warehouse support, plugin registry and streaming

bin/transport

@@ -136,8 +136,10 @@ def register (label:Annotated[str,typer.Argument(help="unique label that will be
               default:bool=typer.Option(default=False,help="set the auth_file as default"),
               path:str=typer.Option(default=REGISTRY_PATH,help="path of the data-transport registry file")):
     """
-    This function will register an auth-file i.e database connection and assign it a label, 
+    This function create a registery of either:
+    an auth-file entries given an auth-file i.e database connection and assign it a label, 
     Learn more about auth-file at https://healthcareio.the-phi.com/data-transport
+    
     """
     try:
         if transport.registry.exists(path) :
@@ -148,8 +150,46 @@ def register (label:Annotated[str,typer.Argument(help="unique label that will be
     except Exception as e:
         _msg = f"""{TIMES_MARK} {e}"""
     print (_msg)
-    
-    pass
+
+@app.command(name='plugin-add') 
+def register_plugs (
+    alias:Annotated[str,typer.Argument(help="unique alias fo the file being registered")],
+    path:Annotated[str,typer.Argument(help="path of the python file, that contains functions")]
+    ):
+    """
+    This function will register a file and the functions within will be refrences <alias>.<function> in a configuration file
+    """
+    transport.registry.plugins.init()
+    _log = transport.registry.plugins.add(alias,path)
+    _mark = TIMES_MARK if not _log else CHECK_MARK
+    _msg  = f"""Could NOT add the \033[1m{alias}\033[0m to the registry""" if not _log else f""" successfully added {alias}, {len(_log)} functions added"""
+    print (f"""{_mark} {_msg}""")
+@app.command(name="plugin-list") 
+def registry_list ():
+
+    transport.registry.plugins.init()
+    _d = []
+    for _alias in transport.registry.plugins._data :
+        _data = transport.registry.plugins._data[_alias]
+        _d +=  [{'alias':_alias,"plugin-count":len(_data['content']),'e.g':'@'.join([_alias,_data['content'][0]]),'plugins':json.dumps(_data['content'])}]
+    if _d:
+        print (pd.DataFrame(_d))
+    else:
+        print (f"""{TIMES_MARK}, Plugin registry is not available or needs initialization""")
+
+@app.command(name="plugin-test") 
+def registry_test (key):
+    """
+    This function allows to test syntax for a plugin i.e in terms of alis@function
+    """
+    _item = transport.registry.plugins.has(key=key)
+    if _item :
+        del _item['pointer']
+        print (f"""{CHECK_MARK} successfully loaded \033[1m{key}\033[0m found, version {_item['version']}""")
+        print (pd.DataFrame([_item]))
+    else:
+        print (f"{TIMES_MARK} unable to load \033[1m{key}\033[0m. Make sure it is registered")
+
 if __name__ == '__main__' :
      app()
 	

setup.py

@@ -19,7 +19,7 @@ args    = {
 
     "packages": find_packages(include=['info','transport', 'transport.*'])}
 args["keywords"]=['mongodb','duckdb','couchdb','rabbitmq','file','read','write','s3','sqlite']
-args["install_requires"] = ['pyncclient','duckdb-engine','pymongo','sqlalchemy','pandas','typer','pandas-gbq','numpy','cloudant','pika','nzpy','termcolor','boto3','boto','pyarrow','google-cloud-bigquery','google-cloud-bigquery-storage','flask-session','smart_open','botocore','psycopg2-binary','mysql-connector-python','numpy','pymssql','pyspark']
+args["install_requires"] = ['pyncclient','duckdb-engine','pymongo','sqlalchemy','pandas','typer','pandas-gbq','numpy','cloudant','pika','nzpy','termcolor','boto3','boto','pyarrow','google-cloud-bigquery','google-cloud-bigquery-storage','flask-session','smart_open','botocore','psycopg2-binary','mysql-connector-python','numpy','pymssql','pyspark','pydrill']
 args["url"] =   "https://healthcareio.the-phi.com/git/code/transport.git"
 args['scripts'] = ['bin/transport']
 # if sys.version_info[0] == 2 :

transport/__init__.py

@@ -28,7 +28,7 @@ from transport.plugins import PluginLoader
 from transport import providers
 import copy 
 from transport import registry
-
+from transport.plugins import Plugin 
 PROVIDERS = {}
 
