From 6f0010d16e0f0f8a7e364be85e8007679fad1d56 Mon Sep 17 00:00:00 2001
From: Daniel Peach <dpeach@google.com>
Date: Wed, 12 Apr 2017 14:29:25 -0400
Subject: [PATCH] fix(appengine): capacity values for automatic scaling (#1568)

---
 .../model/AppengineServerGroup.groovy         | 26 ++++++++++++++++---
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/clouddriver-appengine/src/main/groovy/com/netflix/spinnaker/clouddriver/appengine/model/AppengineServerGroup.groovy b/clouddriver-appengine/src/main/groovy/com/netflix/spinnaker/clouddriver/appengine/model/AppengineServerGroup.groovy
index 79822f4e74e..e09742f3f44 100644
--- a/clouddriver-appengine/src/main/groovy/com/netflix/spinnaker/clouddriver/appengine/model/AppengineServerGroup.groovy
+++ b/clouddriver-appengine/src/main/groovy/com/netflix/spinnaker/clouddriver/appengine/model/AppengineServerGroup.groovy
@@ -88,10 +88,8 @@ class AppengineServerGroup implements ServerGroup, Serializable {
         * For the flexible environment, a version using automatic scaling can be stopped.
         * A stopped version scales down to zero instances and ignores its scaling policy.
         * */
-        def min = servingStatus == ServingStatus.SERVING ?
-          [scalingPolicy.minTotalInstances, scalingPolicy.minIdleInstances].max() : 0
-        def max = servingStatus == ServingStatus.SERVING ?
-          [scalingPolicy.maxTotalInstances, scalingPolicy.maxIdleInstances, instanceCount].max() : instanceCount
+        def min = computeMinForAutomaticScaling(scalingPolicy)
+        def max = computeMaxForAutomaticScaling(scalingPolicy)
         return new ServerGroup.Capacity(min: min,
                                         max: max,
                                         desired: min)
@@ -114,6 +112,26 @@ class AppengineServerGroup implements ServerGroup, Serializable {
     }
   }
 
+  Integer computeMinForAutomaticScaling(AppengineScalingPolicy scalingPolicy) {
+    Integer instanceCount = instances?.size() ?: 0
+    if (servingStatus == ServingStatus.SERVING) {
+      def candidateMinValues = [scalingPolicy.minIdleInstances, scalingPolicy.minTotalInstances, instanceCount].findAll { it != null }
+      return candidateMinValues.min()
+    } else {
+      return 0
+    }
+  }
+
+  Integer computeMaxForAutomaticScaling(AppengineScalingPolicy scalingPolicy) {
+    Integer instanceCount = instances?.size() ?: 0
+    if (servingStatus == ServingStatus.SERVING) {
+      def candidateMaxValues = [scalingPolicy.maxIdleInstances, scalingPolicy.maxTotalInstances, instanceCount].findAll { it != null }
+      return candidateMaxValues.max()
+    } else {
+      return instanceCount
+    }
+  }
+
   static Boolean versionAllowsGradualTrafficMigration(Version version) {
     // Versions do not always have an env property if they are in the standard environment.
     def inStandardEnvironment = version.getEnv()?.toUpperCase() != "FLEXIBLE"