JarCastingfs2-google-cloud-pubsub
A developer-first Google cloud Pub/Sub client in Scala, based on the official Google cloud Java client library.
Getting Started
Publishing messages
With the library you can publish messages to a topic with Publisher which automatically will create the topic for you.
import com.github.hyjay.pubsub.Publisher
val io = for {
// Create a publisher and the returned IO will idempotently create the topic for you.
publisher <- Publisher.create("YOUR_PROJECT_ID", "YOUR_TOPIC")
messageId <- publisher.publish("Hello, world!".getBytes())
} yield ()
io.unsafeRunSync()
Creating a subscription
With the library you can create subscriptions as simple as it can be.
import com.github.hyjay.pubsub.SubscriptionFunctions
val io = SubscriptionFunctions("YOUR_PROJECT_ID").createSubscription("YOUR_TOPIC", "YOUR_SUBSCRIPTION")
io.unsafeRunSync()
Pulling messages
With the library you can pull messages from a subscription as simple as it can be.
import scala.util.Try
import cats.effect.IO
import com.github.hyjay.pubsub.Subscriber
// Return None for parsing failed messages
def parser(payload: Array[Byte]): Option[String] = Try(new String(payload)).toOption
// Print out parsed messages as strings
def run(message: String): IO[Unit] = IO { println(message) }
// Subscriber acknowledges parsing failed messages or messages handled by `run` without an error
// It nacks messages that are parsed but having an error while handling
val printMessages = Subscriber.create("YOUR_PROJECT_ID", "YOUR_SUBSCRIPTION").subscribe(parser)(run)
// The IO ends when pulling stop by any errors.
printMessages.unsafeRunSync()
Dependencies
Add this to your build.sbt:
libraryDependencies += "com.github.hyjay" %% "fs2-google-cloud-pubsub" % Version
Testing
If you want to run the test code in this library, set GOOGLE_APPLICATION_CREDENTIALS envvar to a file location of google application credential json file.
Please note that the test code calls actual Google cloud Pub/Sub APIs.
License
MIT - See LICENSE for more information.