SOLR-11813: Reuse a NodeStateProvider in a session

solr/solrj/src/java/org/apache/solr/client/solrj/cloud/autoscaling/Policy.java

@@ -217,19 +217,23 @@ public class Policy implements MapWriter {
     Set<String> collections = new HashSet<>();
     List<Clause> expandedClauses;
     List<Violation> violations = new ArrayList<>();
+    final NodeStateProvider nodeStateProvider;
     final int znodeVersion;
 
     private Session(List<String> nodes, SolrCloudManager cloudManager,
-                    List<Row> matrix, List<Clause> expandedClauses, int znodeVersion) {
+                    List<Row> matrix, List<Clause> expandedClauses, int znodeVersion, NodeStateProvider nodeStateProvider) {
       this.nodes = nodes;
       this.cloudManager = cloudManager;
       this.matrix = matrix;
       this.expandedClauses = expandedClauses;
       this.znodeVersion = znodeVersion;
+      this.nodeStateProvider = nodeStateProvider;
     }
 
+
     Session(SolrCloudManager cloudManager) {
       ClusterState state = null;
+      this.nodeStateProvider = cloudManager.getNodeStateProvider();
       try {
         state = cloudManager.getClusterStateProvider().getClusterState();
         LOG.trace("-- session created with cluster state: {}", state);
@@ -240,7 +244,7 @@ public class Policy implements MapWriter {
       this.nodes = new ArrayList<>(cloudManager.getClusterStateProvider().getLiveNodes());
       this.cloudManager = cloudManager;
       for (String node : nodes) {
-        collections.addAll(cloudManager.getNodeStateProvider().getReplicaInfo(node, Collections.emptyList()).keySet());
+        collections.addAll(nodeStateProvider.getReplicaInfo(node, Collections.emptyList()).keySet());
       }
 
       expandedClauses = clusterPolicy.stream()
@@ -255,7 +259,7 @@ public class Policy implements MapWriter {
       Collections.sort(expandedClauses);
 
       matrix = new ArrayList<>(nodes.size());
-      for (String node : nodes) matrix.add(new Row(node, params, perReplicaAttributes,cloudManager));
+      for (String node : nodes) matrix.add(new Row(node, params, perReplicaAttributes,this));
       applyRules();
     }
 
@@ -272,7 +276,7 @@ public class Policy implements MapWriter {
     }
 
     Session copy() {
-      return new Session(nodes, cloudManager, getMatrixCopy(), expandedClauses, znodeVersion);
+      return new Session(nodes, cloudManager, getMatrixCopy(), expandedClauses, znodeVersion, nodeStateProvider);
     }
 
     List<Row> getMatrixCopy() {
@@ -328,6 +332,10 @@ public class Policy implements MapWriter {
     public List<Row> getSorted() {
       return Collections.unmodifiableList(matrix);
     }
+
+    public NodeStateProvider getNodeStateProvider() {
+      return nodeStateProvider;
+    }
   }
 
   static void setApproxValuesAndSortNodes(List<Preference> clusterPreferences, List<Row> matrix) {

solr/solrj/src/java/org/apache/solr/client/solrj/cloud/autoscaling/Row.java

@@ -43,14 +43,13 @@ public class Row implements MapWriter {
   boolean anyValueMissing = false;
   boolean isLive = true;
 
-  public Row(String node, List<String> params, List<String> perReplicaAttributes, SolrCloudManager cloudManager) {
-    NodeStateProvider nodeStateProvider = cloudManager.getNodeStateProvider();
-    collectionVsShardVsReplicas = nodeStateProvider.getReplicaInfo(node, perReplicaAttributes);
+  public Row(String node, List<String> params, List<String> perReplicaAttributes, Policy.Session session) {
+    collectionVsShardVsReplicas = session.nodeStateProvider.getReplicaInfo(node, perReplicaAttributes);
     if (collectionVsShardVsReplicas == null) collectionVsShardVsReplicas = new HashMap<>();
     this.node = node;
     cells = new Cell[params.size()];
-    isLive = cloudManager.getClusterStateProvider().getLiveNodes().contains(node);
-    Map<String, Object> vals = isLive ? nodeStateProvider.getNodeValues(node, params) : Collections.emptyMap();
+    isLive = session.cloudManager.getClusterStateProvider().getLiveNodes().contains(node);
+    Map<String, Object> vals = isLive ? session.nodeStateProvider.getNodeValues(node, params) : Collections.emptyMap();
     for (int i = 0; i < params.size(); i++) {
       String s = params.get(i);
       cells[i] = new Cell(i, s, Clause.validate(s,vals.get(s), false));

