Allow users to reset the list of created records

CHANGELOG.rst

@@ -11,6 +11,7 @@ Unreleased_
 -----------
 
 - `Allow "status" and "severity" on In record init <../../pull/111>`_
+- `Allow users to reset the list of created records <../../pull/114>`_
 
 4.1.0_ - 2022-08-05
 -------------------

docs/reference/api.rst

@@ -426,6 +426,12 @@ The following attributes allow more direct access to record creation.
 
     See `../how-to/use-soft-records` for a full example of its usage.
 
+.. function:: ClearRecords()
+    This can be used to remove all created records. This means the same record
+    names can be re-used for different record types. This cannot be used once the
+    record database has been loaded, and is only designed to be used to help with
+    testing.
+
 Finally, the following function is used to load record definitions before
 starting the IOC.
 

softioc/builder.py

@@ -1,6 +1,7 @@
 import os
 import numpy
 
+from .device_core import RecordLookup
 from .softioc import dbLoadDatabase
 
 from epicsdbbuilder import *
@@ -273,9 +274,6 @@ def longStringOut(name, **fields):
 # ----------------------------------------------------------------------------
 #  Support routines for builder
 
-
-_DatabaseWritten = False
-
 def LoadDatabase():
     '''This should be called after all the builder records have been created,
     but before calling iocInit().  The database is loaded into EPICS memory,
@@ -290,6 +288,14 @@ def LoadDatabase():
     pythonSoftIoc.RecordWrapper.reset_builder()
 
 
+def ClearRecords():
+    """Delete all created record information, allowing new record creation"""
+    assert not pythonSoftIoc.RecordWrapper.is_builder_reset(), \
+        'Record database has already been loaded'
+    RecordLookup._RecordDirectory.clear()
+    ResetRecords()
+
+
 # ----------------------------------------------------------------------------
 # Record name configuration.  A device name prefix must be specified.
 
@@ -317,7 +323,7 @@ def UnsetDevice():
     'longStringIn', 'longStringOut',
     'Action',
     # Other builder support functions
-    'LoadDatabase',
+    'LoadDatabase', 'ClearRecords',
     'SetDeviceName', 'UnsetDevice',
     # Device support functions
     'SetBlocking'

softioc/pythonSoftIoc.py

@@ -17,7 +17,7 @@ class RecordWrapper(object):
     __builder_reset = False
 
     def __init__(self, builder, device, name, **fields):
-        assert not self.__builder_reset, \
+        assert not self.is_builder_reset(), \
             'It\'s too late to create records'
         # List of keyword arguments expected by the device constructor.  The
         # remaining arguments are passed to the builder.  It's a shame we
@@ -47,6 +47,12 @@ def reset_builder(cls):
         for instance in cls.__Instances:
             instance.__set('__builder', None)
 
+    @classmethod
+    def is_builder_reset(cls):
+        '''Returns True if it is too late to create records'''
+        return cls.__builder_reset
+
+
 
     # Most attributes delegate directly to the builder instance until the
     # database has been written.  At this point the builder instance has been

softioc/softioc.py

@@ -4,8 +4,6 @@
 from ctypes import *
 from tempfile import NamedTemporaryFile
 
-from epicsdbbuilder.recordset import recordset
-
 from . import imports, device
 from . import cothread_dispatcher
 

tests/conftest.py

@@ -10,8 +10,7 @@
 import pytest
 
 # Must import softioc before epicsdbbuilder
-from softioc.device_core import RecordLookup
-from epicsdbbuilder import ResetRecords
+from softioc.builder import ClearRecords
 
 requires_cothread = pytest.mark.skipif(
     sys.platform.startswith("win"), reason="Cothread doesn't work on windows"
@@ -88,20 +87,12 @@ def asyncio_ioc_override():
     ioc.kill()
     aioca_cleanup()
 
-def _clear_records():
-    # Remove any records created at epicsdbbuilder layer
-    ResetRecords()
-    # And at pythonSoftIoc level
-    # TODO: Remove this hack and use use whatever comes out of
-    # https://github.com/dls-controls/pythonSoftIOC/issues/56
-    RecordLookup._RecordDirectory.clear()
-
 @pytest.fixture(autouse=True)
 def clear_records():
     """Deletes all records before and after every test"""
-    _clear_records()
+    ClearRecords()
     yield
-    _clear_records()
+    ClearRecords()
 
 @pytest.fixture(autouse=True)
 def enable_code_coverage():

tests/test_records.py

@@ -9,7 +9,6 @@
     log,
     create_random_prefix,
     requires_cothread,
-    _clear_records,
     WAVEFORM_LENGTH,
     TIMEOUT,
     select_and_recv,
@@ -19,6 +18,7 @@
 from softioc import asyncio_dispatcher, builder, softioc
 from softioc import alarm
 from softioc.device import SetBlocking
+from softioc.device_core import LookupRecord, LookupRecordList
 
 # Test file for miscellaneous tests related to records
 
@@ -38,7 +38,6 @@ def test_records(tmp_path):
     # Ensure we definitely unload all records that may be hanging over from
     # previous tests, then create exactly one instance of expected records.
     from sim_records import create_records
-    _clear_records()
     create_records()
 
     path = str(tmp_path / "records.db")
@@ -228,6 +227,68 @@ def test_setting_alarm_invalid_keywords(creation_func):
 
     assert e.value.args[0] == 'Can\'t specify both status and STAT'
 
+def test_clear_records():
+    """Test that clearing the known records allows creation of a record of the
+    same name afterwards"""
+
+    device_name = create_random_prefix()
+    builder.SetDeviceName(device_name)
+
+    record_name = "NEW-RECORD"
+
+    builder.aOut(record_name)
+
+    # First check that we cannot create two of the same name
+    with pytest.raises(AssertionError):
+        builder.aOut(record_name)
+
+    builder.ClearRecords()
+
+    # Then confirm we can create one of this name
+    builder.aOut(record_name)
+
+    # Finally prove that the underlying record holder contains only one record
+    # Records are stored as full device:record name
+    full_name = device_name + ":" + record_name
+    assert LookupRecord(full_name)
+    assert len(LookupRecordList()) == 1
+    for key, val in LookupRecordList():
+        assert key == full_name
+
+def clear_records_runner(child_conn):
+    """Tests ClearRecords after loading the database"""
+    builder.aOut("Some-Record")
+    builder.LoadDatabase()
+
+    try:
+        builder.ClearRecords()
+    except AssertionError:
+        # Expected error
+        child_conn.send("D")  # "Done"
+    child_conn.send("F")  # "Fail"
+
+def test_clear_records_too_late():
+    """Test that calling ClearRecords after a database has been loaded raises
+    an exception"""
+    ctx = get_multiprocessing_context()
+
+    parent_conn, child_conn = ctx.Pipe()
+
+    process = ctx.Process(
+        target=clear_records_runner,
+        args=(child_conn,),
+    )
+
+    process.start()
+
+    try:
+        select_and_recv(parent_conn, "D")
+    finally:
+        process.join(timeout=TIMEOUT)
+        if process.exitcode is None:
+            pytest.fail("Process did not terminate")
+
+
 
 def validate_fixture_names(params):
     """Provide nice names for the out_records fixture in TestValidate class"""