Started working on the event bus

handlers/site.go

@@ -1,11 +1,13 @@
 package handlers
 
 import (
+	"bufio"
 	"errors"
 	"fmt"
 	"github.com/gofiber/fiber/v3"
 	"github.com/jackc/pgx/v5"
 	"lmika.dev/lmika/hugo-cms/models"
+	"lmika.dev/lmika/hugo-cms/providers/bus"
 	"lmika.dev/lmika/hugo-cms/services/sites"
 	"net/http"
 	"time"
@@ -13,6 +15,7 @@ import (
 
 type Site struct {
 	Site *sites.Service
+	Bus  *bus.Bus
 }
 
 func (s *Site) Create(c fiber.Ctx) error {
@@ -75,6 +78,41 @@ func (s *Site) Rebuild(c fiber.Ctx) error {
 	return c.Redirect().To(fmt.Sprintf("/sites/%v/posts", GetSite(c).ID))
 }
 
+func (s *Site) SSE(c fiber.Ctx) error {
+	siteOfInterest := GetSite(c)
+
+	c.Set("Content-Type", "text/event-stream")
+	c.Set("Cache-Control", "no-cache")
+	c.Set("Connection", "keep-alive")
+	c.Set("Transfer-Encoding", "chunked")
+
+	return c.SendStreamWriter(func(w *bufio.Writer) {
+		sub := s.Bus.Subscribe()
+		defer s.Bus.Unsubscribe(sub)
+
+		for e := range sub.C {
+			switch e.Type {
+			case models.EventSiteBuildingStart:
+				eventSite := e.Data.(models.Site)
+				if eventSite.ID == siteOfInterest.ID {
+					fmt.Fprintf(w, "event: site-build-status\n")
+					fmt.Fprintf(w, "data: Building\n")
+				}
+			case models.EventSiteBuildingDone:
+				eventSite := e.Data.(models.Site)
+				if eventSite.ID == siteOfInterest.ID {
+					fmt.Fprintf(w, "event: site-build-status\n")
+					fmt.Fprintf(w, "data: \n")
+				}
+			}
+
+			if err := w.Flush(); err != nil {
+				break
+			}
+		}
+	})
+}
+
 func (s *Site) WithSite() fiber.Handler {
 	return func(c fiber.Ctx) (err error) {
 		id := fiber.Params[int](c, "siteId")

main.go

@@ -14,6 +14,7 @@ import (
 	"lmika.dev/lmika/hugo-cms/assets"
 	"lmika.dev/lmika/hugo-cms/config"
 	"lmika.dev/lmika/hugo-cms/handlers"
+	"lmika.dev/lmika/hugo-cms/providers/bus"
 	"lmika.dev/lmika/hugo-cms/providers/db"
 	"lmika.dev/lmika/hugo-cms/providers/git"
 	"lmika.dev/lmika/hugo-cms/providers/hugo"
@@ -77,15 +78,16 @@ func main() {
 	gitProvider := git.New()
 	themesProvider := themes.New()
 	netlifyProvider := netlify.New(cfg.NetlifyAuthToken)
+	bus := bus.New()
 
 	jobService := jobs.New()
-	siteBuilderService := sitebuilder.New(dbp, themesProvider, gitProvider, hugoProvider, netlifyProvider)
+	siteBuilderService := sitebuilder.New(dbp, themesProvider, gitProvider, hugoProvider, netlifyProvider, bus)
 
 	siteService := sites.NewService(cfg, dbp, themesProvider, siteBuilderService, jobService)
 	postService := posts.New(dbp, siteBuilderService, jobService)
 
 	indexHandlers := handlers.IndexHandler{}
-	siteHandlers := handlers.Site{Site: siteService}
+	siteHandlers := handlers.Site{Site: siteService, Bus: bus}
 	postHandlers := handlers.Post{Post: postService}
 	authHandlers := handlers.AuthHandler{UserService: userService}
 
@@ -103,6 +105,9 @@ func main() {
 		cfg.EncryptedCookieKey = encryptcookie.GenerateKey(32)
 	}
 
+	bus.Start()
+	defer bus.Stop()
+
 	app := fiber.New(fiber.Config{
 		Views:             tmplEngine,
 		PassLocalsToViews: true,
@@ -134,6 +139,7 @@ func main() {
 
 	sr.Get("/settings", siteHandlers.Settings)
 	sr.Post("/settings", siteHandlers.SaveSettings)
+	sr.Get("/sse", siteHandlers.SSE)
 
 	jobService.Start()
 	defer jobService.Stop()

