Only gzip metadata if requested. Closes #2419

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Breaking Changes
 
 * Request timeouts for HTTP requests on the REST API now return a 503 status code instead of 500. The response for a request timeout is no longer in JSON format.
+* The metadata endpoint no longer returns gzipped responses by default. This now needs to be explicitly requested with an `Accept-Encoding: gzip` header 
 
 ## 28
 

README.md

@@ -3439,6 +3439,16 @@ The `call` and `workflow` may optionally contain failures shaped like this:
 ]
 ```
 
+### Compressing the metadata response
+
+The response from the metadata endpoint can be quite large depending on the workflow. To help with this Cromwell supports gzip encoding the metadata prior to sending it back to the client. In order to enable this, make sure your client is sending the `Accept-Encoding: gzip` header.
+
+For instance, with cURL:
+                   
+```
+$ curl -H "Accept-Encoding: gzip" http://localhost:8000/api/workflows/v1/b3e45584-9450-4e73-9523-fc3ccf749848/metadata
+```
+
 ## POST /api/workflows/:version/:id/abort
 
 cURL:

engine/src/main/scala/cromwell/webservice/CromwellApiService.scala

@@ -22,7 +22,6 @@ import cromwell.services.metadata.MetadataService._
 import cromwell.webservice.metadata.{MetadataBuilderActor, WorkflowQueryPagination}
 import cromwell.webservice.metadata.MetadataBuilderActor.{BuiltMetadataResponse, FailedMetadataResponse, MetadataBuilderActorResponse}
 import WorkflowJsonSupport._
-import akka.http.scaladsl.coding.{Deflate, Gzip, NoCoding}
 import akka.http.scaladsl.server.Route
 import cats.data.NonEmptyList
 import cats.data.Validated.{Invalid, Valid}
@@ -87,7 +86,7 @@ trait CromwellApiService {
         }
       }
     } ~
-    encodeResponseWith(Gzip, Deflate, NoCoding) {
+    encodeResponse {
       path("workflows" / Segment / Segment / "metadata") { (version, possibleWorkflowId) =>
         parameters(('includeKey.*, 'excludeKey.*, 'expandSubWorkflows.as[Boolean].?)) { (includeKeys, excludeKeys, expandSubWorkflowsOption) =>
           val includeKeysOption = NonEmptyList.fromList(includeKeys.toList)

engine/src/test/scala/cromwell/webservice/CromwellApiServiceSpec.scala

@@ -12,6 +12,7 @@ import cromwell.engine.workflow.workflowstore.WorkflowStoreEngineActor.WorkflowA
 import cromwell.engine.workflow.workflowstore.WorkflowStoreSubmitActor.{WorkflowSubmittedToStore, WorkflowsBatchSubmittedToStore}
 import cromwell.services.metadata.MetadataService._
 import akka.http.scaladsl.model._
+import akka.http.scaladsl.model.headers.{HttpEncodings, `Accept-Encoding`}
 import akka.http.scaladsl.testkit.{RouteTestTimeout, ScalatestRouteTest}
 import akka.http.scaladsl.unmarshalling.Unmarshal
 import akka.stream.ActorMaterializer
@@ -20,7 +21,6 @@ import cromwell.util.SampleWdl.HelloWorld
 import org.scalatest.{AsyncFlatSpec, Matchers}
 import spray.json._
 
-import scala.concurrent.Await
 import scala.concurrent.duration._
 
 class CromwellApiServiceSpec extends AsyncFlatSpec with ScalatestRouteTest with Matchers {
@@ -321,22 +321,36 @@ class CromwellApiServiceSpec extends AsyncFlatSpec with ScalatestRouteTest with
         akkaHttpService.routes ~>
         check {
           status should be(StatusCodes.OK)
-          val decoder: Decoder = Gzip
-          val result = Await.result(Unmarshal(decoder.decodeMessage(response)).to[JsObject], 1.second)
+          val result = responseAs[JsObject]
           result.fields.keys should contain allOf("testKey1", "testKey2")
           result.fields.keys shouldNot contain("testKey3")
           result.fields("testKey1") should be(JsString("myValue1"))
           result.fields("testKey2") should be(JsString("myValue2"))
         }
     }
 
+    it should "return with gzip encoding when requested" in {
+      Get(s"/workflows/$version/${CromwellApiServiceSpec.ExistingWorkflowId}/metadata").addHeader(`Accept-Encoding`(HttpEncodings.gzip)) ~>
+        akkaHttpService.routes ~>
+        check {
+          response.headers.find(_.name == "Content-Encoding").get.value should be("gzip")
+        }
+    }
+
+    it should "not return with gzip encoding when not requested" in {
+      Get(s"/workflows/$version/${CromwellApiServiceSpec.ExistingWorkflowId}/metadata") ~>
+        akkaHttpService.routes ~>
+        check {
+          response.headers.find(_.name == "Content-Encoding") shouldBe None
+        }
+    }
+
     it should "return with included metadata from the metadata route" in {
       Get(s"/workflows/$version/${CromwellApiServiceSpec.ExistingWorkflowId}/metadata?includeKey=testKey1&includeKey=testKey2a") ~>
        akkaHttpService.routes ~>
         check {
           status should be(StatusCodes.OK)
-          val decoder: Decoder = Gzip
-          val result = Await.result(Unmarshal(decoder.decodeMessage(response)).to[JsObject], 1.second)
+          val result = responseAs[JsObject]
           result.fields.keys should contain allOf("testKey1a", "testKey1b", "testKey2a")
           result.fields.keys should contain noneOf("testKey2b", "testKey3")
           result.fields("testKey1a") should be(JsString("myValue1a"))
@@ -350,8 +364,7 @@ class CromwellApiServiceSpec extends AsyncFlatSpec with ScalatestRouteTest with
        akkaHttpService.routes ~>
         check {
           status should be(StatusCodes.OK)
-          val decoder: Decoder = Gzip
-          val result = Await.result(Unmarshal(decoder.decodeMessage(response)).to[JsObject], 1.second)
+          val result = responseAs[JsObject]
           result.fields.keys should contain allOf("testKey1a", "testKey1b", "testKey2a")
           result.fields.keys should contain noneOf("testKey2b", "testKey3")
           result.fields("testKey1a") should be(JsString("myValue1a"))