Send reply mail from the post event bus.

cmd/server/main.go

@@ -37,6 +37,7 @@ func main() {
 		log.Fatalf("mail: %v", err)
 	}
 	bus := events.New()
+	mail.Subscribe(bus, store.NewPostgres(db), notifier)
 	bot, err := discord.FromEnv(store.NewDiscordLinks(db), bus, store.NewPostgres(db), notifier)
 	if err != nil {
 		log.Fatalf("discord: %v", err)
@@ -44,7 +45,7 @@ func main() {
 	if bot != nil {
 		defer bot.Close()
 	}
-	handler := newHandler(db, sessions, uploader, notifier, bus)
+	handler := newHandler(db, sessions, uploader, bus)
 	run(&http.Server{
 		Addr:              listenAddr(),
 		Handler:           handler,
@@ -68,13 +69,12 @@ func openDB() (*sql.DB, *store.SessionStore) {
 	return db, sessions
 }
 
-func newHandler(db *sql.DB, sessions *store.SessionStore, uploader blob.Uploader, notifier mail.Notifier, bus events.Publisher) http.Handler {
+func newHandler(db *sql.DB, sessions *store.SessionStore, uploader blob.Uploader, bus events.Publisher) http.Handler {
 	srv, err := web.New(store.NewPostgres(db), sessions.Store(), plumber.TemplateFS, plumber.StaticFS, web.Config{
 		AdminSetupSecret: strings.TrimSpace(os.Getenv("ADMIN_SETUP_SECRET")),
 		SecureCookie:     secureCookieFromEnv(),
 		TrustedProxies:   parseTrustedProxies(os.Getenv("TRUSTED_PROXY_CIDRS")),
 		Blob:             uploader,
-		Mail:             notifier,
 		Events:           bus,
 		BaseURL:          strings.TrimRight(strings.TrimSpace(os.Getenv("APP_BASE_URL")), "/"),
 	})

internal/mail/subscriber.go

@@ -0,0 +1,89 @@
+package mail
+
+import (
+	"context"
+	"log"
+	"strings"
+	"time"
+
+	"plumber/internal/events"
+	"plumber/internal/store"
+)
+
+// Subscribe sends reply emails from PostCreated events. Nop or nil is a no-op.
+func Subscribe(bus *events.Bus, st store.Store, n Notifier) {
+	if bus == nil || st == nil || n == nil {
+		return
+	}
+	if _, disabled := n.(Nop); disabled {
+		return
+	}
+	s := subscriber{store: st, mail: n}
+	bus.Subscribe(s.handle)
+}
+
+type subscriber struct {
+	store store.Store
+	mail  Notifier
+}
+
+func (s subscriber) handle(_ context.Context, ev any) {
+	created, ok := ev.(events.PostCreated)
+	if !ok {
+		return
+	}
+	if strings.TrimSpace(created.ParentID) == "" {
+		return
+	}
+	go s.notifyReply(created.PostEvent)
+}
+
+func (s subscriber) notifyReply(ev events.PostEvent) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	parent, err := s.store.GetPost(ctx, ev.ParentID)
+	if err != nil {
+		log.Printf("notify reply %s: load parent: %v", ev.PostID, err)
+		return
+	}
+	root, err := s.store.GetPost(ctx, ev.RootID)
+	if err != nil {
+		log.Printf("notify reply %s: load root: %v", ev.PostID, err)
+		return
+	}
+	author, err := s.store.UserByID(ctx, ev.AuthorID)
+	if err != nil {
+		log.Printf("notify reply %s: load author: %v", ev.PostID, err)
+		return
+	}
+	recipientID := parent.AuthorID
+	if author.Admin() {
+		recipientID = root.AuthorID
+	}
+	if recipientID == author.ID {
+		return
+	}
+	msg := PostReply{
+		RootID:          root.ID,
+		RootTitle:       root.Title,
+		ReplyID:         ev.PostID,
+		ReplyBody:       ev.Body,
+		ReplyAuthorName: author.Name,
+	}
+	recipient, err := s.store.UserByID(ctx, recipientID)
+	if err != nil {
+		log.Printf("notify reply %s: load recipient: %v", msg.ReplyID, err)
+		return
+	}
+	if recipient == nil || strings.TrimSpace(recipient.Email) == "" {
+		return
+	}
+	msg.ToEmail = recipient.Email
+	msg.ToName = recipient.Name
+	if err := s.mail.NotifyPostReply(ctx, msg); err != nil {
+		log.Printf("notify reply %s: %v", msg.ReplyID, err)
+		return
+	}
+	log.Printf("notify reply %s: accepted", msg.ReplyID)
+}