 def init():
@@ -120,6 +120,7 @@ def instance (**_args):
         #             loader.set(_delegate)
         
         loader = None if 'plugins' not in _args else _args['plugins']
+        
         return IReader(_agent,loader) if _context == 'read' else IWriter(_agent,loader)
 
     else:

transport/iowrapper.py

@@ -5,11 +5,13 @@ NOTE: Plugins are converted to a pipeline, so we apply a pipeline when reading o
         - upon initialization we will load plugins
         - on read/write we apply a pipeline (if passed as an argument)
 """    
-from transport.plugins import plugin, PluginLoader
+from transport.plugins import PluginLoader
 import transport
 from transport import providers
 from multiprocessing import Process
 import time
+import types
+from . import registry
 
 
 class IO:
@@ -18,20 +20,24 @@ class IO:
     """
     def __init__(self,_agent,plugins):
         self._agent = _agent
+        
         if plugins :
             self._init_plugins(plugins)
         else:
             self._plugins = None
         
-    def _init_plugins(self,_args):
+    def _init_plugins(self,_items):
         """
         This function will load pipelined functions as a plugin loader
         """
-        if 'path' in _args and 'names' in _args :
-            self._plugins = PluginLoader(**_args)
-        else:
-            self._plugins = PluginLoader()
-            [self._plugins.set(_pointer) for _pointer in _args]
+        registry.plugins.init()
+        self._plugins = PluginLoader(registry=registry.plugins)
+        [self._plugins.set(_name) for _name in _items]
+        # if 'path' in _args and 'names' in _args :
+        #     self._plugins = PluginLoader(**_args)
+        # else:
+        #     self._plugins = PluginLoader(registry=registry.plugins)
+        #     [self._plugins.set(_pointer) for _pointer in _args]
         #
         # @TODO: We should have a way to log what plugins are loaded and ready to use
     def meta (self,**_args):
@@ -65,15 +71,26 @@ class IReader(IO):
     """
     def __init__(self,_agent,pipeline=None):
         super().__init__(_agent,pipeline)
+        
+    def _stream (self,_data ):
+        for _segment in _data :
+            
+            yield self._plugins.apply(_segment)
     def read(self,**_args):
         if 'plugins' in _args :
             self._init_plugins(_args['plugins'])
         _data = self._agent.read(**_args)
+        
         if self._plugins and self._plugins.ratio() > 0 :
-            _data = self._plugins.apply(_data)
-        #
-        # output data 
-        return _data
+            
+            if types.GeneratorType == type(_data):
+                
+               return self._stream(_data)
+            else:
+                _data = self._plugins.apply(_data)
+                return _data
+        else:
+            return _data
 class IWriter(IO):
     def __init__(self,_agent,pipeline=None):
         super().__init__(_agent,pipeline)  
@@ -95,6 +112,7 @@ class IETL(IReader) :
     """
     def __init__(self,**_args):
         super().__init__(transport.get.reader(**_args['source']))
+        
         if 'target' in _args:
             self._targets = _args['target'] if type(_args['target']) == list else [_args['target']]
         else:
@@ -113,11 +131,18 @@ class IETL(IReader) :
 
     def read(self,**_args):
         _data = super().read(**_args)
+        if types.GeneratorType == type(_data):
+            for _segment in _data :
+                for _kwars in self._targets :
+                    self.post(_segment,**_kwargs)
+        else:
+            
 
-        for _kwargs in self._targets :
-            self.post(_data,**_kwargs)
+            for _kwargs in self._targets :
+                self.post(_data,**_kwargs)
 
         return _data
+        # return _data
     def post (self,_data,**_args) :
         """
         This function returns an instance of a process that will perform the write operation

transport/other/files.py

@@ -12,7 +12,7 @@ class File :
 		"""
 		self.path 		= params['path'] if 'path' in params else None
 		self.delimiter	= params['delimiter'] if 'delimiter' in params else ','
-		
+		self._chunksize = None if 'chunksize' not in params else int(params['chunksize'])
 	def isready(self):
 		return os.path.exists(self.path) 
 	def meta(self,**_args):
@@ -26,11 +26,15 @@ class Reader (File):
 	