models/events.go

@@ -0,0 +1,31 @@
+package models
+
+import "container/list"
+
+type EventType int
+
+const (
+	// EventTypeSubscribe event type for the bus indicating a new subscription.
+	// Data is a (chan Sub) to send the new subscription
+	EventTypeSubscribe EventType = iota
+
+	// EventTypeUnsubscribe event type for the bus indicating to remove a subscription.
+	// Data is the Sub type
+	EventTypeUnsubscribe
+
+	// EventSiteBuildingStart indicates that the site has started being built. Data = site
+	EventSiteBuildingStart = 2
+
+	// EventSiteBuildingDone indicates that the site has finish building. Data = site
+	EventSiteBuildingDone = 3
+)
+
+type Event struct {
+	Type EventType
+	Data any
+}
+
+type Sub struct {
+	C    chan Event
+	Elem *list.Element
+}

models/job.go

@@ -5,14 +5,3 @@ import "context"
 type Job struct {
 	Do func(ctx context.Context) error
 }
-
-func Jobs(jobs ...Job) Job {
-	return Job{Do: func(ctx context.Context) error {
-		for _, job := range jobs {
-			if err := job.Do(ctx); err != nil {
-				return err
-			}
-		}
-		return nil
-	}}
-}

providers/bus/bus.go

@@ -0,0 +1,64 @@
+package bus
+
+import (
+	"container/list"
+	"lmika.dev/lmika/hugo-cms/models"
+)
+
+type Bus struct {
+	subs       *list.List
+	eventQueue chan models.Event
+}
+
+func New() *Bus {
+	return &Bus{
+		subs:       list.New(),
+		eventQueue: make(chan models.Event, 20),
+	}
+}
+
+func (b *Bus) Fire(event models.Event) {
+	b.eventQueue <- event
+}
+
+func (b *Bus) Start() {
+	go func() {
+		for e := range b.eventQueue {
+			switch e.Type {
+			case models.EventTypeSubscribe:
+				retChan := e.Data.(chan *models.Sub)
+
+				newSub := &models.Sub{C: make(chan models.Event, 1)}
+				newSub.Elem = b.subs.PushBack(newSub)
+
+				retChan <- newSub
+			case models.EventTypeUnsubscribe:
+				sub := e.Data.(*models.Sub)
+				close(sub.C)
+				b.subs.Remove(sub.Elem)
+			default:
+				for f := b.subs.Front(); f != nil; f = f.Next() {
+					sub := f.Value.(*models.Sub)
+					select {
+					case sub.C <- e:
+					default:
+					}
+				}
+			}
+		}
+	}()
+}
+
+func (b *Bus) Stop() {
+	close(b.eventQueue)
+}
+
+func (b *Bus) Subscribe() *models.Sub {
+	resChan := make(chan *models.Sub)
+	b.eventQueue <- models.Event{Type: models.EventTypeSubscribe, Data: resChan}
+	return <-resChan
+}
+
+func (b *Bus) Unsubscribe(sub *models.Sub) {
+	b.eventQueue <- models.Event{Type: models.EventTypeUnsubscribe, Data: sub}
+}

services/sitebuilder/posts.go

@@ -15,11 +15,14 @@ import (
 func (s *Service) WritePost(site models.Site, post models.Post) models.Job {
 	return models.Job{
 		Do: func(ctx context.Context) error {
+			s.signalSiteBuildingStarted(ctx, site)
+			defer s.signalSiteBuildingFinished(ctx, site)
+
 			rbn, err := s.fullRebuildNecessary(ctx, site)
 			if err != nil {
 				return err
 			} else if rbn {
-				return s.RebuildSite(site, site).Do(ctx)
+				return s.rebuildSite(ctx, site, site)
 			}
 
 			if err := s.writePost(site, post); err != nil {
@@ -33,31 +36,24 @@ func (s *Service) WritePost(site models.Site, post models.Post) models.Job {
 func (s *Service) WriteAllPosts(site models.Site) models.Job {
 	return models.Job{
 		Do: func(ctx context.Context) error {
-			var startId int64
-			now := time.Now()
-			for {
-				posts, err := s.db.ListPublishablePosts(ctx, int64(startId), site.ID, now)
-				if err != nil {
+			s.signalSiteBuildingStarted(ctx, site)
+			defer s.signalSiteBuildingFinished(ctx, site)
+
+			if err := s.writeAllPosts(ctx, site); err != nil {
 				return err
-				} else if len(posts) == 0 {
-					return nil
 			}
 
