Blocking Call inside event loop

Hi guys!
I’m trying to build a small custom component to have my energy usage integrated.
There’s an android app called Eon Smart Control(E.ON Smart Control – Apps bei Google Play) that i use with a separate Lora GW which is connected to my electricity meter.

This is what i have been using in past with additional sensor configuration

#!/usr/bin/python3
# encoding: utf8
#

import requests, json
import os, time
from pathlib import Path
from datetime import datetime
from requests.structures import CaseInsensitiveDict

username = "EMAIL"
password = "PASSWORD"
auth_token_file=".auth-token"
today = "{:%Y-%m-%d}".format(datetime.now())
now = "{:%Y-%m-%dT%H:%M:%S.%f}".format(datetime.now())[:-3]
timeout=5

def file_age(filepath):
    seconds = str(time.time() - os.path.getmtime(filepath))
    return int(seconds.split('.')[0])

def get_token(username, password):
    file_location = Path(auth_token_file)
    if not file_location.is_file() or file_age(auth_token_file) >= 3600:
        url = "https://smartcontrol.eon.de/auth"

        headers = CaseInsensitiveDict()
        headers["Accept"] = "application/json"
        headers["Content-Type"] = "application/json"

        data = '{"username":"%s","password":"%s","method":"login"}' % (username, password)
        response = requests.get(url, headers=headers, data=data, allow_redirects=False, timeout=timeout)
        data=json.loads(response.text)
        return(data['access_token'])
    else:
        token=open(auth_token_file, 'r')
        return(token.readline())

def get_watts(access_token):
    url = "https://api.n2g-iona.net/v2/power/%sT00:00:00.000Z/%sZ" % (today, now)
    headers = CaseInsensitiveDict()
    headers["Accept"] = "application/json"
    headers["Authorization"] = "Bearer %s" % (access_token)
    response = requests.get(url, headers=headers, timeout=timeout)
    data=json.loads(response.text)
    my_dict={'power':data['data']['results'][-1]['power']}
    return(my_dict)

def get_kWh(access_token):
    url = "https://api.n2g-iona.net/v2/meter/info"
    headers = CaseInsensitiveDict()
    headers["Accept"] = "application/json"
    headers["Authorization"] = "Bearer %s" % (access_token)
    response = requests.get(url, headers=headers, timeout=timeout)
    data=json.loads(response.text)
    kWh=int(data['data']['Electricity']['CSD'])
    rounded = round(kWh / 1000)
    my_dict={'kWh': rounded}
    return(my_dict)

def main():
    access_token=get_token(username, password)
    print(get_kWh(access_token))
    print(get_watts(access_token))

if __name__ == '__main__':
    main()

This is what you get when you execute it directly

root@homeassistant:/usr/share/hassio/homeassistant# python3 custom_components/smart_control/smart_control_api.py
{'kWh': 8505}
{'power': 380}

This is my current data structure for the custom component:

root@homeassistant:/usr/share/hassio/homeassistant# tree custom_components/smart_control/
custom_components/smart_control/
|-- __init__.py
|-- __pycache__
|   |-- __init__.cpython-39.pyc
|   |-- sensor.cpython-39.pyc
|   `-- smart_control_api.cpython-39.pyc
|-- manifest.json
|-- sensor.py
`-- smart_control_api.py

this is my current sensor.py

"""Platform for sensor integration."""
from __future__ import annotations

from homeassistant.components.sensor import (
    SensorEntity,
    STATE_CLASS_MEASUREMENT,
    DEVICE_CLASS_ENERGY,
)
from homeassistant.const import ENERGY_KILO_WATT_HOUR
from homeassistant.core import HomeAssistant
from homeassistant.helpers.entity_platform import AddEntitiesCallback
from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
from .smart_control_api import get_token, get_watts, get_kWh


import requests, json
import os, time
from pathlib import Path
from datetime import datetime
from requests.structures import CaseInsensitiveDict


import logging

LOGGER = logging.getLogger(__name__)
USERNAME  = "EMAIL"
PASSWORD = "PASSWORD"

def setup_platform(
    hass: HomeAssistant,
    config: ConfigType,
    add_entities: AddEntitiesCallback,
    discovery_info: DiscoveryInfoType | None = None
) -> None:
    """Set up the sensor platform."""
    add_entities([
        SmartControlEnergyConsumptionTotalSensor(),
        SmartControlPowerConsumptionSensor()
    ])


class SmartControlEnergyConsumptionTotalSensor(SensorEntity):
    """Representation of a Smart Control Energy Consumption Total Sensor."""

