Source code for joule.models.element

from sqlalchemy.orm import relationship
from sqlalchemy import Column, Integer, Enum, Float, String, Boolean, ForeignKey
import configparser
import enum
from typing import Optional, Dict, TYPE_CHECKING

from joule.models.meta import Base
from joule.errors import ConfigurationError

if TYPE_CHECKING:  # pragma: no cover
    from joule.models.folder import Stream

[docs]class Element(Base): """ Attributes: name (str): element name index (int): order of element in the stream units (str): data unit (eg Watts, Volts, etc) plottable (bool): whether the data can be visualized as a time series offset (float): linear scaling y=mx+b, only applied to Lumen visualizations scale_factor (float): linear scaling only applied to Lumen visualizations default_min (float): fix lower limit on autoscaling in Lumen visualizations default_max (float): fix upper limit on autoscaling in Lumen visualizations display_type (Element.DISPLAYTYPE): visualization type """ __tablename__ = 'element' id: int = Column(Integer, primary_key=True) index: int = Column(Integer, nullable=False) name: str = Column(String) units: str = Column(String) plottable: bool = Column(Boolean)
display_type: DISPLAYTYPE = Column(Enum(DISPLAYTYPE), default=DISPLAYTYPE.CONTINUOUS) offset: float = Column(Float, default=0, nullable=False) scale_factor: float = Column(Float, default=1.0, nullable=False) default_max: Optional[float] = Column(Float, default=None) default_min: Optional[float] = Column(Float, default=None) stream_id: int = Column(Integer, ForeignKey('')) stream: 'Stream' = relationship("Stream", back_populates="elements") def __repr__(self): return "<Element(name='%s', units='%s', display_type=%s)>" % (, self.units, self.display_type)
[docs] def to_json(self): """ Returns: Dictionary of Element attributes """ if self.display_type is None: # make up a default value self.display_type = Element.DISPLAYTYPE.CONTINUOUS return { 'id':, 'index': self.index, 'name':, 'units': self.units, 'plottable': self.plottable, 'display_type':, 'offset': self.offset, 'scale_factor': self.scale_factor, 'default_max': self.default_max, 'default_min': self.default_min }
def update_attributes(self, attrs: Dict): if 'name' in attrs: = validate_name(attrs['name']) if 'units' in attrs: self.units = attrs['units'] try: if 'plottable' in attrs: self.plottable = bool(attrs['plottable']) if 'offset' in attrs: self.offset = float(attrs['offset']) if 'scale_factor' in attrs: self.scale_factor = float(attrs['scale_factor']) if 'display_type' in attrs: self.display_type = validate_type(attrs['display_type']) if 'default_max' in attrs: x = attrs['default_max'] if x is not None: x = float(x) self.default_max = x if 'default_min' in attrs: x = attrs['default_min'] if x is not None: x = float(x) self.default_min = x except ValueError as e: raise ConfigurationError("Invalid element configuration: %r" % e) if self.default_max is not None and self.default_min is not None: if self.default_max <= self.default_min: raise ConfigurationError("[default_min] must be > [default_max]")
def from_json(data: Dict) -> Element: return Element(id=data["id"], index=data["index"], name=data["name"], units=data["units"], plottable=data["plottable"], display_type=Element.DISPLAYTYPE[data["display_type"]], offset=data["offset"], scale_factor=data["scale_factor"], default_max=data["default_max"], default_min=data["default_min"]) def from_config(config: configparser.ConfigParser): name = validate_name(config["name"]) display_type = validate_type(config.get("display_type", fallback="continuous")) units = config.get("units", fallback=None) plottable = _get_bool("plottable", config, True) offset = _get_float("offset", config, 0.0) scale_factor = _get_float("scale_factor", config, 1.0) default_max = _get_float("default_max", config, None) default_min = _get_float("default_min", config, None) # make sure min<=max if set if ((default_max is not None and default_min is not None) and (default_min >= default_max)): raise ConfigurationError("set default_min<default_max or omit for autoscale") return Element(name=name, units=units, plottable=plottable, display_type=display_type, offset=offset, scale_factor=scale_factor, default_max=default_max, default_min=default_min) def validate_name(name: str) -> str: if name == "": raise ConfigurationError("missing name") return name def validate_type(display_type: str) -> Element.DISPLAYTYPE: try: return Element.DISPLAYTYPE[display_type.upper()] except KeyError as e: valid_types = ", ".join([ for m in Element.DISPLAYTYPE]) raise ConfigurationError("invalid display_type [%s], choose from [%s]" % (display_type, valid_types)) from e def _get_bool(setting: str, config: configparser.ConfigParser, default: bool): try: return config.getboolean(setting, default) except ValueError as e: raise ConfigurationError("[%s] invalid value, use True/False" % setting) from e def _get_float(setting: str, config: configparser.ConfigParser, default): try: if config[setting] == "None": return default return config.getfloat(setting, default) except KeyError: return default except ValueError as e: raise ConfigurationError("[%s] invalid value, must be a number" % setting) from e