Add Extension and Converter ABCs

CHANGES.rst

@@ -17,7 +17,7 @@
 - Drop support for Python 3.5. [#856]
 
 - Add new extension API to support versioned extensions.
-  [#850, #851]
+  [#850, #851, #853]
 
 - Permit wildcard in tag validator URIs. [#858]
 

asdf/asdf.py

@@ -27,6 +27,7 @@
     AsdfExtension,
     ExtensionProxy,
     get_cached_asdf_extension_list,
+    get_cached_extension_manager,
 )
 from .util import NotSet
 from .search import AsdfSearchResult
@@ -71,9 +72,10 @@ def __init__(self, tree=None, uri=None, extensions=None, version=None,
 
         extensions : object, optional
             Additional extensions to use when reading and writing the file.
-            May be any of the following: `asdf.extension.AsdfExtension`, `str`
-            extension URI, `asdf.extension.AsdfExtensionList` or a `list`
-            of URIs and/or extensions.
+            May be any of the following: `asdf.extension.AsdfExtension`,
+            `asdf.extension.Extension`, `str` extension URI,
+            `asdf.extension.AsdfExtensionList` or a `list` of URIs and/or
+            extensions.
 
         version : str, optional
             The ASDF Standard version.  If not provided, defaults to the
@@ -184,7 +186,7 @@ def version(self):
 
     @version.setter
     def version(self, value):
-        """"
+        """
         Set this AsdfFile's ASDF Standard version.
 
         Parameters
@@ -219,7 +221,7 @@ def extensions(self):
 
         Returns
         -------
-        list of asdf.extension.AsdfExtension
+        list of asdf.extension.AsdfExtension or asdf.extension.Extension
         """
         return self._extensions
 
@@ -231,15 +233,30 @@ def extensions(self, value):
 
         Parameters
         ----------
-        value : list of asdf.extension.AsdfExtension
+        value : list of asdf.extension.AsdfExtension or asdf.extension.Extension
         """
         self._extensions = self._process_extensions(value)
+        self._extension_manager = None
         self._extension_list = None
 
+    @property
+    def extension_manager(self):
+        """
+        Get the ExtensionManager for this AsdfFile.
+
+        Returns
+        -------
+        asdf.extension.ExtensionManager
+        """
+        if self._extension_manager is None:
+            self._extension_manager = get_cached_extension_manager(self.extensions)
+        return self._extension_manager
+
     @property
     def extension_list(self):
         """
         Get the AsdfExtensionList for this AsdfFile.
+
         Returns
         -------
         asdf.extension.AsdfExtensionList
@@ -1549,7 +1566,7 @@ def _warn_tag_mismatch(self, tag, best_tag):
     # This function is called from within yamlutil methods to create
     # a context when one isn't explicitly passed in.
     def _create_serialization_context(self):
-        return SerializationContext(self.version_string)
+        return SerializationContext(self.version_string, self.extension_manager)
 
 
 # Inherit docstring from dictionary
@@ -1605,9 +1622,10 @@ def open_asdf(fd, uri=None, mode=None, validate_checksums=False,
 
     extensions : object, optional
         Additional extensions to use when reading and writing the file.
-        May be any of the following: `asdf.extension.AsdfExtension`, `str`
-        extension URI, `asdf.extension.AsdfExtensionList` or a `list`
-        of URIs and/or extensions.
+        May be any of the following: `asdf.extension.AsdfExtension`,
+        `asdf.extension.Extension`, `str` extension URI,
+        `asdf.extension.AsdfExtensionList` or a `list` of URIs and/or
+        extensions.
 
     do_not_fill_defaults : bool, optional
         When `True`, do not fill in missing default values.
@@ -1729,8 +1747,9 @@ class SerializationContext:
     """
     Container for parameters of the current (de)serialization.
     """
-    def __init__(self, version):
+    def __init__(self, version, extension_manager):
         self._version = validate_version(version)
+        self._extension_manager = extension_manager
 
         self._extensions_used = set()
 
@@ -1745,13 +1764,24 @@ def version(self):
         """
         return self._version
 
+    @property
+    def extension_manager(self):
+        """
+        Get the ExtensionManager for enabled extensions.
+
+        Returns
+        -------
+        asdf.extension.ExtensionManager
+        """
+        return self._extension_manager
+
     def mark_extension_used(self, extension):
         """
         Note that an extension was used when reading or writing the file.
 
