Refactor UDF server and external function type system (#57)

* Refactoring function signatures

* Refactor return values

* Fix UDF return values

* Big refactoring of the way parameters / return values work

* Add default values from pydantic / namedtuple / etc

* Fix TypedDict defaults

* Disable lifespan in uvicorn

* Fix multiple vector output in TVFs; fix ucs4 to utf8 transcoding in numpy fixed strings

* Remove debugging code

* Fix masked types; add asgi endpoint for function info

* Fix get_annotations call

* Fix imports; change binary from hex to base64

* Fix show functions call

* Fix fixed length strings / binary; add tests for fixed strings / binary; test no args / no return value

* Add vector type

* Fix fixed length binary values

Author: kesmit13

accel.c

@@ -407,6 +407,18 @@
     environ=['SINGLESTOREDB_EXT_FUNC_LOG_LEVEL'],
 )
 
+register_option(
+    'external_function.name_prefix', 'string', check_str, '',
+    'Prefix to add to external function names.',
+    environ=['SINGLESTOREDB_EXT_FUNC_NAME_PREFIX'],
+)
+
+register_option(
+    'external_function.name_suffix', 'string', check_str, '',
+    'Suffix to add to external function names.',
+    environ=['SINGLESTOREDB_EXT_FUNC_NAME_SUFFIX'],
+)
+
 register_option(
     'external_function.connection', 'string', check_str,
     os.environ.get('SINGLESTOREDB_URL') or None,
@@ -415,7 +427,7 @@
 )
 
 register_option(
-    'external_function.host', 'string', check_str, '127.0.0.1',
+    'external_function.host', 'string', check_str, 'localhost',
     'Specifies the host to bind the server to.',
     environ=['SINGLESTOREDB_EXT_FUNC_HOST'],
 )

singlestoredb/config.py

@@ -1,2 +1,6 @@
 from .decorator import tvf  # noqa: F401
+from .decorator import tvf_with_null_masks  # noqa: F401
 from .decorator import udf  # noqa: F401
+from .decorator import udf_with_null_masks  # noqa: F401
+from .typing import Masked  # noqa: F401
+from .typing import MaskedNDArray  # noqa: F401