*: productionize

1. Use klog instead of plain log (leveled logging is better logging)
2. Use flags instead of env vars (less change of leaks, stronger typing)
3. Rename contexts around to be more canonically named
4. Use ZWJ quoting
5. Clean up message rendering (no trailing semicolons, adjective pick)

dotenv.template

@@ -1,5 +0,0 @@
-FAFOMO_HOMESERVER=matrix.org
-FAFOMO_USERNAME=@fafomo:matrix.org
-FAFOMO_PASSWORD=
-FAFOMO_ROOM=
-FAFOMO_BACKEND=

fafomo.go

@@ -16,21 +16,20 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
-	"log"
+	"flag"
+	"fmt"
 	"net/http"
 	"os"
 	"os/signal"
 	"strings"
-	"sync"
 	"time"
 
+	"k8s.io/klog"
 	"maunium.net/go/mautrix"
 	"maunium.net/go/mautrix/event"
 	"maunium.net/go/mautrix/id"
 )
 
-var backend string
-
 var folks map[string]struct{}
 
 type JSONTop struct {
@@ -51,31 +50,40 @@ func ircquote(s string) string {
 }
 
 func listFmt(list []string) string {
-	return "[ " + strings.Join(list, " ") + " ]"
+	var listQuoted []string
+	for _, l := range list {
+		listQuoted = append(listQuoted, ircquote(l))
+	}
+	return "[ " + strings.Join(listQuoted, " ") + " ]"
 }
 
-func update(ctx context.Context) string {
+func update(ctx context.Context) (string, error) {
-	req, err := http.NewRequestWithContext(ctx, "GET", backend, nil)
+	req, err := http.NewRequestWithContext(ctx, "GET", flagBackendURL, nil)
 	if err != nil {
-		panic(err)
+		return "", err
 	}
 	res, err := http.DefaultClient.Do(req)
 	if err != nil {
-		panic(err)
+		return "", err
 	}
 	defer res.Body.Close()
 
 	var users JSONTop
 
-	json.NewDecoder(res.Body).Decode(&users)
+	if res.StatusCode != 200 {
+		return "", fmt.Errorf("unexpected API status code %d", res.StatusCode)
+	}
+	if err := json.NewDecoder(res.Body).Decode(&users); err != nil {
+		return "", fmt.Errorf("could not decode API response: %v", err)
+	}
 
 	var left []string
 	var arrived []string
 	var unchanged []string
 
-	new_folks := make(map[string]struct{})
+	newFolks := make(map[string]struct{})
 	for _, user := range users.Users {
-		new_folks[user.Login] = struct{}{}
+		newFolks[user.Login] = struct{}{}
 		if _, ok := folks[user.Login]; !ok {
 			arrived = append(arrived, user.Login)
 		} else {
@@ -83,111 +91,137 @@ func update(ctx context.Context) string {
 		}
 	}
 	for user, _ := range folks {
-		if _, ok := new_folks[user]; !ok {
+		if _, ok := newFolks[user]; !ok {
 			left = append(left, user)
 		}
 	}
 
-	folks = new_folks
+	folks = newFolks
 
 	// no change
 	if len(arrived) == 0 && len(left) == 0 {
-		return ""
+		return "", nil
 	}
 
-	message := ""
+	var parts []string
 	if len(arrived) > 0 {
-		message += "arrived: " + listFmt(arrived) + "; "
+		parts = append(parts, fmt.Sprintf("arrived: %s", listFmt(arrived)))
 	}
 	if len(left) > 0 {
-		message += "left: " + listFmt(left) + "; "
+		parts = append(parts, fmt.Sprintf("left: %s", listFmt(left)))
 	}
 	if len(unchanged) > 0 {
-		message += "also there: " + listFmt(unchanged) + "; "
+		adjective := "also"
+		if len(left) > 0 && len(arrived) == 0 {
+			adjective = "still"
+		}
+		parts = append(parts, fmt.Sprintf("%s there: %s", adjective, listFmt(unchanged)))
 	}
 
