more metadata follow-ups

default.yaml

@@ -1111,6 +1111,11 @@ metadata:
     max-subs: 100
     # how many keys can be stored per entity?
     max-keys: 100
+    # rate limiting for client metadata updates, which are expensive to process
+    client-throttle:
+        enabled: true
+        duration: 2m
+        max-attempts: 10
 
 # experimental support for mobile push notifications
 # see the manual for potential security, privacy, and performance implications.

irc/accounts.go

@@ -52,6 +52,7 @@ const (
 	// (not to be confused with their amodes, which a non-always-on client can have):
 	keyAccountChannelToModes    = "account.channeltomodes %s"
 	keyAccountPushSubscriptions = "account.pushsubscriptions %s"
+	keyAccountMetadata          = "account.metadata %s"
 
 	maxCertfpsPerAccount = 5
 )
@@ -137,6 +138,7 @@ func (am *AccountManager) createAlwaysOnClients(config *Config) {
 				am.loadModes(accountName),
 				am.loadRealname(accountName),
 				am.loadPushSubscriptions(accountName),
+				am.loadMetadata(accountName),
 			)
 		}
 	}
@@ -751,6 +753,40 @@ func (am *AccountManager) loadPushSubscriptions(account string) (result []stored
 	}
 }
 
+func (am *AccountManager) saveMetadata(account string, metadata map[string]string) {
+	j, err := json.Marshal(metadata)
+	if err != nil {
+		am.server.logger.Error("internal", "error storing metadata", err.Error())
+		return
+	}
+	val := string(j)
+	key := fmt.Sprintf(keyAccountMetadata, account)
+	am.server.store.Update(func(tx *buntdb.Tx) error {
+		tx.Set(key, val, nil)
+		return nil
+	})
+	return
+}
+
+func (am *AccountManager) loadMetadata(account string) (result map[string]string) {
+	key := fmt.Sprintf(keyAccountMetadata, account)
+	var val string
+	am.server.store.View(func(tx *buntdb.Tx) error {
+		val, _ = tx.Get(key)
+		return nil
+	})
+
+	if val == "" {
+		return nil
+	}
+	if err := json.Unmarshal([]byte(val), &result); err == nil {
+		return result
+	} else {
+		am.server.logger.Error("internal", "error loading metadata", err.Error())
+		return nil
+	}
+}
+
 func (am *AccountManager) addRemoveCertfp(account, certfp string, add bool, hasPrivs bool) (err error) {
 	certfp, err = utils.NormalizeCertfp(certfp)
 	if err != nil {
@@ -1880,6 +1916,7 @@ func (am *AccountManager) Unregister(account string, erase bool) error {
 	pwResetKey := fmt.Sprintf(keyAccountPwReset, casefoldedAccount)
 	emailChangeKey := fmt.Sprintf(keyAccountEmailChange, casefoldedAccount)
 	pushSubscriptionsKey := fmt.Sprintf(keyAccountPushSubscriptions, casefoldedAccount)
+	metadataKey := fmt.Sprintf(keyAccountMetadata, casefoldedAccount)
 
 	var clients []*Client
 	defer func() {
@@ -1939,6 +1976,7 @@ func (am *AccountManager) Unregister(account string, erase bool) error {
 		tx.Delete(pwResetKey)
 		tx.Delete(emailChangeKey)
 		tx.Delete(pushSubscriptionsKey)
+		tx.Delete(metadataKey)
 
 		return nil
 	})

irc/client.go

@@ -130,6 +130,7 @@ type Client struct {
 	pushSubscriptionsExist  atomic.Uint32 // this is a cache on len(pushSubscriptions) != 0
 	pushQueue               pushQueue
 	metadata                map[string]string
+	metadataThrottle        connection_limits.ThrottleDetails
 }
 
 type saslStatus struct {
@@ -427,7 +428,7 @@ func (server *Server) RunClient(conn IRCConn) {
 	client.run(session)
 }
 