-				for _, post := range posts {
-					if err := s.writePost(site, post); err != nil {
-						return err
-					}
-				}
-				startId = posts[len(posts)-1].ID
-			}
+			return s.publish(ctx, site)
 		},
 	}
 }
 
 func (s *Service) DeletePost(site models.Site, post models.Post) models.Job {
-	return models.Jobs(
-		models.Job{
+	return models.Job{
 		Do: func(ctx context.Context) error {
+			s.signalSiteBuildingStarted(ctx, site)
+			defer s.signalSiteBuildingFinished(ctx, site)
+
 			themeMeta, ok := s.themes.Lookup(site.Theme)
 			if !ok {
 				return errors.New("theme not found")
@@ -75,11 +71,29 @@ func (s *Service) DeletePost(site models.Site, post models.Post) models.Job {
 			if os.Remove(postFilename) != nil {
 				return nil
 			}
+			return s.publish(ctx, site)
+		},
+	}
+}
+
+func (s *Service) writeAllPosts(ctx context.Context, site models.Site) error {
+	var startId int64
+	now := time.Now()
+	for {
+		posts, err := s.db.ListPublishablePosts(ctx, int64(startId), site.ID, now)
+		if err != nil {
+			return err
+		} else if len(posts) == 0 {
 			return nil
-			},
-		},
-		s.Publish(site),
-	)
+		}
+
+		for _, post := range posts {
+			if err := s.writePost(site, post); err != nil {
+				return err
+			}
+		}
+		startId = posts[len(posts)-1].ID
+	}
 }
 
 func (s *Service) writePost(site models.Site, post models.Post) error {

services/sitebuilder/publish.go

@@ -8,6 +8,9 @@ import (
 func (s *Service) Publish(site models.Site) models.Job {
 	return models.Job{
 		Do: func(ctx context.Context) error {
+			s.signalSiteBuildingStarted(ctx, site)
+			defer s.signalSiteBuildingFinished(ctx, site)
+			
 			return s.publish(ctx, site)
 		},
 	}

services/sitebuilder/service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"lmika.dev/lmika/hugo-cms/models"
+	"lmika.dev/lmika/hugo-cms/providers/bus"
 	"lmika.dev/lmika/hugo-cms/providers/db"
 	"lmika.dev/lmika/hugo-cms/providers/git"
 	"lmika.dev/lmika/hugo-cms/providers/hugo"
@@ -20,6 +21,7 @@ type Service struct {
 	git     *git.Provider
 	hugo    *hugo.Provider
 	netlify *netlify.Provider
+	bus     *bus.Bus
 }
 
 func New(
@@ -28,6 +30,7 @@ func New(
 	git *git.Provider,
 	hugo *hugo.Provider,
 	netlify *netlify.Provider,
+	bus *bus.Bus,
 ) *Service {
 	return &Service{
 		db:      db,
@@ -35,33 +38,48 @@ func New(
 		git:     git,
 		hugo:    hugo,
 		netlify: netlify,
+		bus:     bus,
 	}
 }
 
 func (s *Service) CreateNewSite(site models.Site) models.Job {
 	return models.Job{
 		Do: func(ctx context.Context) error {
+			s.signalSiteBuildingStarted(ctx, site)
+			defer s.signalSiteBuildingFinished(ctx, site)
+
 			return s.createSite(ctx, site)
 		},
 	}
 }
 
 func (s *Service) RebuildSite(oldSite, newSite models.Site) models.Job {
-	return models.Jobs(
-		models.Job{
+	return models.Job{
 		Do: func(ctx context.Context) error {
+			s.signalSiteBuildingStarted(ctx, newSite)
+			defer s.signalSiteBuildingFinished(ctx, newSite)
+
+			return s.rebuildSite(ctx, oldSite, newSite)
+		},
+	}
+}
+
+func (s *Service) rebuildSite(ctx context.Context, oldSite, newSite models.Site) error {
 	// Teardown the existing site
 	siteDir := s.hugo.SiteStagingDir(oldSite, hugo.BaseSiteDir)
 	if err := os.RemoveAll(siteDir); err != nil {
 		return err
 	}
-				return nil
-			},
-		},
-		s.CreateNewSite(newSite),
-		s.WriteAllPosts(newSite),
-		s.Publish(newSite),
-	)
+
+	if err := s.createSite(ctx, newSite); err != nil {
+		return err
+	}
+
+	if err := s.writeAllPosts(ctx, newSite); err != nil {
+		return err
+	}
+
+	return s.publish(ctx, newSite)
 }
 
 func (s *Service) fullRebuildNecessary(ctx context.Context, site models.Site) (bool, error) {
@@ -122,3 +140,11 @@ func (s *Service) createSite(ctx context.Context, site models.Site) error {
 	}
 	return nil
 }
+
+func (s *Service) signalSiteBuildingStarted(ctx context.Context, site models.Site) {
+	s.bus.Fire(models.Event{Type: models.EventSiteBuildingStart, Data: site})
+}
+
+func (s *Service) signalSiteBuildingFinished(ctx context.Context, site models.Site) {
+	s.bus.Fire(models.Event{Type: models.EventSiteBuildingDone, Data: site})
+}

templates/layouts/site.html

@@ -7,6 +7,7 @@
     <link rel="stylesheet" href="/assets/css/main.css">
     <title>Hugo CMS</title>
     <script src="https://unpkg.com/htmx.org@2.0.4"></script>
+    <script src="https://unpkg.com/htmx-ext-sse@2.2.2/sse.js"></script>
 </head>
 <body class="role-site">
     <header>