eta_nexus.nodes.node module

This module implements the node class, which is used to parametrize connections.

class eta_nexus.nodes.node.MetaNode(name: str, bases: tuple, namespace: dict[str, Any], **kwargs: Any)

Bases: type

Metaclass to define all Node classes as frozen attr dataclasses.

class eta_nexus.nodes.node.Node(name: str, url: str, protocol: str, *args: Any, **kwargs: Any)

Bases: object

The node objects represents a single variable. Valid keyword arguments depend on the protocol.

name: str

Name for the node.

url: str

URL of the connection.

url_parsed: ParseResult

Parse result object of the URL (in case more post-processing is required).

protocol: str

Protocol of the connection.

usr: str | None

Username for login to the connection (default: None).

pwd: str | None

Password for login to the connection (default: None).

interval: str | None

Interval

dtype: Callable | None

Data type of the node (for value conversion). Note that strings will be interpreted as utf-8 encoded. If you do not want this behaviour, use ‘bytes’.

connection_identifier() → str

Unique identifier for the connection that is associated with the node (i.e. would be created by Connection.from_node())

evolve(**kwargs: Any) → Self

Returns a new node instance by copying the current node and changing only specified keyword arguments.

This allows for seamless node instantiation with only a few changes.

Parameters:

kwargs – Keyword arguments to change.

Returns:

New instance of the node.

as_dict(*, filter_none: bool = False, **kwargs: Any) → dict[str, Any]

Return the attrs attribute values of node instance as a dict.

Parameters:

filter_none – Filter none values, defaults to False

Returns:

dict of attribute values

as_tuple(*, filter_none: bool = False, **kwargs: Any) → tuple[Any, ...]

Return the attrs attribute values of inst as a tuple.

Parameters:

filter_none – Filter none values, defaults to False

Returns:

tuple of attribute values

classmethod from_dict(dikt: Sequence[Mapping] | Mapping[str, Any], *, fail: bool = True) → list[Self]

Create nodes from a dictionary of node configurations. The configuration must specify the following fields for each node:

• Code (or name), URL, Protocol (i.e. modbus or opcua or eneffco). The URL should be a complete network location identifier. Alternatively it is possible to specify the location in two fields: IP and Port. These should only contain the respective parts (as in only an IP address and only the port number). The IP-Address should always be given without scheme (https://).

For local nodes no additional fields are required.

For Modbus nodes the following additional fields are required:

• ModbusRegisterType (or mb_register), ModbusSlave (or mb_slave), ModbusChannel (or mb_channel).

For OPC UA nodes the following additional fields are required:

• Identifier.

For Eneffco nodes the code field must be present.

For EntsoE nodes the endpoint field must be present.

Parameters:

• dikt – Configuration dictionary.

• fail – Set this to false, if you would like to log errors instead of raising them.

Returns:

List of Node objects.

classmethod from_excel(path: Path, sheet_name: str, *, fail: bool = True) → list[Self]

Method to read out nodes from an Excel document. The document must specify the following fields:

• Code, IP, Port, Protocol (modbus or opcua or eneffco).

For Modbus nodes the following additional fields are required:

• ModbusRegisterType, ModbusByte, ModbusChannel.

For OPC UA nodes the following additional fields are required:

• Identifier.

For Eneffco nodes the Code field must be present.

The IP-Address should always be given without scheme (https://).

Parameters:

• path – Path to Excel document.

• sheet_name – name of Excel sheet, which will be read out.

• fail – Set this to false, if you would like to log errors instead of raising them.

Returns:

List of Node objects.