restructure handlers

evadb/executor/create_application_executor.py

@@ -16,25 +16,37 @@
 
 from evadb.database import EvaDBDatabase
 from evadb.executor.abstract_executor import AbstractExecutor
+from evadb.executor.executor_utils import ExecutorError
 from evadb.models.storage.batch import Batch
 from evadb.parser.create_statement import CreateApplicationStatement
+from evadb.third_party.applications.interface import get_application_handler
 from evadb.utils.logging_manager import logger
 
 
+
 class CreateApplicationExecutor(AbstractExecutor):
     def __init__(self, db: EvaDBDatabase, node: CreateApplicationStatement):
         super().__init__(db, node)
 
     def exec(self, *args, **kwargs):
-        # todo handle if_not_exists
-
         logger.debug(
             f"Trying to connect to the provided engine {self.node.engine} with params {self.node.param_dict}"
         )
-        # todo handle if the provided application params are valid
 
-        logger.debug(f"Creating application {self.node}")
+        # Check if application already exists.
+        app_catalog_entry = self.catalog().get_application_catalog_entry(
+            self.node.application_name
+        )
+        if app_catalog_entry is not None:
+            raise ExecutorError(f"{self.node.application_name} already exists.")
+
+        # Check the validity of application entry.
+        handler = get_application_handler(self.node.engine, **self.node.param_dict)
+        resp = handler.connect()
+        if not resp.status:
+            raise ExecutorError(f"Cannot establish connection due to {resp.error}")
 
+        logger.debug(f"Creating application {self.node}")
         self.catalog().insert_application_catalog_entry(
             self.node.application_name, self.node.engine, self.node.param_dict
         )

evadb/third_party/applications/interface.py

@@ -0,0 +1,41 @@
+# coding=utf-8
+# Copyright 2018-2023 EvaDB
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import importlib
+import os
+
+def get_application_handler(engine: str, **kwargs):
+    """
+    Return the application handler. User should modify this function for
+    their new integrated handlers.
+    """
+
+    # Dynamically import the top module.
+    try:
+        mod = dynamic_import(engine)
+    except ImportError:
+        req_file = os.path.join(os.path.dirname(__file__), engine, "requirements.txt")
+        if os.path.isfile(req_file):
+            with open(req_file) as f:
+                raise ImportError(f"Please install the following packages {f.read()}")
+
+    if engine == "slack":
+        return mod.SlackHandler(engine, **kwargs)
+    else:
+        raise NotImplementedError(f"Engine {engine} is not supported")
+
+
+def dynamic_import(handler_dir):
+    import_path = f"evadb.third_party.applications.{handler_dir}.{handler_dir}_handler"
+    return importlib.import_module(import_path)

evadb/third_party/applications/slack/__init__.py

@@ -0,0 +1,15 @@
+# coding=utf-8
+# Copyright 2018-2023 EvaDB
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""third party/applications/slack"""