-	return message
+	return strings.Join(parts, "; "), nil
 }
 
+var (
+	flagMatrixHomeserver = "matrix.org"
+	flagMatrixUsername   = "@fafomo:matrix.org"
+	flagMatrixPassword   string
+	flagMatrixRoom       string
+	flagBackendURL       string
+)
+
 func main() {
-	homeserver := os.Getenv("FAFOMO_HOMESERVER")
+	flag.StringVar(&flagMatrixHomeserver, "matrix_homeserver", flagMatrixHomeserver, "Address of Matrix homeserver")
-	username := os.Getenv("FAFOMO_USERNAME")
+	flag.StringVar(&flagMatrixUsername, "matrix_username", flagMatrixUsername, "Matrix login username")
-	password := os.Getenv("FAFOMO_PASSWORD")
+	flag.StringVar(&flagMatrixPassword, "matrix_password", flagMatrixPassword, "Matrix login password")
-	room := os.Getenv("FAFOMO_ROOM")
+	flag.StringVar(&flagMatrixRoom, "matrix_room", flagMatrixRoom, "Matrix room MXID")
-	backend = os.Getenv("FAFOMO_BACKEND")
+	flag.StringVar(&flagBackendURL, "backend_url", flagBackendURL, "Checkinator (backend) addresss")
+	flag.Parse()
 
-	startCtx, _ := context.WithTimeout(context.Background(), 20*time.Second)
+	for _, s := range []struct {
-
+		value string
-	update(startCtx)
+		name  string
-
+	}{
-	client, err := mautrix.NewClient(homeserver, id.UserID(username), "")
+		{flagMatrixHomeserver, "matrix_homeserver"},
-	if err != nil {
+		{flagMatrixUsername, "matrix_username"},
-		panic(err)
+		{flagMatrixPassword, "matrix_password"},
+		{flagMatrixRoom, "matrix_room"},
+		{flagBackendURL, "backend_url"},
+	} {
+		if s.value == "" {
+			klog.Exitf("-%s must be set", s.name)
+		}
 	}
 
-	log.Println("Logging in...")
+	startCtx, startCtxC := context.WithTimeout(context.Background(), 20*time.Second)
+	defer startCtxC()
+
+	if _, err := update(startCtx); err != nil {
+		klog.Exitf("Initial update failed: %v", err)
+	}
+
+	client, err := mautrix.NewClient(flagMatrixHomeserver, id.UserID(flagMatrixUsername), "")
+	if err != nil {
+		klog.Exitf("NewClient failed: %v", err)
+	}
+
+	klog.Infof("Logging in...")
 
 	login, err := client.Login(startCtx, &mautrix.ReqLogin{
 		Type:       mautrix.AuthTypePassword,
-		Identifier: mautrix.UserIdentifier{Type: mautrix.IdentifierTypeUser, User: username},
+		Identifier: mautrix.UserIdentifier{Type: mautrix.IdentifierTypeUser, User: flagMatrixUsername},
-		Password:   password,
+		Password:   flagMatrixPassword,
 	})
+	if err != nil {
+		klog.Exitf("Failed to log in: %v", err)
+	}
 
 	client.AccessToken = login.AccessToken
 
 	syncer := client.Syncer.(*mautrix.DefaultSyncer)
 	syncer.OnEventType(event.EventMessage, func(ctx context.Context, evt *event.Event) {
-		//		log.Info().
+		klog.V(1).Infof("Sender: %s, type: %s, id: %s, body: %q", evt.Sender, evt.Type, evt.ID, evt.Content.AsMessage().Body)
-		//			Str("sender", evt.Sender.String()).
-		//			Str("type", evt.Type.String()).
-		//			Str("id", evt.ID.String()).
-		//			Str("body", evt.Content.AsMessage().Body).
-		//			Msg("Received message")
 	})
 
