PromQL: Allow more keywords as metric names (prometheus#6933)

* Allow more keywords as metric names * Add documentation about forbidden keywords Signed-off-by: Tobias Guggenmos <[email protected]>
kieslee · Mar 5, 2020 · 44ad28d · 44ad28d
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diff --git a/docs/querying/basics.md b/docs/querying/basics.md
@@ -118,6 +118,14 @@ The following expression selects all metrics that have a name starting with `job
 
     {__name__=~"job:.*"}
 
+The metric name must not be one of the keywords `bool`, `on`, `ignoring`, `group_left` and `group_right`. The following expression is illegal:
+
+    on{} # Bad!
+
+A workaround for this restriction is to use the `__name__` label:
+
+    {__name__="on"} # Good!
+
 All regular expressions in Prometheus use [RE2
 syntax](https://github.com/google/re2/wiki/Syntax).
 

diff --git a/promql/parser/generated_parser.y b/promql/parser/generated_parser.y
@@ -535,7 +535,7 @@ metric          : metric_identifier label_set
                 ;
 
 
-metric_identifier: METRIC_IDENTIFIER | IDENTIFIER;
+metric_identifier: AVG | BOTTOMK | BY | COUNT | COUNT_VALUES |  IDENTIFIER |  LAND | LOR | LUNLESS | MAX | METRIC_IDENTIFIER | MIN | OFFSET | QUANTILE | STDDEV | STDVAR | SUM | TOPK;
 
 label_set       : LEFT_BRACE label_set_list RIGHT_BRACE
                         { $$ = labels.New($2...) }