evadb/third_party/applications/slack/slack_handler.py

@@ -0,0 +1,4 @@
+
+
+class SlackHandler():
+    pass

evadb/third_party/applications/types.py

@@ -0,0 +1,129 @@
+# coding=utf-8
+# Copyright 2018-2023 EvaDB
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from dataclasses import dataclass
+from evadb.third_party.types import ThirdPartyResponse, ThirdPartyStatus, ThirdPartyHandler
+import pandas as pd
+
+
+@dataclass
+class AppHandlerResponse (ThirdPartyResponse):
+    """
+    Represents the response from a database handler containing data and an optional error message.
+
+    Attributes:
+        data (pd.DataFrame): A Pandas DataFrame containing the data retrieved from the database.
+        error (str, optional): An optional error message indicating any issues encountered during the operation.
+    """
+
+    data: pd.DataFrame
+    error: str = None
+
+
+@dataclass
+class AppHandlerStatus (ThirdPartyStatus):
+    """
+    Represents the status of a database handler operation, along with an optional error message.
+
+    Attributes:
+        status (bool): A boolean indicating the success (True) or failure (False) of the operation.
+        error (str, optional): An optional error message providing details about any errors that occurred.
+    """
+
+    status: bool
+    error: str = None
+
+
+class AppHandler (ThirdPartyHandler):
+    """
+    Base class for handling database operations.
+
+    Args:
+        name (str): The name associated with the database handler instance.
+    """
+
+    def __init__(self, name: str, **kwargs):
+        self.name = name
+        self.connection = None
+
+    def connect(self):
+        """
+        Establishes a connection to the database.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()
+
+    def disconnect(self):
+        """
+        Disconnects from the database.
+
+        This method can be overridden in derived classes to perform specific disconnect actions.
+        """
+        raise NotImplementedError()
+
+    def check_connection(self) -> AppHandlerStatus:
+        """
+        Checks the status of the database connection.
+
+        Returns:
+            AppHandlerStatus: An instance of AppHandlerStatus indicating the connection status.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()
+
+    def get_tables(self) -> AppHandlerResponse:
+        """
+        Retrieves the list of tables from the database.
+
+        Returns:
+            AppHandlerResponse: An instance of AppHandlerResponse containing the list of tables or an error message. Data is in a pandas DataFrame.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()
+
+    def get_columns(self, table_name: str) -> AppHandlerResponse:
+        """
+        Retrieves the columns of a specified table from the database.
+
+        Args:
+            table_name (str): The name of the table for which to retrieve columns.
+
+        Returns:
+            AppHandlerResponse: An instance of AppHandlerResponse containing the columns or an error message. Data is in a pandas DataFrame. It should have the following two columns: name and dtype. The dtype should be a Python dtype and will default to `str`.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()
+
+    def execute_native_query(self, query_string: str) -> AppHandlerResponse:
+        """
+        Executes the query through the handler's database engine.
+
+        Args:
+            query_string (str): The string representation of the native query.
+
+        Returns:
+            AppHandlerResponse: An instance of AppHandlerResponse containing the columns or an error message. Data is in a pandas DataFrame.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()

evadb/third_party/databases/types.py

@@ -13,12 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from dataclasses import dataclass
-
+from evadb.third_party.types import ThirdPartyResponse, ThirdPartyStatus, ThirdPartyHandler
 import pandas as pd
 
 
 @dataclass
-class DBHandlerResponse:
+class DBHandlerResponse (ThirdPartyResponse):
     """
     Represents the response from a database handler containing data and an optional error message.
 
@@ -32,7 +32,7 @@ class DBHandlerResponse:
 
 
 @dataclass
-class DBHandlerStatus:
+class DBHandlerStatus (ThirdPartyStatus):
     """
     Represents the status of a database handler operation, along with an optional error message.
 
@@ -45,7 +45,7 @@ class DBHandlerStatus:
     error: str = None
 
 
-class DBHandler:
+class DBHandler (ThirdPartyHandler):
     """
     Base class for handling database operations.
 

evadb/third_party/types.py

@@ -0,0 +1,93 @@
+# coding=utf-8
+# Copyright 2018-2023 EvaDB
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from dataclasses import dataclass
+@dataclass
+class ThirdPartyResponse:
+    """
+    Represents the response from a third party service handler
+    """
+    pass
+
+@dataclass
+class ThirdPartyStatus:
+    """
+    Represents the status of a third party service handler operation
+    """
+    pass
+
+class ThirdPartyHandler:
+    """
+    Base class for handling third party service operations.
+
+    Args:
+        name (str): The name associated with the database handler instance.
+    """
+
+    def __init__(self, name: str, **kwargs):
+        self.name = name
+        self.connection = None
+
+    def connect(self):
+        """
+        Establishes a connection to the third party service.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()
+
+    def disconnect(self):
+        """
+        Disconnects from the third party service.
+
+        This method can be overridden in derived classes to perform specific disconnect actions.
+        """
+        raise NotImplementedError()
+
+    def check_connection(self) -> ThirdPartyStatus:
+        """
+        Checks the status of the connection.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()
+
+    def get_tables(self) -> ThirdPartyResponse:
+        """
+        Retrieves the list of tables.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()
+
+    def get_columns(self, table_name: str) -> ThirdPartyResponse:
+        """
+        Retrieves the columns of a specified table.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()
+
+    def execute_native_query(self, query_string: str) -> ThirdPartyResponse:
+        """
+        Executes the query through the handler's engine.
+
+        Raises:
+            NotImplementedError: This method should be implemented in derived classes.
+        """
+        raise NotImplementedError()