refactor(gce): Convert GoogleRegionalServerGroupCachingAgent to java (#…

…4007)

* refactor(gce): remove an unnecessary checkState()

We can survive this condition just fine.

* test(gce): Add a test about on-demand caching behavior

This tests the behavior discussed on the review of #4002. I should have
added it there, but I didn't think about it until now.

* refactor(gce): fix an import

* refactor(gce): remove `static` from a method

* refactor(gce): use getAccountName() consistently

* docs(gce): remove a TODO

It actually does seem to be true that an autoscaler's name always equals
that of its associated instance group. This _might_ even be a GCE rule,
but it's definitely something we always do in Spinnaker (see
UpsertGoogleAutoscalingPolicyAtomicOperation and
GCEUtil#buildAutoscaler).

* refactor(gce): Prepare zonal caching agent for an abstract superclass

About  90% of the code from GoogleZonalServerGroupCachingAgent was just
copied into GoogleRegionalServerGroupCachingAgent. I'm going to extract
all the common code into an abstract base class.

Pretty much all that will be left after I do that are the methods
marked `// @Override`. Those methods will be the abstract ones in the
superclass.

* refactor(gce): Create an AbstractGoogleServerGroupCachingAgent

The code is just copy-pasted directly from
GoogleZonalServerGroupCachingAgent except that I replaced the methods
marked `// @Override` with abstract methods. No other changes were made.

* test(gce): Add tests for GoogleRegionalServerGroupCachingAgent

* refactor(gce): Convert GoogleRegionalServerGroupCachingAgent to java

* refactor(gce): Convert GoogleRegionalServerGroupCachingAgent to java

* test(gce): Move server property tests into a test of the abstract class

It seems somewhat pointless to have two copies of these. They're
essentially just data transformation tests, not really doing anything
fancy depending on the subclass.

A lot of the other tests could potentially also be merged but I think
that would lead to some pretty weird tests that are less useful, so I'd
rather keep those separate.

* fix(gce): fix a small bug in GoogleRegionalServerGroupCachingAgent

This bug is likely pretty innocuous since callers are looking for a
specific key amongst the pendingOnDemandRequests and returning an extra
one won't hurt anything, but I might as well fix it.

It looks like this bug likely exists in other caching agents, too, but
since it's very long-standing and the impact is negligible, I'm going to
ignore that.

* refactor(gce): convert anonymous test class to inner class

* refactor(gce): clean up some of the test code

clouddriver-google/src/main/groovy/com/netflix/spinnaker/clouddriver/google/compute/GoogleComputeApiFactory.java

@@ -59,6 +59,15 @@ public InstanceTemplates createInstanceTemplates(GoogleNamedAccountCredentials c
     return new InstanceTemplates(credentials, operationPoller, registry);
   }
 
+  public RegionAutoscalers createRegionAutoscalers(GoogleNamedAccountCredentials credentials) {
+    return new RegionAutoscalers(credentials, operationPoller, registry);
+  }
+
+  public RegionInstanceGroupManagers createRegionInstanceGroupManagers(
+      GoogleNamedAccountCredentials credentials) {
+    return new RegionInstanceGroupManagers(credentials, operationPoller, registry);
+  }
+
   public ZoneAutoscalers createZoneAutoscalers(GoogleNamedAccountCredentials credentials) {
     return new ZoneAutoscalers(credentials, operationPoller, registry);
   }

