Python and Astor

Development Python
1

Dear all,

I am slowly learning how to use Tango-CS. I have successfully installed all necessary tools on a VM. I have even managed to set up a few C++ device servers and instances of these. I can operate (start/stop) the device servers via Astor, and also configure them via Jive.

I am now creating a replica device server in Python. I can start/stop these device servers via the terminal with a command like:
python PythonDS.py test

After which, Astor lights ‘green’ for this device server. However I am unable to actually start the device server from within Astor itself (in the same way I can turn on device servers for C++). The error I get is:

PythonDS: not found in ‘StartDsPath’ property: - /home/andrea/Documents/AAVS/Tango/dev

This is the path where all my device servers (C++ executables or python files are located), and I have setup Tango to look for device servers there (via StartDsPath). So Astor startup works for C++, but not for Python.

Am I missing something?

Thank you all for any suggestions and help.

2

Hi,

The Starter can only start executable file. Your py script is not.

You have to create a file without extension PythonDS which contains :

#!/usr/bin/env python
# PythonDS device server launch script 

from PythonDS import main

if __name__ == '__main__':
   main()

Normally, with that you will be ok and the Starter will be able to launch PythonDS.

3

Hi,

Thanks a lot for your message.

I have been unsuccessful so far. Let us assume I have generated a new python device server from POGO. I add nothing to the standard POGO template. This file is called PSDS.py

I can configure this server in Jive, and start it via “python PSDS.py test” - that works fine, and Astor can detect it as running (green) as well.

Now assuming I do not start it via command line, I can still create the new server via Jive.
I have an additional file called PSDS (no extension) with the code:


#!/usr/bin/env python
# PSDS device server launch script 

from PSDS import main

if __name__ == '__main__':
   main()

Astor can now find the device, and adds it to my list of devices. However the device is Red, and can’t start from within Astor. If I start the device server from command line, it turns green.

Thanks for your help :slight_smile:

4

Exactly !

Maybe I can add the windows part too :

You have to create a .bat file.

For your example :

PSDS.bat containing:

python c:/MyPath/PSDS.py %1 %2

We need the argument %& and %2 to be able to call the script for several instances of this server.

5

Hi again,

So with Python device servers, you definitely need some sort of external batch file, or python command etc. Astor alone can’t be the “batch” process itself.

That’s not a problem of course - I can create a shell script like the one above, no problem.

Thanks a lot for your help! :slight_smile: