fix: jsonwriter should checkpoint by default

This is a fix aimed to enable jsonwriter to checkpoint in accordance
with delta.checkpointInterval.  It changes the default commitbuilder to
set a post_commit_hook so that checkpointing will be done by default.
Potentially we could also expose CommitProperties as an argument to
flush_and_commit, but that would require a change to the function
signature and would be a breaking change.

Signed-off-by: Justin Jossick <[email protected]>

crates/core/src/writer/json.rs

@@ -659,4 +659,53 @@ mod tests {
             assert_eq!(table.version(), 1);
         }
     }
+
+    #[tokio::test]
+    async fn test_json_write_checkpoint() {
+        use crate::operations::create::CreateBuilder;
+        use std::fs;
+
+        let table_dir = tempfile::tempdir().unwrap();
+        let schema = get_delta_schema();
+        let path = table_dir.path().to_str().unwrap().to_string();
+        let config: HashMap<String, Option<String>> = vec![
+            (
+                "delta.checkpointInterval".to_string(),
+                Some("5".to_string()),
+            ),
+            ("delta.checkpointPolicy".to_string(), Some("v2".to_string())),
+        ]
+        .into_iter()
+        .collect();
+        let mut table = CreateBuilder::new()
+            .with_location(&path)
+            .with_table_name("test-table")
+            .with_comment("A table for running tests")
+            .with_columns(schema.fields().cloned())
+            .with_configuration(config)
+            .await
+            .unwrap();
+        assert_eq!(table.version(), 0);
+        let mut writer = JsonWriter::for_table(&table).unwrap();
+        let data = serde_json::json!(
+            {
+                "id" : "A",
+                "value": 42,
+                "modified": "2021-02-01"
+            }
+        );
+        for _ in 1..6 {
+            writer.write(vec![data.clone()]).await.unwrap();
+            writer.flush_and_commit(&mut table).await.unwrap();
+        }
+        let dir_path = path + "/_delta_log";
+
+        let target_file = "00000000000000000004.checkpoint.parquet";
+        let entries: Vec<_> = fs::read_dir(dir_path)
+            .unwrap()
+            .filter_map(|entry| entry.ok())
+            .filter(|entry| entry.file_name().into_string().unwrap() == target_file)
+            .collect();
+        assert_eq!(entries.len(), 1);
+    }
 }

crates/core/src/writer/mod.rs

@@ -8,7 +8,7 @@ use serde_json::Value;
 
 use crate::errors::DeltaTableError;
 use crate::kernel::{Action, Add};
-use crate::operations::transaction::CommitBuilder;
+use crate::operations::transaction::{CommitBuilder, CommitProperties};
 use crate::protocol::{ColumnCountStat, DeltaOperation, SaveMode};
 use crate::DeltaTable;
 
@@ -174,7 +174,7 @@ pub(crate) async fn flush_and_commit(
         predicate: None,
     };
 
-    let version = CommitBuilder::default()
+    let version = CommitBuilder::from(CommitProperties::default())
         .with_actions(adds)
         .build(Some(snapshot), table.log_store.clone(), operation)
         .await?