Custom / Dynamic table provider factories

.github/workflows/rust.yml

@@ -280,7 +280,9 @@ jobs:
           rustup default stable
           rustup component add rustfmt
       - name: Run
-        run: ci/scripts/rust_fmt.sh
+        run: |
+          echo '' > datafusion/proto/src/generated/datafusion.rs
+          ci/scripts/rust_fmt.sh
 
   coverage:
     name: coverage

datafusion/core/Cargo.toml

@@ -93,6 +93,7 @@ url = "2.2"
 uuid = { version = "1.0", features = ["v4"] }
 
 [dev-dependencies]
+async-trait = "0.1.53"
 criterion = "0.3"
 csv = "1.1.6"
 ctor = "0.1.22"

datafusion/core/src/datasource/datasource.rs

@@ -72,3 +72,12 @@ pub trait TableProvider: Sync + Send {
         Ok(TableProviderFilterPushDown::Unsupported)
     }
 }
+
+/// A factory which creates [`TableProvider`]s at runtime given a URL.
+///
+/// For example, this can be used to create a table "on the fly"
+/// from a directory of files only when that name is referenced.  
+pub trait TableProviderFactory: Sync + Send {
+    /// Create a TableProvider given name and url
+    fn create(&self, name: &str, url: &str) -> Arc<dyn TableProvider>;
+}

datafusion/core/src/execution/context.rs

@@ -68,7 +68,7 @@ use crate::datasource::TableProvider;
 use crate::error::{DataFusionError, Result};
 use crate::logical_plan::{
     provider_as_source, CreateCatalog, CreateCatalogSchema, CreateExternalTable,
-    CreateMemoryTable, CreateView, DropTable, FileType, FunctionRegistry, LogicalPlan,
+    CreateMemoryTable, CreateView, DropTable, FunctionRegistry, LogicalPlan,
     LogicalPlanBuilder, UNNAMED_TABLE,
 };
 use crate::optimizer::common_subexpr_eliminate::CommonSubexprEliminate;
@@ -90,6 +90,7 @@ use crate::config::{
     ConfigOptions, OPT_BATCH_SIZE, OPT_COALESCE_BATCHES, OPT_COALESCE_TARGET_BATCH_SIZE,
     OPT_FILTER_NULL_JOIN_KEYS, OPT_OPTIMIZER_SKIP_FAILED_RULES,
 };
+use crate::datasource::datasource::TableProviderFactory;
 use crate::execution::runtime_env::RuntimeEnv;
 use crate::logical_plan::plan::Explain;
 use crate::physical_plan::file_format::{plan_to_csv, plan_to_json, plan_to_parquet};
@@ -175,6 +176,8 @@ pub struct SessionContext {
     pub session_start_time: DateTime<Utc>,
     /// Shared session state for the session
     pub state: Arc<RwLock<SessionState>>,
+    /// Dynamic table providers
+    pub table_factories: HashMap<String, Arc<dyn TableProviderFactory>>,
 }
 
 impl Default for SessionContext {
@@ -202,6 +205,7 @@ impl SessionContext {
             session_id: state.session_id.clone(),
             session_start_time: chrono::Utc::now(),
             state: Arc::new(RwLock::new(state)),
+            table_factories: HashMap::default(),
         }
     }
 
@@ -211,9 +215,19 @@ impl SessionContext {
             session_id: state.session_id.clone(),
             session_start_time: chrono::Utc::now(),
             state: Arc::new(RwLock::new(state)),
+            table_factories: HashMap::default(),
         }
     }
 
