B4J Library [PyBridge] Console (non-ui) project template

Simple template for console apps. There is an assumption that the global Python will be used.
Put in the additional libraries folder.

Right click inside the libraries tag and choose refresh.

 

[Erel]

Important point - when you run the program from the IDE, the IDE sets an environment variable with the global python folder, based on the path set under Tools - Configure Paths (or the installation folder if not set).

If you want to run the jar from the command line, with the global Python, then you need to set the environment variable:

set B4J_PYTHON=D:\python\python
D:\java\jdk-19.0.2\bin\java -jar your_jar.jar

 

[Daestrum]

Where does version.Print2(...) output to? - its not in the logs and not in cmd window. (Using just the basic template)

 

[Daestrum]

Ok, sorted had to change code to

    End If
    wait for (PrintPythonVersion) Completed
   
    'When possible, kill the python process before exiting:
    CloseProgram

also

java -jar -DB4J_PYTHON=your/python/path your_jar.jar

works too

 

[Erel]

This is actually not the correct solution. The program will never continue after this line.
Better solution is to wait a bit before closing the program:

PrintPythonVersion
Sleep(500)
CloseProgram

I will update the template.

 

[Daestrum]

I set it to 2000 and still never got an output.

Edit: Just tried 10000 and still no output.

Waiting for debugger to connect...
Program started.
Server is listening on port: 58770
Python path: d:/python.3.12.8/python.exe
connected
starting PyBridge v0.70
watchdog set to 30 seconds
Connecting to port: 58770
PyBridge disconnected
Process completed. ExitCode: 1
Program terminated (StartMessageLoop was not called).

 

[Erel]

With this code:

Private Sub Start
    Py.Initialize(Me, "Py")
    Dim opt As PyOptions = Py.CreateOptions("Python/python/python.exe")
    Py.Start(opt)
    Wait For Py_Connected (Success As Boolean)
    If Success = False Then
        LogError("Failed to start Python process.")
        Return
    End If
    PrintPythonVersion
    
    'When possible, kill the python process before exiting:
    Sleep(500)
    CloseProgram
End Sub

?

 

[Daestrum]

yes , its the Py.KillProcess - it kills python before it returns the value.

If I comment out Py.KillProcess it works fine.

 

[Daestrum]

Or this code works fine too

Private Sub CloseProgram
    Sleep(100)
    Py.KillProcess
    Sleep(100)
    StopMessageLoop
End Sub

 

[Erel]

Something is strange here. This is the same as making the Sleep before the call to CloseProgram longer. Maybe it is missing?

Sleep(500) '<------
CloseProgram

 

[Daestrum]

I apologise Erel I miss read post #7 and saw the sleep and assumed it was in the closeprogram sub.

 

[Erel]

The important thing is that the template was updated and now includes the correct code.

For completeness, the Python process logs are read by B4J, using jShell library. They are not sent together with the program responses. This is important for performance reasons.
The process outputs are polled (every 50ms) so if the process is killed right after the commands were sent, they will not appear.