[Feature] Add Postgres data loader (#918)

Co-authored-by: Deven Patel <deven298@yahoo.com>

embedchain/loaders/postgres.py

@@ -0,0 +1,73 @@
+import hashlib
+import logging
+from typing import Any, Dict, Optional
+
+from embedchain.loaders.base_loader import BaseLoader
+
+
+class PostgresLoader(BaseLoader):
+    def __init__(self, config: Optional[Dict[str, Any]] = None):
+        super().__init__()
+        if not config:
+            raise ValueError(f"Must provide the valid config. Received: {config}")
+
+        self.connection = None
+        self.cursor = None
+        self._setup_loader(config=config)
+
+    def _setup_loader(self, config: Dict[str, Any]):
+        try:
+            import psycopg
+        except ImportError as e:
+            raise ImportError(
+                "Unable to import required packages. \
+                    Run `pip install --upgrade 'embedchain[postgres]'`"
+            ) from e
+
+        config_info = ""
+        if "url" in config:
+            config_info = config.get("url")
+        else:
+            conn_params = []
+            for key, value in config.items():
+                conn_params.append(f"{key}={value}")
+            config_info = " ".join(conn_params)
+
+        logging.info(f"Connecting to postrgres sql: {config_info}")
+        self.connection = psycopg.connect(conninfo=config_info)
+        self.cursor = self.connection.cursor()
+
+    def _check_query(self, query):
+        if not isinstance(query, str):
+            raise ValueError(
+                f"Invalid postgres query: {query}",
+                "Provide the valid source to add from postgres, \
+                    make sure you are following `https://docs.embedchain.ai/data-sources/postgres`",
+            )
+
+    def load_data(self, query):
+        self._check_query(query)
+        try:
+            data = []
+            data_content = []
+            self.cursor.execute(query)
+            results = self.cursor.fetchall()
+            for result in results:
+                doc_content = str(result)
+                data.append({"content": doc_content, "meta_data": {"url": f"postgres_query-({query})"}})
+                data_content.append(doc_content)
+            doc_id = hashlib.sha256((query + ", ".join(data_content)).encode()).hexdigest()
+            return {
+                "doc_id": doc_id,
+                "data": data,
+            }
+        except Exception as e:
+            raise ValueError(f"Failed to load data using query={query} with: {e}")
+
+    def close_connection(self):
+        if self.cursor:
+            self.cursor.close()
+            self.cursor = None
+        if self.connection:
+            self.connection.close()
+            self.connection = None