 	def __init__(self,**_args):
 		super().__init__(**_args)
-
+	def _stream(self,path) :
+		reader = pd.read_csv(path,delimiter=self.delimiter,chunksize=self._chunksize)
+		for segment in reader :
+			yield segment
 	def read(self,**args):
 		_path = self.path if 'path' not in args else args['path']
 		_delimiter = self.delimiter if 'delimiter' not in args else args['delimiter']
-		return pd.read_csv(_path,delimiter=self.delimiter)
+		
+		return pd.read_csv(_path,delimiter=self.delimiter) if not self._chunksize else self._stream(_path)
 	def stream(self,**args):
 		raise Exception ("streaming needs to be implemented")
 class Writer (File):

transport/plugins/__init__.py

@@ -12,7 +12,7 @@ import importlib.util
 import sys
 import os
 
-class plugin :
+class Plugin :
     """
     Implementing function decorator for data-transport plugins (post-pre)-processing
     """
@@ -22,8 +22,9 @@ class plugin :
         :mode   restrict to reader/writer
         :about  tell what the function is about    
         """
-        self._name = _args['name']
-        self._about = _args['about']
+        self._name = _args['name'] if 'name' in _args else None
+        self._version = _args['version'] if 'version' in _args else '0.1'
+        self._doc = _args['doc'] if 'doc' in _args else "N/A"
         self._mode = _args['mode'] if 'mode' in _args else 'rw'
     def __call__(self,pointer,**kwargs):
         def wrapper(_args,**kwargs):
@@ -32,57 +33,86 @@ class plugin :
         # @TODO:
         # add attributes to the wrapper object
         #
+        self._name = pointer.__name__ if not self._name else self._name
         setattr(wrapper,'transport',True)
         setattr(wrapper,'name',self._name)
-        setattr(wrapper,'mode',self._mode)
-        setattr(wrapper,'about',self._about)
+        setattr(wrapper,'version',self._version)
+        setattr(wrapper,'doc',self._doc)
         return wrapper
 
-
 class PluginLoader :
     """
     This class is intended to load a plugin and make it available and assess the quality of the developed plugin
     """
+   
     def __init__(self,**_args):
         """
-        :path   location of the plugin (should be a single file)
-        :_names of functions to load
         """
-        _names = _args['names'] if 'names' in _args else None
-        path = _args['path'] if 'path' in _args else None
-        self._names = _names if type(_names) == list else [_names]
+        # _names = _args['names'] if 'names' in _args else None
+        # path = _args['path'] if 'path' in _args else None
+        # self._names = _names if type(_names) == list else [_names]
         self._modules = {}
         self._names = []
-        if path and os.path.exists(path) and _names:
-            for _name in self._names :
+        self._registry = _args['registry']
+        # if path and os.path.exists(path) and _names:
+        #     for _name in self._names :
                 
-                spec = importlib.util.spec_from_file_location('private', path)
-                module = importlib.util.module_from_spec(spec)
-                spec.loader.exec_module(module) #--loads it into sys.modules
-                if hasattr(module,_name) :
-                    if self.isplugin(module,_name) :
-                        self._modules[_name] = getattr(module,_name)
-                    else:
-                        print ([f'Found {_name}', 'not plugin'])
-                else:
-                    #
-                    # @TODO: We should log this somewhere some how
-                    print (['skipping ',_name, hasattr(module,_name)])
-                    pass
-        else:
-            #
-            # Initialization is empty
-            self._names = []
+        #         spec = importlib.util.spec_from_file_location('private', path)
+        #         module = importlib.util.module_from_spec(spec)
+        #         spec.loader.exec_module(module) #--loads it into sys.modules
+        #         if hasattr(module,_name) :
+        #             if self.isplugin(module,_name) :
+        #                 self._modules[_name] = getattr(module,_name)
+        #             else:
+        #                 print ([f'Found {_name}', 'not plugin'])
+        #         else:
+        #             #
+        #             # @TODO: We should log this somewhere some how
+        #             print (['skipping ',_name, hasattr(module,_name)])
+        #             pass
+        # else:
+        #     #
+        #     # Initialization is empty
+        #     self._names = []
         pass
-    def set(self,_pointer) :
+    def load (self,**_args):
+        self._modules = {}
+        self._names = []
+        path = _args ['path']
+        if os.path.exists(path) :
+            _alias = path.split(os.sep)[-1]
+            spec = importlib.util.spec_from_file_location(_alias, path)
+            module = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(module) #--loads it into sys.modules
+            # self._names = [_name for _name in dir(module) if type(getattr(module,_name)).__name__ == 'function']
+            for _name in dir(module) :
+                if self.isplugin(module,_name) :
+                    self._module[_name] = getattr(module,_name)
+                    # self._names [_name]
+    def format (self,**_args):
+        uri = _args['alias'],_args['name']
+    # def set(self,_pointer) :
+    def set(self,_key) :
         """
         This function will set a pointer to the list of modules to be called
         This should be used within the context of using the framework as a library
         """
-        _name = _pointer.__name__
+        # _name = _pointer.__name__ if type(_pointer).__name__ == 'function' else {}
+        
+        # self._modules[_name] = _pointer
+        # self._names.append(_name)
+        
+        _pointer = self._registry.get(key=_key)
+        if _pointer  :
+            self._modules[_key] = _pointer
+            self._names.append(_key)
+        elif type(_key).__name__ == 'function':
+            #
+            # The pointer is in the code provided by the user and loaded in memory
+            #
+            _pointer = _key
+            self._names.append(_key.__name__)
         