internal/mail/subscriber_test.go

@@ -0,0 +1,200 @@
+package mail
+
+import (
+	"context"
+	"testing"
+	"time"
+
+	"plumber/internal/events"
+	"plumber/internal/pacific"
+	"plumber/internal/store"
+)
+
+func TestSubscribeReplyNotifications(t *testing.T) {
+	t.Parallel()
+
+	mem := store.NewMemory()
+	homeowner := seedMailUser(t, mem, "homeowner", store.RoleUser, "sam@example.com")
+	admin := seedMailUser(t, mem, "plumber", store.RoleAdmin, "pat@example.com")
+	root := seedMailRoot(t, mem, homeowner.ID, "Leaky sink", "It drips.")
+	adminReply := seedMailReply(t, mem, admin.ID, root.ID)
+	homeownerReply := seedMailReply(t, mem, homeowner.ID, adminReply.ID)
+
+	bus := events.New()
+	defer bus.Close()
+	recording := &Recording{}
+	Subscribe(bus, mem, recording)
+
+	ctx := context.Background()
+	bus.Publish(ctx, events.PostCreated{PostEvent: events.PostEvent{
+		PostID:   root.ID,
+		RootID:   root.ID,
+		Title:    root.Title,
+		Body:     root.Body,
+		AuthorID: homeowner.ID,
+	}})
+	bus.Publish(ctx, events.PostUpdated{PostEvent: events.PostEvent{
+		PostID:   adminReply.ID,
+		RootID:   root.ID,
+		ParentID: root.ID,
+		Body:     "Edited",
+		AuthorID: admin.ID,
+	}})
+
+	bus.Publish(ctx, events.PostCreated{PostEvent: events.PostEvent{
+		PostID:   adminReply.ID,
+		RootID:   root.ID,
+		ParentID: root.ID,
+		Body:     adminReply.Body,
+		AuthorID: admin.ID,
+	}})
+	msgs := waitForMail(t, recording, 1)
+	if msg := msgs[0]; msg.ToEmail != homeowner.Email ||
+		msg.RootID != root.ID ||
+		msg.RootTitle != root.Title ||
+		msg.ReplyID != adminReply.ID ||
+		msg.ReplyBody != adminReply.Body ||
+		msg.ReplyAuthorName != admin.Name {
+		t.Fatalf("admin reply = %+v", msg)
+	}
+
+	bus.Publish(ctx, events.PostCreated{PostEvent: events.PostEvent{
+		PostID:   homeownerReply.ID,
+		RootID:   root.ID,
+		ParentID: adminReply.ID,
+		Body:     homeownerReply.Body,
+		AuthorID: homeowner.ID,
+	}})
+	msgs = waitForMail(t, recording, 2)
+	if msg := msgs[1]; msg.ToEmail != admin.Email ||
+		msg.RootID != root.ID ||
+		msg.ReplyID != homeownerReply.ID ||
+		msg.ReplyAuthorName != homeowner.Name {
+		t.Fatalf("homeowner reply = %+v", msg)
+	}
+
+	nestedAdmin := seedMailReply(t, mem, admin.ID, adminReply.ID)
+	bus.Publish(ctx, events.PostCreated{PostEvent: events.PostEvent{
+		PostID:   nestedAdmin.ID,
+		RootID:   root.ID,
+		ParentID: adminReply.ID,
+		Body:     nestedAdmin.Body,
+		AuthorID: admin.ID,
+	}})
+	msgs = waitForMail(t, recording, 3)
+	if msg := msgs[2]; msg.ToEmail != homeowner.Email ||
+		msg.RootID != root.ID ||
+		msg.ReplyBody != nestedAdmin.Body ||
+		msg.ReplyAuthorName != admin.Name {
+		t.Fatalf("nested admin reply = %+v", msg)
+	}
+
+	self := seedMailReply(t, mem, homeowner.ID, root.ID)
+	bus.Publish(ctx, events.PostCreated{PostEvent: events.PostEvent{
+		PostID:   self.ID,
+		RootID:   root.ID,
+		ParentID: root.ID,
+		Body:     self.Body,
