// publishUpdate notifies Pub/Sub subscribers that the book identified with
// the given ID has been added/modified.
func publishUpdate(bookID int64) {
if !bookshelf.PubSubEnabled() {
return
}
pubSubCtx, err := bookshelf.PubSubCtx()
if err != nil {
log.Print(err)
return
}
b, err := json.Marshal(bookID)
if err != nil {
return
}
_, err = pubsub.Publish(pubSubCtx, bookshelf.PubSubTopic, &pubsub.Message{
Data: b,
})
log.Printf("Published update to Pub/Sub for Book ID %d: %v", bookID, err)
}
func main() {
var err error
pubSubCtx, err = bookshelf.PubSubCtx()
if err != nil {
log.Fatal(err)
}
booksClient, err = books.New(http.DefaultClient)
if err != nil {
log.Fatalf("could not access Google Books API: %v", err)
}
// ignore returned errors, which will be "already exists". If they're fatal
// errors, then following calls (e.g. in the subscribe function) will also fail.
pubsub.CreateTopic(pubSubCtx, bookshelf.PubSubTopic)
pubsub.CreateSub(pubSubCtx, subName, bookshelf.PubSubTopic, 0, "")
// Start worker goroutine.
go subscribe()
// [START http]
// Publish a count of processed requests to the server homepage.
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
countMu.Lock()
defer countMu.Unlock()
fmt.Fprintf(w, "This worker has processed %d books.", count)
})
port := "8080"
if p := os.Getenv("PORT"); p != "" {
port = p
}
log.Fatal(http.ListenAndServe(":"+port, nil))
// [END http]
}