-        self._modules[_name] = _pointer
-        self._names.append(_name)
     def isplugin(self,module,name):
         """
         This function determines if a module is a recognized plugin

transport/providers/__init__.py

@@ -11,7 +11,7 @@ BIGQUERY	='bigquery'
 FILE 	= 'file'
 ETL = 'etl'
 
-SQLITE = 'sqlite'
+SQLITE = 'sqlite3'
 SQLITE3= 'sqlite3'
 DUCKDB = 'duckdb'
 

transport/registry.py

@@ -3,6 +3,10 @@ import json
 from info import __version__
 import copy
 import transport
+import importlib
+import importlib.util
+import shutil
+
 
 """
 This class manages data from the registry and allows (read only)
@@ -16,28 +20,182 @@ REGISTRY_PATH=os.sep.join([os.environ['HOME'],'.data-transport'])
 if 'DATA_TRANSPORT_REGISTRY_PATH' in os.environ :
     REGISTRY_PATH = os.environ['DATA_TRANSPORT_REGISTRY_PATH']
 REGISTRY_FILE= 'transport-registry.json'
-
 DATA = {}
+class plugins:
+    #
+    # This is a utility function that should enable management of plugins-registry
+    # The class allows to add/remove elements 
+    #
+    # @TODO: add read/write properties to the class (better design practice)
+    #
+    _data = {}
+    FOLDER = os.sep.join([REGISTRY_PATH,'plugins'])
+    CODE = os.sep.join([REGISTRY_PATH,'plugins','code'])
+    FILE = os.sep.join([REGISTRY_PATH,'plugin-registry.json'])
+    @staticmethod
+    def init():
+        
+        if not os.path.exists(plugins.FOLDER) :
+            os.makedirs(plugins.FOLDER)
+        if not os.path.exists(plugins.CODE):
+            os.makedirs(plugins.CODE)
+        if not os.path.exists(plugins.FILE):
+            f = open(plugins.FILE,'w')
+            f.write("{}")
+            f.close()
+        plugins._read() #-- will load data as a side effect
+
+    @staticmethod
+    def copy (path) :
+        
+        shutil.copy2(path,plugins.CODE)
+    @staticmethod
+    def _read ():
+        f = open(plugins.FILE)
+        try:
+            _data = json.loads(f.read())
+            f.close()
+        except Exception as e:
+            print (f"Corrupted registry, resetting ...")
+            _data = {}
+            plugins._write(_data)
+            
+        plugins._data = _data
+    @staticmethod
+    def _write (_data):
+        f = open(plugins.FILE,'w')
+        f.write(json.dumps(_data))
+        f.close()
+        plugins._data = _data
+
+    @staticmethod
+    def inspect (_path):
+        _names = []
+        
+        if os.path.exists(_path) :
+            _filename = _path.split(os.sep)[-1]
+            spec = importlib.util.spec_from_file_location(_filename, _path)
+            module = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(module)
+
+            # _names = [{'name':getattr(getattr(module,_name),'name'),'pointer':getattr(module,_name)} for _name in dir(module) if type( getattr(module,_name)).__name__ == 'function']
+            for _name in dir(module) :
+                _pointer = getattr(module,_name) 
+                if hasattr(_pointer,'transport') :
+                    _item = {'real_name':_name,'name':getattr(_pointer,'name'),'pointer':_pointer,'version':getattr(_pointer,'version')}
+                    _names.append(_item)
+
+            
+        return _names
+    @staticmethod
+    def add (alias,path):
+        """
+        Add overwrite the registry entries
+        """
+        _names = plugins.inspect (path)
+        _log = []
+        
+        if _names :
+            #
+            # We should make sure we have all the plugins with the attributes (transport,name) set
+            _names = [_item for _item in _names if hasattr(_item['pointer'],'transport') ]
+            if _names :
+                plugins.copy(path)
+                _content = []
+                
+                for _item in _names :
+                    _key = '@'.join([alias,_item['name']])
+                    _log.append(_item['name'])
+                #
+                # Let us update the registry 
