Support live re-loading of rules. (#2)

Reviewed-on: #2
Co-authored-by: Anna Rose Wiggins <annabunches@gmail.com>
Co-committed-by: Anna Rose Wiggins <annabunches@gmail.com>

cmd/joyful/main.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"sync"
 
 	"git.annabunches.net/annabunches/joyful/internal/config"
 	"git.annabunches.net/annabunches/joyful/internal/logger"
@@ -63,24 +64,7 @@ func main() {
 	// Initialize physical devices
 	pDevices := initPhysicalDevices(config)
 
-	// Initialize rules
+	rules, eventChannel, doneChannel, wg := loadRules(config, pDevices, getVirtualDevices(vBuffersByName))
-	rules := config.BuildRules(pDevices, getVirtualDevices(vBuffersByName))
-	logger.Logf("Created %d mapping rules.", len(rules))
-
-	// start listening for events on devices and timers
-	eventChannel := make(chan ChannelEvent, 1000)
-	for _, device := range pDevices {
-		go eventWatcher(device, eventChannel)
-	}
-
-	timerCount := 0
-	for _, rule := range rules {
-		if timedRule, ok := rule.(mappingrules.TimedEventEmitter); ok {
-			go timerWatcher(timedRule, eventChannel)
-			timerCount++
-		}
-	}
-	logger.Logf("registered %d timers", timerCount)
 
 	// initialize the mode variable
 	mode := config.GetModes()[0]
@@ -117,6 +101,50 @@ func main() {
 			vBuffersByDevice[channelEvent.Device].AddEvent(channelEvent.Event)
 			// If we get a timer event, flush the output device buffer immediately
 			vBuffersByDevice[channelEvent.Device].SendEvents()
+
+		case ChannelEventReload:
+			// stop existing channels
+			fmt.Println("Reloading rules.")
+			doneChannel <- true
+			fmt.Println("Waiting for existing listeners to exit. Provide input from each of your devices.")
+			wg.Wait()
+			fmt.Println("Listeners exited. Parsing config.")
+			config := readConfig() // reload the config
+			rules, eventChannel, doneChannel, wg = loadRules(config, pDevices, getVirtualDevices(vBuffersByName))
 		}
 	}
 }
+
+func loadRules(
+	config *config.ConfigParser,
+	pDevices map[string]*evdev.InputDevice,
+	vDevices map[string]*evdev.InputDevice) ([]mappingrules.MappingRule, <-chan ChannelEvent, chan bool, *sync.WaitGroup) {
+
+	var wg sync.WaitGroup
+	eventChannel := make(chan ChannelEvent, 1000)
+	doneChannel := make(chan bool)
+
+	// Initialize rules
+	rules := config.BuildRules(pDevices, vDevices)
+	logger.Logf("Created %d mapping rules.", len(rules))
+
+	// start listening for events on devices and timers
+	for _, device := range pDevices {
+		wg.Add(1)
+		go eventWatcher(device, eventChannel, doneChannel, &wg)
+	}
+
+	timerCount := 0
+	for _, rule := range rules {
+		if timedRule, ok := rule.(mappingrules.TimedEventEmitter); ok {
+			wg.Add(1)
+			go timerWatcher(timedRule, eventChannel, doneChannel, &wg)
+			timerCount++
+		}
+	}
+	logger.Logf("registered %d timers", timerCount)
+
+	go consoleWatcher(eventChannel, &wg)
+
+	return rules, eventChannel, doneChannel, &wg
+}

cmd/joyful/threads.go

@@ -1,6 +1,9 @@
 package main
 
 import (
+	"bufio"
+	"os"
+	"sync"
 	"time"
 
 	"git.annabunches.net/annabunches/joyful/internal/logger"
@@ -13,8 +16,24 @@ const (
 	DeviceCheckIntervalMs = 1
 )
 
-func eventWatcher(device *evdev.InputDevice, channel chan<- ChannelEvent) {
+func eventWatcher(
+	device *evdev.InputDevice,
+	channel chan<- ChannelEvent,
+	done chan bool,
+	wg *sync.WaitGroup) {
+
+	defer wg.Done()
+
 	for {
+		select {
+		case cancel := <-done:
+			if cancel {
+				done <- true
+				return
+			}
+		default:
+		}
+
 		event, err := device.ReadOne()
 		if err != nil {
 			logger.LogError(err, "Error while reading event. Disconnecting device.")
@@ -28,8 +47,24 @@ func eventWatcher(device *evdev.InputDevice, channel chan<- ChannelEvent) {
 	}
 }
 
-func timerWatcher(rule mappingrules.TimedEventEmitter, channel chan<- ChannelEvent) {
+func timerWatcher(
+	rule mappingrules.TimedEventEmitter,
+	channel chan<- ChannelEvent,
+	done chan bool,
+	wg *sync.WaitGroup) {
+
+	defer wg.Done()
+
 	for {
+		select {
+		case cancel := <-done:
+			if cancel {
+				done <- true
+				return
+			}
+		default:
+		}
+
 		event := rule.TimerEvent()
 		if event != nil {
 			channel <- ChannelEvent{
@@ -41,3 +76,21 @@ func timerWatcher(rule mappingrules.TimedEventEmitter, channel chan<- ChannelEve
 		time.Sleep(TimerCheckIntervalMs * time.Millisecond)
 	}
 }
+
+// consoleWatcher reads input from stdin, and on receiving anything
+func consoleWatcher(channel chan<- ChannelEvent, wg *sync.WaitGroup) {
+	defer wg.Done()
+	stdin := bufio.NewReader(os.Stdin)
+	for {
+		_, err := stdin.ReadString('\n')
+		if err != nil {
+			logger.LogErrorf(err, "Error in console input thread")
+			continue
+		}
+
+		channel <- ChannelEvent{
+			Type: ChannelEventReload,
+		}
+		return
+	}
+}

cmd/joyful/types.go

@@ -7,6 +7,7 @@ type ChannelEventType int
 const (
 	ChannelEventInput ChannelEventType = iota
 	ChannelEventTimer
+	ChannelEventReload
 )
 
 type ChannelEvent struct {

internal/mappingrules/mapping_rule_axis_to_relaxis.go

@@ -3,7 +3,6 @@ package mappingrules
 import (
 	"time"
 
-	"git.annabunches.net/annabunches/joyful/internal/logger"
 	"github.com/holoplot/go-evdev"
 	"github.com/jonboulle/clockwork"
 )
@@ -53,10 +52,6 @@ func (rule *MappingRuleAxisToRelaxis) MatchEvent(
 		return nil, nil
 	}
 
-	defer func() {
-		logger.Logf("DEBUG: Rule '%s' nextEvent == '%v' with device value '%d'", rule.Name, rule.nextEvent, event.Value)
-	}()
-
 	// If we're inside the deadzone, unset the next event
 	if rule.Input.InDeadZone(event.Value) {
 		rule.nextEvent = NoNextEvent