-func (server *Server) AddAlwaysOnClient(account ClientAccount, channelToStatus map[string]alwaysOnChannelStatus, lastSeen, readMarkers map[string]time.Time, uModes modes.Modes, realname string, pushSubscriptions []storedPushSubscription) {
+func (server *Server) AddAlwaysOnClient(account ClientAccount, channelToStatus map[string]alwaysOnChannelStatus, lastSeen, readMarkers map[string]time.Time, uModes modes.Modes, realname string, pushSubscriptions []storedPushSubscription, metadata map[string]string) {
 	now := time.Now().UTC()
 	config := server.Config()
 	if lastSeen == nil && account.Settings.AutoreplayMissed {
@@ -512,6 +513,10 @@ func (server *Server) AddAlwaysOnClient(account ClientAccount, channelToStatus m
 		}
 	}
 	client.rebuildPushSubscriptionCache()
+
+	if len(metadata) != 0 {
+		client.metadata = metadata
+	}
 }
 
 func (client *Client) resizeHistory(config *Config) {
@@ -1397,7 +1402,7 @@ func (client *Client) destroy(session *Session) {
 
 	// alert monitors
 	if registered {
-		client.server.monitorManager.AlertAbout(details.nick, details.nickCasefolded, false)
+		client.server.monitorManager.AlertAbout(details.nick, details.nickCasefolded, false, nil)
 	}
 
 	// clean up channels
@@ -1849,6 +1854,7 @@ const (
 	IncludeUserModes
 	IncludeRealname
 	IncludePushSubscriptions
+	IncludeMetadata
 )
 
 func (client *Client) markDirty(dirtyBits uint) {
@@ -1930,6 +1936,9 @@ func (client *Client) performWrite(additionalDirtyBits uint) {
 	if (dirtyBits & IncludePushSubscriptions) != 0 {
 		client.server.accounts.savePushSubscriptions(account, client.getPushSubscriptions(true))
 	}
+	if (dirtyBits & IncludeMetadata) != 0 {
+		client.server.accounts.saveMetadata(account, client.ListMetadata())
+	}
 }
 
 // Blocking store; see Channel.Store and Socket.BlockingWrite

irc/config.go

@@ -734,10 +734,11 @@ type Config struct {
 	}
 
 	Metadata struct {
-		Enabled       bool
-		MaxSubs       int `yaml:"max-subs"`
-		MaxKeys       int `yaml:"max-keys"`
-		MaxValueBytes int `yaml:"max-value-length"`
+		Enabled        bool
+		MaxSubs        int            `yaml:"max-subs"`
+		MaxKeys        int            `yaml:"max-keys"`
+		MaxValueBytes  int            `yaml:"max-value-length"`
+		ClientThrottle ThrottleConfig `yaml:"client-throttle"`
 	}
 
 	WebPush struct {

irc/getters.go

@@ -11,6 +11,7 @@ import (
 	"time"
 
 	"github.com/ergochat/ergo/irc/caps"
+	"github.com/ergochat/ergo/irc/connection_limits"
 	"github.com/ergochat/ergo/irc/languages"
 	"github.com/ergochat/ergo/irc/modes"
 	"github.com/ergochat/ergo/irc/utils"
@@ -962,9 +963,18 @@ func (client *Client) GetMetadata(key string) (string, bool) {
 }
 
 func (client *Client) SetMetadata(key string, value string, limit int) (updated bool, err error) {
+	var alwaysOn bool
+	defer func() {
+		if alwaysOn && updated {
+			client.markDirty(IncludeMetadata)
+		}
+	}()
+
 	client.stateMutex.Lock()
 	defer client.stateMutex.Unlock()
 
