import pyngres as py
from loguru import logger

# initialize the OpenAPI and note the envHandle for use later
inp = py.IIAPI_INITPARM()
inp.in_timeout = -1
inp.in_version = py.IIAPI_VERSION

py.IIapi_initialize(inp)
envHandle = inp.in_envHandle

...

# create iiapi_trace() as the callback for trace messages
@py.IIapi_callback
def iiapi_trace(trace_block,parmBlock=None):
    '''trace-message call-back'''

    # get the trace_block argument as a Python IIAPI_TRACEPARM instance
    trp = py.IIapi_getClosure(trace_block,py.IIAPI_TRACEPARM)
    # extract the tr_message member containing a line of trace info
    tr_message = trp.tr_message.decode().rstrip()
    # do something with the trace-message (in this example, send it to loguru)
    logger.info(tr_message)

...

# install iiapi_trace() as the callback to handle trace-messages
tracer = py.IIapi_getCallbackPtr(iiapi_trace)
sep = py.IIAPI_SETENVPRMPARM()
sep.se_envHandle = envHandle
sep.se_paramID = py.IIAPI_EP_TRACE_FUNC
sep.se_paramValue = tracer
py.IIapi_setEnvParam(sep)