lightstream 0.4.3

Composable, zero-copy Arrow IPC and native data streaming for Rust with SIMD-aligned I/O, async support, and memory-mapping.
Documentation 
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
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77

//! Unix Domain Socket Arrow IPC Example
//!
//! Streams Arrow tables over Unix domain sockets using Arrow IPC framing,
//! without the Lightstream multiplexing protocol.
//!
//! 1. Create a temporary socket path via `tempfile`
//! 2. Client writes Arrow tables via `UdsTableWriter`
//! 3. Server reads and verifies via `UdsTableReader`
//!
//! Run with:
//! ```sh
//! cargo run --example uds_arrow --features uds
//! ```

#[path = "../helpers/mod.rs"]
mod helpers;

use helpers::{make_table, table_schema};
use lightstream::enums::IPCMessageProtocol;
use lightstream::models::readers::uds::UdsTableReader;
use lightstream::models::streams::uds::UdsByteStream;
use lightstream::models::writers::uds::UdsTableWriter;
use lightstream::traits::transport_reader::TransportReader;
use lightstream::traits::transport_writer::TransportWriter;
use tokio::net::UnixListener;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    println!("Unix Domain Socket Arrow IPC Example");
    println!("=====================================\n");

    let schema = table_schema();

    // --- Transport setup: temporary socket path ---
    let temp_dir = tempfile::tempdir()?;
    let socket_path = temp_dir.path().join("lightstream.sock");
    println!("Socket path: {}", socket_path.display());

    let listener = UnixListener::bind(&socket_path)?;
    println!("Listener bound.");

    let server = tokio::spawn(async move {
        let (stream, _) = listener.accept().await.unwrap();
        println!("Server accepted connection.");

        let (read_half, _write_half) = stream.into_split();
        let byte_stream =
            UdsByteStream::from_read_half(read_half, lightstream::enums::BufferChunkSize::Http);
        let reader = UdsTableReader::from_stream(byte_stream, IPCMessageProtocol::Stream);
        let tables = reader.read_all_tables().await.unwrap();

        for table in &tables {
            println!(
                "  Server got table: {} rows, {} cols",
                table.n_rows,
                table.cols.len()
            );
        }

        assert_eq!(tables.len(), 3);
        println!("Server received all {} tables.", tables.len());
    });

    // --- Client: connect and write ---
    let mut writer = UdsTableWriter::connect(&socket_path, schema).await?;
    println!("Client connected.");

    writer.write_table(make_table("batch_1", 5)).await?;
    writer.write_table(make_table("batch_2", 3)).await?;
    writer.write_table(make_table("batch_3", 7)).await?;
    writer.finish().await?;

    server.await?;

    println!("\nUDS Arrow IPC example completed successfully!");
    Ok(())
}