It needs to write to ‘standard output’. In other words, if you are at the Linux command line and execute your script, it’s output should appear on the command line (‘standard output’).
Here’s an example of a command line sensor calling a python script:
Here’s an example using shell script but it’s the same principal.
Ok so i have made this :
#!/usr/bin/python2
import requests
import json
from datetime import datetime
import locale
import sys
sensor = sys.argv[1]
body = {"adrid": 24750,"common": False}
headers = {'content-type': 'application/json'}
url = 'https://herlev.renoweb.dk/Legacy/JService.asmx/GetAffaldsplanMateriel_mitAffald'
response = requests.post(url,data=json.dumps(body),headers=headers)
cleaned = ((response.content.replace('"d":"{', '"d":{')).replace('}]}"', '}]}')).replace('\\','')
y = json.loads(cleaned)
locale.setlocale(locale.LC_ALL, 'da_DK.UTF-8')
if sensor == "Dagrenovation":
datetime_object = datetime.strptime(y['d']['list'][0]['toemningsdato'], '%A den %d-%m-%Y')
print(datetime_object.date())
elif sensor == "MadamSkrald":
datetime_object = datetime.strptime(y['d']['list'][2]['toemningsdato'], '%A den %d-%m-%Y')
print(datetime_object.date())
elif sensor == "Storskrald":
datetime_object = datetime.strptime(y['d']['list'][3]['toemningsdato'], '%A den %d-%m-%Y')
print(datetime_object.date())
elif sensor == "Haveaffald":
datetime_object = datetime.strptime(y['d']['list'][5]['toemningsdato'], '%A den %d-%m-%Y')
print(datetime_object.date())
else:
print("unknown")
Now i have to test it in HASS to see if it works.
of course it didn’t work… 
Log Details (ERROR)
Sat May 04 2019 22:26:43 GMT+0200 (Central European Summer Time)
Command failed: python3 /config/herlev_affald.py 'Haveaffald'
and the sensor is unknown so for some reason the argument is not passed correctly
I think that message means Home Assistant’s was either unable to find or to execute the python file.
Are you using hass.io?
Yes i am, it can find the the script. i chmod 755. I made another script with just print("hello") and that worked so i started to add code until it failed and as far as i can see as soon as i try to use response.content the script fails but if i do print(response) i get 200 so i don’t know what’s going on
When I run this from the command-line:
python3 ./herlev_affald.py 'Haveaffald'
I get this response:
Traceback (most recent call last):
File "./herlev_affald.py", line 14, in <module>
cleaned = ((response.content.replace('"d":"{', '"d":{')).replace('}]}"', '}]}')).replace('\\','')
TypeError: a bytes-like object is required, not 'str'
Ouch…i only tested with python 2.7…hmmm i guess then it’s python 3 issue, well spotted, let me upgrade on my mac python to ver 3
So i changed the line, it works locally with python3 but still doesn’t work in HASS
cleaned = ((response.content.decode('utf-8').replace('"d":"{', '"d":{')).replace('}]}"', '}]}')).replace('\\','')
I’ve encountered a hurdle. I have trouble making the script work for me because my locale is not Danish. If I comment out the line that sets the locale, strptime fails to perform the date conversion. In my locale (English Canada), %A and Fredag are incompatible (no surprise there).
All I want to do is try running the script from within Home Assistant to see if I get the same error message as you. Later I will try simplifying the python script just enough so it works for my locale.
Yes you are on to something, i also nailed it down to
datetime_object = datetime.strptime(y['d']['list'][5]['toemningsdato'], '%A den %d-%m-%Y')
maybe because the locale i set isn’t working so strptime is failing…i am too tired now so i can’t concentrate anymore. I will hit the bed…damn it…
I modified the code and this works for me. I now know on which days you can put out garden waste, refuse, bulk items, etc. 
#!/usr/bin/python3
import requests
import json
from datetime import datetime
import sys
if len(sys.argv) == 2:
days = {'Mandag':'Monday', 'Tirsdag':'Tuesday', 'Onsdag':'Wednesday', 'Torsdag':'Thursday', 'Fredag':'Friday'}
types = {'Dagrenovation':0, 'MadamSkrald':2, 'Storskrald':3, 'Haveaffald':5 }
body = {'adrid': 24750,'common': False}
headers = {'content-type': 'application/json'}
url = 'https://herlev.renoweb.dk/Legacy/JService.asmx/GetAffaldsplanMateriel_mitAffald'
response = requests.post(url,data=json.dumps(body),headers=headers)
cleaned = ((response.content.decode('utf-8').replace('"d":"{', '"d":{')).replace('}]}"', '}]}')).replace('\\','')
j = json.loads(cleaned)
t = types.get(sys.argv[1])
if t != None:
d = j['d']['list'][t]['toemningsdato']
for k, v in days.items():
d = d.replace(k, v)
datetime_object = datetime.strptime(d, '%A den %d-%m-%Y')
print(datetime_object.date())
else:
print('unknown')
else:
print('error')
Sensor definition (my python file is located in a sub-directory):
- platform: command_line
name: garden waste
command: "python3 /config/python_scripts/test.py Haveaffald"
@123 Thank you very much, indeed this a solution which solves the problem and works. Weird the one with setting the locale didn’t work. Now i will continue to make a binary sensor that can check the date towards today so i can make an automation to send notification.
Thanks again for your effort 