feat: add list_indices to the async api (#1074)

python/python/lancedb/_lancedb.pyi

@@ -1,4 +1,4 @@
-from typing import Dict, Optional
+from typing import Dict, List, Optional
 
 import pyarrow as pa
 
@@ -39,6 +39,11 @@ class Table:
     async def checkout(self, version): ...
     async def checkout_latest(self): ...
     async def restore(self): ...
+    async def list_indices(self) -> List[IndexConfig]: ...
+
+class IndexConfig:
+    index_type: str
+    columns: List[str]
 
 async def connect(
     uri: str,

python/python/lancedb/index.py

@@ -3,6 +3,9 @@ from typing import Optional
 from ._lancedb import (
     Index as LanceDbIndex,
 )
+from ._lancedb import (
+    IndexConfig,
+)
 
 
 class BTree(object):
@@ -155,3 +158,6 @@ class IvfPq(object):
             max_iterations=max_iterations,
             sample_rate=sample_rate,
         )
+
+
+__all__ = ["BTree", "IvfPq", "IndexConfig"]

python/python/lancedb/table.py

@@ -59,7 +59,7 @@ if TYPE_CHECKING:
 
     from ._lancedb import Table as LanceDBTable
     from .db import LanceDBConnection
-    from .index import BTree, IvfPq
+    from .index import BTree, IndexConfig, IvfPq
 
 
 pd = safe_import_pandas()
@@ -2409,3 +2409,9 @@ class AsyncTable:
         out state and the read_consistency_interval, if any, will apply.
         """
         await self._inner.restore()
+
+    async def list_indices(self) -> IndexConfig:
+        """
+        List all indices that have been created with Self::create_index
+        """
+        return await self._inner.list_indices()

python/python/tests/test_index.py

@@ -41,6 +41,10 @@ async def test_create_scalar_index(some_table: AsyncTable):
     await some_table.create_index("id")
     # Can recreate if replace=True
     await some_table.create_index("id", replace=True)
+    indices = await some_table.list_indices()
+    assert len(indices) == 1
+    assert indices[0].index_type == "BTree"
+    assert indices[0].columns == ["id"]
     # Can't recreate if replace=False
     with pytest.raises(RuntimeError, match="already exists"):
         await some_table.create_index("id", replace=False)
@@ -59,3 +63,7 @@ async def test_create_vector_index(some_table: AsyncTable):
         await some_table.create_index("vector", replace=False)
     # Can also specify index type
     await some_table.create_index("vector", config=IvfPq(num_partitions=100))
+    indices = await some_table.list_indices()
+    assert len(indices) == 1
+    assert indices[0].index_type == "IvfPq"
+    assert indices[0].columns == ["vector"]

python/src/index.rs

@@ -85,3 +85,25 @@ impl Index {
         })
     }
 }
+
+#[pyclass(get_all)]
+/// A description of an index currently configured on a column
+pub struct IndexConfig {
+    /// The type of the index
+    pub index_type: String,
+    /// The columns in the index
+    ///
+    /// Currently this is always a list of size 1.  In the future there may
+    /// be more columns to represent composite indices.
+    pub columns: Vec<String>,
+}
+
+impl From<lancedb::index::IndexConfig> for IndexConfig {
+    fn from(value: lancedb::index::IndexConfig) -> Self {
+        let index_type = format!("{:?}", value.index_type);
+        Self {
+            index_type,
+            columns: value.columns,
+        }
+    }
+}

python/src/lib.rs

@@ -14,7 +14,7 @@
 
 use connection::{connect, Connection};
 use env_logger::Env;
-use index::Index;
+use index::{Index, IndexConfig};
 use pyo3::{pymodule, types::PyModule, wrap_pyfunction, PyResult, Python};
 use table::Table;
 
@@ -33,6 +33,7 @@ pub fn _lancedb(_py: Python, m: &PyModule) -> PyResult<()> {
     m.add_class::<Connection>()?;
     m.add_class::<Table>()?;
     m.add_class::<Index>()?;
+    m.add_class::<IndexConfig>()?;
     m.add_function(wrap_pyfunction!(connect, m)?)?;
     m.add("__version__", env!("CARGO_PKG_VERSION"))?;
     Ok(())

python/src/table.rs

@@ -11,7 +11,10 @@ use pyo3::{
 };
 use pyo3_asyncio::tokio::future_into_py;
 
-use crate::{error::PythonErrorExt, index::Index};
+use crate::{
+    error::PythonErrorExt,
+    index::{Index, IndexConfig},
+};
 
 #[pyclass]
 pub struct Table {
@@ -127,6 +130,19 @@ impl Table {
         })
     }
 
+    pub fn list_indices(self_: PyRef<'_, Self>) -> PyResult<&PyAny> {
+        let inner = self_.inner_ref()?.clone();
+        future_into_py(self_.py(), async move {
+            Ok(inner
+                .list_indices()
+                .await
+                .infer_error()?
+                .into_iter()
+                .map(IndexConfig::from)
+                .collect::<Vec<_>>())
+        })
+    }
+
     pub fn __repr__(&self) -> String {
         match &self.inner {
             None => format!("ClosedTable({})", self.name),