Parameters
Parameters
Parameters are values which can easily be changed without having to reload the rules.
Values will be picked up during runtime as soon as they get edited in the corresponding file.
If the file doesn’t exist yet it will automatically be generated in the configured param folder.
Parameters are perfect for boundaries (e.g. if value is below param switch something on).
Currently there are is Parameter and DictParameter available.
from HABApp import Rule, Parameter
from HABApp.core.events import ValueChangeEventFilter
class MyRuleWithParameters(Rule):
def __init__(self):
super().__init__()
# construct parameter once, default_value can be anything
self.min_value = Parameter( 'param_file_testrule', 'min_value', default_value=10)
# deeper structuring is possible through specifying multiple keys
self.min_value_nested = Parameter(
'param_file_testrule',
'Rule A', 'subkey1', 'subkey2',
default_value=['a', 'b', 'c'] # defaults can also be dicts or lists
)
self.listen_event('test_item', self.on_change_event, ValueChangeEventFilter())
def on_change_event(self, event):
# the parameter can be used like a normal variable, comparison works as expected
if self.min_value < event.value:
pass
# The current value can be accessed through the value-property, but don't cache it!
current_value = self.min_value.value
MyRuleWithParameters()
Created file:
min_value: 10
Rule A:
subkey1:
subkey2:
- a
- b
- c
Changes in the file will be automatically picked up through Parameter.
Validation
Since parameters used to provide flexible configuration for automation classes they can get quite complex and error prone. Thus it is possible to provide a validator for a file which will check the files for constraints, missing keys etc. when the file is loaded.
- set_file_validator(filename, validator, allow_extra_keys=True)
Add a validator for the parameter file. If the file is already loaded this will reload the file.
- Parameters:
filename (
str) – filename which shall be validated (without extension)validator (
Any) – Description of file content - see the library voluptuous for examples. Use None to remove validator.allow_extra_keys – Allow additional keys in the file structure
Example
import HABApp
import voluptuous
# Validator can even and should be specified before loading rules
# allows a dict e.g. { 'key1': {'key2': '5}}
HABApp.parameters.set_file_validator('file1', {str: {str: int}})
# More complex example with an optional key:
validator = {
'Test': int,
'Key': {
'mandatory_key': str,
voluptuous.Optional('optional'): int
}
}
HABApp.parameters.set_file_validator('file1', validator)
Create rules from Parameters
Parameteres are not bound to rule instance and thus work everywhere in the rule file. It is possible to dynamically create rules from the contents of the parameter file.
It’s even possible to automatically reload rules if the parameter file has changed: Just add the “reloads on” entry to the file.
key1:
v: 10
key2:
v: 12
rule
import HABApp
class MyRule(HABApp.Rule):
def __init__(self, k, v):
super().__init__()
print(f'{k}: {v}')
cfg = HABApp.DictParameter('my_param') # this will get the file content
for k, v in cfg.items():
MyRule(k, v)
key1: {'v': 10}
key2: {'v': 12}