feat(python): expose FSCK (repair) operation (#1730)

# Description
This PR exposes the FSCK operation as a `repair` method under the
`DeltaTable `class.

# Related Issue(s)
<!---
For example:

- closes #106
--->
- closes #1727

---------

Co-authored-by: Will Jones <willjones127@gmail.com>

python/deltalake/_internal.pyi

@@ -88,6 +88,7 @@ class RawDeltaTable:
     def create_checkpoint(self) -> None: ...
     def get_add_actions(self, flatten: bool) -> pyarrow.RecordBatch: ...
     def delete(self, predicate: Optional[str]) -> str: ...
+    def repair(self, dry_run: bool) -> str: ...
     def update(
         self,
         updates: Dict[str, str],

python/deltalake/table.py

@@ -826,6 +826,31 @@ def delete(self, predicate: Optional[str] = None) -> Dict[str, Any]:
         metrics = self._table.delete(predicate)
         return json.loads(metrics)
 
+    def repair(self, dry_run: bool = False) -> Dict[str, Any]:
+        """Repair the Delta Table by auditing active files that do not exist in the underlying
+        filesystem and removes them. This can be useful when there are accidental deletions or corrupted files.
+
+        Active files are ones that have an add action in the log, but no corresponding remove action.
+        This operation creates a new FSCK transaction containing a remove action for each of the missing
+        or corrupted files.
+
+        Args:
+            dry_run(bool): when activated, list only the files, otherwise add remove actions to transaction log. Defaults to False.
+        Returns:
+            The metrics from repair (FSCK) action.
+
+        Examples:
+
+        >>> from deltalake import DeltaTable
+        >>> dt = DeltaTable('TEST')
+        >>> dt.repair(dry_run=False)
+        {'dry_run': False,
+        'files_removed': ['6-0d084325-6885-4847-b008-82c1cf30674c-0.parquet',
+        '5-4fba1d3e-3e20-4de1-933d-a8e13ac59f53-0.parquet']}
+        """
+        metrics = self._table.repair(dry_run)
+        return json.loads(metrics)
+
 
 class TableMerger:
     """API for various table MERGE commands."""

python/src/lib.rs

@@ -26,6 +26,7 @@ use deltalake::datafusion::prelude::SessionContext;
 use deltalake::delta_datafusion::DeltaDataChecker;
 use deltalake::errors::DeltaTableError;
 use deltalake::operations::delete::DeleteBuilder;
+use deltalake::operations::filesystem_check::FileSystemCheckBuilder;
 use deltalake::operations::merge::MergeBuilder;
 use deltalake::operations::optimize::{OptimizeBuilder, OptimizeType};
 use deltalake::operations::restore::RestoreBuilder;
@@ -853,6 +854,21 @@ impl RawDeltaTable {
         self._table.state = table.state;
         Ok(serde_json::to_string(&metrics).unwrap())
     }
+
+    /// Execute the File System Check command (FSCK) on the delta table: removes old reference to files that
+    /// have been deleted or are malformed
+    #[pyo3(signature = (dry_run = true))]
+    pub fn repair(&mut self, dry_run: bool) -> PyResult<String> {
+        let cmd =
+            FileSystemCheckBuilder::new(self._table.object_store(), self._table.state.clone())
+                .with_dry_run(dry_run);
+
+        let (table, metrics) = rt()?
+            .block_on(cmd.into_future())
+            .map_err(PythonError::from)?;
+        self._table.state = table.state;
+        Ok(serde_json::to_string(&metrics).unwrap())
+    }
 }
 
 fn convert_partition_filters<'a>(

python/tests/test_repair.py

@@ -0,0 +1,31 @@
+import os
+
+from deltalake import DeltaTable, write_deltalake
+
+
+def test_repair_with_dry_run(tmp_path, sample_data):
+    write_deltalake(tmp_path, sample_data, mode="append")
+    write_deltalake(tmp_path, sample_data, mode="append")
+    dt = DeltaTable(tmp_path)
+    os.remove(dt.file_uris()[0])
+
+    metrics = dt.repair(dry_run=True)
+    last_action = dt.history(1)[0]
+
+    assert len(metrics["files_removed"]) == 1
+    assert metrics["dry_run"] is True
+    assert last_action["operation"] == "WRITE"
+
+
+def test_repair_wo_dry_run(tmp_path, sample_data):
+    write_deltalake(tmp_path, sample_data, mode="append")
+    write_deltalake(tmp_path, sample_data, mode="append")
+    dt = DeltaTable(tmp_path)
+    os.remove(dt.file_uris()[0])
+
+    metrics = dt.repair(dry_run=False)
+    last_action = dt.history(1)[0]
+
+    assert len(metrics["files_removed"]) == 1
+    assert metrics["dry_run"] is False
+    assert last_action["operation"] == "FSCK"

rust/src/operations/filesystem_check.rs

@@ -22,6 +22,7 @@ use futures::future::BoxFuture;
 use futures::StreamExt;
 pub use object_store::path::Path;
 use object_store::ObjectStore;
+use serde::Serialize;
 use url::{ParseError, Url};
 
 use crate::errors::{DeltaResult, DeltaTableError};
@@ -44,7 +45,7 @@ pub struct FileSystemCheckBuilder {
 }
 
 /// Details of the FSCK operation including which files were removed from the log
-#[derive(Debug)]
+#[derive(Debug, Serialize)]
 pub struct FileSystemCheckMetrics {
     /// Was this a dry run
     pub dry_run: bool,