metaflow/clone_util.py

@@ -1,5 +1,5 @@
 import time
-from .metadata import MetaDatum
+from .metadata_provider import MetaDatum
 
 
 def clone_task_helper(