    _attr_name = "Smart Control Energy Consumption Total"
    _attr_unit_of_measurement = ENERGY_KILO_WATT_HOUR
    _attr_device_class = DEVICE_CLASS_ENERGY
    _attr_state_class = STATE_CLASS_MEASUREMENT

    def __init__(self):
        self._attr_native_value = None

    async def async_update(self):
        """Fetch new state data for the sensor."""
        #self._attr_native_value = 1337
        try:
            access_token = get_token(USERNAME, PASSWORD)
            LOGGER.debug("ACCESS_TOKEN", access_token)
            kWh = get_kWh(access_token)
            LOGGER.debug("kWh", kWh)
        except requests.exceptions.ReadTimeout:
            self._attr_native_value = None

class SmartControlPowerConsumptionSensor(SensorEntity):
    """Representation of a Smart Control Power Consumption Sensor."""

    _attr_name = "Smart Control Power Consumption"
    _attr_unit_of_measurement = "W"

    def __init__(self):
        self._attr_native_value = None

    async def async_update(self):
        """Fetch new state data for the sensor."""
        #self._attr_native_value = 69
        try:
            access_token = get_token(USERNAME, PASSWORD)
            watts = get_watts(access_token)
            self._attr_native_value = watts['power']
        except requests.exceptions.ReadTimeout:
            self._attr_native_value = None

So far, i tested the sensor with static values ( see commented lines with self._attr_native_value) and it worked without problems. But now, adding my functions to get the data it doesnt work. As far as i understood, it has to do with requests and async - i’m not that deep into programming and have no knowledge of asynchronous programming at all.

This is, what my logfile looks like:

