Solr queries only on Shards leaders

gistfile1.txt

#
# Solr 8 - Java sample in order to get shards leaders for a collection
#
package fr.eolya.solr.tests;

import org.apache.solr.client.solrj.impl.CloudSolrClient;
import org.apache.solr.common.cloud.Slice;
import org.apache.solr.common.cloud.ZkStateReader;
import org.apache.zookeeper.KeeperException;

import java.util.*;

public class GetLeaders {

    public static void main(String[] args){
        final List<String> zkServers = new ArrayList<String>();
        zkServers.add("zk1:2181");
        zkServers.add("zk2:2181");
        zkServers.add("zk3:2181");
        CloudSolrClient cloudSolrClient = new CloudSolrClient.Builder(zkServers, Optional.empty()).build();
        try {
            Map<String, String> leaders = getShardLeaders(cloudSolrClient, "sirene");
            for (String leader: leaders.values()) {
                System.out.println(leader);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (KeeperException e) {
            e.printStackTrace();
        }
    }

    static private Map<String, String> getShardLeaders(CloudSolrClient cloudSolrClient, String collection) throws InterruptedException, KeeperException {
        Map<String, String> shardleaders = new TreeMap<String, String>();
        ZkStateReader zkStateReader = cloudSolrClient.getZkStateReader();
        for (Slice slice : zkStateReader.getClusterState().getCollection(collection).getSlices()) {
            shardleaders.put(slice.getName(), zkStateReader.getLeaderUrl(collection, slice.getName(), 30000));
        }
        return shardleaders;
    }
}


#
# Sample output
#
http://solr2:8983/solr/sirene_shard1_replica_t2/
http://solr1:8983/solr/sirene_shard2_replica_t4/


#
# Sample query using only shard's leaders
#
http://localhost:8983/solr/sirene/select?q=*:*&shards=solr2:8983/solr/sirene_shard1_replica_t2,solr1:8983/solr/sirene_shard2_replica_t4