+                # 
+                plugins.update(alias,path,_log)        
+        return _log
+    
+    @staticmethod
+    def update (alias,path,_log) :
+        """
+        updating the registry entries of the plugins (management data)
+        """
+        # f = open(plugins.FILE)
+        # _data = json.loads(f.read())
+        # f.close()
+        _data = plugins._data
+        # _log = plugins.add(alias,path)
+        
+        if _log :
+            _data[alias] = {'content':_log,'name':path.split(os.sep)[-1]}
+            plugins._write(_data) #-- will update data as a side effect
+
+        return _log
+    @staticmethod
+    def get(**_args) :
+        # f = open(plugins.FILE)
+        # _data = json.loads(f.read())
+        # f.close()
+        # if 'key' in _args :
+        #     alias,name = _args['key'].split('.') if '.' in _args['key'] else _args['key'].split('@')
+        # else :
+        #     alias = _args['alias']
+        #     name  = _args['name']
+        
+        # if alias in _data :
+            
+        #     _path = os.sep.join([plugins.CODE,_data[alias]['name']])
+        #     _item = [_item for _item in plugins.inspect(_path) if name == _item['name']]
+            
+        #     _item = _item[0] if _item else None
+        #     if _item :
+                
+        #         return _item['pointer'] 
+        # return None
+        _item = plugins.has(**_args)
+        return _item['pointer'] if _item else None
+    
+    @staticmethod
+    def has (**_args):
+        f = open(plugins.FILE)
+        _data = json.loads(f.read())
+        f.close()
+        if 'key' in _args :
+            alias,name = _args['key'].split('.') if '.' in _args['key'] else _args['key'].split('@')
+        else :
+            alias = _args['alias']
+            name  = _args['name']
+        
+        if alias in _data :
+            
+            _path = os.sep.join([plugins.CODE,_data[alias]['name']])
+            _item = [_item for _item in plugins.inspect(_path) if name == _item['name']]
+            
+            _item = _item[0] if _item else None
+            if _item :
+                
+                return copy.copy(_item)
+        return None
+    @staticmethod
+    def synch():
+        pass
 
 def isloaded ():
     return DATA not in [{},None]
-def exists (path=REGISTRY_PATH) :
+def exists (path=REGISTRY_PATH,_file=REGISTRY_FILE) :
     """
     This function determines if there is a registry at all
     """
     p = os.path.exists(path)
-    q = os.path.exists( os.sep.join([path,REGISTRY_FILE]))
+    q = os.path.exists( os.sep.join([path,_file]))
     
     return p and q
-def load (_path=REGISTRY_PATH):
+def load (_path=REGISTRY_PATH,_file=REGISTRY_FILE):
     global DATA
     
     if exists(_path) :
-        path = os.sep.join([_path,REGISTRY_FILE])
+        path = os.sep.join([_path,_file])
         f = open(path)
         DATA = json.loads(f.read())
         f.close()
-def init (email,path=REGISTRY_PATH,override=False):
+def init (email,path=REGISTRY_PATH,override=False,_file=REGISTRY_FILE):
     """
     Initializing the registry and will raise an exception in the advent of an issue
     """
@@ -47,7 +205,7 @@ def init (email,path=REGISTRY_PATH,override=False):
         _config = {"email":email,'version':__version__}
         if not os.path.exists(path):
             os.makedirs(path)
-        filename = os.sep.join([path,REGISTRY_FILE])
+        filename = os.sep.join([path,_file])
         if not os.path.exists(filename) or override == True :
 
             f = open(filename,'w')

transport/sql/__init__.py

@@ -3,7 +3,7 @@ This namespace/package wrap the sql functionalities for a certain data-stores
     - netezza, postgresql, mysql and sqlite
     - mariadb, redshift (also included)
 """
-from . import postgresql, mysql, netezza, sqlite, sqlserver, duckdb
+from . import postgresql, mysql, netezza, sqlite3, sqlserver, duckdb
 