2023-05-27 17:14:35 WARNING (MainThread) [homeassistant.util.async_] Detected blocking call to putrequest inside the event loop. This is causing stability issues. Please report issue to the custom component author for smart_control doing blocking calls at custom_components/smart_control/smart_control_api.py, line 55: response = requests.get(url, headers=headers, timeout=timeout)
2023-05-27 17:14:35 WARNING (MainThread) [homeassistant.util.async_] Detected blocking call to putrequest inside the event loop. This is causing stability issues. Please report issue to the custom component author for smart_control doing blocking calls at custom_components/smart_control/smart_control_api.py, line 45: response = requests.get(url, headers=headers, timeout=timeout)
2023-05-27 17:14:35 ERROR (MainThread) [homeassistant.helpers.entity] Update for sensor.smart_control_energy_consumption_total fails
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 535, in async_update_ha_state
    await self.async_device_update()
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 744, in async_device_update
    raise exc
  File "/config/custom_components/smart_control/sensor.py", line 59, in async_update
    kWh = get_kWh(access_token)
  File "/config/custom_components/smart_control/smart_control_api.py", line 55, in get_kWh
    response = requests.get(url, headers=headers, timeout=timeout)
  File "/usr/local/lib/python3.9/site-packages/requests/api.py", line 75, in get
    return request('get', url, params=params, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/requests/api.py", line 61, in request
    return session.request(method=method, url=url, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/requests/sessions.py", line 529, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/local/lib/python3.9/site-packages/requests/sessions.py", line 645, in send
    r = adapter.send(request, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/requests/adapters.py", line 440, in send
    resp = conn.urlopen(
  File "/usr/local/lib/python3.9/site-packages/urllib3/connectionpool.py", line 703, in urlopen
    httplib_response = self._make_request(
  File "/usr/local/lib/python3.9/site-packages/urllib3/connectionpool.py", line 398, in _make_request
    conn.request(method, url, **httplib_request_kw)
  File "/usr/local/lib/python3.9/site-packages/urllib3/connection.py", line 239, in request
    super(HTTPConnection, self).request(method, url, body=body, headers=headers)
  File "/usr/local/lib/python3.9/http/client.py", line 1285, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/local/lib/python3.9/http/client.py", line 1296, in _send_request
    self.putrequest(method, url, **skips)
  File "/usr/local/lib/python3.9/site-packages/urllib3/connection.py", line 219, in putrequest
    return _HTTPConnection.putrequest(self, method, url, *args, **kwargs)
  File "/usr/src/homeassistant/homeassistant/util/async_.py", line 173, in protected_loop_func
    check_loop(func, strict=strict)
  File "/usr/src/homeassistant/homeassistant/util/async_.py", line 161, in check_loop
    raise RuntimeError(
RuntimeError: Blocking calls must be done in the executor or a separate thread; Use `await hass.async_add_executor_job()` at custom_components/smart_control/smart_control_api.py, line 55: response = requests.get(url, headers=headers, timeout=timeout)
2023-05-27 17:14:35 ERROR (MainThread) [homeassistant.helpers.entity] Update for sensor.smart_control_power_consumption fails
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 535, in async_update_ha_state
    await self.async_device_update()
  File "/usr/src/homeassistant/homeassistant/helpers/entity.py", line 744, in async_device_update
    raise exc
  File "/config/custom_components/smart_control/sensor.py", line 78, in async_update
    watts = get_watts(access_token)
  File "/config/custom_components/smart_control/smart_control_api.py", line 45, in get_watts
    response = requests.get(url, headers=headers, timeout=timeout)
  File "/usr/local/lib/python3.9/site-packages/requests/api.py", line 75, in get
    return request('get', url, params=params, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/requests/api.py", line 61, in request
    return session.request(method=method, url=url, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/requests/sessions.py", line 529, in request
    resp = self.send(prep, **send_kwargs)
  File "/usr/local/lib/python3.9/site-packages/requests/sessions.py", line 645, in send
    r = adapter.send(request, **kwargs)
  File "/usr/local/lib/python3.9/site-packages/requests/adapters.py", line 440, in send
    resp = conn.urlopen(
  File "/usr/local/lib/python3.9/site-packages/urllib3/connectionpool.py", line 703, in urlopen
    httplib_response = self._make_request(
  File "/usr/local/lib/python3.9/site-packages/urllib3/connectionpool.py", line 398, in _make_request
    conn.request(method, url, **httplib_request_kw)
  File "/usr/local/lib/python3.9/site-packages/urllib3/connection.py", line 239, in request
    super(HTTPConnection, self).request(method, url, body=body, headers=headers)
  File "/usr/local/lib/python3.9/http/client.py", line 1285, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/usr/local/lib/python3.9/http/client.py", line 1296, in _send_request
    self.putrequest(method, url, **skips)
  File "/usr/local/lib/python3.9/site-packages/urllib3/connection.py", line 219, in putrequest
    return _HTTPConnection.putrequest(self, method, url, *args, **kwargs)
  File "/usr/src/homeassistant/homeassistant/util/async_.py", line 173, in protected_loop_func
    check_loop(func, strict=strict)
  File "/usr/src/homeassistant/homeassistant/util/async_.py", line 161, in check_loop
    raise RuntimeError(
RuntimeError: Blocking calls must be done in the executor or a separate thread; Use `await hass.async_add_executor_job()` at custom_components/smart_control/smart_control_api.py, line 45: response = requests.get(url, headers=headers, timeout=timeout)
~

Any help is greatly appreciated

BR

Where you are calling functions from your smart_control_api, do it like this

KWh = await hass.async_add_executor_job(getkWh, access_token)

Ie name of function is first entry in brackets, all passed variables next seperate by commas.

1 Like

I have the same warning and the offending line is this:
with open(CONF_file) as f:
can I replace by this:
with await hass.async_add_executor_job(open, CONF_file) as f:
or there is a better way to do it
Thank you

No. File access is a blocking function, so whilst async_add_executor_job will run the open in a thread (so as not to block the event loop), reading the file will also be blocking.

If your function reads a file and returns a value, call the whole function by doing…

val = await hass.async_add_executor_job(CONF_FILE_READING_FUNCTION)

Aternatively, use aiofiles to read your file which is non blocking.

Thanks, with aiofiles do we need to add an import line at the beginnig of python file.
I get aiofiles is undefined

Yes, you always need to import libraries you are using.

so this seem to work

import aiofiles
...
    dev_list = []
    async with aiofiles.open(CONF_file) as f:
        async for line in f:
            dev_list.append(json.loads(line))         
    await f.close()

should I put await in front of line dev_list…