Clickhouse integration (georgia-tech-db#1281)

docs/_toc.yml

@@ -69,6 +69,7 @@ parts:
           - file: source/reference/databases/sqlite
           - file: source/reference/databases/mysql
           - file: source/reference/databases/mariadb
+          - file: source/reference/databases/clickhouse
           - file: source/reference/databases/github
 
       - file: source/reference/vector_databases/index

docs/source/reference/databases/clickhouse.rst

@@ -0,0 +1,37 @@
+Clickhouse
+==========
+
+The connection to Clickhouse is based on the `clickhouse-sqlalchemy <https://pypi.org/project/clickhouse-sqlalchemy/>`_ library.
+
+Dependency
+----------
+
+* clickhouse-sqlalchemy
+
+
+
+Parameters
+----------
+
+Required:
+
+* `user` is the database user.
+* `password` is the database password.
+* `host` is the host name or IP address.
+* `port` is the port used to make TCP/IP connection to the Clickhouse server.
+* `database` is the database name.
+* `protocol` (optional) Default- `native`. Its supported values are `http` and `https`.
+
+
+Create Connection
+-----------------
+
+.. code-block:: text
+
+   CREATE DATABASE clickhouse_data WITH ENGINE = 'clickhouse', PARAMETERS = {
+        "user": "eva", 
+        "password": "password",
+        "host": "localhost",
+        "port": "5432", 
+        "database": "evadb"
+   };

evadb/third_party/databases/clickhouse/__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.
+"""Clickhouse integrations"""

