How to store a Python dictionary as an Environment Variable

Question

I am trying to store an Environment Variable that Python can read in as a Dictionary. If this is a bad idea, please let me know your suggestions, I am eager to learn. I’m worried that if I store the data as many environment variables it might become hard to manage.

I programmed a Raspberry Pi to unlock a door based off the Caller ID’s of incoming phone calls to a Twilio number, it is working great. I want to share my code on Github for feedback but I do not want to share my list of phone numbers with the world so I am trying to save it as an environment variable and then let Python read it in.

The phone numbers are in a Python Dictionary like this.

building_admins = {
    "+27792955555": "De Wet",
    "+27722855555": "Marysol",
    "+27878085555": "Blomerus",
}

I am trying to save it as an Environment Variable like this on Ubuntu 14.04

export BUILDING_ADMINS='{
    "+27792955555": "De Wet",
    "+27722855555": "Marysol",
    "+27878085555": "Blomerus",
}'

1) I can’t get Linux to save the environment variable, is there something I could do to make it work?

2) I feel like there must be a better way to do this and I am going in the wrong direction but nothing I seem to find with Googling is solving the problem I am facing. Please point me in the right direction.

Asked By: dewet

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Source

Answer 1

If you choose to use the environment, you should serialize the Python dictionary as JSON and dump/load that when setting/getting the environment variable. You can access the environment using os module’s environ attribute. You can dump/load JSON using the json module. You might want to watch out for a maximum length on environment variables if there is such a thing.

If I were you I would use a sqlite database, see https://docs.python.org/2/library/sqlite3.html. This would give you persistence, a defined schema, and a nice interface for handling your data.

Answered By: sholsapp

Answer 2

An environment variable is not something a script user would like to set. Use the json module and a file:

import json

with open('numbers') as f:
    numbers = json.load(f)

print numbers['+27792955555']    #  De Wet

When pushing to GitHub don’t commit the numbers file. Maybe commit an example one and add the real one to your .gitignore.

Answered By: enrico.bacis

Answer 3

It is possible! Just do

import os
os.environ.__dict__["_data"]["yourkey"] = {"key":0} #Your data
print (os.environ.__dict__["_data"]["yourkey"]) #Will print out value!

It’s a little complicated but works!

Answered By: Luis Michaelis

Answer 4

I don’t know if this is what you were looking for, but I ended up here while trying to save a dictionary as a Linux environment variable to consume it on my app.

What I did was saving it as a string like this:

export BUILDING_ADMINS="{'+27792955555': 'De Wet','+27722855555': 'Marysol','+27878085555': 'Blomerus'}'

And then on your python code you read it and transform it into a dictionary using this (taken from: Convert a String representation of a Dictionary to a dictionary?):

import ast
import os

ba_dict = ast.literal_eval(os.environ["BUILDING_ADMINS"])

If you type

type(ba_dict)

You should see your string is now a dict.

<class 'dict'>

Hope this helps someone else!

Answered By: Diego Serrano

Answer 5

There is a option named environs, unfortunately, the way of exporting is a little different from the one you want, but I will suggest you because can be an alternative for you or other people (I needed to do this another day).

https://pypi.org/project/environs/

pip install environs

You can export via terminal or even creating a .env file

export BUILDING_ADMINS=+27792955555=De Wet,+27722855555=Marysol, +27878085555=Blomerus

In the code:

from environs import Env

env = Env()
env.read_env() // to allow reading from .env file

building_admins = env.dict('BUILDING_ADMINS', subcast=str)

result:

print(building_admins)

{
    "+27792955555": "De Wet",
    "+27722855555": "Marysol",
    "+27878085555": "Blomerus",
}

Answered By: Thiago Valentim

Answer 6

I would suggest you to use environ just because of the fact that the library does some extra safety checking and has seen all kinds of use cases.

https://pypi.org/project/environs/

pip install environs

Your config.py

import environ

# Django cookiecutter does it like this.
env = environ.Env()
ROOT_DIR = (
    environ.Path(__file__)
) # let's say your configs sit at the root of the project and it's called .env
env.read_env(str(ROOT_DIR.path(".env")))

# Your env variable looks like a JSON
# There are multiple types available that you can go for if you don't think JSON is correct.
BUILDING_ADMINS = env.json('BUILDING_ADMINS')

>> from configs import *
>> print(BUILDING_ADMINS)
{
    "+27792955555": "De Wet",
    "+27722855555": "Marysol",
    "+27878085555": "Blomerus"
}
>> type(BUILDING_ADMINS)
<class 'dict'>

Answered By: Sukhinderpal Mann

Answer 7

As I didn’t want to have to insert a new package environs, I tried all others exposed solutions, but in Python 3.6, none worked for me.

My solution for tranform this below env variable into dict object is :

MY_ENV_VAR_DICT="{'test1':'test1','test2':'test2'}"

Code:

import os

my_dict = eval(os.environ['MY_ENV_VAR_DICT'].replace('"',''))
print(my_dict.items())

Output :

dict_items([('test1', 'test1'), ('test2', 'test2')])

This works fine for me (with no superfluous imports) ! 🙂

Answered By: Hlodowig91

How to store a Python dictionary as an Environment Variable

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