From what I've read, any changes to the environment variables in a Python instance are only available within that instance, and disappear once the instance is closed. Is there any way to make them stick by committing them to the system?
The reason I need to do this is because at the studio where I work, tools like Maya rely heavily on environment variables to configure paths across multiple platforms.
My test code is
import os
os.environ['FAKE'] = 'C:\\'
Opening another instance of Python and requesting os.environ['FAKE'] yields a KeyError.
NOTE: Portability will be an issue, but the small API I'm writing will be able to check OS version and trigger different commands if necessary.
That said, I've gone the route of using the Windows registry technique and will simply write alternative methods that will call shell scripts on other platforms as they become requirements.
You can using SETX at the command-line.
By default these actions go on the USER env vars.
To set and modify SYSTEM vars use the /M flag
import os
env_var = "BUILD_NUMBER"
env_val = "3.1.3.3.7"
os.system("SETX {0} {1} /M".format(env_var,env_val))
make them stick by committing them to
the system?
I think you are a bit confused here. There is no 'system' environment. Each process has their own environment as part its memory. A process can only change its own environment. A process can set the initial environment for processes it creates.
If you really do think you need to set environment variables for the system you will need to look at changing them in the location they get initially loaded from like the registry on windows or your shell configuration file on Linux.
Under Windows it's possible for you to make changes to environment variables persistent via the registry with this recipe, though it seems like overkill.
To echo Brian's question, what are you trying to accomplish? There is probably an easier way.
Seems like there is simplier solution for Windows
import subprocess
subprocess.call(['setx', 'Hello', 'World!'], shell=True)
I don't believe you can do this; there are two work-arounds I can think of.
The os.putenv function sets the environment for processes you start with, i.e. os.system, popen, etc. Depending on what you're trying to do, perhaps you could have one master Python instance that sets the variable, and then spawns new instances.
You could run a shell script or batch file to set it for you, but that becomes much less portable. See this article:
http://code.activestate.com/recipes/159462/
Think about it this way.
You're not setting shell environment variables.
You're spawning a subshell with some given environment variable settings; this subshell runs your application with the modified environment.
According to this discussion, you cannot do it. What are you trying to accomplish?
You are forking a new process and cannot change the environment of the parent process as you cannot do if you start a new shell process from the shell
You might want to try Python Win32 Extensions, developed by Mark Hammond, which is included in the ActivePython (or can be installed separately). You can learn how to perform many Windows related tasks in Hammond's and Robinson's book.
Using PyWin32 to access windows COM objects, a Python program can use the Environment Property (a collection of environment variables) of the WScript.Shell object.
Try to use py-setenv that will allow you to set variable via registry
python -m pip install py-setenv
From within Python? No, it can't be done!
If you are not bound to Python, you should consider using shell scripts (sh, bash, etc). The "source" command allows you to run a script that modifies the environment and will "stick" like you want to the shell you "sourced" the script in. What's going on here is that the shell executes the script directly rather creating a sub-process to execute the script.
This will be quite portable - you can use cygwin on windows to do this.
In case someone might need this info. I realize this was asked 7 yrs ago, but even I forget how sometimes. .
Yes there is a way to make them "stick" in windows. Simply go control panel, system, advanced system settings,when the system properties window opens you should see an option (button) for Environment Variables. .The process for getting to this is a little different depending on what OS you're using (google it).
Choose that (click button), then the Environment Variables window will open. It has 2 split windows, the top one should be your "User Variables For yourusername". . .choose "new", then simply set the variable. For instance one of mine is "Database_Password = mypassword".
Then in your app you can access them like this: import os, os.environ.get('Database_Password'). You can do something like pass = os.environ.get('Database_Password').
I've been looking and so far been unable to find a way of validating/linting my Jenkinsfile. At least not by using tox, pycharm or another way outside of visual code for example (I did saw some examples of that, more or less).
Does anyone know of a way to do this? I would like to perform some simple checks, like:
return a warning if an environment variable inside the file is used but isn't declared (so I know I have to check if it is set on server level, for example).
Creating some custom checks would be a huge plus: e.g. if strings, without variables, use single quotes instead of double.
Jenkins can validate, or "lint", a Declarative Pipeline from the command line before actually running it. This can be done using a Jenkins CLI command.
Linting via the CLI with SSH
# ssh (Jenkins CLI)
# JENKINS_SSHD_PORT=[sshd port on controller]
# JENKINS_HOSTNAME=[Jenkins controller hostname]
ssh -p $JENKINS_SSHD_PORT $JENKINS_HOSTNAME declarative-linter < Jenkinsfile
More info available at : Linter
Additional reference: Validate Jenkinsfile
I am trying to retrieve the parameters set from the jenkins build into my python script, but am having trouble. I understand the parameters set from here:
Are set as env variables and all I have to do in python is do:
# Env variables
UPDATE_DATA = os.environ.get('update_data')
ALL_BUILDS = os.environ.get('all_builds')
However I am getting None for those values. When I do an echo of those parameters in my jenkins script before my python script runs, I could see them being printed out correctly. However, for some reason python does not see them. If I go manually into a terminal and export a variable and run my python script, it works.. So I'm completely lost here.
Jenkins server is running on linux. Using python 2.7
You can use the boolean variable like this:
Output:
It seems like when I ran the python script in the Jenkins config (not inside a file within my project) like how #souravatta suggested, it found the env variable. So that means the env variable Jenkins is setting, is on a different instance somehow (even though they are on the same computer, same user). I just did a workaround where I wrote the env variables to a file and then just read that file in my python script.
I want to write a python script to get list of "jenkins" variables and show them.
I wrote this, but it returned all environment variables instead of jenkins variables.
import os
print os.environ
How can I get them in python script?
Jenkins variables are environment variables. There isn't really anything that separates them.
You can use EnvInject plugin to clean the Jenkins environment of all OS environment variables that are inherited, this way you are left with "just Jenkins environment variables", but careful as this may break your tools as none of the paths will be set.
If you want to view just the Build Parameters, you can use the Jenkins API for each job, or parse the job's XML file
There is a specific set of built-in variable that a base Jenkins install adds to each execution step; here is a list from the reference:
https://wiki.jenkins-ci.org/display/JENKINS/Building+a+software+project#Buildingasoftwareproject-below
As Slav says, these are just like any other environment variable, and if you want to access one you would just ask for it by name e.g., for $WORKSPACE, you would use os.environ['WORKSPACE']
You could enumerate the variables at the url above in a list ['WORKSPACE', ...] and print them that way...
In my build (I'm using Linux) I need to call a Python script and set some env variables. I need these variables to be set even after I exit the script. I am able to set it using os.environ within the script but whenever I exit the script and try to see if the env variable is set from the terminal (echo $myenv) - I get nothing.
I am new to Python and did quite a bit googling to figure this out. However, I am not quite sure if it's possible. I tried using the subprocess:
subprocess.call('setenv myenv 4s3', shell=True)
Also tried using os.system:
os.system("setenv myenv 4s3")
So far, I didn't succeed.
You cannot set environment variables from a child process and have them be visible in the parent process. Every process gets its own copy of the environment, and changes do not propagate upwards.
What you could do is have the Python script print the settings it wants to change and have the outside shell execute the appropriate commands.
Maybe if you find some equivalent function like c vfork for Python.
When you vfork, both processes share memory space so, you might overwrite environment variables in parent process from child process.
Warning: vfork has many security issues, and therefore not recommended. Just use it if you are desperate.