handle ConnectException for failover

CHANGELOG.md

@@ -1,3 +1,7 @@
+# 2.2.0
+
+* handle ConnectException with failover
+
 # 2.1.0
 
 * changed env flag for hosts BITCOIN_RPC_HOST -> BITCOIN_RPC_HOSTS

build.sbt

@@ -1,6 +1,6 @@
 lazy val commonSettings = Seq(
   organization := "io.tokenanalyst",
-  version := "2.1.0",
+  version := "2.2.0",
   scalaVersion := "2.12.10",
   description := "bitcoin-rpc")
 

src/main/scala/RPCClient.scala

@@ -27,7 +27,7 @@ import org.http4s.dsl.io._
 import org.http4s.headers.{Authorization, _}
 import org.http4s.{BasicCredentials, MediaType, Request, Uri}
 
-import java.net.SocketTimeoutException
+import java.net.{ConnectException, SocketTimeoutException}
 import scala.concurrent.ExecutionContext
 import scala.concurrent.duration._
 
@@ -86,7 +86,10 @@ object RPCClient {
         .withConnectTimeout(5.seconds)
         .withRequestTimeout(2.minutes)
         .resource
-      socket <- ZeroMQ.socket(config.hosts.head, config.zmqPort.getOrElse(28332))
+      socket <- ZeroMQ.socket(
+        config.hosts.head,
+        config.zmqPort.getOrElse(28332)
+      )
     } yield new RPCClient(client, socket, config)
   }
 }
@@ -119,8 +122,8 @@ class RPCClient(client: Client[IO], zmq: ZeroMQ.Socket, config: Config)
       request: A
   ): IO[Request[IO]] = {
     val uri = Uri
-    .fromString(s"http://${host}:${config.port.getOrElse(8332)}")
-    .getOrElse(throw new Exception("Could not parse URL"))
+      .fromString(s"http://${host}:${config.port.getOrElse(8332)}")
+      .getOrElse(throw new Exception("Could not parse URL"))
     (config.username, config.password) match {
       case (Some(user), Some(pass)) =>
         POST(
@@ -138,15 +141,19 @@ class RPCClient(client: Client[IO], zmq: ZeroMQ.Socket, config: Config)
     }
   }
 
-  def retry[A](fallbacks: Seq[String], current: Int = 0, maxRetries: Int = 10)(
+  def retry[A](fallbacks: Seq[String], current: Int = 0, max: Int = 10)(
       f: String => IO[A]
-  ): IO[A] =
+  ): IO[A] = {
+    val handle = (e: Exception) => {
+      if (current <= max)
+        retry(fallbacks, current + 1, max)(f)
+      else
+        IO.raiseError(new Exception(s"Running out of retries for: ${e}"))
+    }
     f(fallbacks(current % fallbacks.size)).handleErrorWith {
-      case e: SocketTimeoutException =>
-        if (current <= maxRetries)
-          retry(fallbacks, current + 1, maxRetries)(f)
-        else
-          IO.raiseError(new Exception(s"Running out of retries for: ${e}"))
-      case e => IO.raiseError(e)
+      case e: ConnectException       => handle(e)
+      case e: SocketTimeoutException => handle(e)
+      case e                         => IO.raiseError(e)
     }
+  }
 }

src/main/scala/ZeroMQ.scala

@@ -19,7 +19,7 @@ object ZeroMQ {
   class Socket(host: String, port: Int) extends Closeable {
     val context = new ZContext()
     val socket: ZMQ.Socket = context.createSocket(SocketType.SUB)
-
+  
     //http://api.zeromq.org/2-1:zmq-setsockopt
     socket.setHWM(0)
     socket.subscribe("hashblock".map(_.toByte).toArray)