Custom Build

Get the Device USB Camera Source Code

Change into the edgex directory:
```
cd ~/edgex
```

Clone the device-usb-camera repository:

git clone https://github.com/edgexfoundry/device-usb-camera.git

Checkout the latest release (v3.0):
```
git checkout v3.0
```

Define the device profile

Each device resource should have a mandatory attribute named command to indicate what action the device service should take for it.

Commands can be one of two types:

Commands starting with METADATA_ prefix are used to get camera metadata.

Snippet from general.usb.device.yaml

deviceResources:
- name: "CameraInfo"
    description: >-
    Camera information including driver name, device name, bus info, and capabilities.
    See https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/vidioc-querycap.html.
    attributes:
    { command: "METADATA_DEVICE_CAPABILITY" }
    properties:
    valueType: "Object"
    readWrite: "R"

Commands starting with VIDEO_ prefix are related to video stream.

Snippet from general.usb.device.yaml

deviceResources:
- name: "StreamURI"
    description: "Get video-streaming URI."
    attributes:
    { command: "VIDEO_STREAM_URI" }
    properties:
    valueType: "String"
    readWrite: "R"

For all supported commands, refer to the sample at cmd/res/profiles/general.usb.camera.yaml.

Note

In general, this sample should be applicable to all types of USB cameras.

Note

You don't need to define device profile yourself unless you want to modify resource names or set default values for video options.

Define the device

The device's protocol properties contain: * Path is a file descriptor of camera created by OS. You can find the path of the connected USB camera through v4l2-ctl utility. * AutoStreaming indicates whether the device service should automatically start video streaming for cameras. Default value is false.

Snippet from general.usb.camera.yaml.example

deviceList:
- name: "example-camera"
profileName: "USB-Camera-General"
description: "Example Camera"
labels: [ "device-usb-camera-example", ]
protocols:
    USB:
    Path: "/dev/video0"
    AutoStreaming: "false"

See the examples at cmd/res/devices

Note

When a new device is created in Core Metadata, a callback function of the device service will be called to add the device card name and serial number to protocol properties for identification purposes. These two pieces of information are obtained through V4L2 API and udev utility.

Configurable RTSP server hostname and port

The hostname and port of the RTSP server can be configured in the Driver section of the device-usb-camera/cmd/res/configuration.yaml file. The default values can be used for this guide. The RtspAuthenticationServer value indicates the internal hostname and port on which the device service will listen for RTSP authentication requests on. If this value is changed, you will have to also change the mediamtx configuration to point to the new hostname/port as well.

Snippet from configuration.yaml

Driver:
    RtspServerHostName: "localhost"
    RtspTcpPort: "8554"
    RtspAuthenticationServer: "localhost:8000"

Configurable RTSP authentication

Set the username and password

Snippet from configuration.yaml

...
Writable:
    LogLevel: "INFO"
    InsecureSecrets:
        rtspauth:
        SecretName: rtspauth
        SecretData:
            username: "<set-username>"
            password: "<set-password>"

For more information on rtsp authentication, including how to disable it, see here

Building the docker image

Change into newly created directory:
```
cd ~/edgex/device-usb-camera
```
Build the docker image of the device-usb-camera service:
```
make docker
```
[Optional] Build with NATS Messaging
Currently, the NATS Messaging capability (NATS MessageBus) is opt-in at build time. This means that the published Docker image and Snaps do not include the NATS messaging capability. To build the docker image using NATS, run make docker-nats:
```
make docker-nats
```
See Compose Builder nat-bus option to generate compose file for NATS and local dev images.
Navigate to the Edgex compose directory.

cd ~/edgex/edgex-compose/compose-builder

Update .env file to add the registry and image version variable for device-usb-camera:

Add the following registry and version information:

DEVICE_USBCAM_VERSION=0.0.0-dev

Update the add-device-usb-camera.yml to point to the local image:

services:
device-usb-camera:
   image: edgexfoundry/device-usb-camera${ARCH}:${DEVICE_USBCAM_VERSION}

Deploy the device service>