From 6971244134b57e82e922b3bcbfb24b3462bace20 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jan=20H=C3=B8ydahl?= <janhoy@users.noreply.github.com>
Date: Tue, 12 May 2020 10:57:33 +0200
Subject: [PATCH] SOLR-14463: Solr Admin ZkStatus page now works with ZK 3.6
 (#1499)

---
 solr/CHANGES.txt                              |  2 ++
 .../handler/admin/ZookeeperStatusHandler.java |  5 ++-
 .../admin/ZookeeperStatusHandlerTest.java     | 35 +++++++++++++++++++
 3 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/solr/CHANGES.txt b/solr/CHANGES.txt
index 3cfab7bb406..620ef35f7a0 100644
--- a/solr/CHANGES.txt
+++ b/solr/CHANGES.txt
@@ -161,6 +161,8 @@ Bug Fixes
 
 * SOLR-14431: SegmentsInfoRequestHandler does not release IndexWriter (Tiziano Degaetano, ab)
 
+* SOLR-14463: Solr Admin ZkStatus page now works with ZK 3.6, without 'For input string: "null"' error (janhoy, Bernd Wahlen)
+
 Other Changes
 ---------------------
 * SOLR-14197: SolrResourceLoader: marked many methods as deprecated, and in some cases rerouted exiting logic to avoid
diff --git a/solr/core/src/java/org/apache/solr/handler/admin/ZookeeperStatusHandler.java b/solr/core/src/java/org/apache/solr/handler/admin/ZookeeperStatusHandler.java
index dd1833b3a75..65c737d7df9 100644
--- a/solr/core/src/java/org/apache/solr/handler/admin/ZookeeperStatusHandler.java
+++ b/solr/core/src/java/org/apache/solr/handler/admin/ZookeeperStatusHandler.java
@@ -147,7 +147,10 @@ public class ZookeeperStatusHandler extends RequestHandlerBase {
           followers++;
         } else if ("leader".equals(state)) {
           leaders++;
-          reportedFollowers = Integer.parseInt(String.valueOf(stat.get("zk_followers")));
+          reportedFollowers = Math.max(
+              Integer.parseInt((String) stat.getOrDefault("zk_followers", "0")),
+              Integer.parseInt((String) stat.getOrDefault("zk_synced_followers", "0"))
+          );
         } else if ("standalone".equals(state)) {
           standalone++;
         }
diff --git a/solr/core/src/test/org/apache/solr/handler/admin/ZookeeperStatusHandlerTest.java b/solr/core/src/test/org/apache/solr/handler/admin/ZookeeperStatusHandlerTest.java
index 693accf93cc..1363048ad33 100644
--- a/solr/core/src/test/org/apache/solr/handler/admin/ZookeeperStatusHandlerTest.java
+++ b/solr/core/src/test/org/apache/solr/handler/admin/ZookeeperStatusHandlerTest.java
@@ -165,4 +165,39 @@ public class ZookeeperStatusHandlerTest extends SolrCloudTestCase {
   public void validateEmptyResponse() {
     new ZookeeperStatusHandler(null).validateZkRawResponse(Collections.emptyList(), "zoo1:2181", "mntr");
   }
+
+  @Test
+  public void testMntrBugZk36Solr14463() {
+    assumeWorkingMockito();
+    ZookeeperStatusHandler zkStatusHandler = mock(ZookeeperStatusHandler.class);
+    when(zkStatusHandler.getZkRawResponse("zoo1:2181", "ruok")).thenReturn(Arrays.asList("imok"));
+    when(zkStatusHandler.getZkRawResponse("zoo1:2181", "mntr")).thenReturn(
+        Arrays.asList("zk_version\t3.5.5-390fe37ea45dee01bf87dc1c042b5e3dcce88653, built on 05/03/2019 12:07 GMT",
+            "zk_avg_latency\t1",
+            "zk_server_state\tleader",
+            "zk_synced_followers\t2"));
+    when(zkStatusHandler.getZkRawResponse("zoo1:2181", "conf")).thenReturn(
+        Arrays.asList("clientPort=2181"));
+    when(zkStatusHandler.getZkStatus(anyString(), any())).thenCallRealMethod();
+    when(zkStatusHandler.monitorZookeeper(anyString())).thenCallRealMethod();
+    when(zkStatusHandler.validateZkRawResponse(ArgumentMatchers.any(), any(), any())).thenAnswer(Answers.CALLS_REAL_METHODS);
+
+    Map<String, Object> mockStatus = zkStatusHandler.getZkStatus("zoo1:2181", ZkDynamicConfig.fromZkConnectString("zoo1:2181"));
+    String expected = "{\n" +
+        "  \"mode\":\"ensemble\",\n" +
+        "  \"dynamicReconfig\":true,\n" +
+        "  \"ensembleSize\":1,\n" +
+        "  \"details\":[{\n" +
+        "      \"zk_synced_followers\":\"2\",\n" +
+        "      \"zk_version\":\"3.5.5-390fe37ea45dee01bf87dc1c042b5e3dcce88653, built on 05/03/2019 12:07 GMT\",\n" +
+        "      \"zk_avg_latency\":\"1\",\n" +
+        "      \"host\":\"zoo1:2181\",\n" +
+        "      \"clientPort\":\"2181\",\n" +
+        "      \"ok\":true,\n" +
+        "      \"zk_server_state\":\"leader\"}],\n" +
+        "  \"zkHost\":\"zoo1:2181\",\n" +
+        "  \"errors\":[\"Leader reports 2 followers, but we only found 0. Please check zkHost configuration\"],\n" +
+        "  \"status\":\"red\"}";
+    assertEquals(expected, JSONUtil.toJSON(mockStatus));
+  }
 }
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