From c09fc3b87e4cf99c57cb393098b7dbd729688442 Mon Sep 17 00:00:00 2001
From: Zach Smith <zach@driver.xyz>
Date: Thu, 31 Aug 2017 18:48:16 -0700
Subject: Proposed solution for autocreating subscriptions

---
 src/main/scala/xyz/driver/core/pubsub.scala | 35 ++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/src/main/scala/xyz/driver/core/pubsub.scala b/src/main/scala/xyz/driver/core/pubsub.scala
index d8e64e7..fcd096d 100644
--- a/src/main/scala/xyz/driver/core/pubsub.scala
+++ b/src/main/scala/xyz/driver/core/pubsub.scala
@@ -6,7 +6,7 @@ import akka.stream.Materializer
 import com.google.api.core.{ApiFutureCallback, ApiFutures}
 import com.google.cloud.pubsub.spi.v1._
 import com.google.protobuf.ByteString
-import com.google.pubsub.v1.{PubsubMessage, SubscriptionName, TopicName}
+import com.google.pubsub.v1.{PubsubMessage, PushConfig, SubscriptionName, TopicName}
 import com.typesafe.scalalogging.Logger
 
 import scala.concurrent.{ExecutionContext, Future, Promise}
@@ -90,12 +90,13 @@ object pubsub {
     def stopListening(): Unit
   }
 
-  class GooglePubsubSubscriber[Message](projectId: String,
-                                        subscriptionId: String,
-                                        receiver: Message => Future[Unit],
-                                        log: Logger)(implicit messageMarshaller: Unmarshaller[String, Message],
-                                                     mat: Materializer,
-                                                     ex: ExecutionContext)
+  class GooglePubsubSubscriber[Message](
+          projectId: String,
+          subscriptionId: String,
+          receiver: Message => Future[Unit],
+          log: Logger,
+          autoCreateSettings: Option[GooglePubsubSubscriber.SubscriptionSettings] = None
+  )(implicit messageMarshaller: Unmarshaller[String, Message], mat: Materializer, ex: ExecutionContext)
       extends PubsubSubscriber {
 
     private val subscriptionName = SubscriptionName.create(projectId, subscriptionId)
@@ -110,7 +111,21 @@ object pubsub {
       }
     }
 
-    private val subscriber = Subscriber.defaultBuilder(subscriptionName, messageReceiver).build()
+    private val subscriber = {
+      autoCreateSettings.foreach { subscriptionSettings =>
+        val adminClient        = SubscriptionAdminClient.create()
+        val subscriptionExists = Try(adminClient.getSubscription(subscriptionName)).isSuccess
+        if (!subscriptionExists) {
+          val topicName = TopicName.create(projectId, subscriptionSettings.topic)
+          adminClient.createSubscription(subscriptionName,
+                                         topicName,
+                                         subscriptionSettings.pushConfig,
+                                         subscriptionSettings.ackDeadlineSeconds)
+        }
+      }
+
+      Subscriber.defaultBuilder(subscriptionName, messageReceiver).build()
+    }
 
     subscriber.startAsync()
 
@@ -119,6 +134,10 @@ object pubsub {
     }
   }
 
+  object GooglePubsubSubscriber {
+    final case class SubscriptionSettings(topic: String, pushConfig: PushConfig, ackDeadlineSeconds: Int)
+  }
+
   class FakePubsubSubscriber extends PubsubSubscriber {
     def stopListening(): Unit = ()
   }
-- 
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