Implement and use config set_value()

doc/changes.rst

@@ -5,6 +5,8 @@ desisurvey change log
 0.9.3 (unreleased)
 ------------------
 
+* Fixes #18, #49, #54.
+* Add progress columns to track fiber assignment and planning.
 * Add support for optional depth-first survey strategy.
 * Docs now auto-generated at http://desisurvey.readthedocs.io/en/latest/
 

py/desisurvey/config.py

@@ -14,6 +14,18 @@
 to astropy quantities.  Strings of the form YYYY-MM-DD are converted to
 datetime.date objects.
 
+To change a value after the configuration has been loaded into memory use,
+for example::
+
+    >>> config.full_moon_nights.set_value(5)
+
+Assigned values must have the appropriate converted types, for example::
+
+    >>> import datetime
+    >>> config.last_day.set_value(datetime.date(2024, 1, 1))
+    >>> import astropy.units as u
+    >>> config.location.temperature.set_value(-5 * u.deg_C)
+
 The configuration is implemented as a singleton so the YAML file is only
 loaded and parsed the first time a Configuration() is built.  Subsequent
 calls to Configuration() always return the same object.
@@ -98,6 +110,21 @@ def __call__(self):
             raise RuntimeError(
                 '{0} is a non-terminal config node.'.format(self.path))
 
+    def set_value(self, new_value):
+        """Set a terminal node's value or raise a RuntimeError for
+        a non-terminal node.
+        """
+        try:
+            old_value = self._value
+            if not isinstance(new_value, type(old_value)):
+                raise RuntimeError(
+                'new type ({}) does not match old type ({}).'
+                .format(type(new_value), type(old_value)))
+            self._value = new_value
+        except AttributeError:
+            raise RuntimeError(
+                '{0} is a non-terminal config node.'.format(self.path))
+
 
 class Configuration(Node):
     """Top-level configuration data node.

py/desisurvey/test/test_config.py

@@ -65,12 +65,25 @@ def test_terminal_value(self):
         self.assertEqual(c.const.pi(), 3.141)
         self.assertEqual(c.output_path(), '.')
 
+    def test_set_value(self):
+        """Terminal node values changed with set_value()"""
+        Configuration.reset()
+        c = Configuration(self.simple)
+        c.const.pi.set_value(4.0)
+        self.assertEqual(c.const.pi(), 4.0)
+        with self.assertRaises(RuntimeError):
+            c.const.pi.set_value(4) # type(4) != float
+        with self.assertRaises(RuntimeError):
+            c.const.gravity.set_value(9.81) # type(9.81) != u.Quantity
+
     def test_non_terminal_value(self):
         """Non-terminal nodes do not have an associated value"""
         Configuration.reset()
         c = Configuration(self.simple)
         with self.assertRaises(RuntimeError):
             c.const()
+        with self.assertRaises(RuntimeError):
+            c.const.set_value(123)
 
     def test_node_path(self):
         """Config nodes have associated paths"""

py/desisurvey/test/test_scripts.py

@@ -19,15 +19,15 @@ def setUpClass(cls):
         # Just run for 2 days for testing
         start = datetime.date(2019,12,1)
         stop = datetime.date(2019,12,3)
-        config.first_day._value = start
-        config.last_day._value = stop
+        config.first_day.set_value(start)
+        config.last_day.set_value(stop)
         # Use just a subset of the tiles for faster testing
         tiles = Table(desimodel.io.load_tiles())
         subset = (35 < tiles['RA']) & (tiles['RA'] < 55) & \
                  (-10 < tiles['DEC']) & (tiles['DEC'] < 20)
         tiles_file = os.path.join(cls.tmpdir, 'tiles-subset.fits')
         tiles[subset].write(tiles_file)
-        config.tiles_file._value = tiles_file
+        config.tiles_file.set_value(tiles_file)
 
     @classmethod
     def tearDownClass(cls):