WIP

libs/knowledge-store/ragstack_knowledge_store/graph_store.py

@@ -367,6 +367,7 @@ def mmr_traversal_search(
         lambda_mult: float = 0.5,
         score_threshold: float = float("-inf"),
         metadata_filter: dict[str, Any] = {},  # noqa: B006
+        tag_filter: set[tuple[str, str]],
     ) -> Iterable[Node]:
         """Retrieve documents from this graph store using MMR-traversal.
 
@@ -398,6 +399,7 @@ def mmr_traversal_search(
             score_threshold: Only documents with a score greater than or equal
                 this threshold will be chosen. Defaults to -infinity.
             metadata_filter: Optional metadata to filter the results.
+            tag_filter: Optional tags to filter graph edges to be traversed.
         """
         query_embedding = self._embedding.embed_query(query)
         helper = MmrHelper(
@@ -444,9 +446,14 @@ def fetch_neighborhood(neighborhood: Sequence[str]) -> None:
             new_candidates = {}
             for adjacent in adjacents:
                 if adjacent.target_content_id not in outgoing_tags:
-                    outgoing_tags[adjacent.target_content_id] = (
-                        adjacent.target_link_to_tags
-                    )
+                    if tag_filter.len() == 0:
+                        outgoing_tags[adjacent.target_content_id] = (
+                            adjacent.target_link_to_tags
+                        )
+                    else:
+                        outgoing_tags[adjacent.target_content_id] = (
+                            tag_filter.intersection(adjacent.target_link_to_tags)
+                        )
 
                     new_candidates[adjacent.target_content_id] = (
                         adjacent.target_text_embedding
@@ -474,7 +481,10 @@ def fetch_initial_candidates() -> None:
             for row in fetched:
                 if row.content_id not in outgoing_tags:
                     candidates[row.content_id] = row.text_embedding
-                    outgoing_tags[row.content_id] = set(row.link_to_tags or [])
+                    if tag_filter.len() == 0:
+                        outgoing_tags[row.content_id] = set(row.link_to_tags or [])
+                    else:
+                        outgoing_tags[row.content_id] = tag_filter.intersection(set(row.link_to_tags or []))
             helper.add_candidates(candidates)
 
         if initial_roots:
@@ -522,9 +532,14 @@ def fetch_initial_candidates() -> None:
                 new_candidates = {}
                 for adjacent in adjacents:
                     if adjacent.target_content_id not in outgoing_tags:
-                        outgoing_tags[adjacent.target_content_id] = (
-                            adjacent.target_link_to_tags
-                        )
+                        if tag_filter.len() == 0:
+                            outgoing_tags[adjacent.target_content_id] = (
+                                adjacent.target_link_to_tags
+                            )
+                        else:
+                            outgoing_tags[adjacent.target_content_id] = (
+                                tag_filter.intersection(adjacent.target_link_to_tags)
+                            )
                         new_candidates[adjacent.target_content_id] = (
                             adjacent.target_text_embedding
                         )

libs/knowledge-store/tests/integration_tests/test_graph_store.py

@@ -211,6 +211,12 @@ def test_mmr_traversal(
     results = gs.mmr_traversal_search("0.0", fetch_k=2, k=4, initial_roots=["v0"])
     assert _result_ids(results) == ["v1", "v3", "v2"]
 
+    results = gs.mmr_traversal_search("0.0", k=2, fetch_k=2, tag_filter=set(("explicit", "link")))
+    assert _result_ids(results) == ["v0", "v2"]
+
+    results = gs.mmr_traversal_search("0.0", k=2, fetch_k=2, tag_filter=set(("no", "match")))
+    assert _result_ids(results) == []
+
 
 def test_write_retrieve_keywords(
     graph_store_factory: Callable[[MetadataIndexingType], GraphStore],