class platypush.backend.sensor.distance.SensorDistanceBackend(plugin=None, plugin_args=None, thresholds=None, tolerance=1e-07, poll_seconds=None, enabled_sensors=None, **kwargs)[source]

Backend to poll a distance sensor.



__init__(plugin=None, plugin_args=None, thresholds=None, tolerance=1e-07, poll_seconds=None, enabled_sensors=None, **kwargs)
  • plugin (str) – If set, then this plugin instance, referenced by plugin id, will be polled through get_plugin(). Example: 'gpio.sensor.bme280' or 'gpio.sensor.envirophat'.

  • plugin_args (dict) – If plugin is set and its get_measurement() method accepts optional arguments, then you can pass those arguments through plugin_args.

  • thresholds – Thresholds can be either a scalar value or a dictionary (e.g. {"temperature": 20.0}). Sensor threshold events will be fired when measurements get above or below these values. Set it as a scalar if your get_measurement() code returns a scalar, as a dictionary if it returns a dictionary of values. For instance, if your sensor code returns both humidity and temperature in a format like {'humidity':60.0, 'temperature': 25.0}, you’ll want to set up a threshold on temperature with a syntax like {'temperature':20.0} to trigger events when the temperature goes above/below 20 degrees.

  • tolerance (dict or float) –

    If set, then the sensor change events will be triggered only if the difference between the new value and the previous value is higher than the specified tolerance. Example:

        "temperature": 0.01,  # Tolerance on the 2nd decimal digit
        "humidity": 0.1       # Tolerance on the 1st decimal digit

  • poll_seconds (float) – If set, the thread will wait for the specified number of seconds between a read and the next one.

  • enabled_sensors (dict (in the form name -> [True/False]), set or list) – If get_measurement() returns data in dict form, then enabled_sensors selects which keys should be taken into account when monitoring for new events (e.g. “temperature” or “humidity”).

property daemon

A boolean value indicating whether this thread is a daemon thread.

This must be set before start() is called, otherwise RuntimeError is raised. Its initial value is inherited from the creating thread; the main thread is not a daemon thread and therefore all threads created in the main thread default to daemon = False.

The entire Python program exits when only daemon threads are left.


Return a string used for identification purposes only.

This method is deprecated, use the name attribute instead.


get_measurement implementation

property ident

Thread identifier of this thread or None if it has not been started.

This is a nonzero integer. See the get_ident() function. Thread identifiers may be recycled when a thread exits and another thread is created. The identifier is available even after the thread has exited.


Return whether this thread is a daemon.

This method is deprecated, use the daemon attribute instead.


Return whether the thread is alive.

This method returns True just before the run() method starts until just after the run() method terminates. See also the module function enumerate().


Wait until the thread terminates.

This blocks the calling thread until the thread whose join() method is called terminates – either normally or through an unhandled exception or until the optional timeout occurs.

When the timeout argument is present and not None, it should be a floating point number specifying a timeout for the operation in seconds (or fractions thereof). As join() always returns None, you must call is_alive() after join() to decide whether a timeout happened – if the thread is still alive, the join() call timed out.

When the timeout argument is not present or None, the operation will block until the thread terminates.

A thread can be join()ed many times.

join() raises a RuntimeError if an attempt is made to join the current thread as that would cause a deadlock. It is also an error to join() a thread before it has been started and attempts to do so raises the same exception.

property name

A string used for identification purposes only.

It has no semantics. Multiple threads may be given the same name. The initial name is set by the constructor.

property native_id

Native integral thread ID of this thread, or None if it has not been started.

This is a non-negative integer. See the get_native_id() function. This represents the Thread ID as reported by the kernel.


Callback when a message is received on the backend. It parses and posts the message on the main bus. It should be called by the derived classes whenever a new message should be processed.


msg – Received message. It can be either a key-value dictionary, a platypush.message.Message object, or a string/byte UTF-8 encoded string


Callback invoked when the process stops

register_service(port: Optional[int] = None, name: Optional[str] = None, srv_type: Optional[str] = None, srv_name: Optional[str] = None, udp: bool = False, properties: Optional[Dict] = None)

Initialize the Zeroconf service configuration for this backend.

  • port – Service listen port (default: the backend port attribute if available, or None).

  • name – Service short name (default: backend name).

  • srv_type – Service type (default: _platypush-{name}._{proto}.local.).

  • srv_name – Full service name (default: {hostname or device_id}.{type}).

  • udp – Set to True if this is a UDP service.

  • properties

    Extra properties to be passed on the service. Default:

        "name": "Platypush",
        "vendor": "Platypush",
        "version": "{platypush_version}"


Starts the backend thread. To be implemented in the derived classes if the loop method isn’t defined.

send_event(event, **kwargs)

Send an event message on the backend.


event – Event to send. It can be a dict, a string/bytes UTF-8 JSON, or a platypush.message.event.Event object.

send_message(msg, queue_name=None, **_)

Sends a platypush.message.Message to a node. To be implemented in the derived classes. By default, if the Redis backend is configured then it will try to deliver the message to other consumers through the configured Redis main queue.

  • msg – The message to send

  • queue_name – Send the message on a specific queue (default: the queue_name configured on the Redis backend)

send_request(request, on_response=None, response_timeout=5, **kwargs)

Send a request message on the backend.

  • request – The request, either a dict, a string/bytes UTF-8 JSON, or a platypush.message.request.Request object.

  • on_response (function) – Optional callback that will be called when a response is received. If set, this method will synchronously wait for a response before exiting.

  • response_timeout (float) – If on_response is set, the backend will raise an exception if the response isn’t received within this number of seconds (default: None)

send_response(response, request, **kwargs)

Send a response message on the backend.

  • response – The response, either a dict, a string/bytes UTF-8 JSON, or a platypush.message.response.Response object.

  • request – Associated request, used to set the response parameters that will link them


Set whether this thread is a daemon.

This method is deprecated, use the .daemon property instead.


Set the name string for this thread.

This method is deprecated, use the name attribute instead.


Start the thread’s activity.

It must be called at most once per thread object. It arranges for the object’s run() method to be invoked in a separate thread of control.

This method will raise a RuntimeError if called more than once on the same thread object.


Stops the backend thread by sending a STOP event on its bus


Unregister the Zeroconf service configuration if available.