-	if err != nil {
+	klog.Infof("Now running...")
-		panic(err)
-	}
 
-	log.Println("Now running...")
+	ctx, ctxC := signal.NotifyContext(context.Background(), os.Interrupt)
-
+	defer ctxC()
-	syncCtx, _ := context.WithCancel(context.Background())
-	syncCtx, stop := signal.NotifyContext(syncCtx, os.Interrupt)
-	defer stop()
-
-	var syncStopWait sync.WaitGroup
-	syncStopWait.Add(1)
 
+	// Run Matrix sync process in the background.
+	syncDone := make(chan struct{})
 	go func() {
-		err = client.SyncWithContext(syncCtx)
+		err = client.SyncWithContext(ctx)
-		defer syncStopWait.Done()
+		defer close(syncDone)
-		if err != nil && !errors.Is(err, context.Canceled) {
+		if err != nil && !errors.Is(err, ctx.Err()) {
-			panic(err)
+			klog.Exitf("Sync failed: %v", err)
 		}
 	}()
 
+	// Update space members every minute.
 	ticker := time.NewTicker(60 * time.Second)
+process:
 	for {
 		select {
 		case <-ticker.C:
-			ctx, _ := context.WithTimeout(syncCtx, 5*time.Second)
+			ctx, _ := context.WithTimeout(ctx, 5*time.Second)
 
-			message := update(ctx)
+			message, err := update(ctx)
-			if message != "" {
-				log.Printf("Sent update: %s\n", message)
-				_, err := client.SendText(ctx, id.RoomID(room), message)
 			if err != nil {
-					log.Printf("Failed to send event: %v\n", err)
+				klog.Errorf("Update failed: %v", err)
+			} else if message != "" {
+				klog.Infof("Sent update: %s\n", message)
+				_, err := client.SendText(ctx, id.RoomID(flagMatrixRoom), message)
+				if err != nil {
+					klog.Errorf("Failed to send event: %v\n", err)
 				}
 			}
 
-		case <-syncCtx.Done():
+		case <-ctx.Done():
-			return
+			break process
 		}
 	}
 
-	stop()
+	klog.Infof("Waiting for graceful sync before exiting...")
-	syncStopWait.Wait()
+	<-syncDone
-
+	klog.Infof("Done.")
-	log.Println("Exited")
 }

go.mod

@@ -2,7 +2,10 @@ module fa-fo.de/fafomo
 
 go 1.23.0
 
-require maunium.net/go/mautrix v0.21.0
+require (
+	k8s.io/klog v1.0.0
+	maunium.net/go/mautrix v0.21.0
+)
 
 require (
 	filippo.io/edwards25519 v1.1.0 // indirect

go.sum

@@ -3,6 +3,7 @@ filippo.io/edwards25519 v1.1.0/go.mod h1:BxyFTGdWcka3PhytdK4V28tE5sGfRvvvRV7EaN4
 github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/go-logr/logr v0.1.0/go.mod h1:ixOQHD9gLJUVQQ2ZOR7zLEifBX6tGkNJF4QyIY7sIas=
 github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/mattn/go-colorable v0.1.13 h1:fFA4WZxdEF4tXPZVKMLwD8oUnCTTo08duU7wxecdEvA=
 github.com/mattn/go-colorable v0.1.13/go.mod h1:7S9/ev0klgBDR4GtXTXX8a3vIGJpMovkB8vQcUbaXHg=
@@ -41,5 +42,7 @@ golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
 golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+k8s.io/klog v1.0.0 h1:Pt+yjF5aB1xDSVbau4VsWe+dQNzA0qv1LlXdC2dF6Q8=
+k8s.io/klog v1.0.0/go.mod h1:4Bi6QPql/J/LkTDqv7R/cd3hPo4k2DG6Ptcz060Ez5I=
 maunium.net/go/mautrix v0.21.0 h1:Z6nVu+clkJgj6ANwFYQQ1BtYeVXZPZ9lRgwuFN57gOY=
 maunium.net/go/mautrix v0.21.0/go.mod h1:qm9oDhcHxF/Xby5RUuONIGpXw1SXXqLZj/GgvMxJxu0=