+    /// Register a `TableProviderFactory` for a given `file_type` identifier
+    pub fn register_table_factory(
+        &mut self,
+        file_type: &str,
+        factory: Arc<dyn TableProviderFactory>,
+    ) {
+        self.table_factories.insert(file_type.to_string(), factory);
+    }
+
     /// Return the [RuntimeEnv] used to run queries with this [SessionContext]
     pub fn runtime_env(&self) -> Arc<RuntimeEnv> {
         self.state.read().runtime_env.clone()
@@ -236,70 +250,12 @@ impl SessionContext {
     pub async fn sql(&self, sql: &str) -> Result<Arc<DataFrame>> {
         let plan = self.create_logical_plan(sql)?;
         match plan {
-            LogicalPlan::CreateExternalTable(CreateExternalTable {
-                ref schema,
-                ref name,
-                ref location,
-                ref file_type,
-                ref has_header,
-                ref delimiter,
-                ref table_partition_cols,
-                ref if_not_exists,
-            }) => {
-                let (file_format, file_extension) = match file_type {
-                    FileType::CSV => (
-                        Arc::new(
-                            CsvFormat::default()
-                                .with_has_header(*has_header)
-                                .with_delimiter(*delimiter as u8),
-                        ) as Arc<dyn FileFormat>,
-                        DEFAULT_CSV_EXTENSION,
-                    ),
-                    FileType::Parquet => (
-                        Arc::new(ParquetFormat::default()) as Arc<dyn FileFormat>,
-                        DEFAULT_PARQUET_EXTENSION,
-                    ),
-                    FileType::Avro => (
-                        Arc::new(AvroFormat::default()) as Arc<dyn FileFormat>,
-                        DEFAULT_AVRO_EXTENSION,
-                    ),
-                    FileType::NdJson => (
-                        Arc::new(JsonFormat::default()) as Arc<dyn FileFormat>,
-                        DEFAULT_JSON_EXTENSION,
-                    ),
-                };
-                let table = self.table(name.as_str());
-                match (if_not_exists, table) {
-                    (true, Ok(_)) => self.return_empty_dataframe(),
-                    (_, Err(_)) => {
-                        // TODO make schema in CreateExternalTable optional instead of empty
-                        let provided_schema = if schema.fields().is_empty() {
-                            None
-                        } else {
-                            Some(Arc::new(schema.as_ref().to_owned().into()))
-                        };
-                        let options = ListingOptions {
-                            format: file_format,
-                            collect_stat: false,
-                            file_extension: file_extension.to_owned(),
-                            target_partitions: self.copied_config().target_partitions,
-                            table_partition_cols: table_partition_cols.clone(),
-                        };
-                        self.register_listing_table(
-                            name,
-                            location,
-                            options,
-                            provided_schema,
-                        )
-                        .await?;
-                        self.return_empty_dataframe()
-                    }
-                    (false, Ok(_)) => Err(DataFusionError::Execution(format!(
-                        "Table '{:?}' already exists",
-                        name
-                    ))),
+            LogicalPlan::CreateExternalTable(cmd) => match cmd.file_type.as_str() {
+                "PARQUET" | "CSV" | "JSON" | "AVRO" => {
+                    self.create_listing_table(&cmd).await
                 }
-            }
+                _ => self.create_custom_table(&cmd).await,
+            },
 
             LogicalPlan::CreateMemoryTable(CreateMemoryTable {
                 name,
@@ -480,6 +436,84 @@ impl SessionContext {
         Ok(Arc::new(DataFrame::new(self.state.clone(), &plan)))
     }
 
