examples: Update VISA examples to use the new session management API

.env.sample

@@ -42,6 +42,15 @@
 # MEASUREMENTLINK_NISWITCH_SIMULATE=1
 # MEASUREMENTLINK_NISWITCH_TOPOLOGY=2567/Independent
 
+#----------------------------------------------------------------------
+# VISA Example Measurement Options
+#----------------------------------------------------------------------
+
+# To enable simulation with the VISA example measurements, uncomment the
+# following line.
+
+# MEASUREMENTLINK_VISA_DMM_SIMULATE=1
+
 #----------------------------------------------------------------------
 # NI gRPC Device Server Configuration
 #----------------------------------------------------------------------

.env.simulation

@@ -1,5 +1,6 @@
 # This is a sample ni-measurementlink-service configuration file that enables
-# simulated devices for NI modular instrument drivers.
+# simulated devices for NI modular instrument drivers and VISA example
+# measurements.
 #
 # To use it:
 # - Copy this file to your service's directory or one of its parent directories
@@ -31,3 +32,5 @@ MEASUREMENTLINK_NISCOPE_MODEL=5162 (4CH)
 
 MEASUREMENTLINK_NISWITCH_SIMULATE=1
 MEASUREMENTLINK_NISWITCH_TOPOLOGY=2567/Independent
+
+MEASUREMENTLINK_VISA_DMM_SIMULATE=1

examples/nivisa_dmm_measurement/_visa_dmm.py

@@ -31,7 +31,16 @@
 _RESOLUTION_DIGITS_TO_VALUE = {"3.5": 0.001, "4.5": 0.0001, "5.5": 1e-5, "6.5": 1e-6}
 
 # Supported NI-VISA DMM instrument IDs, both real and simulated, can be added here
-_SUPPORTED_INSTRUMENT_IDS = ["Waveform Generator Simulator", "34401"]
+_SUPPORTED_INSTRUMENT_IDS = [
+    # Keysight/Agilent/HP 34401A
+    "34401",
+    "34410",
+    "34411",
+    "L4411",
+    # NI Instrument Simulator v2.0
+    "Instrument Simulator",  # single instrument
+    "Waveform Generator Simulator",  # multi-instrument
+]
 
 
 class Function(Enum):

examples/nivisa_dmm_measurement/measurement.py

@@ -3,20 +3,14 @@
 import logging
 import pathlib
 import sys
-from typing import Any, Tuple
+from typing import Tuple
 
 import click
 import ni_measurementlink_service as nims
-from _constants import USE_SIMULATION
-from _helpers import (
-    ServiceOptions,
-    configure_logging,
-    create_session_management_client,
-    get_service_options,
-    use_simulation_option,
-    verbosity_option,
-)
+from _helpers import configure_logging, verbosity_option
 from _visa_dmm import INSTRUMENT_TYPE_VISA_DMM, Function, Session
+from decouple import AutoConfig
+from ni_measurementlink_service.session_management import SessionInformation
 
 script_or_exe = sys.executable if getattr(sys, "frozen", False) else __file__
 service_directory = pathlib.Path(script_or_exe).resolve().parent
@@ -25,7 +19,10 @@
     version="0.1.0.0",
     ui_file_paths=[service_directory / "NIVisaDmmMeasurement.measui"],
 )
-service_options = ServiceOptions()
+
+# Search for the `.env` file starting with the current directory.
+_config = AutoConfig(str(pathlib.Path.cwd()))
+_VISA_DMM_SIMULATE: bool = _config("MEASUREMENTLINK_VISA_DMM_SIMULATE", default=False, cast=bool)
 
 
 @measurement_service.register_measurement
@@ -53,31 +50,32 @@ def measure(
         resolution_digits,
     )
 
-    session_management_client = create_session_management_client(measurement_service)
-
-    with session_management_client.reserve_session(
-        context=measurement_service.context.pin_map_context,
-        pin_or_relay_names=[pin_name],
-    ) as reservation:
-        with Session(
-            reservation.session_info.resource_name,
-            simulate=service_options.use_simulation,
-        ) as session:
+    with measurement_service.context.reserve_session(pin_name) as reservation:
+        with reservation.create_session(_create_session, INSTRUMENT_TYPE_VISA_DMM) as session_info:
+            session = session_info.session
             session.configure_measurement_digits(measurement_type, range, resolution_digits)
             measured_value = session.read()
 
     logging.info("Completed measurement: measured_value=%g", measured_value)
     return (measured_value,)
 
 
+def _create_session(session_info: SessionInformation) -> Session:
+    # When this measurement is called from outside of TestStand (session_exists
+    # == False), reset the instrument to a known state. In TestStand,
+    # ProcessSetup resets the instrument.
+    return Session(
+        session_info.resource_name,
+        reset_device=not session_info.session_exists,
+        simulate=_VISA_DMM_SIMULATE,
+    )
+
+
 @click.command
 @verbosity_option
-@use_simulation_option(default=USE_SIMULATION)
-def main(verbosity: int, **kwargs: Any) -> None:
+def main(verbosity: int) -> None:
     """Perform a DMM measurement using NI-VISA and an NI Instrument Simulator v2.0."""
     configure_logging(verbosity)
-    global service_options
-    service_options = get_service_options(**kwargs)
 
     with measurement_service.host_service():
         input("Press enter to close the measurement service.\n")

examples/nivisa_dmm_measurement/pyproject.toml

@@ -11,6 +11,7 @@ PyVISA = "^1.13.0"
 PyVISA-sim = "^0.5.1"
 click = ">=7.1.2, !=8.1.4" # mypy fails with click 8.1.4: https://github.com/pallets/click/issues/2558
 grpcio = "*"
+python-decouple = ">=3.8"
 
 [tool.poetry.group.dev.dependencies]
 ni-python-styleguide = ">=0.4.1"
@@ -24,4 +25,11 @@ requires = ["poetry-core>=1.2.0"]
 build-backend = "poetry.core.masonry.api"
 
 [tool.mypy]
-disallow_untyped_defs = true
+disallow_untyped_defs = true
+
+[[tool.mypy.overrides]]
+module = [
+  # https://github.com/HBNetwork/python-decouple/issues/122 - Add support for type stubs
+  "decouple.*",
+]
+ignore_missing_imports = true