DeviceHub Drivers

13 min

The drivers module provides access to DeviceHub driver definitions and a bundled template library for offline use.

Imports

from litmussdk.devicehub import drivers                       # live API
from litmussdk.devicehub.record import DriverTemplates        # bundled templates

Driver API

Listing Drivers

from litmussdk.devicehub import drivers

all_drivers = drivers.list_all_drivers()              # list[Driver]

Pass raw=True to skip pydantic validation and return the API JSON unchanged. Useful when the driver schema drifts ahead of your installed SDK.

all_raw = drivers.list_all_drivers(raw=True)          # list[dict[str, Any]]

Each Driver is a Pydantic model with fields including:

id: str

name: str

driver_gen: str: "Gen1" or "Gen2"

group_id: str

properties: list[Property]: valid device-level configuration fields

registers: list[SupportedRegister]: valid register (tag) types for this driver

meta: Meta: browse support, discovery support, version, etc.

# Find a driver by name
driver = next((d for d in drivers.list_all_drivers() if d.name == "Simulator (Gen1)"), None)
driver_id = driver.id

# Or, with raw dicts
driver = next((d for d in drivers.list_all_drivers(raw=True) if d["Name"] == "Simulator (Gen1)"), None)
driver_id = driver["ID"]

# Get supported registers for a driver
details = next((d for d in drivers.list_all_drivers() if d.name == "Simulator (Gen1)"), None)
registers = details.registers

Driver Templates

The SDK ships with a bundled set of driver definitions compiled from the Litmus Edge API. These let you look up driver IDs and validate device configuration without making live API calls.

Templates are regenerated via the download_dh_record CLI command or during CI builds. Run list_dh_versions to see available versions and get_dh_cache_dir to find where they are cached.

Getting a Driver by Name or ID

from litmussdk.devicehub.record import DriverTemplates, get_driver_by_name, driver_library_by_id

# From the DriverTemplates class (known drivers)
simulator = DriverTemplates.simulator_gen1
driver_id = simulator.id

# By name (searches the full library)
driver = get_driver_by_name("Simulator (Gen1)")

# By ID
driver = driver_library_by_id["50E3EDA1-11F9-41D6-9232-778A28665580"]

Inspecting Driver Properties

registers = DriverTemplates.simulator_gen1.registers
properties = DriverTemplates.simulator_gen1.properties

Validating Device Configuration (JSON Schema)

Both DriverTemplate and RegisterType objects can generate a JSON Schema for their configuration fields, useful for client-side validation before making API calls.

import jsonschema
from litmussdk.devicehub.record import DriverTemplates

device_config = {
    "networkAddress": "192.168.1.10",
    "networkPort": 102,
    "slotNumber": 0,
}

# Validates successfully against the Siemens S7 schema
jsonschema.validate(device_config, DriverTemplates.siemens_s7.schema)

# Raises ValidationError, wrong driver
jsonschema.validate(device_config, DriverTemplates.simulator_gen1.schema)

Template Data Classes

DriverTemplate

Represents a driver type with the following fields:

name: str

id: str

driver_gen: str

group_id: str

properties: list[PropertyType]

registers: list[RegisterType]

description: str (optional)

RegisterType

Represents a valid tag/register type for a driver:

name: str

readonly: bool

properties: list[PropertyType]

description: str (optional)

PropertyType

Describes a single configuration field:

name: str

value_type: str

required: bool

description: str | None

default_value: str | None

number_min: int | None, number_max: int | None