FEAT: Discovery Video Service Subscription

cms/go.mod

@@ -3,7 +3,7 @@ module thamanyah/cms/v2
 go 1.25.12
 
 require (
-	github.com/aws/aws-sdk-go-v2 v1.44.0
+	github.com/aws/aws-sdk-go-v2 v1.45.1
 	github.com/aws/aws-sdk-go-v2/config v1.32.36
 	github.com/aws/aws-sdk-go-v2/service/mediaconvert v1.97.2
 	github.com/aws/aws-sdk-go-v2/service/s3 v1.107.1
@@ -20,14 +20,15 @@ require (
 	github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.7.17 // indirect
 	github.com/aws/aws-sdk-go-v2/credentials v1.19.35 // indirect
 	github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.18.36 // indirect
-	github.com/aws/aws-sdk-go-v2/internal/configsources v1.4.40 // indirect
-	github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.7.40 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/configsources v1.5.1 // indirect
+	github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.8.1 // indirect
 	github.com/aws/aws-sdk-go-v2/internal/v4a v1.4.37 // indirect
 	github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.13.16 // indirect
 	github.com/aws/aws-sdk-go-v2/service/internal/checksum v1.9.29 // indirect
 	github.com/aws/aws-sdk-go-v2/service/internal/presigned-url v1.13.36 // indirect
 	github.com/aws/aws-sdk-go-v2/service/internal/s3shared v1.19.37 // indirect
 	github.com/aws/aws-sdk-go-v2/service/signin v1.5.5 // indirect
+	github.com/aws/aws-sdk-go-v2/service/sns v1.44.1 // indirect
 	github.com/aws/aws-sdk-go-v2/service/sso v1.33.5 // indirect
 	github.com/aws/aws-sdk-go-v2/service/ssooidc v1.38.5 // indirect
 	github.com/aws/aws-sdk-go-v2/service/sts v1.45.5 // indirect

