hystrix take 2

3 files changed, 77 insertions, 0 deletions

diff --git a/build.sbt b/build.sbt
index c4331fe..b218909 100644
--- a/build.sbt
+++ b/build.sbt
@@ -59,6 +59,7 @@ lazy val rootProject = (project in file("."))
     json4s,
     braveBackend,
     prometheusBackend,
+    hystrixBackend,
     tests
   )
 
@@ -203,6 +204,17 @@ lazy val prometheusBackend: Project = (project in file("metrics/prometheus-backe
   )
   .dependsOn(core)
 
+lazy val hystrixBackend: Project = (project in file("circuit-breaker/hystrix-backend"))
+  .settings(commonSettings: _*)
+  .settings(
+    name := "hystrix-backend",
+    libraryDependencies ++= Seq(
+      "com.netflix.hystrix" % "hystrix-core" % "1.5.12",
+      scalaTest % "test"
+    )
+  )
+  .dependsOn(core)
+
 lazy val tests: Project = (project in file("tests"))
   .settings(commonSettings: _*)
   .settings(
diff --git a/circuit-breaker/hystrix-backend/src/main/scala/com/softwaremill/sttp/hystrix/HystrixBackend.scala b/circuit-breaker/hystrix-backend/src/main/scala/com/softwaremill/sttp/hystrix/HystrixBackend.scala
new file mode 100644
index 0000000..bd57357
--- /dev/null
+++ b/circuit-breaker/hystrix-backend/src/main/scala/com/softwaremill/sttp/hystrix/HystrixBackend.scala
@@ -0,0 +1,33 @@
+package com.softwaremill.sttp.hystrix
+
+import com.netflix.hystrix.HystrixCommand.Setter
+import com.netflix.hystrix.{HystrixCommand, HystrixCommandGroupKey, HystrixCommandProperties}
+import com.softwaremill.sttp.{MonadError, Request, Response, SttpBackend}
+
+class HystrixBackend[R[_], S] private (delegate: SttpBackend[R, S]) extends SttpBackend[R, S] {
+
+  class SttpCMD[T](request: Request[T, S], delegate: SttpBackend[R, S])
+    extends HystrixCommand[R[Response[T]]](
+      Setter.withGroupKey(HystrixCommandGroupKey.Factory.asKey("SttpCommand"))
+        .andCommandPropertiesDefaults(HystrixCommandProperties.Setter().withMetricsHealthSnapshotIntervalInMilliseconds(10))
+    ) {
+
+    override def run(): R[Response[T]] = delegate.send(request)
+  }
+
+  override def send[T](request: Request[T, S]): R[Response[T]] = {
+    new SttpCMD(request, delegate).execute()
+  }
+
+  override def close(): Unit = delegate.close()
+
+  /**
+    * The monad in which the responses are wrapped. Allows writing wrapper
+    * backends, which map/flatMap over the return value of [[send]].
+    */
+  override def responseMonad: MonadError[R] = delegate.responseMonad
+}
+
+object HystrixBackend {
+  def apply[R[_], S](delegate: SttpBackend[R, S]) = new HystrixBackend(delegate)
+}
\ No newline at end of file
diff --git a/circuit-breaker/hystrix-backend/src/test/scala/com/softwaremill/sttp/hystrix/HystrixBackendTest.scala b/circuit-breaker/hystrix-backend/src/test/scala/com/softwaremill/sttp/hystrix/HystrixBackendTest.scala
new file mode 100644
index 0000000..15cc55a
--- /dev/null
+++ b/circuit-breaker/hystrix-backend/src/test/scala/com/softwaremill/sttp/hystrix/HystrixBackendTest.scala
@@ -0,0 +1,32 @@
+package com.softwaremill.sttp.prometheus
+
+import com.netflix.hystrix.{HystrixCommandKey, HystrixCommandMetrics}
+import com.softwaremill.sttp.hystrix.HystrixBackend
+import com.softwaremill.sttp.testing.SttpBackendStub
+import com.softwaremill.sttp.{HttpURLConnectionBackend, Id, sttp, _}
+import org.scalatest.concurrent.Eventually
+import org.scalatest.{BeforeAndAfter, FlatSpec, Matchers, OptionValues}
+
+class HystrixBackendTest extends FlatSpec with Matchers with BeforeAndAfter with Eventually with OptionValues {
+
+  before {
+  }
+
+  it should "use default hystrix commands" in {
+    // given
+    val backendStub = SttpBackendStub(HttpURLConnectionBackend()).whenAnyRequest.thenRespondOk()
+    val backend = HystrixBackend[Id, Nothing](backendStub)
+    val requestsNumber = 10
+
+    // when
+    (0 until requestsNumber).map(_ => backend.send(sttp.get(uri"http://127.0.0.1/foo"))).foreach(println)
+
+    // then
+    val metrics = HystrixCommandMetrics.getInstance(HystrixCommandKey.Factory.asKey("SttpCMD"))
+    println(metrics.getExecutionTimeMean)
+    println(metrics.getExecutionTimePercentile(10))
+    println(metrics.getHealthCounts)
+    println(metrics.getCommandGroup)
+  }
+
+}