solr/solrj/src/java/org/apache/solr/client/solrj/cloud/autoscaling/Suggester.java

@@ -44,7 +44,7 @@ import org.apache.solr.common.util.Utils;
  *  b) it causes no new violations
  *
  */
-public abstract class Suggester {
+public abstract class Suggester implements MapWriter {
   protected final EnumMap<Hint, Object> hints = new EnumMap<>(Hint.class);
   Policy.Session session;
   SolrRequest operation;
@@ -105,7 +105,7 @@ public abstract class Suggester {
         // the source node is dead so live nodes may not have it
         for (String srcNode : srcNodes) {
           if(session.matrix.stream().noneMatch(row -> row.node.equals(srcNode)))
-            session.matrix.add(new Row(srcNode, session.getPolicy().params, session.getPolicy().perReplicaAttributes, session.cloudManager));
+            session.matrix.add(new Row(srcNode, session.getPolicy().params, session.getPolicy().perReplicaAttributes, session));
         }
       }
       session.applyRules();
@@ -279,5 +279,13 @@ public abstract class Suggester {
 
   }
 
+  @Override
+  public String toString() {
+    return jsonStr();
+  }
 
+  @Override
+  public void writeMap(EntryWriter ew) throws IOException {
+    ew.put("hints", (MapWriter) ew1 -> hints.forEach((hint, o) -> ew1.putNoEx(hint.toString(), o)));
+  }
 }

solr/solrj/src/java/org/apache/solr/common/MapWriter.java

@@ -24,6 +24,8 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.apache.solr.common.util.Utils;
+
 /**
  * Use this class to push all entries of a Map into an output.
  * This avoids creating map instances and is supposed to be memory efficient.
@@ -31,6 +33,9 @@ import java.util.Map;
  */
 public interface MapWriter extends MapSerializable {
 
+  default String jsonStr(){
+    return Utils.toJSONString(this);
+  }
   @Override
   default Map toMap(Map<String, Object> map) {
     try {
@@ -83,6 +88,14 @@ public interface MapWriter extends MapSerializable {
      * @param v The value can be any supported object
      */
     EntryWriter put(String k, Object v) throws IOException;
+    default EntryWriter putNoEx(String k, Object v) {
+      try {
+        put(k,v);
+      } catch (IOException e) {
+        throw new RuntimeException(e);
+      }
+      return this;
+    }
 
     default EntryWriter putIfNotNull(String k, Object v) throws IOException {
       if(v != null) put(k,v);

solr/solrj/src/java/org/apache/solr/common/util/Pair.java

@@ -16,13 +16,16 @@
  */
 package org.apache.solr.common.util;
 
+import java.io.IOException;
 import java.io.Serializable;
 import java.util.Objects;
 
+import org.apache.solr.common.MapWriter;
+
 import static org.apache.solr.common.util.Utils.makeMap;
 import static org.apache.solr.common.util.Utils.toJSONString;
 
-public class Pair<T1, T2> implements Serializable {
+public class Pair<T1, T2> implements Serializable, MapWriter {
   private final T1 first;
   private final T2 second;
 
@@ -56,4 +59,10 @@ public class Pair<T1, T2> implements Serializable {
     return Objects.hash(first, second);
   }
 
+  @Override
+  public void writeMap(EntryWriter ew) throws IOException {
+    ew.put("first", first);
+    ew.put("second", second);
+  }
+
 }