Stream Send

Overview

Sending one queue message per call works fine for occasional traffic, but each call carries its own round trip. At high volume — event ingestion, sensor telemetry, log shipping — that per-call overhead caps your throughput well below what the connection can support.

client.send_queue_message(msg) sends each message as an individual RPC call. For higher throughput, the SDK also exposes client.queue_upstream(), which opens a persistent gRPC stream that batches multiple messages over one connection instead of paying the per-message RPC cost — the right choice once you're publishing enough volume that connection overhead, not bandwidth, is the bottleneck.

Gotchas: the simple send_queue_message loop shown here awaits each send before starting the next, so throughput is bounded by round-trip latency — don't reach for it in a hot ingestion path; switch to queue_upstream() instead. Pick unique, deliberate channel names and client IDs before running against a shared server — the example's channel is easy to collide with across runs. Always client.close().await when done so the connection is released cleanly rather than left to time out.

Prerequisites

• KubeMQ server running on localhost:50000
• Rust SDK installed (cargo add kubemq)

Code

use kubemq::prelude::*;
use kubemq::QueueMessageBuilder;

#[tokio::main]
async fn main() -> kubemq::Result<()> {
    let client = KubemqClient::builder()
        .host("localhost")
        .port(50000)
        .build()
        .await?;

    let channel = "rust-queues.stream-send";

    for i in 0..20 {
        let msg = QueueMessageBuilder::new()
            .channel(channel)
            .body(format!("stream-msg-{}", i).into_bytes())
            .build();
        client.send_queue_message(msg).await?;
    }

    println!("Sent 20 messages to queue: {}", channel);
    client.close().await?;
    Ok(())
}

How It Works

• For high-throughput scenarios, consider using the queue stream upstream API (client.queue_upstream()).
• The simple API (send_queue_message) sends each message individually over a single RPC call.
• The upstream stream API batches multiple messages over a single persistent gRPC connection for lower per-message overhead.
• Review timeouts, channel names, and client IDs before running against shared environments.
• Run the program while the server from the prerequisites is available.

Related

• Queues overview
• Rust SDK Reference
• Stream Receive