Relax metrics arg validation

node/metrics.go

@@ -7,7 +7,6 @@ import (
 	"flag"
 	"log"
 	"net/http"
-	"regexp"
 	"strings"
 	"time"
 
@@ -80,9 +79,6 @@ func (p *metricsProxy) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	})
 }
 
-// Regexp used to validate query arguments.
-var argRx = regexp.MustCompile(`^[-_.a-zA-Z0-9]*$`)
-
 func (p *metricsProxy) queryFromRequest(r *http.Request) (string, v1.Range, error) {
 	name := r.FormValue("query")
 	d, err := time.ParseDuration(r.FormValue("t"))
@@ -90,8 +86,9 @@ func (p *metricsProxy) queryFromRequest(r *http.Request) (string, v1.Range, erro
 		d = time.Hour
 	}
 
+	// We only care that the argument does not contain quotes.
 	arg := r.FormValue("arg")
-	if !argRx.MatchString(arg) {
+	if strings.Contains(arg, "\"") {
 		return "", v1.Range{}, errors.New("bad argument")
 	}
 	q, ok := knownQueries[name]