1 files changed, 45 insertions, 0 deletions
diff --git a/project/PollingUtils.scala b/project/PollingUtils.scala
new file mode 100644
index 0000000..34b92ac
--- /dev/null
+++ b/project/PollingUtils.scala
@@ -0,0 +1,45 @@
+import java.io.FileNotFoundException
+import java.net.{ConnectException, URL}
+
+import scala.concurrent.TimeoutException
+import scala.concurrent.duration._
+
+object PollingUtils {
+
+  def waitUntilServerAvailable(url: URL): Unit = {
+    val connected = poll(5.seconds, 250.milliseconds)({
+      urlConnectionAvailable(url)
+    })
+    if (!connected) {
+      throw new TimeoutException(s"Failed to connect to $url")
+    }
+  }
+
+  def poll(timeout: FiniteDuration, interval: FiniteDuration)(poll: => Boolean): Boolean = {
+    val start = System.nanoTime()
+
+    def go(): Boolean = {
+      if (poll) {
+        true
+      } else if ((System.nanoTime() - start) > timeout.toNanos) {
+        false
+      } else {
+        Thread.sleep(interval.toMillis)
+        go()
+      }
+    }
+    go()
+  }
+
+  def urlConnectionAvailable(url: URL): Boolean = {
+    try {
+      url.openConnection()
+        .getInputStream
+        .close()
+      true
+    } catch {
+      case _: ConnectException => false
+      case _: FileNotFoundException => true // on 404
+    }
+  }
+}