+	alwaysOn = client.registered && client.alwaysOn
+
 	if client.metadata == nil {
 		client.metadata = make(map[string]string)
 	}
@@ -981,11 +991,20 @@ func (client *Client) SetMetadata(key string, value string, limit int) (updated
 }
 
 func (client *Client) UpdateMetadataFromPrereg(preregData map[string]string, limit int) (updates map[string]string) {
+	var alwaysOn bool
+	defer func() {
+		if alwaysOn && len(updates) > 0 {
+			client.markDirty(IncludeMetadata)
+		}
+	}()
+
 	updates = make(map[string]string, len(preregData))
 
 	client.stateMutex.Lock()
 	defer client.stateMutex.Unlock()
 
+	alwaysOn = client.registered && client.alwaysOn
+
 	if client.metadata == nil {
 		client.metadata = make(map[string]string)
 	}
@@ -1002,6 +1021,7 @@ func (client *Client) UpdateMetadataFromPrereg(preregData map[string]string, lim
 		client.metadata[k] = v
 		updates[k] = v
 	}
+
 	return
 }
 
@@ -1013,6 +1033,12 @@ func (client *Client) ListMetadata() map[string]string {
 }
 
 func (client *Client) DeleteMetadata(key string) (updated bool) {
+	defer func() {
+		if updated {
+			client.markDirty(IncludeMetadata)
+		}
+	}()
+
 	client.stateMutex.Lock()
 	defer client.stateMutex.Unlock()
 
@@ -1023,11 +1049,17 @@ func (client *Client) DeleteMetadata(key string) (updated bool) {
 	return updated
 }
 
-func (client *Client) ClearMetadata() map[string]string {
+func (client *Client) ClearMetadata() (oldMap map[string]string) {
+	defer func() {
+		if len(oldMap) > 0 {
+			client.markDirty(IncludeMetadata)
+		}
+	}()
+
 	client.stateMutex.Lock()
 	defer client.stateMutex.Unlock()
 
-	oldMap := client.metadata
+	oldMap = client.metadata
 	client.metadata = nil
 
 	return oldMap
@@ -1039,3 +1071,22 @@ func (client *Client) CountMetadata() int {
 
 	return len(client.metadata)
 }
+
+func (client *Client) checkMetadataThrottle() (throttled bool, remainingTime time.Duration) {
+	config := client.server.Config()
+	if !config.Metadata.ClientThrottle.Enabled {
+		return false, 0
+	}
+
+	client.stateMutex.Lock()
+	defer client.stateMutex.Unlock()
+
+	// copy client.metadataThrottle locally and then back for processing
+	var throttle connection_limits.GenericThrottle
+	throttle.ThrottleDetails = client.metadataThrottle
+	throttle.Duration = config.Metadata.ClientThrottle.Duration
+	throttle.Limit = config.Metadata.ClientThrottle.MaxAttempts
+	throttled, remainingTime = throttle.Touch()
+	client.metadataThrottle = throttle.ThrottleDetails
+	return
+}

irc/handlers.go

@@ -3197,6 +3197,18 @@ func metadataRegisteredHandler(client *Client, config *Config, subcommand string
 			return
 		}
 
+		// only rate limit clients changing their own metadata:
+		// channel metadata updates are not any more costly than a PRIVMSG
+		if client == targetClient {
+			if throttled, remainingTime := client.checkMetadataThrottle(); throttled {
+				retryAfter := strconv.Itoa(int(remainingTime.Seconds()) + 1)
+				rb.Add(nil, server.name, "FAIL", "METADATA", "RATE_LIMITED",
+					target, utils.SafeErrorParam(key), retryAfter,
+					fmt.Sprintf(client.t("Please wait at least %v and try again"), remainingTime.Round(time.Millisecond)))
+				return
+			}
+		}
+
 		if len(params) > 3 {
 			value := params[3]
 

irc/metadata.go

@@ -21,7 +21,7 @@ var (
 	errMetadataNotFound    = errors.New("key not found")
 )
 
-type MetadataHaver = interface {
+type MetadataHaver interface {
 	SetMetadata(key string, value string, limit int) (updated bool, err error)
 	GetMetadata(key string) (string, bool)
 	DeleteMetadata(key string) (updated bool)

irc/monitor.go

@@ -38,7 +38,7 @@ func (manager *MonitorManager) AddMonitors(users utils.HashSet[*Session], cfnick
 }
 
