An outline device service, template.c is provided here.
A number of example device services illustrating specific concepts are provided within their own subdirectories:
| Example | Notes |
|---|---|
| Random | A simple device service |
| Counters | Device addressing via ProtocolProperties |
| Discovery | Dynamic device discovery and provision watchers |
| Gyro | Use of resourceCommand to aggregate Readings |
| Terminal | One possible mechanism for accepting actuation commands |
| Bitfields | Use mask and shift attributes to access bitfields within a device register |
| File | Use of devsdk_post_readings to generate Events autonomously |
template.c shows a device service in outline. All requests for get and set operations result in debugging output showing the device and resource addressing that is supplied to the driver.
The environment variable CSDK_DIR should be set to a directory containing the C SDK include files and libraries.
Set LD_LIBRARY_PATH to $CSDK_DIR/lib:/opt/iotech/iot/1.5/lib
gcc -I$CSDK_DIR/include -I/opt/iotech/iot/1.5/include -L$CSDK_DIR/lib -L/opt/iotech/iot/1.5/lib -o template template.c -lcsdk -liot
An example device profile for the simulated device is provided in the res directory. This will be uploaded to core-metadata by the device service on first run.
The supplied configuration file res/configuration.toml includes definitions for a single device, including an AutoEvent which causes readings to be generated at ten-second intervals. On first run of the device service, this device will be created in metadata.
An EdgeX system containing at least a database and the core-data and core-metadata services must be running. The configuration file must be edited to reflect the locations of the core-data and core-metadata services.
./template -c res
Once the service is running it will begin to send a sequence of Events every ten seconds. It will also respond to the REST API for device services. To obtain a reading manually,
curl 0:59999/api/v3/device/name/Device1/SensorOne
Note that the template device service returns a constant String reading regardless of the requested operation.