+    async fn create_custom_table(
+        &self,
+        cmd: &CreateExternalTable,
+    ) -> Result<Arc<DataFrame>> {
+        let factory = &self.table_factories.get(&cmd.file_type).ok_or_else(|| {
+            DataFusionError::Execution(format!(
+                "Unable to find factory for {}",
+                cmd.file_type
+            ))
+        })?;
+        let table = (*factory).create(cmd.name.as_str(), cmd.location.as_str());
+        self.register_table(cmd.name.as_str(), table)?;
+        let plan = LogicalPlanBuilder::empty(false).build()?;
+        Ok(Arc::new(DataFrame::new(self.state.clone(), &plan)))
+    }
+
+    async fn create_listing_table(
+        &self,
+        cmd: &CreateExternalTable,
+    ) -> Result<Arc<DataFrame>> {
+        let (file_format, file_extension) = match cmd.file_type.as_str() {
+            "CSV" => (
+                Arc::new(
+                    CsvFormat::default()
+                        .with_has_header(cmd.has_header)
+                        .with_delimiter(cmd.delimiter as u8),
+                ) as Arc<dyn FileFormat>,
+                DEFAULT_CSV_EXTENSION,
+            ),
+            "PARQUET" => (
+                Arc::new(ParquetFormat::default()) as Arc<dyn FileFormat>,
+                DEFAULT_PARQUET_EXTENSION,
+            ),
+            "AVRO" => (
+                Arc::new(AvroFormat::default()) as Arc<dyn FileFormat>,
+                DEFAULT_AVRO_EXTENSION,
+            ),
+            "JSON" => (
+                Arc::new(JsonFormat::default()) as Arc<dyn FileFormat>,
+                DEFAULT_JSON_EXTENSION,
+            ),
+            _ => Err(DataFusionError::Execution(
+                "Only known FileTypes can be ListingTables!".to_string(),
+            ))?,
+        };
+        let table = self.table(cmd.name.as_str());
+        match (cmd.if_not_exists, table) {
+            (true, Ok(_)) => self.return_empty_dataframe(),
+            (_, Err(_)) => {
+                // TODO make schema in CreateExternalTable optional instead of empty
+                let provided_schema = if cmd.schema.fields().is_empty() {
+                    None
+                } else {
+                    Some(Arc::new(cmd.schema.as_ref().to_owned().into()))
+                };
+                let options = ListingOptions {
+                    format: file_format,
+                    collect_stat: false,
+                    file_extension: file_extension.to_owned(),
+                    target_partitions: self.copied_config().target_partitions,
+                    table_partition_cols: cmd.table_partition_cols.clone(),
+                };
+                self.register_listing_table(
+                    cmd.name.as_str(),
+                    cmd.location.clone(),
+                    options,
+                    provided_schema,
+                )
+                .await?;
+                self.return_empty_dataframe()
+            }
+            (false, Ok(_)) => Err(DataFusionError::Execution(format!(
+                "Table '{:?}' already exists",
+                cmd.name
+            ))),
+        }
+    }
+
     fn find_and_deregister<'a>(
         &self,
         table_ref: impl Into<TableReference<'a>>,

datafusion/core/src/logical_plan/mod.rs

@@ -45,10 +45,9 @@ pub use datafusion_expr::{
             build_join_schema, union_with_alias, LogicalPlanBuilder, UNNAMED_TABLE,
         },
         CreateCatalog, CreateCatalogSchema, CreateExternalTable, CreateMemoryTable,
-        CreateView, CrossJoin, DropTable, EmptyRelation, FileType, JoinConstraint,
-        JoinType, Limit, LogicalPlan, Partitioning, PlanType, PlanVisitor, Repartition,
-        StringifiedPlan, Subquery, TableScan, ToStringifiedPlan, Union,
-        UserDefinedLogicalNode, Values,
+        CreateView, CrossJoin, DropTable, EmptyRelation, JoinConstraint, JoinType, Limit,
+        LogicalPlan, Partitioning, PlanType, PlanVisitor, Repartition, StringifiedPlan,
+        Subquery, TableScan, ToStringifiedPlan, Union, UserDefinedLogicalNode, Values,
     },
     lower, lpad, ltrim, max, md5, min, not_exists, not_in_subquery, now, nullif,
     octet_length, or, power, random, regexp_match, regexp_replace, repeat, replace,

datafusion/core/src/logical_plan/plan.rs

@@ -23,8 +23,8 @@ pub use datafusion_expr::{
         display::{GraphvizVisitor, IndentVisitor},
         Aggregate, Analyze, CreateCatalog, CreateCatalogSchema, CreateExternalTable,
         CreateMemoryTable, CreateView, CrossJoin, Distinct, DropTable, EmptyRelation,
-        Explain, Extension, FileType, Filter, Join, JoinConstraint, JoinType, Limit,
-        LogicalPlan, Partitioning, PlanType, PlanVisitor, Projection, Repartition, Sort,
+        Explain, Extension, Filter, Join, JoinConstraint, JoinType, Limit, LogicalPlan,
+        Partitioning, PlanType, PlanVisitor, Projection, Repartition, Sort,
         StringifiedPlan, Subquery, SubqueryAlias, TableScan, ToStringifiedPlan, Union,
         UserDefinedLogicalNode, Values, Window,
     },

datafusion/core/tests/sql/create_drop.rs

@@ -15,8 +15,13 @@
 // specific language governing permissions and limitations
 // under the License.
 
