Treat unitless values as ms, add test

Resolves:
- #1612 (comment)
- #1612 (comment)

cmd/options.go

@@ -91,7 +91,10 @@ func optionFlagSet() *pflag.FlagSet {
 	flags.StringSlice("tag", nil, "add a `tag` to be applied to all samples, as `[name]=[value]`")
 	flags.String("console-output", "", "redirects the console logging to the provided output file")
 	flags.Bool("discard-response-bodies", false, "Read but don't process or save HTTP response bodies")
-	flags.String("dns", "ttl=inf,strategy=first", "DNS configuration")
+	flags.String("dns", "ttl=inf,strategy=first", "DNS configuration. Possible ttl values are: 'inf' "+
+		"for a persistent cache, '0' to disable the cache,\nor a positive duration, e.g. '1s', '1m', etc. "+
+		"Milliseconds are assumed if no unit is provided.\n"+
+		"Possible values for the strategy to use to select a single IP are: 'first', 'random' or 'round-robin'.\n")
 	return flags
 }
 

core/local/local_test.go

@@ -1009,6 +1009,12 @@ func TestDNSResolver(t *testing.T) {
 					Strategy: lib.DefaultDNSConfig().Strategy,
 				}},
 			},
+			"1000ms": { // cache IPs for 1s, test that unitless values are interpreted as ms
+				lib.Options{DNS: &lib.DNSConfig{
+					TTL:      null.StringFrom("1000"),
+					Strategy: lib.DefaultDNSConfig().Strategy,
+				}},
+			},
 			"2s": {
 				lib.Options{DNS: &lib.DNSConfig{
 					TTL:      null.StringFrom("2s"),
@@ -1064,6 +1070,9 @@ func TestDNSResolver(t *testing.T) {
 					case "0":
 						require.Len(t, entries, 5)
 						checkLog(t, entries)
+					case "1000ms":
+						require.Len(t, entries, 3)
+						checkLog(t, entries)
 					case "2s":
 						require.Len(t, entries, 2)
 						checkLog(t, entries)

js/runner.go

@@ -353,9 +353,9 @@ func parseTTL(ttlS string) (types.NullDuration, error) {
 		// disable cache
 	default:
 		origTTLs := ttlS
-		// Treat unitless values as seconds
+		// Treat unitless values as milliseconds
 		if t, err := strconv.ParseFloat(ttlS, 32); err == nil {
-			ttlS = fmt.Sprintf("%.2fs", t)
+			ttlS = fmt.Sprintf("%.2fms", t)
 		}
 		ttlD, err := types.ParseExtendedDuration(ttlS)
 		if ttlD < 0 || err != nil {