cms/go.sum

@@ -6,6 +6,8 @@ github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERo
 github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
 github.com/aws/aws-sdk-go-v2 v1.44.0 h1:4IbaHhtzy+4h37z4JQyO9a2QsiCml3CNYHtq5hIHigo=
 github.com/aws/aws-sdk-go-v2 v1.44.0/go.mod h1:bttEH6JqnUL8LepvDVfdrds/fZ5bCIxzpe3abyUrhDU=
+github.com/aws/aws-sdk-go-v2 v1.45.1 h1:iIoG3NaLhV6UZpPXyPXlDj2I9oS8tV/nMcMnITCC6Ks=
+github.com/aws/aws-sdk-go-v2 v1.45.1/go.mod h1:bttEH6JqnUL8LepvDVfdrds/fZ5bCIxzpe3abyUrhDU=
 github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.7.17 h1:mn+Vxb9zgz/FE/yDTcFim3DZ1qpcrxR+qBQkBrl6bzA=
 github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.7.17/go.mod h1:eDfmEFxu+BSVsUGLbzJhWjpOurv1mqczClS97yI8wdk=
 github.com/aws/aws-sdk-go-v2/config v1.32.36 h1:mX6ietU7UlB4w/2IUaexJdsyUDvhTd+jYPjVePiyi6s=
@@ -16,8 +18,12 @@ github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.18.36 h1:gucL1KH/PAYbpTpBg09CiV
 github.com/aws/aws-sdk-go-v2/feature/ec2/imds v1.18.36/go.mod h1:usTB+PHhNMhrx2dxUeHcM7OrT5pySvmjYI++IsefPN0=
 github.com/aws/aws-sdk-go-v2/internal/configsources v1.4.40 h1:UIXlbijuB2XK1Kr57fo8iIxCuaSHJzwZ1uo+2tbEYIk=
 github.com/aws/aws-sdk-go-v2/internal/configsources v1.4.40/go.mod h1:wcEsL6jscjZjVUinb0Q5qD/GXOG1yT3GNfmT9HuDwzU=
+github.com/aws/aws-sdk-go-v2/internal/configsources v1.5.1 h1:pc138gM1CW+XPc60rEwUlwwuwWFQK16CI1T7v1F9Oec=
+github.com/aws/aws-sdk-go-v2/internal/configsources v1.5.1/go.mod h1:1+koxpPIbfBdfzP6vojm5/zTpTQ/micYwlxIiNB3TxI=
 github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.7.40 h1:xLQVRDs2NddDmK9BEyh5KSlJ1Gpy5/GIJXrV6WcVGAE=
 github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.7.40/go.mod h1:XRXnpFVFGLaEVK+olDdFIM1vNa04ETW452oFGEPUxAo=
+github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.8.1 h1:K0JsbZQj+1h208Ro1zHeA4l7bMp0NvRffHQ91q8Ol1s=
+github.com/aws/aws-sdk-go-v2/internal/endpoints/v2 v2.8.1/go.mod h1:W3/vL6EtCIatICGy9ab29QhMuae+cOKPWcMxv02CO+Q=
 github.com/aws/aws-sdk-go-v2/internal/v4a v1.4.37 h1:oyd3ke4V9AhKcRR7rRgxk1VyI+DjK2CBQtbxh3OkdaA=
 github.com/aws/aws-sdk-go-v2/internal/v4a v1.4.37/go.mod h1:aA9D7SqfG9IC1b7FLD7Iyc8Q4JN0a8gHhNjN4zPlIaI=
 github.com/aws/aws-sdk-go-v2/service/internal/accept-encoding v1.13.16 h1:iE4NGbvqUZnHDqddQAauZzCILYtFjOHwRM5MOOKLB5A=
@@ -34,6 +40,8 @@ github.com/aws/aws-sdk-go-v2/service/s3 v1.107.1 h1:VUTtUJMuRNMkb/7NIKmd8NQaeQLP
 github.com/aws/aws-sdk-go-v2/service/s3 v1.107.1/go.mod h1:WvUaO0lP5GNMs1R6cs6qvB3mqo16GLta8yfOuf55Rpc=
 github.com/aws/aws-sdk-go-v2/service/signin v1.5.5 h1:0VTFBfOgPJrUSpGMgzoi8qLcXF5dbmiBuxpo14eBWUw=
 github.com/aws/aws-sdk-go-v2/service/signin v1.5.5/go.mod h1:sNZYlBxoohYMBYl47BO/bFtAM6I8HSsPa1qwwPPRGoQ=
+github.com/aws/aws-sdk-go-v2/service/sns v1.44.1 h1:dMIcbUQ8fPJPbX9jZV19JtL2lCAgEh1LUNlpe6sdgqE=
+github.com/aws/aws-sdk-go-v2/service/sns v1.44.1/go.mod h1:ucBUMGW8avqGmbyQoXyoC6Cgt+WsNBrhL9DA4Bb+jN4=
 github.com/aws/aws-sdk-go-v2/service/sqs v1.47.0 h1:vNsYthHgT4sUo0KVqpkZlz+8ZDqy/MdlqdvZdP6IoAc=
 github.com/aws/aws-sdk-go-v2/service/sqs v1.47.0/go.mod h1:FSB4mnod1TCBhs3vp2tWVVGHbqxluzA0Fo6LBOXZByw=
 github.com/aws/aws-sdk-go-v2/service/sso v1.33.5 h1:jDQARFp1mJ2PEnllQf01nfFXGfWMJ59e0/HCHUTTZCk=

cms/internal/consumers/mediaconvert.go

@@ -187,7 +187,7 @@ func (c MediaConvertEvents) handleJobEvent(ctx context.Context, body string) boo
 		}
 	}
 
-	err := repositories.VideoRepo.UpdateVideoOutcomeByJobID(ctx, event.Detail.JobID, status, playbackURL)
+	video, err := repositories.VideoRepo.UpdateVideoOutcomeByJobID(ctx, event.Detail.JobID, status, playbackURL)
 	if errors.Is(err, repositories.ErrVideoNotFound) {
 		// Not a fault: the topic carries every job in the account, including
 		// ones this service never submitted.
@@ -202,5 +202,29 @@ func (c MediaConvertEvents) handleJobEvent(ctx context.Context, body string) boo
 	}
 
