[improve][cli] Add current option in the Clusters list cmd (#21139)

pulsar-client-tools/src/main/java/org/apache/pulsar/admin/cli/CmdClusters.java

@@ -24,6 +24,7 @@
 import com.google.common.collect.Sets;
 import java.util.Arrays;
 import java.util.function.Supplier;
+import java.util.stream.Collectors;
 import lombok.Getter;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.pulsar.admin.cli.utils.CmdUtils;
@@ -41,8 +42,18 @@ public class CmdClusters extends CmdBase {
 
     @Parameters(commandDescription = "List the existing clusters")
     private class List extends CliCommand {
+
+        @Parameter(names = { "-c", "--current" },
+                description = "Print the current cluster with (*)", required = false)
+        private boolean current = false;
+
         void run() throws PulsarAdminException {
-            print(getAdmin().clusters().getClusters());
+            java.util.List<String> clusters = getAdmin().clusters().getClusters();
+            String clusterName = getAdmin().brokers().getRuntimeConfigurations().get("clusterName");
+            final java.util.List<String> result = clusters.stream().map(c ->
+                    c.equals(clusterName) ? (current ? c + "(*)" : c) : c
+            ).collect(Collectors.toList());
+            print(result);
         }
     }
 

pulsar-client-tools/src/test/java/org/apache/pulsar/admin/cli/TestCmdClusters.java

@@ -18,21 +18,27 @@
  */
 package org.apache.pulsar.admin.cli;
 
+import com.google.common.collect.Lists;
+import org.apache.pulsar.client.admin.Brokers;
 import org.apache.pulsar.client.api.ProxyProtocol;
-
 import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
-
+import java.io.ByteArrayOutputStream;
 import java.io.File;
+import java.io.PrintStream;
 import java.nio.file.Files;
+import java.util.List;
+import java.util.Map;
 import org.apache.pulsar.admin.cli.utils.CmdUtils;
 import org.apache.pulsar.common.policies.data.ClusterData;
 import org.apache.pulsar.client.admin.Clusters;
 import org.apache.pulsar.client.admin.PulsarAdmin;
 import org.apache.pulsar.common.util.ObjectMapperFactory;
+import org.assertj.core.util.Maps;
 import org.testng.Assert;
 import org.testng.annotations.BeforeMethod;
 import org.testng.annotations.Test;
@@ -87,4 +93,33 @@ public ClusterData buildClusterData() {
                 .brokerClientTlsTrustStorePassword("clientpw")
                 .build();
     }
+
+    @Test
+    public void testListCmd() throws Exception {
+        List<String> clusterList = Lists.newArrayList("us-west", "us-east", "us-cent");
+        List<String> clusterResultList = Lists.newArrayList("us-west", "us-east", "us-cent(*)");
+        Map<String, String> configurations = Maps.newHashMap("clusterName", "us-cent");
+
+        Clusters clusters = mock(Clusters.class);
+        Brokers brokers = mock(Brokers.class);
+        PulsarAdmin admin = mock(PulsarAdmin.class);
+        when(admin.clusters()).thenReturn(clusters);
+        when(admin.brokers()).thenReturn(brokers);
+        doReturn(clusterList).when(clusters).getClusters();
+        doReturn(configurations).when(brokers).getRuntimeConfigurations();
+
+        CmdClusters cmd = new CmdClusters(() -> admin);
+
+        PrintStream defaultSystemOut = System.out;
+        try (ByteArrayOutputStream out = new ByteArrayOutputStream(); PrintStream ps = new PrintStream(out)) {
+            System.setOut(ps);
+            cmd.run("list".split("\\s+"));
+            Assert.assertEquals(out.toString(), String.join("\n", clusterList) + "\n");
+            out.reset();
+            cmd.run("list -c".split("\\s+"));
+            Assert.assertEquals(out.toString(), String.join("\n", clusterResultList) + "\n");
+        } finally {
+            System.setOut(defaultSystemOut);
+        }
+    }
 }