Add Preformatted class for logging preformatted messages

pyomo/common/log.py

@@ -107,11 +107,14 @@ def __init__(self, **kwds):
         super(WrappingFormatter, self).__init__(**kwds)
 
     def format(self, record):
+        msg = record.getMessage()
+        if record.msg.__class__ is not str and isinstance(record.msg, Preformatted):
+            return msg
+
         _orig = {
             k: getattr(record, k) for k in ('msg', 'args', 'pathname', 'levelname')
         }
         _id = getattr(record, 'id', None)
-        msg = record.getMessage()
         record.msg = self._flag
         record.args = None
         if _id:
@@ -212,6 +215,19 @@ def emit(self, record):
         super(StdoutHandler, self).emit(record)
 
 
+class Preformatted(object):
+    __slots__ = ('msg',)
+
+    def __init__(self, msg):
+        self.msg = msg
+
+    def __str__(self):
+        return str(self.msg)
+
+    def __repr__(self):
+        return f'Preformatted({self.msg!r})'
+
+
 class _GlobalLogFilter(object):
     def __init__(self):
         self.logger = logging.getLogger()

pyomo/common/tests/test_log.py

@@ -25,11 +25,12 @@
 import pyomo.common.unittest as unittest
 
 from pyomo.common.log import (
-    LoggingIntercept,
-    WrappingFormatter,
     LegacyPyomoFormatter,
+    LoggingIntercept,
     LogHandler,
     LogStream,
+    Preformatted,
+    WrappingFormatter,
     pyomo_formatter,
 )
 
@@ -271,6 +272,54 @@ def test_numbered_level(self):
         )
         self.assertEqual(self.stream.getvalue(), ans)
 
+    def test_preformatted(self):
+        self.handler.setFormatter(
+            LegacyPyomoFormatter(
+                base=os.path.dirname(__file__),
+                verbosity=lambda: logger.isEnabledFor(logging.DEBUG),
+            )
+        )
+
+        msg = """This is a long multi-line message that in normal circumstances \
+would be line-wrapped
+        with additional information
+        that normally would be combined."""
+
+        logger.setLevel(logging.WARNING)
+        logger.info(msg)
+        self.assertEqual(self.stream.getvalue(), "")
+
+        logger.warning(Preformatted(msg))
+        ans = msg + "\n"
+        self.assertEqual(self.stream.getvalue(), ans)
+
+        logger.warning(msg)
+        ans += (
+            "WARNING: This is a long multi-line message that in normal "
+            "circumstances would\n"
+            "be line-wrapped with additional information that normally would be combined.\n"
+        )
+        self.assertEqual(self.stream.getvalue(), ans)
+
+        logger.setLevel(logging.DEBUG)
+
+        logger.warning(Preformatted(msg))
+        ans += msg + "\n"
+        self.assertEqual(self.stream.getvalue(), ans)
+
+        logger.warning(msg)
+        lineno = getframeinfo(currentframe()).lineno - 1
+        ans += 'WARNING: "[base]%stest_log.py", %d, test_preformatted\n' % (
+            os.path.sep,
+            lineno,
+        )
+        ans += (
+            "    This is a long multi-line message that in normal "
+            "circumstances would be\n"
+            "    line-wrapped with additional information that normally would be combined.\n"
+        )
+        self.assertEqual(self.stream.getvalue(), ans)
+
     def test_long_messages(self):
         self.handler.setFormatter(
             LegacyPyomoFormatter(
@@ -495,3 +544,18 @@ def test_log_stream(self):
                 self.assertEqual(OUT.getvalue(), "INFO: line 1\n")
             # Exiting the context manager flushes the LogStream
             self.assertEqual(OUT.getvalue(), "INFO: line 1\nINFO: line 2\n")
+
+
+class TestPreformatted(unittest.TestCase):
+    def test_preformatted_api(self):
+        ref = 'a message'
+        msg = Preformatted(ref)
+        self.assertIs(msg.msg, ref)
+        self.assertEqual(str(msg), ref)
+        self.assertEqual(repr(msg), "Preformatted('a message')")
+
+        ref = 2
+        msg = Preformatted(ref)
+        self.assertIs(msg.msg, ref)
+        self.assertEqual(str(msg), '2')
+        self.assertEqual(repr(msg), "Preformatted(2)")