evadb/third_party/databases/clickhouse/clickhouse_handler.py

@@ -0,0 +1,174 @@
+# 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 pandas as pd
+from sqlalchemy import create_engine
+
+from evadb.third_party.databases.types import (
+    DBHandler,
+    DBHandlerResponse,
+    DBHandlerStatus,
+)
+
+
+class ClickHouseHandler(DBHandler):
+    def __init__(self, name: str, **kwargs):
+        """
+        Initialize the handler.
+        Args:
+            name (str): name of the DB handler instance
+            **kwargs: arbitrary keyword arguments for establishing the connection.
+        """
+        super().__init__(name)
+        self.host = kwargs.get("host")
+        self.port = kwargs.get("port")
+        self.user = kwargs.get("user")
+        self.password = kwargs.get("password")
+        self.database = kwargs.get("database")
+        self.protocol = kwargs.get("protocol")
+        protocols_map = {
+            "native": "clickhouse+native",
+            "http": "clickhouse+http",
+            "https": "clickhouse+https",
+        }
+        if self.protocol in protocols_map:
+            self.protocol = protocols_map[self.protocol]
+
+    def connect(self):
+        """
+        Set up the connection required by the handler.
+        Returns:
+            DBHandlerStatus
+        """
+        try:
+            protocol = self.protocol
+            host = self.host
+            port = self.port
+            user = self.user
+            password = self.password
+            database = self.database
+            url = f"{protocol}://{user}:{password}@{host}:{port}/{database}"
+            if self.protocol == "clickhouse+https":
+                url = url + "?protocol=https"
+
+            engine = create_engine(url)
+            self.connection = engine.raw_connection()
+            return DBHandlerStatus(status=True)
+        except Exception as e:
+            return DBHandlerStatus(status=False, error=str(e))
+
+    def disconnect(self):
+        """
+        Close any existing connections.
+        """
+        if self.connection:
+            self.disconnect()
+
+    def check_connection(self) -> DBHandlerStatus:
+        """
+        Check connection to the handler.
+        Returns:
+            DBHandlerStatus
+        """
+        if self.connection:
+            return DBHandlerStatus(status=True)
+        else:
+            return DBHandlerStatus(status=False, error="Not connected to the database.")
+
+    def get_tables(self) -> DBHandlerResponse:
+        """
+        Return the list of tables in the database.
+        Returns:
+            DBHandlerResponse
+        """
+        if not self.connection:
+            return DBHandlerResponse(data=None, error="Not connected to the database.")
+
+        try:
+            query = f"SHOW TABLES FROM {self.connection_data['database']}"
+            tables_df = pd.read_sql_query(query, self.connection)
+            return DBHandlerResponse(data=tables_df)
+        except Exception as e:
+            return DBHandlerResponse(data=None, error=str(e))
+
+    def get_columns(self, table_name: str) -> DBHandlerResponse:
+        """
+        Returns the list of columns for the given table.
+        Args:
+            table_name (str): name of the table whose columns are to be retrieved.
+        Returns:
+            DBHandlerResponse
+        """
+        if not self.connection:
+            return DBHandlerResponse(data=None, error="Not connected to the database.")
+
+        try:
+            query = f"DESCRIBE {table_name}"
+            columns_df = pd.read_sql_query(query, self.connection)
+            columns_df["dtype"] = columns_df["dtype"].apply(
+                self._clickhouse_to_python_types
+            )
+            return DBHandlerResponse(data=columns_df)
+        except Exception as e:
+            return DBHandlerResponse(data=None, error=str(e))
+
+    def _fetch_results_as_df(self, cursor):
+        try:
+            res = cursor.fetchall()
+            if not res:
+                return pd.DataFrame({"status": ["success"]})
+            res_df = pd.DataFrame(res, columns=[desc[0] for desc in cursor.description])
+            return res_df
+        except Exception as e:
+            if str(e) == "no results to fetch":
+                return pd.DataFrame({"status": ["success"]})
+            raise e
+
+    def execute_native_query(self, query_string: str) -> DBHandlerResponse:
+        """
+        Executes the native query on the database.
+        Args:
+            query_string (str): query in native format
+        Returns:
+            DBHandlerResponse
+        """
+        if not self.connection:
+            return DBHandlerResponse(data=None, error="Not connected to the database.")
+
+        try:
+            cursor = self.connection.cursor()
+            cursor.execute(query_string)
+            return DBHandlerResponse(data=self._fetch_results_as_df(cursor))
+        except Exception as e:
+            return DBHandlerResponse(data=None, error=str(e))
+
+    def _clickhouse_to_python_types(self, clickhouse_type: str):
+        mapping = {
+            "char": str,
+            "varchar": str,
+            "text": str,
+            "boolean": bool,
+            "integer": int,
+            "int": int,
+            "float": float,
+            "double": float,
+            # Add more mappings as needed
+        }
+
+        if clickhouse_type in mapping:
+            return mapping[clickhouse_type]
+        else:
+            raise Exception(
+                f"Unsupported column {clickhouse_type} encountered in the clickhouse table. Please raise a feature request!"
+            )

evadb/third_party/databases/clickhouse/requirements.txt

@@ -0,0 +1 @@
+sqlalchemy

evadb/third_party/databases/interface.py

@@ -42,6 +42,8 @@ def _get_database_handler(engine: str, **kwargs):
         return mod.MysqlHandler(engine, **kwargs)
     elif engine == "mariadb":
         return mod.MariaDbHandler(engine, **kwargs)
+    elif engine == "clickhouse":
+        return mod.ClickHouseHandler(engine, **kwargs)
     elif engine == "github":
         return mod.GithubHandler(engine, **kwargs)
     else:

test/third_party_tests/test_native_executor.py

@@ -210,6 +210,25 @@ def test_should_run_query_in_mariadb(self):
         self._execute_native_query()
         self._execute_evadb_query()
 
+    def test_should_run_query_in_clickhouse(self):
+        # Create database.
+        params = {
+            "user": "eva",
+            "password": "password",
+            "host": "localhost",
+            "port": "9000",
+            "database": "evadb",
+        }
+        query = f"""CREATE DATABASE test_data_source
+                    WITH ENGINE = "clickhouse",
+                    PARAMETERS = {params};"""
+        execute_query_fetch_all(self.evadb, query)
+
+        # Test executions.
+        self._execute_native_query()
+        self._execute_evadb_query()
+
+
     def test_should_run_query_in_sqlite(self):
         # Create database.
         import os