JSON label extraction field validation expression overly strict

CHANGELOG.md

@@ -1,5 +1,6 @@
 ## Main
 
+* [6372](https://github.com/grafana/loki/pull/6372) **splitice**: Add support for numbers in JSON fields
 * [6105](https://github.com/grafana/loki/pull/6105) **rutgerke** Export metrics for the promtail journal target
 * [6099](https://github.com/grafana/loki/pull/6099/files) **cstyan**: Drop lines with malformed JSON in Promtail JSON pipeline stage
 * [6136](https://github.com/grafana/loki/pull/6136) **periklis**: Add support for alertmanager header authorization

pkg/logql/log/jsonexpr/jsonexpr_test.go

@@ -119,6 +119,12 @@ func TestJSONExpressionParser(t *testing.T) {
 			nil,
 			fmt.Errorf("syntax error: unexpected $end, expecting RSB"),
 		},
+		{
+			"identifier with number",
+			`utf8`,
+			[]interface{}{"utf8"},
+			nil,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

pkg/logql/log/jsonexpr/lexer.go

@@ -68,7 +68,7 @@ func (sc *Scanner) lex(lval *JSONExprSymType) int {
 			return RSB
 		case r == '.':
 			return DOT
-		case isIdentifier(r):
+		case isStartIdentifier(r):
 			sc.unread()
 			lval.field = sc.scanField()
 			return FIELD
@@ -83,21 +83,20 @@ func (sc *Scanner) lex(lval *JSONExprSymType) int {
 	}
 }
 
-func isIdentifier(r rune) bool {
+func isStartIdentifier(r rune) bool {
 	return (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || r == '_'
 }
 
+func isIdentifier(r rune) bool {
+	return isStartIdentifier(r) || (r >= '0' && r <= '9')
+}
+
 func (sc *Scanner) scanField() string {
 	var str []rune
 
 	for {
 		r := sc.read()
-		if !isIdentifier(r) {
-			sc.unread()
-			break
-		}
-
-		if r == '.' || isEndOfInput(r) {
+		if !isIdentifier(r) || isEndOfInput(r) {
 			sc.unread()
 			break
 		}

pkg/logql/syntax/parser_test.go

@@ -2954,17 +2954,35 @@ func TestParse(t *testing.T) {
 			},
 		},
 		{
-			in: `{app="foo"} | json response_code, api_key="request.headers[\"X-API-KEY\"]"`,
+			in: `{app="foo"} | json response_code, api_key="request.headers[\"X-API-KEY\"]", layer7_something_specific="layer7_something_specific"`,
 			exp: &PipelineExpr{
 				Left: newMatcherExpr([]*labels.Matcher{{Type: labels.MatchEqual, Name: "app", Value: "foo"}}),
 				MultiStages: MultiStageExpr{
 					newJSONExpressionParser([]log.JSONExpression{
 						log.NewJSONExpr("response_code", `response_code`),
 						log.NewJSONExpr("api_key", `request.headers["X-API-KEY"]`),
+						log.NewJSONExpr("layer7_something_specific", `layer7_something_specific`),
 					}),
 				},
 			},
 		},
+		{
+			in: `count_over_time({ foo ="bar" } | json layer7_something_specific="layer7_something_specific" [12m])`,
+			exp: &RangeAggregationExpr{
+				Left: &LogRange{
+					Left: &PipelineExpr{
+						MultiStages: MultiStageExpr{
+							newJSONExpressionParser([]log.JSONExpression{
+								log.NewJSONExpr("layer7_something_specific", `layer7_something_specific`),
+							}),
+						},
+						Left: &MatchersExpr{Mts: []*labels.Matcher{mustNewMatcher(labels.MatchEqual, "foo", "bar")}},
+					},
+					Interval: 12 * time.Minute,
+				},
+				Operation: "count_over_time",
+			},
+		},
 	} {
 		t.Run(tc.in, func(t *testing.T) {
 			ast, err := ParseExpr(tc.in)