fix(source resolver): prefer older servergroup when copying capacity (#…

…3161)

If there are multiple possible server groups to choose as the source,
and all are of the same size, prefer the older server group.

This supports a use case where multiple simultaneous clone operations
are performed against a single source (the intention is to have
multiple active server groups in the region). Because a server group
can have its capacity manipulated during the deploy lifecycle, we
don't want the second deploy to choose the first deploy as its source
and result in snapshotting a capacity that may have had the min
size pinned high

orca-clouddriver/src/main/groovy/com/netflix/spinnaker/orca/kato/pipeline/support/SourceResolver.groovy

@@ -110,8 +110,13 @@ class SourceResolver {
       regionalAsgs = onlyEnabled
     }
 
+    def instanceSize = { Map asg -> (asg.instances as Collection)?.size() ?: 0 }
+    def created = { Map asg -> asg.createdTime as Long ?: 0 }
+    if (stageData.useSourceCapacity) {
+      regionalAsgs = regionalAsgs.sort { a1, a2 -> instanceSize(a1) <=> instanceSize(a2) ?: created(a2) <=> created(a1) }
+    }
     //with useSourceCapacity prefer the largest ASG over the newest ASG
-    def latestAsg = stageData.useSourceCapacity ? regionalAsgs.sort { (it.instances as Collection)?.size() ?: 0 }.last() : regionalAsgs.last()
+    def latestAsg = regionalAsgs.last()
     return new StageData.Source(
       account: stageData.account, region: latestAsg["region"] as String, asgName: latestAsg["name"] as String, serverGroupName: latestAsg["name"] as String
     )

orca-clouddriver/src/test/groovy/com/netflix/spinnaker/orca/kato/pipeline/support/SourceResolverSpec.groovy

@@ -246,4 +246,64 @@ class SourceResolverSpec extends Specification {
     existing*.name == ['foo-test-v999', 'foo-test-v000', 'foo-test-v000', 'foo-test-v001']
   }
 
+  void 'should prefer the largest oldest enabled server group'() {
+    given:
+    OortService oort = Mock(OortService)
+    SourceResolver resolver = new SourceResolver(oortService: oort, mapper: new ObjectMapper(), resolver: Mock(TargetServerGroupResolver))
+
+    when:
+    def source = resolver.getSource(stage)
+
+    then:
+    1 * oort.getCluster('foo', 'test', 'foo-test', 'aws') >> new Response('http://oort.com', 200, 'Okay', [], new TypedString(serverGroups))
+    source != null
+
+    source.serverGroupName == "foo-test-v000"
+    source.account == 'test'
+    source.region == "us-west-1"
+
+    where:
+    stage = new Stage(
+      Execution.newPipeline("orca"),
+      "test",
+      [
+        application: "foo",
+        stack: "test",
+        credentials: "test",
+        region: "us-west-1",
+        useSourceCapacity: true
+      ]
+    )
+
+    serverGroups = '''\
+    {
+      "serverGroups": [{
+        "name": "foo-test-v001",
+        "region": "us-west-1",
+        "createdTime": 4,
+        "disabled": false,
+        "instances": [ 1, 2, 3 ]
+      },{
+        "name": "foo-test-v000",
+        "region": "us-west-1",
+        "disabled": false,
+        "instances": [ 1, 2, 3 ],
+        "createdTime": 3
+      },{
+        "name": "foo-test-v000",
+        "region": "us-east-1",
+        "disabled": false,
+        "instances": [ 1, 2, 3 ],
+        "createdTime": 2
+      },{
+        "name": "foo-test-v999",
+        "region": "us-east-1",
+        "disabled": false,
+        "instances": [ 1, 2, 3 ],
+        "createdTime": 1
+      }]
+    }'''.stripIndent()
+
+  }
+
 }