 	log.Printf("Recorded A Job Outcome: job=%q status=%q playback=%q", event.Detail.JobID, status, playbackURL)
+
+	// Only a video that came out ready is worth showing, so only that one is
+	// announced. A failed job has already had its status recorded above, and
+	// the catalogue has no use for it.
+	if status != models.VideoStatusReady {
+		return true
+	}
+
+	if err := services.CatalogueClient.AnnounceVideo(ctx, services.CatalogueVideo{
+		VideoID:     video.ID,
+		Title:       video.Title,
+		PlaybackURL: video.PlaybackURL,
+		Categories:  video.CategoryNames,
+	}); err != nil {
+		// Worth another attempt: the outcome is already recorded, and the
+		// update is idempotent, so a redelivery re-runs it and tries the
+		// announcement again. The cost is that a consumer can see the same
+		// video twice, which is what at-least-once delivery means anyway.
+		log.Printf("Something Went Wrong Announcing A Ready Video: video=%q job=%q: %s",
+			video.ID, event.Detail.JobID, err)
+		return false
+	}
+
+	log.Printf("Announced A Ready Video: video=%q playback=%q", video.ID, video.PlaybackURL)
 	return true
 }

cms/internal/db/repositories/videos.go

@@ -21,25 +21,52 @@ var VideoRepo VideoRepository
 // is cleared along with the status. It returns ErrVideoNotFound when no video
 // carries that job id, which the consumer treats as a message to drop rather
 // than a fault.
-func (svc VideoRepository) UpdateVideoOutcomeByJobID(ctx context.Context, jobID string, status models.VideoStatus, playbackURL string) error {
-	result, err := svc.SQLDB.ExecContext(ctx, `
+//
+// It returns the video it updated, carrying the members an announcement is
+// built from — the row's id and title, and the names of the categories it is
+// filed under. The consumer would otherwise have to read back what it just
+// wrote, and reading it here keeps that SQL on this side of the seam.
+func (svc VideoRepository) UpdateVideoOutcomeByJobID(ctx context.Context, jobID string, status models.VideoStatus, playbackURL string) (models.Video, error) {
+	updated := models.Video{
+		Status:            status,
+		PlaybackURL:       playbackURL,
+		MediaConvertJobID: jobID,
+	}
+
+	err := svc.SQLDB.QueryRowContext(ctx, `
 		UPDATE videos
 		SET status = $1, playback_url = $2, updated_at = now()
 		WHERE mediaconvert_job_id = $3
-	`, string(status), playbackURL, jobID)
+		RETURNING id, title
+	`, string(status), playbackURL, jobID).Scan(&updated.ID, &updated.Title)
+	if errors.Is(err, sql.ErrNoRows) {
+		return models.Video{}, ErrVideoNotFound
+	}
 	if err != nil {
-		return err
+		return models.Video{}, err
 	}
 
-	affected, err := result.RowsAffected()
+	rows, err := svc.SQLDB.QueryContext(ctx, `
+		SELECT c.name
+		FROM video_categories vc
+		JOIN categories c ON c.id = vc.category_id
+		WHERE vc.video_id = $1
+		ORDER BY c.name
+	`, updated.ID)
 	if err != nil {
-		return err
+		return models.Video{}, err
 	}
-	if affected == 0 {
-		return ErrVideoNotFound
+	defer rows.Close()
+
+	for rows.Next() {
+		var name string
+		if err := rows.Scan(&name); err != nil {
+			return models.Video{}, err
+		}
+		updated.CategoryNames = append(updated.CategoryNames, name)
 	}
 
-	return nil
+	return updated, rows.Err()
 }
 
 // GetVideoByID reads one video and the ids of the categories it is filed

cms/internal/models/video.go

@@ -3,10 +3,14 @@ package models
 import "time"
 
 type Video struct {
-	ID                string
-	Title             string
-	Description       string
-	CategoryIDs       []int16
+	ID          string
+	Title       string
+	Description string
+	CategoryIDs []int16
+	// CategoryNames is the same filing read by name rather than id. It is
+	// filled only where a caller needs categories to be self-describing —
+	// the catalogue announcement — and is empty elsewhere.
+	CategoryNames     []string
 	Tags              string
 	FileName          string
 	StorageKey        string

