Webcam

Start and stop an MJPEG video stream from a USB camera attached to the box. A person or a vision tool can then watch the DUT while a test runs.

Handle

use lager::LagerBox;

let lager = LagerBox::from_env()?;
let cam = lager.webcam("cam1");

Methods

Method	Description
`name()`	The net name this handle addresses
`start()`	Start the stream and return its URL
`stop()`	Stop the stream
`status()`	Whether a stream is running, and where
`url()`	The stream URL, or `None` when nothing is running
`snapshot()`	One JPEG frame from the running stream
`start_as()`	Start the stream, and record who started it

Types

pub struct WebcamStream {
    pub url: String,
    pub port: Option<i64>,
    pub already_running: bool,   // true when an existing stream was reused
}

pub struct WebcamStatus {
    pub running: bool,
    pub url: Option<String>,
    pub port: Option<i64>,
    pub video_device: Option<String>,   // e.g. "/dev/video0"
    pub source: Option<String>,         // which surface started the stream (box 0.47.0+)
    pub started_by: Option<String>,     // who started it
}

Method Reference

`start() -> Result<WebcamStream>`

Start the MJPEG stream. Idempotent: called while a stream is already up, it reports the existing one with already_running: true rather than starting a second.

let s = cam.start()?;
println!("watch at {} (reused: {})", s.url, s.already_running);

This call gets a 30-second budget, because starting the stream subprocess takes a few seconds.

`stop() -> Result<bool>`

Stop the stream. Returns: false if no stream was active.

`status() -> Result<WebcamStatus>` and `url() -> Result<Option<String>>`

Whether a stream is active and where, or just the URL.

`snapshot() -> Result<Vec<u8>>`

Capture one JPEG frame from the running stream, and return its bytes. Start the stream first: the box refuses a snapshot when no stream runs. It requires box software 0.47.0 or later.

cam.start()?;
std::fs::write("target/bench.jpg", cam.snapshot()?).expect("write the frame");

`start_as(source: &str, started_by: Option<&str>) -> Result<WebcamStream>`

Like start(), and the box records which surface started the stream, and who. status() reports them in source and started_by.

Examples

Record the bench while a long test runs

use lager::LagerBox;

let lager = LagerBox::from_env()?;
let cam = lager.webcam("cam1");

let stream = cam.start()?;
println!("::notice::watch the DUT at {}", stream.url);

let result = run_the_long_test(&lager);

cam.stop()?;
result?;

Supported Hardware

Camera	Notes
Logitech BRIO, C920, C922, C925e, C930e, C270, C615, StreamCam	Any UVC camera the box enumerates

Notes

The stream URL points at the box as the client reached it. A URL captured on one network does not always resolve from another, so do not persist it across environments.
To watch the stream, point an MJPEG consumer (a browser, VLC, OpenCV) at the URL. To keep one frame from a test, call snapshot().
Always stop() in teardown. A running stream holds the camera open. A start on the same net reports the running stream. A stream on a different net that uses the same camera is refused until this one stops.

Getting Started

Development

Power & Simulation

Measurement

I/O & Communication

Utilities

Security

Guides

Handle

Methods

Types

Method Reference

`start() -> Result<WebcamStream>`

`stop() -> Result<bool>`

`status() -> Result<WebcamStatus>` and `url() -> Result<Option<String>>`

`snapshot() -> Result<Vec<u8>>`

`start_as(source: &str, started_by: Option<&str>) -> Result<WebcamStream>`

Examples

Record the bench while a long test runs

Supported Hardware

Notes

​Handle

​Methods

​Types

​Method Reference

​start() -> Result<WebcamStream>

​stop() -> Result<bool>

​status() -> Result<WebcamStatus> and url() -> Result<Option<String>>

​snapshot() -> Result<Vec<u8>>

​start_as(source: &str, started_by: Option<&str>) -> Result<WebcamStream>

​Examples

​Record the bench while a long test runs

​Supported Hardware

​Notes

Handle

Methods

Types

Method Reference

`start() -> Result<WebcamStream>`

`stop() -> Result<bool>`

`status() -> Result<WebcamStatus>` and `url() -> Result<Option<String>>`

`snapshot() -> Result<Vec<u8>>`

`start_as(source: &str, started_by: Option<&str>) -> Result<WebcamStream>`

Examples

Record the bench while a long test runs

Supported Hardware

Notes