fix: require cert-file and key-file options

cert-file is used to derive certain required identifiers within the MQTT and HTTP clients. This effectively makes the cert-file a required field, but we have to manually check for their non-empty values because of limitations in the cli package. See urfave/cli#849.

Fixes RHCLOUD-12333

Signed-off-by: Link Dupont <link@sub-pop.net>

cmd/yggd/main.go

@@ -84,7 +84,9 @@ func main() {
 			if err != nil {
 				return err
 			}
-			return altsrc.ApplyInputSourceValues(c, inputSource, app.Flags)
+			if err := altsrc.ApplyInputSourceValues(c, inputSource, app.Flags); err != nil {
+				return err
+			}
 		}
 		return nil
 	}
@@ -106,6 +108,12 @@ func main() {
 			return nil
 		}
 
+		for _, f := range []string{"cert-file", "key-file"} {
+			if c.String(f) == "" {
+				return cli.Exit(fmt.Errorf("required flag '%v' not set", f), 1)
+			}
+		}
+
 		if c.String("topic-prefix") != "" {
 			yggdrasil.TopicPrefix = c.String("topic-prefix")
 		}