Add FileScanConfig::new() API

datafusion-examples/examples/csv_opener.rs

@@ -17,7 +17,6 @@
 
 use std::{sync::Arc, vec};
 
-use datafusion::common::Statistics;
 use datafusion::{
     assert_batches_eq,
     datasource::{
@@ -58,16 +57,11 @@ async fn main() -> Result<()> {
 
     let path = std::path::Path::new(&path).canonicalize()?;
 
-    let scan_config = FileScanConfig {
-        object_store_url: ObjectStoreUrl::local_filesystem(),
-        file_schema: schema.clone(),
-        file_groups: vec![vec![PartitionedFile::new(path.display().to_string(), 10)]],
-        statistics: Statistics::new_unknown(&schema),
-        projection: Some(vec![12, 0]),
-        limit: Some(5),
-        table_partition_cols: vec![],
-        output_ordering: vec![],
-    };
+    let scan_config =
+        FileScanConfig::new(ObjectStoreUrl::local_filesystem(), schema.clone())
+            .with_projection(Some(vec![12, 0]))
+            .with_limit(Some(5))
+            .with_file(PartitionedFile::new(path.display().to_string(), 10));
 
     let result =
         FileStream::new(&scan_config, 0, opener, &ExecutionPlanMetricsSet::new())

datafusion-examples/examples/json_opener.rs

@@ -29,7 +29,6 @@ use datafusion::{
     error::Result,
     physical_plan::metrics::ExecutionPlanMetricsSet,
 };
-use datafusion_common::Statistics;
 
 use futures::StreamExt;
 use object_store::ObjectStore;
@@ -61,16 +60,11 @@ async fn main() -> Result<()> {
         Arc::new(object_store),
     );
 
-    let scan_config = FileScanConfig {
-        object_store_url: ObjectStoreUrl::local_filesystem(),
-        file_schema: schema.clone(),
-        file_groups: vec![vec![PartitionedFile::new(path.to_string(), 10)]],
-        statistics: Statistics::new_unknown(&schema),
-        projection: Some(vec![1, 0]),
-        limit: Some(5),
-        table_partition_cols: vec![],
-        output_ordering: vec![],
-    };
+    let scan_config =
+        FileScanConfig::new(ObjectStoreUrl::local_filesystem(), schema.clone())
+            .with_projection(Some(vec![1, 0]))
+            .with_limit(Some(5))
+            .with_file(PartitionedFile::new(path.to_string(), 10));
 
     let result =
         FileStream::new(&scan_config, 0, opener, &ExecutionPlanMetricsSet::new())

datafusion/core/src/datasource/file_format/mod.rs

@@ -154,16 +154,11 @@ pub(crate) mod test_util {
         let exec = format
             .create_physical_plan(
                 state,
-                FileScanConfig {
-                    object_store_url: ObjectStoreUrl::local_filesystem(),
-                    file_schema,
-                    file_groups,
-                    statistics,
-                    projection,
-                    limit,
-                    table_partition_cols: vec![],
-                    output_ordering: vec![],
-                },
+                FileScanConfig::new(ObjectStoreUrl::local_filesystem(), file_schema)
+                    .with_file_groups(file_groups)
+                    .with_statistics(statistics)
+                    .with_projection(projection)
+                    .with_limit(limit),
                 None,
             )
             .await?;

datafusion/core/src/datasource/listing/table.rs

@@ -805,16 +805,13 @@ impl TableProvider for ListingTable {
             .format
             .create_physical_plan(
                 state,
-                FileScanConfig {
-                    object_store_url,
-                    file_schema: Arc::clone(&self.file_schema),
-                    file_groups: partitioned_file_lists,
-                    statistics,
-                    projection: projection.cloned(),
-                    limit,
-                    output_ordering,
-                    table_partition_cols,
-                },
+                FileScanConfig::new(object_store_url, Arc::clone(&self.file_schema))
+                    .with_file_groups(partitioned_file_lists)
+                    .with_statistics(statistics)
+                    .with_projection(projection.cloned())
+                    .with_limit(limit)
+                    .with_output_ordering(output_ordering)
+                    .with_table_partition_cols(table_partition_cols),
                 filters.as_ref(),
             )
             .await

datafusion/core/src/datasource/physical_plan/avro.rs

@@ -271,16 +271,11 @@ mod tests {
             .infer_schema(&state, &store, &[meta.clone()])
             .await?;
 
