Autoscaling decision return absolute capacity (elastic#61575) (elastic#62670)

The autoscaling decision API now returns an absolute capacity,
and leaves the actual decision of whether a scale up or down
is needed to the orchestration system.

The decision API now returns both a tier and node level required
and current capacity as wells as a decider level breakdown of the
same though with in particular current memory still not populated.

Author: henningandersen

docs/reference/autoscaling/apis/delete-autoscaling-policy.asciidoc

@@ -17,7 +17,7 @@ PUT /_autoscaling/policy/my_autoscaling_policy
 {
   "policy": {
     "deciders": {
-      "always": {
+      "fixed": {
       }
     }
   }

docs/reference/autoscaling/apis/get-autoscaling-policy.asciidoc

@@ -17,7 +17,7 @@ PUT /_autoscaling/policy/my_autoscaling_policy
 {
   "policy": {
     "deciders": {
-      "always": {
+      "fixed": {
       }
     }
   }

docs/reference/autoscaling/apis/put-autoscaling-policy.asciidoc

@@ -17,7 +17,7 @@ PUT /_autoscaling/policy/<name>
 {
   "policy": {
     "deciders": {
-      "always": {
+      "fixed": {
       }
     }
   }
@@ -59,7 +59,7 @@ PUT /_autoscaling/policy/my_autoscaling_policy
 {
   "policy": {
     "deciders": {
-      "always": {
+      "fixed": {
       }
     }
   }

x-pack/plugin/autoscaling/qa/rest/src/yamlRestTest/resources/rest-api-spec/test/autoscaling/delete_autoscaling_policy.yml

@@ -6,7 +6,7 @@
         body:
           policy:
             deciders:
-              always: {}
+              fixed: {}
 
   - match: { "acknowledged": true }
 

x-pack/plugin/autoscaling/qa/rest/src/yamlRestTest/resources/rest-api-spec/test/autoscaling/get_autoscaling_decision.yml

@@ -6,24 +6,34 @@
   - match: { "decisions": [] }
 
 ---
-"Test get always autoscaling decision":
+"Test get fixed autoscaling decision":
   - do:
       autoscaling.put_autoscaling_policy:
         name: my_autoscaling_policy
         body:
           policy:
             deciders:
-              always: {}
+              fixed:
+                storage: 1337b
+                memory: 7331b
+                nodes: 10
 
   - match: { "acknowledged": true }
 
   - do:
       autoscaling.get_autoscaling_decision: {}
 
-  - match: { decisions.0.my_autoscaling_policy.decision: scale_up }
-  - match: { decisions.0.my_autoscaling_policy.decisions.0.name: always }
-  - match: { decisions.0.my_autoscaling_policy.decisions.0.type: scale_up }
-  - match: { decisions.0.my_autoscaling_policy.decisions.0.reason: always }
+  - match: { decisions.0.tier: my_autoscaling_policy }
+  - match: { decisions.0.required_capacity.tier.storage: 13370b }
+  - match: { decisions.0.required_capacity.tier.memory: 73310b }
+  - match: { decisions.0.required_capacity.node.storage: 1337b }
+  - match: { decisions.0.required_capacity.node.memory: 7331b }
+  - match: { decisions.0.decisions.0.name: fixed }
+  - match: { decisions.0.decisions.0.required_capacity.tier.storage: 13370b }
+  - match: { decisions.0.decisions.0.required_capacity.tier.memory: 73310b }
+  - match: { decisions.0.decisions.0.required_capacity.node.storage: 1337b }
+  - match: { decisions.0.decisions.0.required_capacity.node.memory: 7331b }
+  - match: { decisions.0.decisions.0.reason_summary: "fixed storage [1.3kb] memory [7.1kb] nodes [10]" }
 
   # test cleanup
   - do:

x-pack/plugin/autoscaling/qa/rest/src/yamlRestTest/resources/rest-api-spec/test/autoscaling/get_autoscaling_policy.yml

@@ -6,15 +6,15 @@
         body:
           policy:
             deciders:
-              always: {}
+              fixed: {}
 
   - match: { "acknowledged": true }
 
   - do:
       autoscaling.get_autoscaling_policy:
         name: my_autoscaling_policy
 
-  - match: { policy.deciders.always: {} }
+  - match: { policy.deciders.fixed: {} }
 
   # test cleanup
   - do:

x-pack/plugin/autoscaling/qa/rest/src/yamlRestTest/resources/rest-api-spec/test/autoscaling/put_autoscaling_policy.yml

@@ -6,7 +6,7 @@
         body:
           policy:
             deciders:
-              always: {}
+              fixed: {}
 