 // AlertAbout alerts everyone monitoring `client`'s nick that `client` is now {on,off}line.
-func (manager *MonitorManager) AlertAbout(nick, cfnick string, online bool) {
+func (manager *MonitorManager) AlertAbout(nick, cfnick string, online bool, client *Client) {
 	var watchers []*Session
 	// safely copy the list of clients watching our nick
 	manager.RLock()
@@ -52,8 +52,21 @@ func (manager *MonitorManager) AlertAbout(nick, cfnick string, online bool) {
 		command = RPL_MONONLINE
 	}
 
+	var metadata map[string]string
+	if online && client != nil {
+		metadata = client.ListMetadata()
+	}
+
 	for _, session := range watchers {
 		session.Send(nil, session.client.server.name, command, session.client.Nick(), nick)
+
+		if metadata != nil && session.capabilities.Has(caps.Metadata) {
+			for key := range session.MetadataSubscriptions() {
+				if val, ok := metadata[key]; ok {
+					session.Send(nil, client.server.name, "METADATA", nick, key, "*", val)
+				}
+			}
+		}
 	}
 }
 

irc/nickname.go

@@ -128,9 +128,11 @@ func performNickChange(server *Server, client *Client, target *Client, session *
 	}
 
 	newCfnick := target.NickCasefolded()
-	if newCfnick != details.nickCasefolded {
-		client.server.monitorManager.AlertAbout(details.nick, details.nickCasefolded, false)
-		client.server.monitorManager.AlertAbout(assignedNickname, newCfnick, true)
+	// send MONITOR updates only for nick changes, not for new connection registration;
+	// defer MONITOR for new connection registration until pre-registration metadata is applied
+	if hadNick && newCfnick != details.nickCasefolded {
+		client.server.monitorManager.AlertAbout(details.nick, details.nickCasefolded, false, nil)
+		client.server.monitorManager.AlertAbout(assignedNickname, newCfnick, true, target)
 	}
 	return nil
 }

irc/numerics.go

@@ -183,12 +183,13 @@ const (
 	RPL_MONLIST            = "732"
 	RPL_ENDOFMONLIST       = "733"
 	ERR_MONLISTFULL        = "734"
-	RPL_KEYVALUE           = "761" // metadata numerics
+	RPL_WHOISKEYVALUE      = "760" // metadata numerics
+	RPL_KEYVALUE           = "761"
 	RPL_KEYNOTSET          = "766"
 	RPL_METADATASUBOK      = "770"
 	RPL_METADATAUNSUBOK    = "771"
 	RPL_METADATASUBS       = "772"
-	RPL_METADATASYNCLATER  = "774"
+	RPL_METADATASYNCLATER  = "774" // end metadata numerics
 	RPL_LOGGEDIN           = "900"
 	RPL_LOGGEDOUT          = "901"
 	ERR_NICKLOCKED         = "902"

irc/server.go

@@ -430,6 +430,8 @@ func (server *Server) tryRegister(c *Client, session *Session) (exiting bool) {
 
 	c.applyPreregMetadata(session)
 
+	c.server.monitorManager.AlertAbout(c.Nick(), c.NickCasefolded(), true, c)
+
 	// this is not a reattach, so if the client is always-on, this is the first time
 	// the Client object was created during the current server uptime. mark dirty in
 	// order to persist the realname and the user modes:

traditional.yaml

@@ -1082,6 +1082,11 @@ metadata:
     max-subs: 100
     # how many keys can be stored per entity?
     max-keys: 100
+    # rate limiting for client metadata updates, which are expensive to process
+    client-throttle:
+        enabled: true
+        duration: 2m
+        max-attempts: 10
 
 # experimental support for mobile push notifications
 # see the manual for potential security, privacy, and performance implications.