-        let avro_exec = AvroExec::new(FileScanConfig {
-            object_store_url: ObjectStoreUrl::local_filesystem(),
-            file_groups: vec![vec![meta.into()]],
-            statistics: Statistics::new_unknown(&file_schema),
-            file_schema,
-            projection: Some(vec![0, 1, 2]),
-            limit: None,
-            table_partition_cols: vec![],
-            output_ordering: vec![],
-        });
+        let avro_exec = AvroExec::new(
+            FileScanConfig::new(ObjectStoreUrl::local_filesystem(), file_schema)
+                .with_file(meta.into())
+                .with_projection(Some(vec![0, 1, 2])),
+        );
         assert_eq!(
             avro_exec
                 .properties()
@@ -348,16 +343,11 @@ mod tests {
         // Include the missing column in the projection
         let projection = Some(vec![0, 1, 2, actual_schema.fields().len()]);
 
-        let avro_exec = AvroExec::new(FileScanConfig {
-            object_store_url,
-            file_groups: vec![vec![meta.into()]],
-            statistics: Statistics::new_unknown(&file_schema),
-            file_schema,
-            projection,
-            limit: None,
-            table_partition_cols: vec![],
-            output_ordering: vec![],
-        });
+        let avro_exec = AvroExec::new(
+            FileScanConfig::new(object_store_url, file_schema)
+                .with_file(meta.into())
+                .with_projection(projection),
+        );
         assert_eq!(
             avro_exec
                 .properties()
@@ -422,18 +412,19 @@ mod tests {
         let mut partitioned_file = PartitionedFile::from(meta);
         partitioned_file.partition_values = vec![ScalarValue::from("2021-10-26")];
 
-        let avro_exec = AvroExec::new(FileScanConfig {
-            // select specific columns of the files as well as the partitioning
-            // column which is supposed to be the last column in the table schema.
-            projection: Some(vec![0, 1, file_schema.fields().len(), 2]),
-            object_store_url,
-            file_groups: vec![vec![partitioned_file]],
-            statistics: Statistics::new_unknown(&file_schema),
-            file_schema,
-            limit: None,
-            table_partition_cols: vec![Field::new("date", DataType::Utf8, false)],
-            output_ordering: vec![],
-        });
+        let projection = Some(vec![0, 1, file_schema.fields().len(), 2]);
+        let avro_exec = AvroExec::new(
+            FileScanConfig::new(object_store_url, file_schema)
+                // select specific columns of the files as well as the partitioning
+                // column which is supposed to be the last column in the table schema.
+                .with_projection(projection)
+                .with_file(partitioned_file)
+                .with_table_partition_cols(vec![Field::new(
+                    "date",
+                    DataType::Utf8,
+                    false,
+                )]),
+        );
         assert_eq!(
             avro_exec
                 .properties()

datafusion/core/src/datasource/physical_plan/csv.rs

@@ -561,7 +561,7 @@ mod tests {
             tmp_dir.path(),
         )?;
 
-        let mut config = partitioned_csv_config(file_schema, file_groups)?;
+        let mut config = partitioned_csv_config(file_schema, file_groups);
         config.projection = Some(vec![0, 2, 4]);
 
         let csv = CsvExec::new(
@@ -627,7 +627,7 @@ mod tests {
             tmp_dir.path(),
         )?;
 
-        let mut config = partitioned_csv_config(file_schema, file_groups)?;
+        let mut config = partitioned_csv_config(file_schema, file_groups);
         config.projection = Some(vec![4, 0, 2]);
 
         let csv = CsvExec::new(
@@ -693,7 +693,7 @@ mod tests {
             tmp_dir.path(),
         )?;
 
