e2e-tests: Add FlushProjectsCache related scenarios

Add a FlushProjectsCache scenario to this core framework. Make it reuse
the added GetProjectsCacheEntries and CheckProjectsCacheFlushEntries
scenarios, which can also be run independently as usual. Make all these
added scenarios extend the introduced CacheFlushSimulation core class,
for consistency and further reusability purposes.

In order for CheckProjectsCacheFlushEntries to run independently, as
opposed to otherwise being composed, introduce the PROJECTS_ENTRIES
optional JAVA_OPTS property ([1]). Default that value to 1, based on the
initial projects cache cardinality showed by locally testing this case.

[1] https://gerrit-review.googlesource.com/Documentation/dev-e2e-tests.html#_environment_properties

Change-Id: Ic5b6554332730763b538767d4946787d37baa9c1

e2e-tests/src/test/resources/data/com/google/gerrit/scenarios/CheckProjectsCacheFlushEntries.json

@@ -0,0 +1,6 @@
+[
+  {
+    "url": "http://HOSTNAME:HTTP_PORT/a/config/server/caches/projects",
+    "entries": "PROJECTS_ENTRIES"
+  }
+]

e2e-tests/src/test/resources/data/com/google/gerrit/scenarios/FlushProjectsCache.json

@@ -0,0 +1,5 @@
+[
+  {
+    "url": "http://HOSTNAME:HTTP_PORT/a/config/server/caches/projects/flush"
+  }
+]

e2e-tests/src/test/resources/data/com/google/gerrit/scenarios/GetProjectsCacheEntries.json

@@ -0,0 +1,5 @@
+[
+  {
+    "url": "http://HOSTNAME:HTTP_PORT/a/config/server/caches/projects"
+  }
+]

e2e-tests/src/test/scala/com/google/gerrit/scenarios/CacheFlushSimulation.scala

@@ -0,0 +1,32 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.scenarios
+
+class CacheFlushSimulation extends GerritSimulation {
+  protected val entriesKey = "entries"
+  protected val memKey = "mem"
+  protected var producer: Option[CacheFlushSimulation] = None
+  protected var consumer: Option[CacheFlushSimulation] = None
+
+  private var cacheEntriesBeforeFlush: Int = 0
+
+  def entriesBeforeFlush(entries: Int): Unit = {
+    cacheEntriesBeforeFlush = entries
+  }
+
+  def expectedEntriesAfterFlush(): Int = {
+    cacheEntriesBeforeFlush - 1
+  }
+}

e2e-tests/src/test/scala/com/google/gerrit/scenarios/CheckProjectsCacheFlushEntries.scala

@@ -0,0 +1,48 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.scenarios
+
+import io.gatling.core.Predef.{atOnceUsers, _}
+import io.gatling.core.feeder.FeederBuilder
+import io.gatling.core.structure.ScenarioBuilder
+import io.gatling.http.Predef._
+
+class CheckProjectsCacheFlushEntries extends CacheFlushSimulation {
+  private val data: FeederBuilder = jsonFile(resource).convert(keys).queue
+
+  def this(producer: CacheFlushSimulation) {
+    this()
+    this.producer = Some(producer)
+  }
+
+  val test: ScenarioBuilder = scenario(unique)
+      .feed(data)
+      .exec(session => {
+        if (producer.nonEmpty) {
+          session.set(entriesKey, producer.get.expectedEntriesAfterFlush())
+        } else {
+          session
+        }
+      })
+      .exec(http(unique).get("${url}")
+          .check(regex("\"" + memKey + "\": (\\d+)")
+              .is(session => session(entriesKey).as[String])))
+
+  setUp(
+    test.inject(
+      atOnceUsers(1)
+    ),
+  ).protocols(httpProtocol)
+}

e2e-tests/src/test/scala/com/google/gerrit/scenarios/FlushProjectsCache.scala

@@ -0,0 +1,60 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.scenarios
+
+import io.gatling.core.Predef._
+import io.gatling.core.feeder.FeederBuilder
+import io.gatling.core.structure.ScenarioBuilder
+
+import scala.concurrent.duration._
+
+class FlushProjectsCache extends CacheFlushSimulation {
+  private val data: FeederBuilder = jsonFile(resource).convert(keys).queue
+  private val default: String = name
+
+  override def relativeRuntimeWeight = 2
+
+  private val flushCache: ScenarioBuilder = scenario(unique)
+      .feed(data)
+      .exec(httpRequest)
+
+  private val createProject = new CreateProject(default)
+  private val getCacheEntriesAfterProject = new GetProjectsCacheEntries(this)
+  private val checkCacheEntriesAfterFlush = new CheckProjectsCacheFlushEntries(this)
+  private val deleteProject = new DeleteProject(default)
+
+  setUp(
+    createProject.test.inject(
+      nothingFor(stepWaitTime(createProject) seconds),
+      atOnceUsers(1)
+    ),
+    getCacheEntriesAfterProject.test.inject(
+      nothingFor(stepWaitTime(getCacheEntriesAfterProject) seconds),
+      atOnceUsers(1)
+    ),
+    flushCache.inject(
+      nothingFor(stepWaitTime(this) seconds),
+      atOnceUsers(1)
+    ),
+    checkCacheEntriesAfterFlush.test.inject(
+      nothingFor(stepWaitTime(checkCacheEntriesAfterFlush) seconds),
+      atOnceUsers(1)
+    ),
+    deleteProject.test.inject(
+      nothingFor(stepWaitTime(deleteProject) seconds),
+      atOnceUsers(1)
+    ),
+  ).protocols(httpProtocol)
+}

e2e-tests/src/test/scala/com/google/gerrit/scenarios/GerritSimulation.scala

@@ -68,6 +68,8 @@ class GerritSimulation extends Simulation {
     case ("project", project) =>
       val precedes = replaceKeyWith("_project", name, project.toString)
       replaceProperty("project", precedes)
+    case ("entries", entries) =>
+      replaceProperty("projects_entries", "1", entries.toString)
   }
 
   private def replaceProperty(term: String, in: String): String = {

e2e-tests/src/test/scala/com/google/gerrit/scenarios/GetProjectsCacheEntries.scala

@@ -0,0 +1,45 @@
+// Copyright (C) 2020 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.scenarios
+
+import io.gatling.core.Predef._
+import io.gatling.core.feeder.FeederBuilder
+import io.gatling.core.structure.ScenarioBuilder
+import io.gatling.http.Predef.{http, _}
+
+class GetProjectsCacheEntries extends CacheFlushSimulation {
+  private val data: FeederBuilder = jsonFile(resource).convert(keys).queue
+
+  def this(consumer: CacheFlushSimulation) {
+    this()
+    this.consumer = Some(consumer)
+  }
+
+  val test: ScenarioBuilder = scenario(unique)
+      .feed(data)
+      .exec(http(unique).get("${url}")
+          .check(regex("\"" + memKey + "\": (\\d+)").saveAs(entriesKey)))
+      .exec(session => {
+        if (consumer.nonEmpty) {
+          consumer.get.entriesBeforeFlush(session(entriesKey).as[Int])
+        }
+        session
+      })
+
+  setUp(
+    test.inject(
+      atOnceUsers(1)
+    )).protocols(httpProtocol)
+}