introduce support for checking multiple rooms in one go

config/config.go

@@ -10,6 +10,8 @@ import (
 	"time"
 )
 
+type rooms []string
+
 type configOption[T any] struct {
 	flagName         string
 	flagDefaultValue T
@@ -20,7 +22,7 @@ type configOption[T any] struct {
 type configOptions struct {
 	userID                       configOption[string]
 	token                        configOption[string]
-	room                         configOption[string]
+	rooms                        configOption[rooms]
 	printHomeserverMemberCount   configOption[bool]
 	homeserverVersionInfoTimeout configOption[time.Duration]
 }
@@ -28,7 +30,7 @@ type configOptions struct {
 type Config struct {
 	UserID                       string
 	Token                        string
-	Room                         string
+	Rooms                        rooms
 	PrintHomeserverMemberCount   bool
 	HomeserverVersionInfoTimeout time.Duration
 }
@@ -36,11 +38,20 @@ type Config struct {
 var configOpts = configOptions{
 	userID:                       configOption[string]{"user-id", "", "The Matrix user ID to use.", "MRVC_USER_ID"},
 	token:                        configOption[string]{"token", "", "The Matrix access token to use.", "MRVC_TOKEN"},
-	room:                         configOption[string]{"room", "", "The Matrix room to check.", "MRVC_ROOM"},
+	rooms:                        configOption[rooms]{"room", []string{}, "The Matrix room to check. The flag can be set multiple times to check multiple rooms.", "MRVC_ROOM"},
 	printHomeserverMemberCount:   configOption[bool]{"print-homeserver-member-count", false, "Print the member count for each homeserver.", "MRVC_PRINT_HOMESERVER_MEMBER_COUNT"},
 	homeserverVersionInfoTimeout: configOption[time.Duration]{"homeserver-version-info-timeout", time.Second * 5, "Timeout for getting the homeservers version information per homeserver.", "MRVC_HOMESERVER_VERSION_INFO_TIMEOUT"},
 }
 
+func (r *rooms) String() string {
+	return fmt.Sprint(*r)
+}
+
+func (r *rooms) Set(value string) error {
+	*r = append(*r, value)
+	return nil
+}
+
 func (configOpt configOption[T]) getFlagHelp() string {
 	return fmt.Sprintf("%s (EnvVar: %s)", configOpt.flagHelpBase, configOpt.envVarName)
 }
@@ -74,10 +85,15 @@ func (configOpt configOption[T]) getConfigValueWithError(configFlag *T, visitedF
 
 var userIdFlag = flag.String(configOpts.userID.getFlagArgs())
 var tokenFlag = flag.String(configOpts.token.getFlagArgs())
-var roomFlag = flag.String(configOpts.room.getFlagArgs())
 var printHomeserverMemberCountFlag = flag.Bool(configOpts.printHomeserverMemberCount.getFlagArgs())
 var homeserverVersionInfoTimeoutFlag = flag.Duration(configOpts.homeserverVersionInfoTimeout.getFlagArgs())
 
+var roomsFlag rooms
+
+func init() {
+	flag.Var(&roomsFlag, configOpts.rooms.flagName, configOpts.rooms.getFlagHelp())
+}
+
 func Get() Config {
 	flag.Parse()
 
@@ -98,7 +114,7 @@ func Get() Config {
 	if err != nil {
 		log.Fatal("A Matrix access token must be provided.")
 	}
-	config.Room, err = configOpts.room.getConfigValueWithError(roomFlag, visitedFlags, func(envVar string) string { return envVar })
+	config.Rooms, err = configOpts.rooms.getConfigValueWithError(&roomsFlag, visitedFlags, func(envVar string) rooms { return []string{envVar} })
 	if err != nil {
 		log.Fatal("A Matrix room must be provided.")
 	}