 
 #
@@ -11,7 +11,7 @@ from . import postgresql, mysql, netezza, sqlite, sqlserver, duckdb
 #
 mariadb     = mysql
 redshift    = postgresql
-sqlite3     = sqlite
+# sqlite3     = sqlite
 
 
 # from transport import sql

transport/sql/sqlite3.py

@@ -1,7 +1,7 @@
 import sqlalchemy
 import pandas as pd
 from transport.sql.common import Base, BaseReader, BaseWriter
-class SQLite (BaseReader):
+class SQLite3 (BaseReader):
     def __init__(self,**_args):
         super().__init__(**_args)
         if 'path' in _args :
@@ -12,7 +12,7 @@ class SQLite (BaseReader):
         path = self._database
         return f'sqlite:///{path}' # ensure this is the correct path for the sqlite file. 
 
-class Reader(SQLite,BaseReader):
+class Reader(SQLite3,BaseReader):
     def __init__(self,**_args):
         super().__init__(**_args)
     # def read(self,**_args):
@@ -20,6 +20,6 @@ class Reader(SQLite,BaseReader):
     #     return pd.read_sql(sql,self._engine)
 
 
-class Writer (SQLite,BaseWriter):
+class Writer (SQLite3,BaseWriter):
     def __init__(self,**_args):
         super().__init__(**_args)

transport/warehouse/drill.py

@@ -0,0 +1,54 @@
+import sqlalchemy
+import pandas as pd
+from .. sql.common import BaseReader , BaseWriter
+import sqlalchemy as sqa
+
+class Drill :
+    def __init__(self,**_args):
+
+        self._host = _args['host'] if 'host' in _args else 'localhost'
+        self._port = _args['port'] if 'port' in _args else self.get_default_port()
+        self._ssl = False if 'ssl' not in _args else _args['ssl']
+        
+        self._table = _args['table'] if 'table' in _args else None
+        if self._table and '.' in self._table :
+            _seg = self._table.split('.')
+            if len(_seg) > 2 :
+                self._schema,self._database = _seg[:2]
+        else:
+            
+            self._database=_args['database']
+            self._schema = self._database.split('.')[0]
+
+    def _get_uri(self,**_args):
+        return f'drill+sadrill://{self._host}:{self._port}/{self._schema}?use_ssl={self._ssl}'
+    def get_provider(self):
+        return "drill+sadrill"
+    def get_default_port(self):
+        return "8047"
+    def meta(self,**_args):
+        _table = _args['table'] if 'table' in _args else self._table
+        if '.' in _table :
+            _schema = _table.split('.')[:2]
+            _schema = '.'.join(_schema)
+            _table = _table.split('.')[-1]
+        else:
+            _schema = self._schema
+        
+        # _sql = f"select COLUMN_NAME AS name, CASE WHEN DATA_TYPE ='CHARACTER VARYING' THEN 'CHAR ( 125 )' ELSE DATA_TYPE END AS type from INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA='{_schema}' and TABLE_NAME='{_table}'"
+        _sql = f"select COLUMN_NAME AS name, CASE WHEN DATA_TYPE ='CHARACTER VARYING' THEN 'CHAR ( '||COLUMN_SIZE||' )' ELSE DATA_TYPE END AS type from INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA='{_schema}' and TABLE_NAME='{_table}'"
+        try:
+            _df  = pd.read_sql(_sql,self._engine)
+            return _df.to_dict(orient='records')
+        except Exception as e:
+            print (e)
+            pass
+        return []
+class Reader (Drill,BaseReader) :
+    def __init__(self,**_args):
+        super().__init__(**_args)
+        self._chunksize = 0 if 'chunksize' not in _args else _args['chunksize']
+        self._engine= sqa.create_engine(self._get_uri(),future=True)
+class Writer(Drill,BaseWriter):
+    def __init__(self,**_args):
+        super().__init__(self,**_args)