Set up a red light alarm to check your website status with python, cron and the Philips hue API
Just to let you know, there are much better ways to monitor your services. But I found this quite funny to make and it’s a first step on creating incredibly useful Hue apps \o/.
The result
A cron tab is set on the NAS which run my python script every minutes. The script then check for the website and if it’s down, it makes the lamps blink.
Play with the Philips hue API
Before diving in the code, I suggest to you to read the official hue beginner’s guide if you never have used a REST application before.
Write your script
For the script, I choosed to use Python because it’s really easy to get started.
Before working on the module which would have helped me interface the Hue API, I have made some researches and I came across with phue, a lightweight Python library for the Philips Hue system. It’s even easier to manage your lights.
Getting started with phue
To install it, just run pip install phue. If you have pip but it’s not available in your path or you want to use a sepcific version of Python, use this instead: python -m pip install phue.
Then create your file for your script using your favorite editor.
vim webCheck.py
We now need to connect to the Bridge which will then provides us all the required functions to play with our lights.
#!/usr/bin/python
from phue import Bridge
b = Bridge('192.168.0.12') # You should know your bridge's ip if you had read Phillips' guide
b.connect()
Now run the script using python webCheck.py and you should get an exception telling you that you haven’t any API key. This is b.connect() that actually fails, you have to press the button on your Bridge and re-run the script.
phue will then create a file in your user directory containing the API key, this will prevent you to press the button each time you want to run the script. But I suggest you to specify a key file, because when you will deploy your script, you won’t have to press the button again and if you use a system user to run your script (highly recommended), it will still work.
So let’s define this key file based on our script path.
...
import os
from phue import Bridge
SCRIPT_PATH = os.path.dirname(__file__) # Directory of the current file
KEY_FILE = os.path.join(SCRIPT_PATH, ".python_hue") # Path to hidden key file
b = Bridge(IP_ADDRESS, config_file_path=KEY_FILE)
b.connect()
You should have to press the button again or copy the file .python_hue from your user or documents directory into your script’s directory.
You can now easily play with your lights, just modify your script and run it again.
...
b.set_light(1,'on', False)
Checkout the phue GitHub page to see what you can do with it.
Red alarm animation
We will create a function for this, it’s basically turning the light on and off multiple times with a defined animation time.
from time import sleep
...
def alarm(bridge, light_id, tr_time, blink_count):
animIn = {'transitiontime': tr_time,
'on': True,
'bri':254, # Full luminosity
'sat': 254, # Full saturation
'hue': 65535 # Red
}
animOut = {'transitiontime': tr_time,
'on': True,
'bri':5, # Almost off
'sat': 70, # Less saturation
'hue': 65535 # Still red
}
sleep_time = float(tr_time + 1) / 10.0
for i in range(0, blink_count):
b.set_light(light_id, animIn)
sleep(sleep_time)
b.set_light(light_id, animOut)
sleep(sleep_time)
This will turn the light red then on and off blink_count times with a transition time of tr_time. The unit time used by the Philips hue API is 1/100 seconds, so you have to set it to 10 if you want a transition of 1 seconds – which is very long, I personally use 5 for 500ms.
Each time you send an animation to the lamp, you have to wait the end of the animation before starting another, this is what sleep does. But sleep requires seconds, if you give 1 to it, it will sleep for 1 second. So divide it by 10 to get the same time as the light animation. I use a float conversion before dividing to avoid weird results that you can get when mixing integers and floats (which is totally normal by the way).
This is not enough, this script won’t set our light to it’s initial state after the alarm ends. To do this, we must get the light state before and reset it after the animation.
def alarm(bridge, light_id, tr_time, blink_count):
default = b.get_light(light_id) # Default state
....
animOut = {
'on': default['state']['on'],
'sat': default['state']['sat'],
'hue': default['state']['hue'],
'bri': default['state']['bri'],
}
b.set_light(light_id, animOut) # Reset to default
You can test your animation by running your function at the end of your script and running your python file.
...
alarm(b, 1, 5, 10)
Detect if your website is down
Simply sending a request and looking the response code is enough to determine if the website is ok or not. A response code above or equal to 400 on our main page (/) is when we suppose that the site is down.
from requests import get
...
site_down = False
try:
r = get("http://yourwbesite.tld/")
if r.status_code >= 400:
site_down = True
except Exception:
site_down = True
Then silmply call the function if the site is down.
if site_down:
alarm(b, 1, 5, 10)
That’s it. Let met show the full script before going further.
#!/usr/bin/python
"""
Set a red alarm on a given light when the specified website is down
"""
import os
from phue import Bridge
from time import sleep
from requests import get
import sys
SCRIPT_PATH = os.path.dirname(__file__) # Directory of the current file
KEY_FILE = os.path.join(SCRIPT_PATH, ".python_hue") # Path to hidden key file
def alarm(bridge, light_id, tr_time, blink_count):
default = b.get_light(light_id) # Default state
animIn = {'transitiontime': tr_time,
'on': True,
'bri':254, # Full luminosity
'sat': 254, # Full saturation
'hue': 65535 # Red
}
animOut = {'transitiontime': tr_time,
'on': True,
'bri':5, # Almost off
'sat': 70, # Less saturation
'hue': 65535 # Still red
}
sleep_time = float(tr_time + 1) / 10.0
for i in range(0, blink_count):
b.set_light(light_id, animIn)
sleep(sleep_time)
b.set_light(light_id, animOut)
sleep(sleep_time)
animOut = {
'on': default['state']['on'],
'sat': default['state']['sat'],
'hue': default['state']['hue'],
'bri': default['state']['bri'],
}
b.set_light(light_id, animOut) # Reset to default state
if __name__ == "__main__":
b = Bridge(IP_ADDRESS, config_file_path=KEY_FILE)
b.connect()
site_down = False
try:
r = get("http://yourwbesite.tld/") # Or you can use sys.argv to specifiy the url when calling the script
if r.status_code >= 400:
site_down = True
except Exception:
site_down = True
if site_down:
alarm(b, 1, 5, 10)
sys.exit(0)
Use cron to call your script every minutes
You can install cron on your personal machine or on your server to run your scripts every minutes to check your website. Of course, this will only work if your computer is in the same network as the light. If you have a NAS, you should have a Scheduled Tasks program which allow you to execute something whenever you want; This is generally cron with a GUI.
Copy the script on your server, and then edit your cron configuration. And don’t forget to install python, pip, phue and cron on the server.
crontab -e
This will open your cron configuration with your pre-configured (or not) editor. At the end of it, add a line like the following:
* * * * * /usr/bin/python[3/2.7/...] /home/login/path/to/the/script/webCheck.py > /dev/null
That should call the given command every minute of every hour of every day of the current month for every months and for every days in the current week.Just that :)
If you want to run it every 15 minutes, just change the first star by */15.
> /dev/null allow you to ignore standard outputs, which has the effect to only send you mails if your script fails (if you have a mail service configured).
Credits
Thanks to Lucas who owns these lights and the NAS on which I made this stuff.