+		AuthorID: homeowner.ID,
+	}})
+
+	noEmail := seedMailUser(t, mem, "quiet", store.RoleUser, "")
+	quietRoot := seedMailRoot(t, mem, noEmail.ID, "Quiet thread", "No email.")
+	quietReply := seedMailReply(t, mem, admin.ID, quietRoot.ID)
+	bus.Publish(ctx, events.PostCreated{PostEvent: events.PostEvent{
+		PostID:   quietReply.ID,
+		RootID:   quietRoot.ID,
+		ParentID: quietRoot.ID,
+		Body:     quietReply.Body,
+		AuthorID: admin.ID,
+	}})
+
+	time.Sleep(50 * time.Millisecond)
+	if recording.Len() != 3 {
+		t.Fatalf("self, root, edit, or no-email sent mail: %+v", recording.Snapshot())
+	}
+}
+
+func TestSubscribeNopIgnoresReplies(t *testing.T) {
+	t.Parallel()
+
+	mem := store.NewMemory()
+	homeowner := seedMailUser(t, mem, "homeowner", store.RoleUser, "sam@example.com")
+	admin := seedMailUser(t, mem, "plumber", store.RoleAdmin, "pat@example.com")
+	root := seedMailRoot(t, mem, homeowner.ID, "Leaky sink", "It drips.")
+	reply := seedMailReply(t, mem, admin.ID, root.ID)
+
+	bus := events.New()
+	defer bus.Close()
+	recording := &Recording{}
+	Subscribe(bus, mem, Nop{})
+	Subscribe(nil, mem, recording)
+	Subscribe(bus, mem, nil)
+
+	bus.Publish(context.Background(), events.PostCreated{PostEvent: events.PostEvent{
+		PostID:   reply.ID,
+		RootID:   root.ID,
+		ParentID: root.ID,
+		Body:     reply.Body,
+		AuthorID: admin.ID,
+	}})
+	time.Sleep(50 * time.Millisecond)
+	if recording.Len() != 0 {
+		t.Fatalf("Nop or nil subscribe sent mail: %+v", recording.Snapshot())
+	}
+}
+
+func seedMailUser(t *testing.T, mem *store.Memory, username string, role store.Role, email string) *store.User {
+	t.Helper()
+	u := &store.User{
+		Username:     username,
+		Name:         username,
+		Email:        email,
+		PasswordHash: "x",
+		Role:         role,
+	}
+	if err := mem.CreateUser(context.Background(), u); err != nil {
+		t.Fatal(err)
+	}
+	return u
+}
+
+func seedMailRoot(t *testing.T, mem *store.Memory, authorID, title, body string) *store.Post {
+	t.Helper()
+	root := &store.Post{
+		AuthorID: authorID,
+		Title:    title,
+		Body:     body,
+		PostDate: pacific.Today(),
+	}
+	if err := mem.CreatePost(context.Background(), root); err != nil {
+		t.Fatal(err)
+	}
+	return root
+}
+
+func seedMailReply(t *testing.T, mem *store.Memory, authorID, parentID string) *store.Post {
+	t.Helper()
+	reply := &store.Post{
+		ParentID: &parentID,
+		AuthorID: authorID,
+		Body:     "Reply from " + authorID,
+	}
+	if err := mem.CreatePost(context.Background(), reply); err != nil {
+		t.Fatal(err)
+	}
+	return reply
+}
+
+func waitForMail(t *testing.T, recording *Recording, want int) []PostReply {
+	t.Helper()
+	deadline := time.Now().Add(2 * time.Second)
+	for time.Now().Before(deadline) {
+		if recording.Len() >= want {
+			return recording.Snapshot()
+		}
+		time.Sleep(10 * time.Millisecond)
+	}
+	t.Fatalf("recorded %d notifications, want %d", recording.Len(), want)
+	return nil
+}

