From eaa1ca7143a239f93f8308597707a6e677aa4714 Mon Sep 17 00:00:00 2001
From: Lei Zhang <27994433+SWJTU-ZhangLei@users.noreply.github.com>
Date: Wed, 22 Nov 2023 10:46:59 +0800
Subject: [PATCH] [fix](fe) Fix show frontends npt in some situations (#27295)

```
java.lang.NullPointerException: null
    at com.sleepycat.je.rep.util.ReplicationGroupAdmin.getMasterSocket(ReplicationGroupAdmin.java:191)
    at com.sleepycat.je.rep.util.ReplicationGroupAdmin.doMessageExchange(ReplicationGroupAdmin.java:607)
    at com.sleepycat.je.rep.util.ReplicationGroupAdmin.getGroup(ReplicationGroupAdmin.java:406)
    at org.apache.doris.ha.BDBHA.getElectableNodes(BDBHA.java:132)
    at org.apache.doris.common.proc.FrontendsProcNode.getFrontendsInfo(FrontendsProcNode.java:84)
    at org.apache.doris.qe.ShowExecutor.handleShowFrontends(ShowExecutor.java:1923)
    at org.apache.doris.qe.ShowExecutor.execute(ShowExecutor.java:355)
    at org.apache.doris.qe.StmtExecutor.handleShow(StmtExecutor.java:2113)
    ...
```
---
 .../apache/doris/common/proc/FrontendsProcNode.java    |  1 -
 .../src/main/java/org/apache/doris/ha/BDBHA.java       | 10 ++++++----
 .../org/apache/doris/journal/bdbje/BDBEnvironment.java |  5 +++++
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/common/proc/FrontendsProcNode.java b/fe/fe-core/src/main/java/org/apache/doris/common/proc/FrontendsProcNode.java
index b49874b6e9..be126e9bc5 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/common/proc/FrontendsProcNode.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/common/proc/FrontendsProcNode.java
@@ -127,7 +127,6 @@ public class FrontendsProcNode implements ProcNodeInterface {
         }
 
         for (Frontend fe : env.getFrontends(null /* all */)) {
-
             List<String> info = new ArrayList<String>();
             info.add(fe.getNodeName());
             info.add(fe.getHost());
diff --git a/fe/fe-core/src/main/java/org/apache/doris/ha/BDBHA.java b/fe/fe-core/src/main/java/org/apache/doris/ha/BDBHA.java
index 40de732922..046bca5bac 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/ha/BDBHA.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/ha/BDBHA.java
@@ -104,11 +104,12 @@ public class BDBHA implements HAProtocol {
 
     @Override
     public List<InetSocketAddress> getObserverNodes() {
+        List<InetSocketAddress> ret = new ArrayList<InetSocketAddress>();
         ReplicationGroupAdmin replicationGroupAdmin = environment.getReplicationGroupAdmin();
         if (replicationGroupAdmin == null) {
-            return null;
+            return ret;
         }
-        List<InetSocketAddress> ret = new ArrayList<InetSocketAddress>();
+
         try {
             ReplicationGroup replicationGroup = replicationGroupAdmin.getGroup();
             for (ReplicationNode replicationNode : replicationGroup.getSecondaryNodes()) {
@@ -123,11 +124,12 @@ public class BDBHA implements HAProtocol {
 
     @Override
     public List<InetSocketAddress> getElectableNodes(boolean leaderIncluded) {
+        List<InetSocketAddress> ret = new ArrayList<InetSocketAddress>();
         ReplicationGroupAdmin replicationGroupAdmin = environment.getReplicationGroupAdmin();
         if (replicationGroupAdmin == null) {
-            return null;
+            return ret;
         }
-        List<InetSocketAddress> ret = new ArrayList<InetSocketAddress>();
+
         try {
             ReplicationGroup replicationGroup = replicationGroupAdmin.getGroup();
             for (ReplicationNode replicationNode : replicationGroup.getElectableNodes()) {
diff --git a/fe/fe-core/src/main/java/org/apache/doris/journal/bdbje/BDBEnvironment.java b/fe/fe-core/src/main/java/org/apache/doris/journal/bdbje/BDBEnvironment.java
index 5dec4a4c57..1b608751c7 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/journal/bdbje/BDBEnvironment.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/journal/bdbje/BDBEnvironment.java
@@ -209,6 +209,11 @@ public class BDBEnvironment {
                 .filter(Frontend::isAlive)
                 .map(fe -> new InetSocketAddress(fe.getHost(), fe.getEditLogPort()))
                 .collect(Collectors.toSet());
+
+        if (addresses.isEmpty()) {
+            LOG.info("addresses is empty");
+            return null;
+        }
         return new ReplicationGroupAdmin(PALO_JOURNAL_GROUP, addresses);
     }