exempt a configurable number of MARKREAD commands from fakelag

default.yaml

@@ -849,6 +849,14 @@ fakelag:
     # sending any commands:
     cooldown: 2s
 
+    # exempt a certain number of command invocations per session from fakelag;
+    # this is to speed up "resynchronization" of client state during reattach
+    command-budgets:
+        "CHATHISTORY": 16
+        "MARKREAD":    16
+        "MONITOR":     1
+        "WHO":         4
+
 # the roleplay commands are semi-standardized extensions to IRC that allow
 # sending and receiving messages from pseudo-nicknames. this can be used either
 # for actual roleplaying, or for bridging IRC with other protocols.

irc/client.go

@@ -668,12 +668,21 @@ func (client *Client) run(session *Session) {
 			}
 		}
 
+		msg, err := ircmsg.ParseLineStrict(line, true, MaxLineLen)
+		// XXX defer processing of command error parsing until after fakelag
+
 		if client.registered {
-			touches := session.deferredFakelagCount + 1
+			// apply deferred fakelag
+			for i := 0; i < session.deferredFakelagCount; i++ {
+				session.fakelag.Touch("")
+			}
 			session.deferredFakelagCount = 0
-			for i := 0; i < touches; i++ {
-				session.fakelag.Touch()
+			// touch for the current command
+			var command string
+			if err == nil {
+				command = msg.Command
 			}
+			session.fakelag.Touch(command)
 		} else {
 			// DoS hardening, #505
 			session.registrationMessages++
@@ -683,7 +692,6 @@ func (client *Client) run(session *Session) {
 			}
 		}
 
-		msg, err := ircmsg.ParseLineStrict(line, true, MaxLineLen)
 		if err == ircmsg.ErrorLineIsEmpty {
 			continue
 		} else if err == ircmsg.ErrorTagsTooLong {

irc/config.go

@@ -524,6 +524,7 @@ type FakelagConfig struct {
 	BurstLimit        uint `yaml:"burst-limit"`
 	MessagesPerWindow uint `yaml:"messages-per-window"`
 	Cooldown          time.Duration
+	CommandBudgets    map[string]int `yaml:"command-budgets"`
 }
 
 type TorListenersConfig struct {
@@ -1428,6 +1429,17 @@ func LoadConfig(filename string) (config *Config, err error) {
 	}
 	config.Server.capValues[caps.Languages] = config.languageManager.CapValue()
 
+	if len(config.Fakelag.CommandBudgets) != 0 {
+		// normalize command names to uppercase:
+		commandBudgets := make(map[string]int, len(config.Fakelag.CommandBudgets))
+		for command, budget := range config.Fakelag.CommandBudgets {
+			commandBudgets[strings.ToUpper(command)] = budget
+		}
+		config.Fakelag.CommandBudgets = commandBudgets
+	} else {
+		config.Fakelag.CommandBudgets = nil
+	}
+
 	if config.Server.Relaymsg.Enabled {
 		for _, char := range protocolBreakingNameCharacters {
 			if strings.ContainsRune(config.Server.Relaymsg.Separators, char) {

irc/fakelag.go

@@ -5,6 +5,8 @@ package irc
 
 import (
 	"time"
+
+	"github.com/ergochat/ergo/irc/utils"
 )
 
 // fakelag is a system for artificially delaying commands when a user issues
@@ -36,6 +38,10 @@ type Fakelag struct {
 
 func (fl *Fakelag) Initialize(config FakelagConfig) {
 	fl.config = config
+	// XXX don't share mutable member CommandBudgets:
+	if config.CommandBudgets != nil {
+		fl.config.CommandBudgets = utils.CopyMap(config.CommandBudgets)
+	}
 	fl.nowFunc = time.Now
 	fl.sleepFunc = time.Sleep
 	fl.state = FakelagBursting
@@ -58,11 +64,16 @@ func (fl *Fakelag) Unsuspend() {
 }
 
 // register a new command, sleep if necessary to delay it
-func (fl *Fakelag) Touch() {
+func (fl *Fakelag) Touch(command string) {
 	if !fl.config.Enabled {
 		return
 	}
 
+	if budget, ok := fl.config.CommandBudgets[command]; ok && budget > 0 {
+		fl.config.CommandBudgets[command] = budget - 1
+		return
+	}
+
 	now := fl.nowFunc()
 	// XXX if lastTouch.IsZero(), treat it as "very far in the past", which is fine
 	elapsed := now.Sub(fl.lastTouch)

irc/fakelag_test.go

@@ -60,7 +60,7 @@ func TestFakelag(t *testing.T) {
 	window, _ := time.ParseDuration("1s")
 	fl, mt := newFakelagForTesting(window, 3, 2, window)
 
-	fl.Touch()
+	fl.Touch("")
 	slept, _ := mt.lastSleep()
 	if slept {
 		t.Fatalf("should not have slept")
@@ -69,7 +69,7 @@ func TestFakelag(t *testing.T) {
 	interval, _ := time.ParseDuration("100ms")
 	for i := 0; i < 2; i++ {
 		mt.pause(interval)
-		fl.Touch()
+		fl.Touch("")
 		slept, _ := mt.lastSleep()
 		if slept {
 			t.Fatalf("should not have slept")
@@ -77,7 +77,7 @@ func TestFakelag(t *testing.T) {
 	}
 
 	mt.pause(interval)
-	fl.Touch()
+	fl.Touch("")
 	if fl.state != FakelagThrottled {
 		t.Fatalf("should be throttled")
 	}
@@ -91,7 +91,7 @@ func TestFakelag(t *testing.T) {
 	}
 
 	// send another message without a pause; we should have to sleep for 500 msec
-	fl.Touch()
+	fl.Touch("")
 	if fl.state != FakelagThrottled {
 		t.Fatalf("should be throttled")
 	}
@@ -102,7 +102,7 @@ func TestFakelag(t *testing.T) {
 	}
 
 	mt.pause(interval * 6)
-	fl.Touch()
+	fl.Touch("")
 	if fl.state != FakelagThrottled {
 		t.Fatalf("should still be throttled")
 	}
@@ -112,7 +112,7 @@ func TestFakelag(t *testing.T) {
 	}
 
 	mt.pause(window * 2)
-	fl.Touch()
+	fl.Touch("")
 	if fl.state != FakelagBursting {
 		t.Fatalf("should be bursting again")
 	}

traditional.yaml

@@ -821,6 +821,14 @@ fakelag:
     # sending any commands:
     cooldown: 2s
 
+    # exempt a certain number of command invocations per session from fakelag;
+    # this is to speed up "resynchronization" of client state during reattach
+    command-budgets:
+        "CHATHISTORY": 16
+        "MARKREAD":    16
+        "MONITOR":     1
+        "WHO":         4
+
 # the roleplay commands are semi-standardized extensions to IRC that allow
 # sending and receiving messages from pseudo-nicknames. this can be used either
 # for actual roleplaying, or for bridging IRC with other protocols.