feat: Provide optional client for ChromadbRM

dspy/retrieve/chromadb_rm.py

@@ -26,9 +26,6 @@
     from chromadb.config import Settings
     from chromadb.utils import embedding_functions
 except ImportError:
-    chromadb = None
-
-if chromadb is None:
     raise ImportError(
         "The chromadb library is required to use ChromadbRM. Install it with `pip install dspy-ai[chromadb]`",
     )
@@ -46,6 +43,7 @@ class ChromadbRM(dspy.Retrieve):
         persist_directory (str): chromadb persist directory
         embedding_function (Optional[EmbeddingFunction[Embeddable]]): Optional function to use to embed documents. Defaults to DefaultEmbeddingFunction.
         k (int, optional): The number of top passages to retrieve. Defaults to 7.
+        client(Optional[chromadb.Client]): Optional chromadb client provided by user, default to None
 
     Returns:
         dspy.Prediction: An object containing the retrieved passages.
@@ -54,12 +52,25 @@ class ChromadbRM(dspy.Retrieve):
         Below is a code snippet that shows how to use this as the default retriever:
         ```python
         llm = dspy.OpenAI(model="gpt-3.5-turbo")
+        # using default chromadb client
         retriever_model = ChromadbRM('collection_name', 'db_path')
         dspy.settings.configure(lm=llm, rm=retriever_model)
         # to test the retriever with "my query"
         retriever_model("my query")
         ```
 
+        Use provided chromadb client
+        ```python
+        import chromadb
+        llm = dspy.OpenAI(model="gpt-3.5-turbo")
+        # say you have a chromadb running on a different port
+        client = chromadb.HttpClient(host='localhost', port=8889)
+        retriever_model = ChromadbRM('collection_name', 'db_path', client=client)
+        dspy.settings.configure(lm=llm, rm=retriever_model)
+        # to test the retriever with "my query"
+        retriever_model("my query")
+        ```
+
         Below is a code snippet that shows how to use this in the forward() function of a module
         ```python
         self.retrieve = ChromadbRM('collection_name', 'db_path', k=num_passages)
@@ -73,9 +84,10 @@ def __init__(
         embedding_function: Optional[
             EmbeddingFunction[Embeddable]
         ] = ef.DefaultEmbeddingFunction(),
+        client: Optional[chromadb.Client] = None,
         k: int = 7,
     ):
-        self._init_chromadb(collection_name, persist_directory)
+        self._init_chromadb(collection_name, persist_directory, client=client)
         self.ef = embedding_function
 
         super().__init__(k=k)
@@ -84,22 +96,26 @@ def _init_chromadb(
         self,
         collection_name: str,
         persist_directory: str,
+        client: Optional[chromadb.Client] = None,
     ) -> chromadb.Collection:
         """Initialize chromadb and return the loaded index.
 
         Args:
             collection_name (str): chromadb collection name
             persist_directory (str): chromadb persist directory
+            client (chromadb.Client): chromadb client provided by user
 
-
-        Returns:
+        Returns: collection per collection_name
         """
 
-        self._chromadb_client = chromadb.Client(
-            Settings(
-                persist_directory=persist_directory,
-                is_persistent=True,
-            ),
+        if client:
+            self._chromadb_client = client
+        else:
+            self._chromadb_client = chromadb.Client(
+                Settings(
+                    persist_directory=persist_directory,
+                    is_persistent=True,
+                ),
         )
         self._chromadb_collection = self._chromadb_client.get_or_create_collection(
             name=collection_name,