expose update_incremental API to python binding (#332)

README.adoc

@@ -43,7 +43,7 @@ link:https://github.com/rajasekarv/vega[vega], etc. It also provides bindings to
 
 | Stream table update
 | :heavy_check_mark: 
-|
+| :heavy_check_mark: 
 |
 
 | Filter files with partitions

python/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "deltalake-python"
-version = "0.5.1"
+version = "0.5.2"
 authors = ["Qingping Hou <[email protected]>"]
 homepage = "https://github.com/delta-io/delta-rs"
 license = "Apache-2.0"
@@ -45,7 +45,7 @@ requires-dist = [
     'numpy<1.20.0;python_version<="3.6"',
     'dataclasses;python_version<="3.6"',
     'types-dataclasses;python_version<="3.6" and extra == "pandas"',
-    "pandas; extra == 'pandas'",
+    "pandas; extra == 'pandas' or extra == 'devel'",
     "mypy; extra == 'devel'",
     "isort; extra == 'devel'",
     "pytest; extra == 'devel'",

python/deltalake/table.py

@@ -269,3 +269,10 @@ def to_pandas(
         :return: a pandas dataframe
         """
         return self.to_pyarrow_table(partitions, columns).to_pandas()
+
+    def update_incremental(self) -> None:
+        """
+        Updates the DeltaTable to the latest version by incrementally applying
+        newer versions.
+        """
+        self._table.update_incremental()

python/src/lib.rs

@@ -165,6 +165,12 @@ impl RawDeltaTable {
         )
         .map_err(|_| PyDeltaTableError::new_err("Got invalid table schema"))
     }
+
+    pub fn update_incremental(&mut self) -> PyResult<()> {
+        rt()?
+            .block_on(self._table.update_incremental())
+            .map_err(PyDeltaTableError::from_raw)
+    }
 }
 
 #[pyfunction]

python/tests/test_table_read.py

@@ -18,6 +18,14 @@ def test_read_simple_table_by_version_to_dict():
     assert dt.to_pyarrow_dataset().to_table().to_pydict() == {"value": [1, 2, 3]}
 
 
+def test_read_simple_table_update_incremental():
+    table_path = "../rust/tests/data/simple_table"
+    dt = DeltaTable(table_path, version=0)
+    assert dt.to_pyarrow_dataset().to_table().to_pydict() == {"id": [0, 1, 2, 3, 4]}
+    dt.update_incremental()
+    assert dt.to_pyarrow_dataset().to_table().to_pydict() == {"id": [5, 7, 9]}
+
+
 def test_read_partitioned_table_to_dict():
     table_path = "../rust/tests/data/delta-0.8.0-partitioned"
     dt = DeltaTable(table_path)

rust/src/delta.rs

@@ -631,8 +631,7 @@ impl DeltaTable {
         Ok(())
     }
 
-    /// Updates the DeltaTable to the most recent state committed to the transaction by
-    /// incrementally applying each version since current.
+    /// Updates the DeltaTable to the latest version by incrementally applying newer versions.
     pub async fn update_incremental(&mut self) -> Result<(), DeltaTableError> {
         self.version += 1;
         self.apply_logs_from_current_version().await