+use async_trait::async_trait;
+use std::any::Any;
 use std::io::Write;
 
+use datafusion::datasource::datasource::TableProviderFactory;
+use datafusion::execution::context::SessionState;
+use datafusion_expr::TableType;
 use tempfile::TempDir;
 
 use super::*;
@@ -360,6 +365,76 @@ async fn create_pipe_delimited_csv_table() -> Result<()> {
     Ok(())
 }
 
+struct TestTableProvider {}
+
+impl TestTableProvider {}
+
+#[async_trait]
+impl TableProvider for TestTableProvider {
+    fn as_any(&self) -> &dyn Any {
+        unimplemented!("TestTableProvider is a stub for testing.")
+    }
+
+    fn schema(&self) -> SchemaRef {
+        unimplemented!("TestTableProvider is a stub for testing.")
+    }
+
+    fn table_type(&self) -> TableType {
+        unimplemented!("TestTableProvider is a stub for testing.")
+    }
+
+    async fn scan(
+        &self,
+        _ctx: &SessionState,
+        _projection: &Option<Vec<usize>>,
+        _filters: &[Expr],
+        _limit: Option<usize>,
+    ) -> Result<Arc<dyn ExecutionPlan>> {
+        unimplemented!("TestTableProvider is a stub for testing.")
+    }
+}
+
+struct TestTableFactory {}
+
+impl TableProviderFactory for TestTableFactory {
+    fn create(&self, _name: &str, _path: &str) -> Arc<dyn TableProvider> {
+        Arc::new(TestTableProvider {})
+    }
+}
+
+#[tokio::test]
+async fn create_custom_table() -> Result<()> {
+    let mut ctx = SessionContext::new();
+    ctx.register_table_factory("DELTATABLE", Arc::new(TestTableFactory {}));
+
+    let sql = "CREATE EXTERNAL TABLE dt STORED AS DELTATABLE LOCATION 's3://bucket/schema/table';";
+    ctx.sql(sql).await.unwrap();
+
+    let cat = ctx.catalog("datafusion").unwrap();
+    let schema = cat.schema("public").unwrap();
+    let exists = schema.table_exist("dt");
+    assert!(exists, "Table should have been created!");
+
+    Ok(())
+}
+
+#[tokio::test]
+async fn create_bad_custom_table() {
+    let ctx = SessionContext::new();
+
+    let sql = "CREATE EXTERNAL TABLE dt STORED AS DELTATABLE LOCATION 's3://bucket/schema/table';";
+    let res = ctx.sql(sql).await;
+    match res {
+        Ok(_) => panic!("Registration of tables without factories should fail"),
+        Err(e) => {
+            assert!(
+                e.to_string().contains("Unable to find factory for"),
+                "Registration of tables without factories should throw correct error"
+            )
+        }
+    }
+}
+
 #[tokio::test]
 async fn create_csv_table_empty_file() -> Result<()> {
     let ctx =

datafusion/core/tests/sql/timestamp.rs

@@ -1398,6 +1398,7 @@ async fn timestamp_sub_interval_days() -> Result<()> {
 }
 
 #[tokio::test]
+#[ignore] // https://github.com/apache/arrow-datafusion/issues/3327
 async fn timestamp_add_interval_months() -> Result<()> {
     let ctx = SessionContext::new();
 

datafusion/expr/src/logical_plan/mod.rs

@@ -24,9 +24,9 @@ pub use builder::{table_scan, LogicalPlanBuilder};
 pub use plan::{
     Aggregate, Analyze, CreateCatalog, CreateCatalogSchema, CreateExternalTable,
     CreateMemoryTable, CreateView, CrossJoin, Distinct, DropTable, DropView,
-    EmptyRelation, Explain, Extension, FileType, Filter, Join, JoinConstraint, JoinType,
-    Limit, LogicalPlan, Partitioning, PlanType, PlanVisitor, Projection, Repartition,
-    Sort, StringifiedPlan, Subquery, SubqueryAlias, TableScan, ToStringifiedPlan, Union,
+    EmptyRelation, Explain, Extension, Filter, Join, JoinConstraint, JoinType, Limit,
+    LogicalPlan, Partitioning, PlanType, PlanVisitor, Projection, Repartition, Sort,
+    StringifiedPlan, Subquery, SubqueryAlias, TableScan, ToStringifiedPlan, Union,
     Values, Window,
 };