app/vmselect/graphite: properly handle wildcards and charsets inside curly braces

For example, `foo{bar*,[a-f]a*b}` should match `foobar`, `foobar123`, `foofab`, etc.

See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/952

app/vmselect/graphite/metrics_api.go

@@ -350,47 +350,8 @@ func getRegexpForQuery(query string, delimiter byte) (*regexp.Regexp, error) {
 	if re := regexpCache[k]; re != nil {
 		return re.re, re.err
 	}
-	a := make([]string, 0, len(query))
-	quotedDelimiter := regexp.QuoteMeta(string([]byte{delimiter}))
-	tillNextDelimiter := "[^" + quotedDelimiter + "]*"
-	for i := 0; i < len(query); i++ {
-		switch query[i] {
-		case '*':
-			a = append(a, tillNextDelimiter)
-		case '{':
-			tmp := query[i+1:]
-			if n := strings.IndexByte(tmp, '}'); n < 0 {
-				a = append(a, regexp.QuoteMeta(query[i:]))
-				i = len(query)
-			} else {
-				a = append(a, "(?:")
-				opts := strings.Split(tmp[:n], ",")
-				for j, opt := range opts {
-					opts[j] = regexp.QuoteMeta(opt)
-				}
-				a = append(a, strings.Join(opts, "|"))
-				a = append(a, ")")
-				i += n + 1
-			}
-		case '[':
-			tmp := query[i:]
-			if n := strings.IndexByte(tmp, ']'); n < 0 {
-				a = append(a, regexp.QuoteMeta(query[i:]))
-				i = len(query)
-			} else {
-				a = append(a, tmp[:n+1])
-				i += n
-			}
-		default:
-			a = append(a, regexp.QuoteMeta(query[i:i+1]))
-		}
-	}
-	s := strings.Join(a, "")
-	if !strings.HasSuffix(s, quotedDelimiter) {
-		s += quotedDelimiter + "?"
-	}
-	s = "^(?:" + s + ")$"
-	re, err := regexp.Compile(s)
+	rs := getRegexpStringForQuery(query, delimiter, false)
+	re, err := regexp.Compile(rs)
 	regexpCache[k] = &regexpCacheEntry{
 		re:  re,
 		err: err,
@@ -406,6 +367,63 @@ func getRegexpForQuery(query string, delimiter byte) (*regexp.Regexp, error) {
 	return re, err
 }
 
+func getRegexpStringForQuery(query string, delimiter byte, isSubquery bool) string {
+	var a []string
+	quotedDelimiter := regexp.QuoteMeta(string([]byte{delimiter}))
+	tillNextDelimiter := "[^" + quotedDelimiter + "]*"
+	j := 0
+	for i := 0; i < len(query); i++ {
+		switch query[i] {
+		case '*':
+			a = append(a, regexp.QuoteMeta(query[j:i]))
+			a = append(a, tillNextDelimiter)
+			j = i + 1
+		case '{':
+			if isSubquery {
+				break
+			}
+			a = append(a, regexp.QuoteMeta(query[j:i]))
+			tmp := query[i+1:]
+			if n := strings.IndexByte(tmp, '}'); n < 0 {
+				rs := getRegexpStringForQuery(query[i:], delimiter, true)
+				a = append(a, rs)
+				i = len(query)
+			} else {
+				a = append(a, "(?:")
+				opts := strings.Split(tmp[:n], ",")
+				for j, opt := range opts {
+					opts[j] = getRegexpStringForQuery(opt, delimiter, true)
+				}
+				a = append(a, strings.Join(opts, "|"))
+				a = append(a, ")")
+				i += n + 1
+			}
+			j = i + 1
+		case '[':
+			a = append(a, regexp.QuoteMeta(query[j:i]))
+			tmp := query[i:]
+			if n := strings.IndexByte(tmp, ']'); n < 0 {
+				a = append(a, regexp.QuoteMeta(query[i:]))
+				i = len(query)
+			} else {
+				a = append(a, tmp[:n+1])
+				i += n
+			}
+			j = i + 1
+		}
+	}
+	a = append(a, regexp.QuoteMeta(query[j:]))
+	s := strings.Join(a, "")
+	if isSubquery {
+		return s
+	}
+	if !strings.HasSuffix(s, quotedDelimiter) {
+		s += quotedDelimiter + "?"
+	}
+	s = "^(?:" + s + ")$"
+	return s
+}
+
 type regexpCacheEntry struct {
 	re  *regexp.Regexp
 	err error

app/vmselect/graphite/metrics_api_test.go

@@ -28,6 +28,9 @@ func TestGetRegexpForQuery(t *testing.T) {
 	f("foo_[ab]*", '_', `^(?:foo_[ab][^_]*_?)$`)
 	f("foo_[ab]_", '_', `^(?:foo_[ab]_)$`)
 	f("foo.[ab].", '.', `^(?:foo\.[ab]\.)$`)
+	f("foo{b{ar*,ba*z[1-9]}", '.', `^(?:foo(?:b\{ar[^\.]*|ba[^\.]*z[1-9])\.?)$`)
+	f("{foo*}", '.', `^(?:(?:foo[^\.]*)\.?)$`)
+	f("{foo*,}", '.', `^(?:(?:foo[^\.]*|)\.?)$`)
 }
 
 func TestSortPaths(t *testing.T) {
@@ -72,4 +75,5 @@ func TestAddAutomaticVariants(t *testing.T) {
 	f("foo,bar.baz", "_", "{foo,bar.baz}")
 	f("foo,bar_baz*", "_", "{foo,bar}_baz*")
 	f("foo.bar,baz,aa.bb,cc", ".", "foo.{bar,baz,aa}.{bb,cc}")
+	f("foo.b*r,b[a-xz]z,aa.bb,cc", ".", "foo.{b*r,b[a-xz]z,aa}.{bb,cc}")
 }

docs/CHANGELOG.md

@@ -9,6 +9,7 @@
 * FEATURE: export `vm_promscrape_scrapers_started_total{type="<sd_type>"}` and `vm_promscrape_scrapers_stopped_total{type="<sd_type>"}` metrics for tracking churn rate for scrapers
   per each service discovery type.
 
+* BUGFIX: properly handle `*` and `[...]` inside curly braces in query passed to Graphite Metrics API. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/952
 * BUGFIX: vmagent: fix memory leak when big number of targets is discovered via service discovery.
 * BUGFIX: vmagent: properly pass `datacenter` filter to Consul API server. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/574#issuecomment-740454170
 * BUGFIX: properly handle CPU limits set on the host system or host container. The bugfix may result in lower memory usage on systems with CPU limits. See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/946