How to access environment variable values

Question

I set an environment variable that I want to access in my Python application   How do I get its value

User · Answer

To check if the key exists  returns True or False    HOME  in os environ   You can also use get   when printing the key  useful if you want to use a default   print os environ get  HOME     home username       where  home username  is the default

User · Answer

You can also try this  First  install python-decouple  pip install python-decouple   import it in your file   from decouple import config   Then get the env variable   SECRET KEY config  SECRET KEY     Read more about the python library here

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Environment variables are accessed through os environ  import os print os environ  HOME      Or you can see a list of all the environment variables using   os environ   As sometimes you might need to see a complete list     using get will return  None  if a key is not present rather than raise a  KeyError  print os environ get  KEY THAT MIGHT EXIST       os getenv is equivalent  and can also give a default value instead of  None  print os getenv  KEY THAT MIGHT EXIST   default value     Python default installation on Windows is C  Python  If you want to find out while running python you can do   import sys print sys prefix

User · Answer

import os for a in os environ      print  Var     a   Value     os getenv a   print  all done     That will print all of the environment variables along with their values

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Actually it can be done this away  import os  for item  value in os environ items        print          format item  value    Or simply  for i  j in os environ items        print i  j   For view the value in the parameter  print os environ  HOME     Or  print os environ get  HOME     To set the value  os environ  HOME       new value

User · Answer

You can access to the environment variables using  import os print os environ   Try to see the content of PYTHONPATH or PYTHONHOME environment variables  maybe this will be helpful for your second question  However you should clarify it

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For django see  https   github com joke2k django-environ     pip install django-environ  import environ env   environ Env    set casting  default value DEBUG  bool  False      reading  env file environ Env read env      False if not in os environ DEBUG   env  DEBUG      Raises django s ImproperlyConfigured exception if SECRET KEY not in os environ SECRET KEY   env  SECRET KEY

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env File Here is my  env file  I changed multiple characters in each key to prevent people hacking my accounts   SECRET KEY 6g18169690e33af0cb10f3eb6b3cb36cb448b7d31f751cde AWS SECRET ACCESS KEY 18df6c6e95ab3832c5d09486779dcb1466ebbb12b141a0c4 DATABASE URL  postgres   drjpczkqhnuvkc f0ba6afd133c53913a4df103187b2a34c14234e7ae4b644952534c4dba74352d ec2-54-146-4-66 compute-1 amazonaws com 5432 ddnl5mnb76cne4  AWS ACCESS KEY ID AKIBUGFPPLQFTFVDVIFE DISABLE COLLECTSTATIC 1 EMAIL HOST PASSWORD COMING SOON MAILCHIMP API KEY a9782cc1adcd8160907ab76064411efe-us17 MAILCHIMP EMAIL LIST ID 5a6a2c63b7 STRIPE PUB KEY pk test 51HEF86ARPAz7urwyGw9xwLkgbgfCYT48LttlwjEkb88I7Ljb5soBtuKXBaPiKfuu0Cx2BzIowR3jJFkC8ybFBAEf00DFY46tB8 STRIPE SECRET KEY sk test 19HEF55BCEAz7urwytx7tO3QCxV4R8DEFXbqj6esg7OKuybiSTI8iJD8mmJUQpg4RKENxuS04DKOCzYHpDkAjUttO00LOmsT5Eg  settings I was told my data was corrupted  I was struggling to work out what was going on  I had a suspicion the values from  env were not being passed into my settings file  print os environ get  AWS SECRET ACCESS KEY    print os environ get  AWS ACCESS KEY ID    print os environ get  AWS SECRET ACCESS KEY    print os environ get  DATABASE URL    print os environ get  SECRET KEY    print os environ get  DISABLE COLLECTSTATIC    print os environ get  EMAIL HOST PASSWORD    print os environ get  MAILCHIMP API KEY    print os environ get  MAILCHIMP EMAIL LIST ID    print os environ get  STRIPE PUB KEY    print os environ get  STRIPE SECRET KEY     The only value being printed correctly was the SECRET KEY  I reviewed the  env file and for the life of me could not see any reason why the SECRET KEY was working and nothing else  I got everything working eventually by putting this above the print statements  from dotenv import load dotenv    for python-dotenv method load dotenv                       for python-dotenv method  And doing pip install -U python-dotenv  I am still not sure why SECRET KEY was working when all the others were broken

User · Answer

There s also a number of great libraries  Envs for example will allow you to parse objects out of your environment variables  which is rad  For example   from envs import env env  SECRET KEY      your secret key here  env  SERVER NAMES  var type  list      your    list    here

User · Answer

If you are planning to use the code in a production web application code  using any web framework like Django Flask  use projects like envparse   using it you can read the value as your defined type   from envparse import env   will read WHITE LIST hello world hi to white list     hello    world    hi   white list   env list  WHITE LIST   default        Perfect for reading boolean DEBUG   env bool  DEBUG   default False    NOTE  kennethreitz s autoenv is a recommended tool for making project specific environment variables  please note that those who are using autoenv please keep the  env file private  inaccessible to public

User · Answer

A performance-driven approach - calling environ is expensive  so it s better to call it once and save it to a dictionary  Full example  from os import environ     Slower print environ  quot USER quot    environ  quot NAME quot       Faster env dict   dict environ  print env dict  quot USER quot    env dict  quot NAME quot     P S- if you worry about exposing private environment variables  then sanitize env dict after the assignment

User · Answer

The original question  first part  was  how to check environment variables in Python     Here s how to check if  FOO is set    try       os environ  FOO   except KeyError      print  Please set the environment variable FOO     sys exit 1

User · Answer

As for the environment variables   import os print os environ  HOME     I m afraid you d have to flesh out your second point a little bit more before a decent answer is possible

[python] How to access environment variable values?

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