I'm developing a Django app which runs Matlab scripts with Python's Popen class. The python script that calls Matlab scripts lives in the main folder of my Django app (with views.py). When I call the script from command line, it runs like a charm but when I make a request from the client in order to run the corresponding python script, I receive the following warning:
"< M A T L A B (R) > Copyright 1984-2018 The MathWorks, Inc. R2018a (9.4.0.813654) 64-bit (glnxa64) February 23, 2018 To get started, type one of these: helpwin, helpdesk, or demo. For product information, visit www.mathworks.com. >> [Warning: Unable to create preferences folder in /var/www/.matlab/R2018a. Preferences folder location must be writable. Using a temporary preferences folder for this MATLAB session. See the preferences documentation for more details.] >>
My app uses a Python virtual environment and it is being deployed with Apache web server.
Here is my python script that calls Matlab scripts:
import os
import subprocess as sp
import pymat_config
def pymat_run():
pwd = pymat_config.pwd_config['pwd']
cmd1 = "-r \"Arg_in = '/path/to/my/main/folder/input.txt'; Arg_out = '/path/to/my/main/folder/file.txt'; matlab_script1\""
baseCmd1 = ['/usr/local/MATLAB/R2018a/bin/matlab', '-nodesktop', '-nosplash', '-nodisplay', 'nojvm', cmd1]
os.chdir('/path/to/matlab_script1')
sudo_cmd = sp.Popen(['echo', pwd], stdout=sp.PIPE)
exec1 = sp.Popen(['sudo', '-S'] + baseCmd1, stdin=sudo_cmd.stdout, stdout=sp.PIPE, stderr=sp.PIPE)
out, err = exec1.communicate()
return out
Any suggestions ?
Finally I managed to find the solution of that issue by myself. The problem came from the kind of user who called the Matlab's script. When I was running the above script from a Python interpreter or from the shell, it was the user (with the user password) who was running the script while when I was calling the script from the client the user was the web server's user: www-data.
So at first to avoid the above warning I gave permissions to www-data user to the /var/www folder with the following command:
sudo chown -R www-data /var/www/
After that, the "Warning" disappeared but the script still didn't run because it was asking for www-data's password internally and taking user's password from pymat_config file.
To solve this, I edited /etc/sudoers file in order for www-data to be able to call Matlab scripts without asking password. So I added the following line:
www-data ALL=(ALL) NOPASSWD: /usr/local/MATLAB/R2018a/bin/matlab
and now it runs like a charm !
Related
I have EV3 Lego Mindstorms and I instaled on it ev3dev operating system. I set the connection with the PC via SSH and using PuTTY I started to "programming". I used the cat > test2.py and wrote this code:
#!/usr/bin/env python3
import ev3dev.ev3 as ev3
motor = ev3.LargeMotor('outA')
motor.run_timed(time_sp = 1000, speed_sp = 500)
I saved the file and initialized it using ./test2.py. I got this output:
-bash: ./test2.py: Persmission denied
What caused it and what should I change?
try this:
sudo python3 test2.py
that will allows you to open almost anything in linux
Use ls -la ./test2.py in order to see the file permissions.
Look at the beginning of the output, you'll see something like this:
-rw-rw-r--
The first - means if is a directory or a file. In this case means that is a file.
Now If you observe the remaining chars there are 3 sets of 3 chars with means the permissions for the owner of the file, the owner group and the last set is for the rest of the users.
We have permissions to read, write and execute and in the example I showed there are read and write permissions for the owner user and the owner group but non permissions for the other users.
As Is said above you can just use sudo every time you execute the script but to run it with root privileges. However I would recommend you change your file permissions and using chmod
sudo chmod +x ./test2.py
This will let you execute the script. Take a look at chmod documentation to learn more: https://help.ubuntu.com/community/FilePermissions
I have a python script that queries a database. I run it from the terminal with python3 myscript.py
I've added a cron task for it in my crontab file
*/30 9-17 * * 1-5 python3 /path/to/my/python/script\ directory\ space/myscript.py
The script imports a function in the same directory that parses login info for a database located in database.ini in the same directory. The database.ini is:
[postgresql]
host=my-db-host-1-link.11.thedatabase.com
database=dbname
user=username
password=password
port=10898
But currently cron outputs to the file in my mail folder:
Section postgresql not found in the database.ini file
The section is clearly present in the database.ini file, so what am I missing here?
