Add Couchbase Reader (#892)

* Add the initial version of Couchbase documents reader

* Update the Readme

* Add doc strings

* Update the examples link

---------

Co-authored-by: Nithish Raghunandanan <[email protected]>

llama_hub/couchbase/README.md

@@ -0,0 +1,56 @@
+# Couchbase Loader
+
+This loader loads documents from Couchbase cluster.
+The user specifies a Couchbase client or credentials to initialize the reader. They can specify the SQL++ query to
+fetch the relevant docs.
+
+## Usage
+
+Here's an example usage of the CouchbaseReader.
+
+```python
+from llama_index import download_loader
+import os
+
+CouchbaseLoader = download_loader('CouchbaseReader')
+
+connection_string = "couchbase://localhost" # valid Couchbase connection string
+db_username = "<valid_database_user_with_read_access_to_bucket_with_data>"
+db_password = "<password_for_database_user>"
+
+# query is a valid SQL++ query that is passed to client.query()
+query = """
+    SELECT h.* FROM `travel-sample`.inventory.hotel h
+        WHERE h.country = 'United States'
+        LIMIT 5
+        """
+
+reader = CouchbaseLoader(
+        connection_string=connection_string,
+        db_username=db_username,
+        db_password=db_password
+    )
+
+# It is also possible to pass an initialized Couchbase client to the document loader
+# from couchbase.auth import PasswordAuthenticator  # noqa: E402
+# from couchbase.cluster import Cluster # noqa: E402
+# from couchbase.options import ClusterOptions # noqa: E402
+
+# auth = PasswordAuthenticator(
+#    db_username,
+#    db_password,
+# )
+
+# couchbase_client = Cluster(connection_string, ClusterOptions(auth))
+# reader = CouchbaseLoader(client=couchbase_client)
+
+# fields to be written to the document
+text_fields=["name", "title", "address", "reviews"]
+
+# metadata fields to be written to the document's metadata
+metadata_fields=["country", "city"],
+
+documents = reader.load_data(query=query, text_fields=text_fields, metadata_fields=metadata_fields)
+```
+
+This loader is designed to be used as a way to load data into [LlamaIndex](https://github.com/run-llama/llama_index/tree/main/llama_index) and/or subsequently used as a Tool in a [LangChain](https://github.com/hwchase17/langchain) Agent. See [here](https://github.com/run-llama/llama-hub/tree/main) for examples.

llama_hub/couchbase/__init__.py

@@ -0,0 +1,6 @@
+"""Init file."""
+from llama_hub.couchbase.base import (
+    CouchbaseReader,
+)
+
+__all__ = ["CouchbaseReader"]

llama_hub/couchbase/base.py

@@ -0,0 +1,107 @@
+"""Couchbase document loader"""
+
+from typing import Any, Iterable, List, Optional
+from llama_index.readers.base import BaseReader
+from llama_index.readers.schema.base import Document
+
+
+class CouchbaseReader(BaseReader):
+    """Couchbase document loader.
+
+    Loads data from a Couchbase cluster into Document used by LlamaIndex.
+
+    Args:
+        client(Optional[Any]): A Couchbase client to use.
+            If not provided, the client will be created based on the connection_string
+            and database credentials.
+        connection_string (Optional[str]): The connection string to the Couchbase cluster.
+        db_username (Optional[str]): The username to connect to the Couchbase cluster.
+        db_password (Optional[str]): The password to connect to the Couchbase cluster.
+    """
+
+    def __init__(
+        self,
+        client: Optional[Any] = None,
+        connection_string: Optional[str] = None,
+        db_username: Optional[str] = None,
+        db_password: Optional[str] = None,
+    ) -> None:
+        """Initialize Couchbase document loader."""
+        import_err_msg = "`couchbase` package not found, please run `pip install --upgrade couchbase`"
+        try:
+            from couchbase.auth import PasswordAuthenticator
+            from couchbase.cluster import Cluster
+            from couchbase.options import ClusterOptions
+        except ImportError:
+            raise ImportError(import_err_msg)
+
+        if not client:
+            if not connection_string or not db_username or not db_password:
+                raise ValueError(
+                    "You need to pass either a couchbase client or connection_string and credentials must be provided."
+                )
+            else:
+                auth = PasswordAuthenticator(
+                    db_username,
+                    db_password,
+                )
+
+                self._client: Cluster = Cluster(connection_string, ClusterOptions(auth))
+        else:
+            self._client = client
+
+    def lazy_load_data(
+        self,
+        query: str,
+        text_fields: Optional[List[str]] = None,
+        metadata_fields: Optional[List[str]] = [],
+    ) -> Iterable[Document]:
+        """Load data from the Couchbase cluster lazily.
+
+        Args:
+            query (str): The SQL++ query to execute.
+            text_fields (Optional[List[str]]): The columns to write into the
+                `text` field of the document. By default, all columns are
+                written.
+            metadata_fields (Optional[List[str]]): The columns to write into the
+                `metadata` field of the document. By default, no columns are written.
+        """
+        from datetime import timedelta
+
+        if not query:
+            raise ValueError("Query must be provided.")
+
+        # Ensure connection to Couchbase cluster
+        self._client.wait_until_ready(timedelta(seconds=5))
+
+        # Run SQL++ Query
+        result = self._client.query(query)
+        for row in result:
+            if not text_fields:
+                text_fields = list(row.keys())
+
+            metadata = {field: row[field] for field in metadata_fields}
+
+            document = "\n".join(
+                f"{k}: {v}" for k, v in row.items() if k in text_fields
+            )
+
+            yield (Document(text=document, metadata=metadata))
+
+    def load_data(
+        self,
+        query: str,
+        text_fields: Optional[List[str]] = None,
+        metadata_fields: Optional[List[str]] = None,
+    ) -> List[Document]:
+        """Load data from the Couchbase cluster.
+
+        Args:
+            query (str): The SQL++ query to execute.
+            text_fields (Optional[List[str]]): The columns to write into the
+                `text` field of the document. By default, all columns are
+                written.
+            metadata_fields (Optional[List[str]]): The columns to write into the
+                `metadata` field of the document. By default, no columns are written.
+        """
+        return list(self.lazy_load_data(query, text_fields, metadata_fields))

llama_hub/couchbase/requirements.txt

@@ -0,0 +1 @@
+couchbase

llama_hub/library.json

@@ -1223,5 +1223,14 @@
   "XMLReader": {
     "id": "file/xml",
     "author": "mmaatouk"
+  },
+  "CouchbaseReader": {
+    "id": "couchbase",
+    "author": "nithishr",
+    "keywords": [
+      "Couchbase",
+      "Capella",
+      "NoSQL"
+    ]
   }
-}
+}