-        let mut config = partitioned_csv_config(file_schema, file_groups)?;
+        let mut config = partitioned_csv_config(file_schema, file_groups);
         config.limit = Some(5);
 
         let csv = CsvExec::new(
@@ -756,7 +756,7 @@ mod tests {
             tmp_dir.path(),
         )?;
 
-        let mut config = partitioned_csv_config(file_schema, file_groups)?;
+        let mut config = partitioned_csv_config(file_schema, file_groups);
         config.limit = Some(5);
 
         let csv = CsvExec::new(
@@ -809,7 +809,7 @@ mod tests {
             tmp_dir.path(),
         )?;
 
-        let mut config = partitioned_csv_config(file_schema, file_groups)?;
+        let mut config = partitioned_csv_config(file_schema, file_groups);
 
         // Add partition columns
         config.table_partition_cols = vec![Field::new("date", DataType::Utf8, false)];
@@ -914,7 +914,7 @@ mod tests {
         )
         .unwrap();
 
-        let config = partitioned_csv_config(file_schema, file_groups).unwrap();
+        let config = partitioned_csv_config(file_schema, file_groups);
         let csv = CsvExec::new(
             config,
             true,

datafusion/core/src/datasource/physical_plan/file_scan_config.rs

@@ -64,12 +64,41 @@ pub fn wrap_partition_value_in_dict(val: ScalarValue) -> ScalarValue {
 
 /// The base configurations to provide when creating a physical plan for
 /// any given file format.
+///
+/// # Example
+/// ```
+/// # use std::sync::Arc;
+/// # use arrow_schema::Schema;
+/// use datafusion::datasource::listing::PartitionedFile;
+/// # use datafusion::datasource::physical_plan::FileScanConfig;
+/// # use datafusion_execution::object_store::ObjectStoreUrl;
+/// # let file_schema = Arc::new(Schema::empty());
+/// // create FileScan config for reading data from file://
+/// let object_store_url = ObjectStoreUrl::local_filesystem();
+/// let config = FileScanConfig::new(object_store_url, file_schema)
+///   .with_limit(Some(1000))            // read only the first 1000 records
+///   .with_projection(Some(vec![2, 3])) // project columns 2 and 3
+///    // Read /tmp/file1.parquet with known size of 1234 bytes in a single group
+///   .with_file(PartitionedFile::new("file1.parquet", 1234))
+///   // Read /tmp/file2.parquet 56 bytes and /tmp/file3.parquet 78 bytes
+///   // in a  single row group
+///   .with_file_group(vec![
+///    PartitionedFile::new("file2.parquet", 56),
+///    PartitionedFile::new("file3.parquet", 78),
+///   ]);
+/// ```
 #[derive(Clone)]
 pub struct FileScanConfig {
     /// Object store URL, used to get an [`ObjectStore`] instance from
     /// [`RuntimeEnv::object_store`]
     ///
+    /// This `ObjectStoreUrl` should be the prefix of the absolute url for files
+    /// as `file://` or `s3://my_bucket`. It should not include the path to the
+    /// file itself. The relevant URL prefix must be registered via
+    /// [`RuntimeEnv::register_object_store`]
+    ///
     /// [`ObjectStore`]: object_store::ObjectStore
+    /// [`RuntimeEnv::register_object_store`]: datafusion_execution::runtime_env::RuntimeEnv::register_object_store
     /// [`RuntimeEnv::object_store`]: datafusion_execution::runtime_env::RuntimeEnv::object_store
     pub object_store_url: ObjectStoreUrl,
     /// Schema before `projection` is applied. It contains the all columns that may
@@ -87,6 +116,7 @@ pub struct FileScanConfig {
     /// sequentially, one after the next.
     pub file_groups: Vec<Vec<PartitionedFile>>,
     /// Estimated overall statistics of the files, taking `filters` into account.
+    /// Defaults to [`Statistics::new_unknown`].
     pub statistics: Statistics,
     /// Columns on which to project the data. Indexes that are higher than the
     /// number of columns of `file_schema` refer to `table_partition_cols`.
@@ -101,6 +131,86 @@ pub struct FileScanConfig {
 }
 