   - match: { "acknowledged": true }
 

x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/Autoscaling.java

@@ -45,8 +45,9 @@
 import org.elasticsearch.xpack.autoscaling.action.TransportGetAutoscalingDecisionAction;
 import org.elasticsearch.xpack.autoscaling.action.TransportGetAutoscalingPolicyAction;
 import org.elasticsearch.xpack.autoscaling.action.TransportPutAutoscalingPolicyAction;
-import org.elasticsearch.xpack.autoscaling.decision.AlwaysAutoscalingDeciderConfiguration;
-import org.elasticsearch.xpack.autoscaling.decision.AlwaysAutoscalingDeciderService;
+import org.elasticsearch.xpack.autoscaling.decision.AutoscalingDecision;
+import org.elasticsearch.xpack.autoscaling.decision.FixedAutoscalingDeciderConfiguration;
+import org.elasticsearch.xpack.autoscaling.decision.FixedAutoscalingDeciderService;
 import org.elasticsearch.xpack.autoscaling.decision.AutoscalingDeciderConfiguration;
 import org.elasticsearch.xpack.autoscaling.decision.AutoscalingDeciderService;
 import org.elasticsearch.xpack.autoscaling.decision.AutoscalingDecisionService;
@@ -181,8 +182,13 @@ public List<NamedWriteableRegistry.Entry> getNamedWriteables() {
             new NamedWriteableRegistry.Entry(NamedDiff.class, AutoscalingMetadata.NAME, AutoscalingMetadata.AutoscalingMetadataDiff::new),
             new NamedWriteableRegistry.Entry(
                 AutoscalingDeciderConfiguration.class,
-                AlwaysAutoscalingDeciderConfiguration.NAME,
-                AlwaysAutoscalingDeciderConfiguration::new
+                FixedAutoscalingDeciderConfiguration.NAME,
+                FixedAutoscalingDeciderConfiguration::new
+            ),
+            new NamedWriteableRegistry.Entry(
+                AutoscalingDecision.Reason.class,
+                FixedAutoscalingDeciderConfiguration.NAME,
+                FixedAutoscalingDeciderService.FixedReason::new
             )
         );
     }
@@ -193,8 +199,8 @@ public List<NamedXContentRegistry.Entry> getNamedXContent() {
             new NamedXContentRegistry.Entry(Metadata.Custom.class, new ParseField(AutoscalingMetadata.NAME), AutoscalingMetadata::parse),
             new NamedXContentRegistry.Entry(
                 AutoscalingDeciderConfiguration.class,
-                new ParseField(AlwaysAutoscalingDeciderConfiguration.NAME),
-                AlwaysAutoscalingDeciderConfiguration::parse
+                new ParseField(FixedAutoscalingDeciderConfiguration.NAME),
+                FixedAutoscalingDeciderConfiguration::parse
             )
         );
     }
@@ -210,7 +216,7 @@ public void loadExtensions(ExtensionLoader loader) {
 
     @Override
     public Collection<AutoscalingDeciderService<? extends AutoscalingDeciderConfiguration>> deciders() {
-        return org.elasticsearch.common.collect.List.of(new AlwaysAutoscalingDeciderService());
+        return org.elasticsearch.common.collect.List.of(new FixedAutoscalingDeciderService());
     }
 
     public Set<AutoscalingDeciderService<? extends AutoscalingDeciderConfiguration>> createDeciderServices() {

x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/action/GetAutoscalingDecisionAction.java

@@ -17,7 +17,6 @@
 import org.elasticsearch.xpack.autoscaling.decision.AutoscalingDecisions;
 
 import java.io.IOException;
-import java.util.Map;
 import java.util.Objects;
 import java.util.SortedMap;
 import java.util.TreeMap;
@@ -89,12 +88,8 @@ public XContentBuilder toXContent(final XContentBuilder builder, final Params pa
             {
                 builder.startArray("decisions");
                 {
-                    for (final Map.Entry<String, AutoscalingDecisions> decision : decisions.entrySet()) {
-                        builder.startObject();
-                        {
-                            builder.field(decision.getKey(), decision.getValue());
-                        }
-                        builder.endObject();
+                    for (final AutoscalingDecisions decision : decisions.values()) {
+                        decision.toXContent(builder, params);
                     }
                 }
                 builder.endArray();

x-pack/plugin/autoscaling/src/main/java/org/elasticsearch/xpack/autoscaling/action/TransportGetAutoscalingDecisionAction.java

@@ -9,6 +9,7 @@
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.support.ActionFilters;
 import org.elasticsearch.action.support.master.TransportMasterNodeAction;
+import org.elasticsearch.cluster.ClusterInfoService;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.block.ClusterBlockException;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
@@ -26,6 +27,7 @@ public class TransportGetAutoscalingDecisionAction extends TransportMasterNodeAc
     GetAutoscalingDecisionAction.Response> {
 
     private final AutoscalingDecisionService decisionService;
+    private final ClusterInfoService clusterInfoService;
 
     @Inject
     public TransportGetAutoscalingDecisionAction(
@@ -34,7 +36,8 @@ public TransportGetAutoscalingDecisionAction(
         final ThreadPool threadPool,
         final ActionFilters actionFilters,
         final IndexNameExpressionResolver indexNameExpressionResolver,
-        final AutoscalingDecisionService.Holder decisionServiceHolder
+        final AutoscalingDecisionService.Holder decisionServiceHolder,
+        final ClusterInfoService clusterInfoService
     ) {
         super(
             GetAutoscalingDecisionAction.NAME,
@@ -46,6 +49,7 @@ public TransportGetAutoscalingDecisionAction(
             indexNameExpressionResolver
         );
         this.decisionService = decisionServiceHolder.get();
+        this.clusterInfoService = clusterInfoService;
         assert this.decisionService != null;
     }
 
@@ -65,7 +69,7 @@ protected void masterOperation(
         final ClusterState state,
         final ActionListener<GetAutoscalingDecisionAction.Response> listener
     ) {
-        listener.onResponse(new GetAutoscalingDecisionAction.Response(decisionService.decide(state)));
+        listener.onResponse(new GetAutoscalingDecisionAction.Response(decisionService.decide(state, clusterInfoService.getClusterInfo())));
     }
 
     @Override