Monitor metrics alerts: Support custom namespace. Add guidance for us…

…ing ANTLR code-gen. (#10108)

* Fix #9460. Add guidance for using ANTLR code-gen.

* Code review feedback.

* Code review feedback.

src/azure-cli/HISTORY.rst

@@ -67,6 +67,10 @@ Release History
 * Fixed issue where `az functionapp create` does not accept Standard_RAGRS storage account type.
 * Fixed an issue where az webapp up would fail if run using older versions of python
 
+**Monitor**
+
+* `metrics alert create`: Allow '/' and '.' characters in namespace name to support custom metrics.
+
 **Network**
 
 * network nic ip-config add: Fixes #9861 where --ids was inadvertently exposed but did not work.

src/azure-cli/azure/cli/command_modules/monitor/grammar/MetricAlertCondition.g4

@@ -8,7 +8,7 @@ expression          : aggregation (namespace '.')* (QUOTE metric QUOTE WHITESPAC
 
 aggregation         : WORD WHITESPACE ;
 
-namespace           : WORD ;
+namespace           : (WORD | '/' | '.')+;
 
 metric              : (WORD | WHITESPACE | '.' | '/' | '_' | '\\' | ':' | '%')+;
 

src/azure-cli/azure/cli/command_modules/monitor/grammar/MetricAlertConditionLexer.py

@@ -5,14 +5,15 @@
 
 # pylint: disable=all
 
-# Generated from MetricAlertCondition.g4 by ANTLR 4.7.1
+# Generated from MetricAlertCondition.g4 by ANTLR 4.7.2
 # encoding: utf-8
 from __future__ import print_function
 from antlr4 import *
 from io import StringIO
 import sys
 
 
+
 def serializedATN():
     with StringIO() as buf:
         buf.write(u"\3\u608b\ua72a\u8133\ub9ed\u417c\u3be7\u7786\u5964\2")
@@ -154,7 +155,7 @@ class MetricAlertConditionLexer(Lexer):
 
     def __init__(self, input=None, output=sys.stdout):
         super(MetricAlertConditionLexer, self).__init__(input, output=output)
-        self.checkVersion("4.7.1")
+        self.checkVersion("4.7.2")
         self._interp = LexerATNSimulator(self, self.atn, self.decisionsToDFA, PredictionContextCache())
         self._actions = None
         self._predicates = None

src/azure-cli/azure/cli/command_modules/monitor/grammar/MetricAlertConditionListener.py

@@ -5,7 +5,7 @@
 
 # pylint: disable=all
 
-# Generated from MetricAlertCondition.g4 by ANTLR 4.7.1
+# Generated from MetricAlertCondition.g4 by ANTLR 4.7.2
 from antlr4 import *
 
 # This class defines a complete listener for a parse tree produced by MetricAlertConditionParser.