 impl FileScanConfig {
+    /// Create a new `FileScanConfig` with default settings for scanning files.
+    ///
+    /// See example on [`FileScanConfig`]
+    ///
+    /// No file groups are added by default. See [`Self::with_file`], [`Self::with_file_group]` and
+    /// [`Self::with_file_groups`].
+    ///
+    /// # Parameters:
+    /// * `object_store_url`: See [`Self::object_store_url`]
+    /// * `file_schema`: See [`Self::file_schema`]
+    pub fn new(object_store_url: ObjectStoreUrl, file_schema: SchemaRef) -> Self {
+        let statistics = Statistics::new_unknown(&file_schema);
+        Self {
+            object_store_url,
+            file_schema,
+            file_groups: vec![],
+            statistics,
+            projection: None,
+            limit: None,
+            table_partition_cols: vec![],
+            output_ordering: vec![],
+        }
+    }
+
+    /// Set the statistics of the files
+    pub fn with_statistics(mut self, statistics: Statistics) -> Self {
+        self.statistics = statistics;
+        self
+    }
+
+    /// Set the projection of the files
+    pub fn with_projection(mut self, projection: Option<Vec<usize>>) -> Self {
+        self.projection = projection;
+        self
+    }
+
+    /// Set the limit of the files
+    pub fn with_limit(mut self, limit: Option<usize>) -> Self {
+        self.limit = limit;
+        self
+    }
+
+    /// Add a file as a single group
+    ///
+    /// See [Self::file_groups] for more information.
+    pub fn with_file(self, file: PartitionedFile) -> Self {
+        self.with_file_group(vec![file])
+    }
+
+    /// Add the file groups
+    ///
+    /// See [Self::file_groups] for more information.
+    pub fn with_file_groups(
+        mut self,
+        mut file_groups: Vec<Vec<PartitionedFile>>,
+    ) -> Self {
+        self.file_groups.append(&mut file_groups);
+        self
+    }
+
+    /// Add a new file group
+    ///
+    /// See [Self::file_groups] for more information
+    pub fn with_file_group(mut self, file_group: Vec<PartitionedFile>) -> Self {
+        self.file_groups.push(file_group);
+        self
+    }
+
+    /// Set the partitioning columns of the files
+    pub fn with_table_partition_cols(mut self, table_partition_cols: Vec<Field>) -> Self {
+        self.table_partition_cols = table_partition_cols;
+        self
+    }
+
+    /// Set the output ordering of the files
+    pub fn with_output_ordering(mut self, output_ordering: Vec<LexOrdering>) -> Self {
+        self.output_ordering = output_ordering;
+        self
+    }
+
     /// Project the schema and the statistics on the given column indices
     pub fn project(&self) -> (SchemaRef, Statistics, Vec<LexOrdering>) {
         if self.projection.is_none() && self.table_partition_cols.is_empty() {
@@ -1117,16 +1227,10 @@ mod tests {
         statistics: Statistics,
         table_partition_cols: Vec<Field>,
     ) -> FileScanConfig {
-        FileScanConfig {
-            file_schema,
-            file_groups: vec![vec![]],
-            limit: None,
-            object_store_url: ObjectStoreUrl::parse("test:///").unwrap(),
-            projection,
-            statistics,
-            table_partition_cols,
-            output_ordering: vec![],
-        }
+        FileScanConfig::new(ObjectStoreUrl::parse("test:///").unwrap(), file_schema)
+            .with_projection(projection)
+            .with_statistics(statistics)
+            .with_table_partition_cols(table_partition_cols)
     }
 
     /// Convert partition columns from Vec<String DataType> to Vec<Field>