qmp

QEMU QMP client library.

Goals:

• Pure Rust, async-first.
• Unix/TCP socket support.
• Correct greeting + qmp_capabilities negotiation.
• JSON request/response encoding/decoding with serde.
• Event stream (subscribe, multi-consumer).
• Command calls with timeout and cooperative cancellation.
• Optional, higher-level safe ops layer:
  • allow-list policies (white-list)
  • per-command mutex / idempotency
  • retry/backoff with jitter
  • structured errors
  • (optional) tracing observability

Quick start

Low-level client

use qmp::{Client, Endpoint};

# async fn demo() -> qmp::Result<()> {
let client = Client::connect(Endpoint::unix("/var/run/qemu-server/100.qmp")).await?;

let status: serde_json::Value = client.execute("query-status", Option::<()>::None).await?;
println!("status = {status}");

let mut events = client.events();
while let Ok(ev) = events.recv().await {
    println!("event: {} data={}", ev.name, ev.data);
}
# Ok(()) }

Safe ops layer

use qmp::{Client, Endpoint};
use qmp::ops::{OpsClient, Profile};

# async fn demo() -> qmp::Result<()> {
let client = Client::connect(Endpoint::unix("/var/run/qemu-server/100.qmp")).await?;

// Read-only allow-list by default.
let ops = OpsClient::from_profile(client, Profile::ReadOnly);

let v = ops.query_version().await?;
println!("qemu {}.{}.{} ({})", v.qemu.major, v.qemu.minor, v.qemu.micro, v.package);
# Ok(()) }