cms/internal/services/catalogue.go

@@ -0,0 +1,75 @@
+package services
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/aws/aws-sdk-go-v2/aws"
+	"github.com/aws/aws-sdk-go-v2/service/sns"
+)
+
+var CatalogueClient Catalogue
+
+// CatalogueVideo is what cms announces when a video becomes ready. It is a
+// published contract — every subscriber of the catalogue topic decodes it —
+// so the JSON names here are as much an API as the ones in internal/api, and
+// changing one is a change every subscriber sees.
+//
+// Categories are named rather than numbered on purpose: the ids are cms's
+// own, and a consumer holding a name needs nothing from cms to make sense
+// of it.
+type CatalogueVideo struct {
+	VideoID     string   `json:"videoId"`
+	Title       string   `json:"title"`
+	PlaybackURL string   `json:"playbackUrl"`
+	Categories  []string `json:"categories"`
+}
+
+type Catalogue interface {
+	AnnounceVideo(ctx context.Context, video CatalogueVideo) error
+}
+
+type CatalogueConcrete struct {
+	SNSClient *sns.Client
+	TopicARN  string
+}
+
+// AnnounceVideo publishes one video to the catalogue topic, which fans it out
+// to whatever has subscribed. Delivery is at-least-once: the caller
+// republishes when a later step fails, so a subscriber has to tolerate seeing
+// the same video twice.
+//
+// A topic delivers only to the subscriptions that exist at the moment it
+// publishes, so a subscriber that wants the backlog needs its queue in place
+// before the announcement, not after.
+func (svc CatalogueConcrete) AnnounceVideo(ctx context.Context, video CatalogueVideo) error {
+	// A nil slice marshals to null, which would make "has no categories" and
+	// "categories unknown" indistinguishable to a reader. An empty list says
+	// the first, which is what an unfiled video means.
+	if video.Categories == nil {
+		video.Categories = []string{}
+	}
+
+	body, err := json.Marshal(video)
+	if err != nil {
+		return err
+	}
+
+	_, err = svc.SNSClient.Publish(ctx, &sns.PublishInput{
+		TopicArn: aws.String(svc.TopicARN),
+		Message:  aws.String(string(body)),
+	})
+	return err
+}
+
+// AssertSuccessfulConnection verifies the topic exists and is readable with
+// the configured credentials. It panics on failure: a service that cannot
+// announce would transcode videos the catalogue never hears about.
+func (svc CatalogueConcrete) AssertSuccessfulConnection(ctx context.Context) {
+	if _, err := svc.SNSClient.GetTopicAttributes(ctx, &sns.GetTopicAttributesInput{
+		TopicArn: aws.String(svc.TopicARN),
+	}); err != nil {
+		panic(fmt.Errorf("sns: cannot connect to catalogue topic %q: %w", svc.TopicARN, err))
+	}
+}

cms/main.go

@@ -15,6 +15,7 @@ import (
 	"github.com/aws/aws-sdk-go-v2/config"
 	"github.com/aws/aws-sdk-go-v2/service/mediaconvert"
 	"github.com/aws/aws-sdk-go-v2/service/s3"
+	"github.com/aws/aws-sdk-go-v2/service/sns"
 	"github.com/aws/aws-sdk-go-v2/service/sqs"
 	_ "github.com/lib/pq"
 	httpSwagger "github.com/swaggo/http-swagger/v2"
@@ -73,6 +74,13 @@ func runServer() {
 		panic(fmt.Errorf("missing required env var: MEDIACONVERT_EVENTS_QUEUE_URL"))
 	}
 
+	// The topic ready videos are announced on, which fans out to whatever has
+	// subscribed — the read side's queue, today.
+	catalogueEventsTopicARN := os.Getenv("CATALOGUE_EVENTS_TOPIC_ARN")
+	if catalogueEventsTopicARN == "" {
+		panic(fmt.Errorf("missing required env var: CATALOGUE_EVENTS_TOPIC_ARN"))
+	}
+
 	// The public host the encoded output is served from — the CloudFront
 	// distribution in front of the output bucket. MediaConvert reports where
 	// it wrote as an s3:// path into a bucket that blocks public access, so
@@ -117,6 +125,14 @@ func runServer() {
 
 	services.SQSClient = concreteSQSClient
 
+	concreteCatalogueClient := &services.CatalogueConcrete{
+		SNSClient: sns.NewFromConfig(awsConfig),
+		TopicARN:  catalogueEventsTopicARN,
+	}
+	concreteCatalogueClient.AssertSuccessfulConnection(context.Background())
+
+	services.CatalogueClient = concreteCatalogueClient
+
 	concreteDBClient := db.CreateDBConnection(requireDBConnectionString())
 	defer db.CloseConnection(concreteDBClient)
 	db.AssertSuccessfulConnection(context.Background(), concreteDBClient)