internal/web/posts.go

@@ -5,15 +5,12 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
-	"log"
 	"net/http"
 	"net/url"
 	"strings"
-	"time"
 
 	"github.com/go-chi/chi/v5"
 
-	"plumber/internal/mail"
 	"plumber/internal/store"
 )
 
@@ -82,9 +79,6 @@ func (s *Server) handleCreatePost(w http.ResponseWriter, r *http.Request) {
 	if root == nil {
 		root = post
 	}
-	if parent != nil {
-		s.notifyPostReply(parent, root, post, user)
-	}
 	s.publishPostCreated(post, root, user)
 	http.Redirect(
 		w,
@@ -94,59 +88,6 @@ func (s *Server) handleCreatePost(w http.ResponseWriter, r *http.Request) {
 	)
 }
 
-// notifyPostReply emails the root homeowner for admin replies and the direct
-// parent author for homeowner replies.
-func (s *Server) notifyPostReply(
-	parent *store.Post,
-	root *store.Post,
-	reply *store.Post,
-	replyAuthor *store.User,
-) {
-	if parent == nil ||
-		root == nil ||
-		reply == nil ||
-		replyAuthor == nil ||
-		s.cfg.Mail == nil {
-		return
-	}
-	if _, disabled := s.cfg.Mail.(mail.Nop); disabled {
-		return
-	}
-	recipientID := parent.AuthorID
-	if replyAuthor.Admin() {
-		recipientID = root.AuthorID
-	}
-	if recipientID == replyAuthor.ID {
-		return
-	}
-	msg := mail.PostReply{
-		RootID:          root.ID,
-		RootTitle:       root.Title,
-		ReplyID:         reply.ID,
-		ReplyBody:       reply.Body,
-		ReplyAuthorName: replyAuthor.Name,
-	}
-	go func() {
-		ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
-		defer cancel()
-		recipient, err := s.store.UserByID(ctx, recipientID)
-		if err != nil {
-			log.Printf("notify reply %s: load recipient: %v", msg.ReplyID, err)
-			return
-		}
-		if recipient == nil || strings.TrimSpace(recipient.Email) == "" {
-			return
-		}
-		msg.ToEmail = recipient.Email
-		msg.ToName = recipient.Name
-		if err := s.cfg.Mail.NotifyPostReply(ctx, msg); err != nil {
-			log.Printf("notify reply %s: %v", msg.ReplyID, err)
-			return
-		}
-		log.Printf("notify reply %s: accepted", msg.ReplyID)
-	}()
-}
-
 // handleEditPost updates only a post's body after verifying that the current
 // homeowner owns it or that an admin is editing an admin-authored post.
 func (s *Server) handleEditPost(w http.ResponseWriter, r *http.Request) {

internal/web/posts_test.go

@@ -9,6 +9,7 @@ import (
 	"testing"
 	"time"
 
+	"plumber/internal/events"
 	"plumber/internal/mail"
 	"plumber/internal/pacific"
 	"plumber/internal/store"
@@ -263,8 +264,12 @@ func TestEditPostRoutePermissions(t *testing.T) {
 func TestPostReplyNotifications(t *testing.T) {
 	t.Parallel()
 
+	mem := store.NewMemory()
+	bus := events.New()
+	defer bus.Close()
 	recording := &mail.Recording{}
-	srv, mem := newTestServer(t, Config{Mail: recording})
+	mail.Subscribe(bus, mem, recording)
+	srv := newTestServerStore(t, mem, Config{Events: bus})
 	handler := srv.Handler()
 	homeowner := seedUser(t, mem, uniq("homeowner"), "hunter22", store.RoleUser)
 	admin := seedUser(t, mem, uniq("admin"), "hunter22", store.RoleAdmin)

internal/web/server.go

@@ -22,7 +22,6 @@ import (
 	"plumber/internal/blob"
 	"plumber/internal/events"
 	"plumber/internal/geo"
-	"plumber/internal/mail"
 	"plumber/internal/pacific"
 	"plumber/internal/store"
 )
@@ -35,7 +34,6 @@ type Config struct {
 	// TrustedProxies are CIDRs allowed to set X-Forwarded-For (direct peer).
 	TrustedProxies []*net.IPNet
 	Blob           blob.Uploader
-	Mail           mail.Notifier
 	Events         events.Publisher
 	BaseURL        string
 }
@@ -110,9 +108,6 @@ func New(st store.Store, sessionStore scs.Store, templateFS fs.FS, staticFS fs.F
 	if cfg.Blob == nil {
 		cfg.Blob = blob.Disabled{}
 	}
-	if cfg.Mail == nil {
-		cfg.Mail = mail.Nop{}
-	}
 	if cfg.Events == nil {
 		cfg.Events = events.Nop{}
 	}