         Parameters
         ----------
-        extension : asdf.extension.AsdfExtension
+        extension : asdf.extension.AsdfExtension or asdf.extension.Extension
         """
         self._extensions_used.add(ExtensionProxy.maybe_wrap(extension))
 
@@ -1762,6 +1792,6 @@ def extensions_used(self):
 
         Returns
         -------
-        set of asdf.extension.AsdfExtension
+        set of asdf.extension.AsdfExtension or asdf.extension.Extension
         """
         return self._extensions_used

asdf/config.py

@@ -139,7 +139,7 @@ def extensions(self):
 
         Returns
         -------
-        list of asdf.extension.AsdfExtension
+        list of asdf.extension.AsdfExtension or asdf.extension.Extension
         """
         if self._extensions is None:
             with self._lock:
@@ -154,7 +154,7 @@ def add_extension(self, extension):
 
         Parameters
         ----------
-        extension : asdf.extension.AsdfExtension
+        extension : asdf.extension.AsdfExtension or asdf.extension.Extension
         """
         with self._lock:
             extension = ExtensionProxy.maybe_wrap(extension)
@@ -166,8 +166,8 @@ def remove_extension(self, extension=None, *, package=None):
 
         Parameters
         ----------
-        extension : asdf.extension.AsdfExtension or str, optional
-            An extension instance or URI or URI pattern to remove.
+        extension : asdf.extension.AsdfExtension or asdf.extension.Extension or str, optional
+            An extension instance or URI pattern to remove.
         package : str, optional
             Remove only extensions provided by this package.  If the `extension`
             argument is omitted, then all extensions from this package will
@@ -206,7 +206,7 @@ def get_extension(self, extension_uri):
 
         Returns
         -------
-        asdf.extension.AsdfExtension
+        asdf.extension.AsdfExtension or asdf.extension.Extension
 
         Raises
         ------

asdf/entry_points.py

@@ -7,6 +7,7 @@
 
 
 RESOURCE_MAPPINGS_GROUP = "asdf.resource_mappings"
+EXTENSIONS_GROUP = "asdf.extensions"
 LEGACY_EXTENSIONS_GROUP = "asdf_extensions"
 
 
@@ -15,9 +16,10 @@ def get_resource_mappings():
 
 
 def get_extensions():
+    extensions = _list_entry_points(EXTENSIONS_GROUP, ExtensionProxy)
     legacy_extensions = _list_entry_points(LEGACY_EXTENSIONS_GROUP, ExtensionProxy)
 
-    return legacy_extensions
+    return extensions + legacy_extensions
 
 
 def _list_entry_points(group, proxy_class):

asdf/extension/__init__.py

@@ -2,7 +2,10 @@
 Support for plugins that extend asdf to serialize
 additional custom types.
 """
-from ._extension import ExtensionProxy
+from ._extension import Extension, ExtensionProxy
+from ._manager import ExtensionManager, get_cached_extension_manager
+from ._tag import TagDefinition
+from ._converter import Converter, ConverterProxy
 from ._legacy import (
     AsdfExtension,
     AsdfExtensionList,
@@ -15,7 +18,13 @@
 
 __all__ = [
     # New API
+    "Extension",
     "ExtensionProxy",
+    "ExtensionManager",
+    "get_cached_extension_manager",
+    "TagDefinition",
+    "Converter",
+    "ConverterProxy",
     # Legacy API
     "AsdfExtension",
     "AsdfExtensionList",