In the context of Python, a Python environment variable refers to an environment variable that often interacts with environment variables to access configuration settings, manage the runtime working of a process, or retrieve sensitive information. These variables belong to the environment where the interpreter of Python runs.
What is an Environment Variable?
First of all, An environment variable is a type of value that can change the working or behaviour of different processes running on the computer. Furthermore, these variables belong to the environment in which a process runs or is running. In addition, they can be utilized to store configuration settings, system paths, or any other information or a script that might be useful.
Secondly, an environment variable is a type of variable that is outside of the program or script but not beyond their access at any time. So, these variables can be referenced by the program or script. These variables are typically key-value pairs, where the key will be the name of the variable, and the data will be the value or information which that variable holds.
How to Access Python Environment Variables?
In Python, environment variables are accessed using an ‘os’ module. Here, OS means Operating System. To get objects that represent the current process we write ‘os.environ’ .By using this object, further modifications can be added which then resultantly will modify the working of those variables in your scripts.
Example:
import os as OS
#Getting the value of an environment variable
any_value=OS.environ.get(‘MY_VARIABLE’)
#Now Accessing the value of the environment variable directly
any_value=OS.environ[“MY_VARIABLE”]
How to use the OS Module and Retrieve Specific Environment Variables?
There is a certain way in Python in which we can interact with the operating system module, which then allows you to perform several system-related tasks. Some famous or common functions of operating system variables are:
os.listdir(path) #returns the list of files in that given directory.
os.getcwd() #returns the current working directory.
os.chdir(path) #changes the current working directory to the specified path
os.path.join(first_path,second_path,…) #joins one or more paths intelligently
os.path.exists(given_path) #returns true if the path exists and false when it doesn’t
os.open() #opens a file and obtains file descriptor
os.exit() #exits the process
os.abort() #immediately terminates the running process
os.close() #closes the specified file descriptor
What are the Scope and Lifecycle of Environment Variables?
The scope and lifecycle of environment variables are determined by the context in which they are being accessed and are also being set. More generally, in terms of scope, any changes or modifications that are being made to environment variables within a process do not affect the other processes running on the system.
However, the lifecycle of the environment variable exists as long as the process is alive. Furthermore, they are created when the process starts and can be accessed or modified during the process’s execution.
In the process’s termination, the Python environment variables also get eliminated.
Types of Environment Variables
Environment variables can be categorized into different types based on their purpose or usage. Following are some of the environment variables.
System Environment Variables
PATH, HOME, TEMP, and USERPROFILE are examples of system environment variables.
User Environment Variables
USER, LANG, and LC_ALL are a few prominent types of user environment variables.
Application-specific
DJANGO_SETTINGS_MODULE is used by Django, and JAVA_HOME is utilized by Java applications.
Development and Debugging
DEBUG, VERBOSE, and LOG_LEVEL are examples of Development and Debugging Environment Variables.
Security-related
API_KEY and SECRET_KEY are the security-related environment variables.
Configuration-related
DATABASE_URL and AWS_KEY_ID are some of the configuration-related environment variables.
Path-related
PATH and LD_LIBRARY_PATH are path-related environment variables.
Temporary Environment Variables
TMPDIR, TMP, and TEMP which are used to specify directories are some of the temporary environment-related variables.
System Environment Variables
These types of variables are set by the operating system itself and are accessible to all the processes that are running on the system. The type of information these types of variables usually contain is system path, configuration settings and many more. Moreover, the examples of the system environment variables have been mentioned in Types of Variables.
User Environment Variables
As seen by name, these variables often refer to a specific user and are used to customize the behaviour or working of the application for that user.
Conclusion
The conclusion cannot differ much from the introduction heading of this article. However, environment variables are dynamic variables that influence the behaviour of the process. There is a module named ‘os’ that allows us the functionality to do so in Python, as mentioned earlier in the article. Moreover, you can read more about these Environment variables on Python’s official website.