Instead of running "python3 myscript.py" in the directory where it is present, try running it from some other directory (like home directory). Most likely you will see the same issue.
Note that cron's current-working-directory is different on different systems. So, the safest method is to explicitly switch to the directory where your script is and run the command there:
cd /path/to/my/python/script\ directory\ space/ && python3 myscript.py
Try this:
import os
...
change --> filename=database.ini
for --------> filename=os.path.dirname(__file__)+'/database.ini'
I have a Django project hosted on a remote server. This contains a file called tmp_file.py. There's a function called fetch_data() inside that file. Usually I follow the below approach to run that function.
# Inside Django Project
$ python manage.py shell
[Shell] from tmp_file import feth_data
[Shell] fetch_data()
Also the file doesn't contain __name__ section. So can't run as a stand alone script. What's the best way to perform this task using Ansible. I couldn't find anything useful from Ansible docs.
There's --command switch for shell django-admin command.
So you can try in Ansible:
- name: Fetch data
command: "django-admin shell --command='from tmp_file import feth_data; fetch_data()'"
args:
chdir: /path/to/tmp_file
I am writing a test suite for a web application using Selenium.
In the course of which I need to test behaviour of the app in case a certain service is running or not.
I wanted to create a cgi call to a Python script turning that service on and off.
I know that the cgi call is in the context of the webserver (Apache) however thought that issuing sudo calls like so:
import subprocess
import os
command = 'sudo -S launchctl unload /Library/LaunchAgents/com.my.daemon.plist'
pwd = 'pwd123'
test1 = subprocess.Popen( command, shell=True, stdin=subprocess.PIPE)
test1.communicate(input=pwd)
test2 = os.system( 'echo %s|%s' % (pwd,command) )
would do the trick, well they don't I get return code 256.
What can I do to have this call be executed w/o touching the context in which Apache runs?
As for security: this will only run on a test machine.
The user that Apache runs as needs to be in the /etc/sudoers file, or belong to the sudo group, which I guess it usually doesn't. You also need to make it not ask for a password, which is configured in /etc/sudoers
For Ubuntu, check these out: https://askubuntu.com/questions/7477/how-can-i-add-a-new-user-as-sudoer-using-the-command-line
https://askubuntu.com/questions/147241/execute-sudo-without-password
It could potentially be a pathing issue..
Have you tried writing out the full path like this:
command = '/usr/bin/sudo -S launchctl unload /Library/LaunchAgents/com.my.daemon.plist'
command should be a list, not a string. Try with:
command = ['sudo', '-S', 'launchctl', 'unload', '/Library/LaunchAgents/com.my.daemon.plist']
Cant run sudo this way -- sudo needs a controlling terminal to run.
I call two executables from a python script one which needs Administrator privileges and one which does not need them. Is there any way by which I can set the Administrator privilege before executing the executable so that it does not ask me for my password.
My script is as follows
import subprocess
subprocess.check_call(['DoesnotNeedAdminPrivilege.exe'])
subprocess.check_call(['NeedsAdminPrivilege.exe'])
I tried to run this script from cmd by starting the cmd to run as an Adminstrator. Is there any way to pass these admin rights to the second executable so that it works without any problem
I found a nasty workaround
f = open('test.cmd', 'w+')
f.write("execute.exe")
f.close()
os.system("runas /savecred /profile /user:Administrator \"test.cmd\"")
or you can use subprocess
Try this out for entering an administrative password.
import subprocess as sp
sp.check_call(['DoesnotNeedAdminPrivilege.exe'])
prog = sp.Popen(['runas', '/noprofile', '/user:Administrator', 'NeedsAdminPrivilege.exe'],stdin=sp.PIPE)
prog.stdin.write('password')
prog.communicate()
Here are the docs on:
Popen - http://docs.python.org/2/library/subprocess.html#popen-constructor
runas - http://technet.microsoft.com/en-us/library/cc771525.aspx
if this works will depend on the program NeedsAdminPrivilege.