nautilus_serialization/
parquet.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
// -------------------------------------------------------------------------------------------------
//  Copyright (C) 2015-2025 Nautech Systems Pty Ltd. All rights reserved.
//  https://nautechsystems.io
//
//  Licensed under the GNU Lesser General Public License Version 3.0 (the "License");
//  You may not use this file except in compliance with the License.
//  You may obtain a copy of the License at https://www.gnu.org/licenses/lgpl-3.0.en.html
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
// -------------------------------------------------------------------------------------------------

use std::{error::Error, fs::File, path::Path};

use arrow::record_batch::RecordBatch;
use parquet::{arrow::ArrowWriter, file::properties::WriterProperties};

/// Writes a `RecordBatch` to a Parquet file at the specified `filepath`, with optional compression.
pub fn write_batch_to_parquet(
    batch: RecordBatch,
    filepath: &Path,
    compression: Option<parquet::basic::Compression>,
) -> Result<(), Box<dyn Error>> {
    write_batches_to_parquet(&[batch], filepath, compression, None)
}

/// Writes a `RecordBatch` to a Parquet file at the specified `filepath`, with optional compression.
pub fn write_batches_to_parquet(
    batches: &[RecordBatch],
    filepath: &Path,
    compression: Option<parquet::basic::Compression>,
    max_row_group_size: Option<usize>,
) -> Result<(), Box<dyn Error>> {
    // Ensure the parent directory exists
    if let Some(parent) = filepath.parent() {
        std::fs::create_dir_all(parent)?;
    }

    let file = File::create(filepath)?;

    // Configure writer properties, defaulting to Zstandard compression if not specified
    let default_compression = parquet::basic::Compression::SNAPPY;
    let writer_props = WriterProperties::builder()
        .set_compression(compression.unwrap_or(default_compression))
        .set_max_row_group_size(max_row_group_size.unwrap_or(5000))
        .build();

    let mut writer = ArrowWriter::try_new(file, batches[0].schema(), Some(writer_props))?;
    for batch in batches {
        writer.write(batch)?;
    }
    writer.close()?;

    Ok(())
}