PyKX

PyKX with Prefect

Posted by cleung on June 22, 2023 at 12:00 am

Hi There,

We’re trying to integrate our KDB Processes with Prefect by running PyKX via an IPC port. We are running flows/tasks via Prefect that contain PyKX libraries to establish a connection. A snippet of the code can be found below:

import os 
import time 
import subprocess 
from prefect import flow, task, get_run_logger 
from prefect_shell import ShellOperation 
import pykx as kx 
def setup(): 
     token = subprocess.Popen('\\ccl\data\extlib\KDBSecToken.exe', stdout=subprocess.PIPE).communicate()[0].decode('utf-8') 
     masterConn = kx.SyncQConnection( host='v-kdbr-01', port=5000, username='cleung', password=token, timeout=3.0 ) 
     user = masterConn('.z.u') 
     print('User = ' + user.py()) 
     port = masterConn('getProcessClient[`prefect_testing_base;`pykx_test]') 
     print('Port = ' + str(port.py())) 
     masterConn.close() 
     global conn 
     conn = kx.SyncQConnection( host='v-kdbr-01', port=port.py(), username='cleung', password=token) 
     user = conn('.z.u') 
     print('User = ' + user.py()) 

@flow() 
def ibes_pykx():
     setup() logger = get_run_logger() 
     logger.info("Initializing initial arguments") 
     dailyDates = conn('dailyDates: .dt.drb[.dt.shiftdateb[exec max date from QModelD;-3]; exec max date from QModelD];') 
     logFile = conn('inLogFile:`') 
     updateIBESTickers_result = updateIBESTickers.submit() 
     saveRecRevAI260_result = saveRecRevAI260.submit(wait_for=[updateIBESTickers_result])

This works fine when running it on the console (on Visual Studio Code). However, when it comes time to deploy, we keep getting this issue. A deployment on prefect essentially builds the function so it can be used on the Prefect UI.

Script at ‘./Script/ibes_pykx.py’ encountered an exception: ValueError(‘signal only works in main thread’)

Were not sure what to do as it seems like an OS level issue. So far, I am confident that it is the

import pykx as kx

line that is messing it up. However, Im unsure as to what the best approach is to solve this.

Thanks so much for the help, I know it’s a pretty niche area and any advice would be GREATLY appreciated

rocuinneagain replied 1 week, 1 day ago 2 Members · 2 Replies

2 Replies

rocuinneagain

Member

June 27, 2023 at 12:00 am

I have tested and 1.6.0 will allow the import to continue after this error.

This runs for me:

from prefect import flow
from prefect.deployments import Deployment
import os
os.environ["QARGS"] = "--unlicensed"

import pykx as kx

def setup():
    print("testing pykx")
    masterConn = kx.SyncQConnection( host='localhost', port=5000, timeout=3.0 )
    user = masterConn('.z.u')
    print('User = ' + user.py())
    port = masterConn('5000')
    print('Port = ' + str(port.py()))
    masterConn.close()
    global conn
    conn = kx.SyncQConnection( host='localhost', port=port.py())
    user = conn('.z.u')
    print('User = ' + user.py())

@flow()
def test_pykx():
    setup()
    logger = get_run_logger()
    logger.info("Initializing initial arguments")
    dailyDates = conn('dailyDates:(.z.d-7)+til 7')
    logFile = conn('inLogFile:`')


def deploy():
    deployment = Deployment.build_from_flow(
        flow=test_pykx,
        name="prefect-example-deployment"
    )
    deployment.apply()

if __name__ == "__main__":
    deploy()

If you want to run in licensed mode you need to move the import of pykx to avoid a nosocket error

from prefect import flow
from prefect.deployments import Deployment

def setup():
    import pykx as kx
    print("testing pykx")
    masterConn = kx.SyncQConnection( host='localhost', port=5000, timeout=3.0 )
    user = masterConn('.z.u')
    print('User = ' + user.py())
    port = masterConn('5000')
    print('Port = ' + str(port.py()))
    masterConn.close()
    global conn
    conn = kx.SyncQConnection( host='localhost', port=port.py())
    user = conn('.z.u')
    print('User = ' + user.py())

@flow()
def test_pykx():
    setup()
    logger = get_run_logger()
    logger.info("Initializing initial arguments")
    dailyDates = conn('dailyDates:(.z.d-7)+til 7')
    logFile = conn('inLogFile:`')


def deploy():
    deployment = Deployment.build_from_flow(
        flow=test_pykx,
        name="prefect-example-deployment"
    )
    deployment.apply()

if __name__ == "__main__":
    deploy()

rocuinneagain

Member
April 19, 2024 at 12:13 pm
We added some functionality in version 2.3.0

https://code.kx.com/pykx/2.4/release-notes/changelog.html#pykx-230

If you enable beta features as well as pykx threading all calls into q from any python thread will be run as if they were calling from the main thread which allows python multithreaded programs to use IPC connections in licensed mode.

You can enable this functionality like this:
```
import os
os.environ['PYKX_THREADING'] = '1'
os.environ['PYKX_BETA_FEATURES'] = '1'
import pykx as kx
```
You will also want to ensure that kx.shutdown_thread() is called when the script finishes. The safest way to do this is within a try – finally block like this.
```
if __name__ == '__main__':
    try:
        main()
    finally:
        kx.shutdown_thread()
```
More information about this functionality and an example can be found within our documentation:

https://code.kx.com/pykx/2.4/examples/threaded_execution/threading.html

KX Community

PyKX with Prefect

rocuinneagain

rocuinneagain