Async I/O (Rust)¶

Enable the tokio feature for a full async API that mirrors the sync stack: AsyncScpiSession, AsyncDiscovery, AsyncDeviceCatalog, and typed classes (AsyncDmm, AsyncDcPowerSupply, AsyncFunctionGenerator, AsyncOscilloscope, AsyncSwitch, AsyncCounter).

Sync remains the default. Async is additive behind tokio.

Enable¶

[dependencies]
instrument-components = { version = "0.1", features = ["visa", "tokio"] }
tokio = { version = "1", features = ["rt-multi-thread", "macros"] }

The published crates.io 0.1.0 tag does not include this async API. Use git/latest until 0.2.0.

Feature chain:

instrument-components/tokio
  → instrument-core/async

instrument-components/visa + tokio
  → instrument-visa/tokio → visa-rs/tokio

Default (features = ["visa"] only) does not pull in tokio.

Mock quick start (no VISA)¶

use instrument::prelude::*;

#[tokio::main]
async fn main() -> Result<()> {
    let fixture = ScriptedFixture::builder()
        .idn("Acme", "DMM1", "SN1", "1.0")
        .kinds([InstrumentKind::Dmm])
        .on_query(":MEAS:VOLT:DC?", "1.0")
        .build();

    let catalog = AsyncDeviceCatalog::from_fixture("mock://dmm", fixture).await?;
    let mut dmm = catalog.open_dmm("mock://dmm").await?;
    let volts = dmm.measure_voltage_dc(None).await?;
    println!("{volts} V");
    Ok(())
}

cargo run -p instrument-components --example mock_fixture_ci_async --features tokio --no-default-features

Hardware quick start¶

VISA session open is sync (visa-rs limitation); read/write after open are async.

use instrument::prelude::*;

#[tokio::main]
async fn main() -> Result<()> {
    let catalog = AsyncDiscovery::visa()?.scan().await?;
    let mut dmm = catalog
        .open_dmm(&catalog.devices_by_kind(InstrumentKind::Dmm)[0].address.raw)
        .await?;
    let volts = dmm.measure_voltage_dc(None).await?;
    println!("{volts} V");
    Ok(())
}

Async type map¶

Sync	Async
`Transport`	`AsyncTransport`
`ScpiSession`	`AsyncScpiSession`
`InstrumentSession`	`AsyncInstrumentSession`
`Discovery::scan()`	`AsyncDiscovery::scan().await`
`DeviceCatalog`	`AsyncDeviceCatalog`
`DeviceRef`	`AsyncDeviceRef`
`Dmm`	`AsyncDmm`
`DcPowerSupply`	`AsyncDcPowerSupply`
`FunctionGenerator`	`AsyncFunctionGenerator`
`Oscilloscope`	`AsyncOscilloscope`
`Switch`	`AsyncSwitch`
`Counter`	`AsyncCounter`
`VisaTransport`	`VisaAsyncTransport`
`VisaSessionOpener`	`VisaAsyncSessionOpener`

Low-level adapter¶

InstrumentTokioAdapter from visa-rs is still re-exported for raw byte I/O without SCPI framing:

use instrument::prelude::*;
use tokio::io::{AsyncReadExt, AsyncWriteExt};

async fn raw_idn(adapter: &mut InstrumentTokioAdapter) -> std::io::Result<()> {
    adapter.write_all(b"*IDN?\n").await?;
    let mut buf = vec![0u8; 256];
    let n = adapter.read(&mut buf).await?;
    println!("{}", String::from_utf8_lossy(&buf[..n]));
    Ok(())
}

Prefer AsyncScpiSession / typed classes for framing, retries, and diagnostics.

Testing¶

cargo test -p instrument-core --features async
cargo test -p instrument-components --features tokio --no-default-features