clouddriver-google/src/main/groovy/com/netflix/spinnaker/clouddriver/google/compute/RegionAutoscalers.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2019 Google, LLC
+ *
+ * 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.netflix.spinnaker.clouddriver.google.compute;
+
+import com.google.api.services.compute.Compute;
+import com.google.api.services.compute.model.Autoscaler;
+import com.google.api.services.compute.model.RegionAutoscalerList;
+import com.netflix.spectator.api.Registry;
+import com.netflix.spinnaker.clouddriver.google.deploy.GoogleOperationPoller;
+import com.netflix.spinnaker.clouddriver.google.security.GoogleNamedAccountCredentials;
+import java.io.IOException;
+
+public final class RegionAutoscalers {
+
+  private final Compute.RegionAutoscalers computeApi;
+  private final GoogleNamedAccountCredentials credentials;
+  private final RegionalGoogleComputeRequestFactory requestFactory;
+
+  RegionAutoscalers(
+      GoogleNamedAccountCredentials credentials,
+      GoogleOperationPoller operationPoller,
+      Registry registry) {
+    this.computeApi = credentials.getCompute().regionAutoscalers();
+    this.credentials = credentials;
+    this.requestFactory =
+        new RegionalGoogleComputeRequestFactory(
+            "regionAutoscalers", credentials, operationPoller, registry);
+  }
+
+  public GoogleComputeGetRequest<Compute.RegionAutoscalers.Get, Autoscaler> get(
+      String region, String name) throws IOException {
+    return requestFactory.wrapGetRequest(
+        computeApi.get(credentials.getProject(), region, name), "get", region);
+  }
+
+  public PaginatedComputeRequest<Compute.RegionAutoscalers.List, Autoscaler> list(String region) {
+    return new PaginatedComputeRequestImpl<>(
+        pageToken ->
+            requestFactory.wrapRequest(
+                computeApi.list(credentials.getProject(), region).setPageToken(pageToken),
+                "list",
+                region),
+        RegionAutoscalerList::getNextPageToken,
+        RegionAutoscalerList::getItems);
+  }
+}

clouddriver-google/src/main/groovy/com/netflix/spinnaker/clouddriver/google/compute/RegionInstanceGroupManagers.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2019 Google, LLC
+ *
+ * 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.netflix.spinnaker.clouddriver.google.compute;
+
+import com.google.api.services.compute.Compute;
+import com.google.api.services.compute.model.InstanceGroupManager;
+import com.google.api.services.compute.model.RegionInstanceGroupManagerList;
+import com.google.common.collect.ImmutableList;
+import com.netflix.spectator.api.Registry;
+import com.netflix.spinnaker.clouddriver.google.deploy.GoogleOperationPoller;
+import com.netflix.spinnaker.clouddriver.google.security.GoogleNamedAccountCredentials;
+import java.io.IOException;
+import java.util.Optional;
+
+public final class RegionInstanceGroupManagers {
+
+  private final Compute.RegionInstanceGroupManagers computeApi;
+  private final GoogleNamedAccountCredentials credentials;
+  private final RegionalGoogleComputeRequestFactory requestFactory;
+
+  RegionInstanceGroupManagers(
+      GoogleNamedAccountCredentials credentials,
+      GoogleOperationPoller operationPoller,
+      Registry registry) {
+    this.computeApi = credentials.getCompute().regionInstanceGroupManagers();
+    this.credentials = credentials;
+    this.requestFactory =
+        new RegionalGoogleComputeRequestFactory(
+            "regionInstanceGroupManagers", credentials, operationPoller, registry);
+  }
+
+  public GoogleComputeGetRequest<Compute.RegionInstanceGroupManagers.Get, InstanceGroupManager> get(
+      String region, String name) throws IOException {
+    return requestFactory.wrapGetRequest(
+        computeApi.get(credentials.getProject(), region, name), "get", region);
+  }
+
+  public PaginatedComputeRequest<Compute.RegionInstanceGroupManagers.List, InstanceGroupManager>
+      list(String region) {
+    return new PaginatedComputeRequestImpl<>(
+        pageToken ->
+            requestFactory.wrapRequest(
+                computeApi.list(credentials.getProject(), region).setPageToken(pageToken),
+                "list",
+                region),
+        RegionInstanceGroupManagerList::getNextPageToken,
+        response -> Optional.ofNullable(response.getItems()).orElseGet(ImmutableList::of));
+  }
+}