[incubator-ratis] branch master updated: RATIS-717. NPE thrown on the follower while instantiating RaftLeaderMetrics. Contributed by Aravindan Vijayan.

[shashikant]

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shashikant pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-ratis.git


The following commit(s) were added to refs/heads/master by this push:
     new f36acab  RATIS-717. NPE thrown on the follower while instantiating 
RaftLeaderMetrics. Contributed by Aravindan Vijayan.
f36acab is described below

commit f36acabc58d6ed0146a9998150b5d7a038bdda7d
Author: Shashikant Banerjee <shashik...@apache.org>
AuthorDate: Fri Oct 18 15:42:47 2019 +0530

    RATIS-717. NPE thrown on the follower while instantiating 
RaftLeaderMetrics. Contributed by Aravindan Vijayan.
---
 .../java/org/apache/ratis/server/impl/RaftLeaderMetrics.java  | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git 
a/ratis-server/src/main/java/org/apache/ratis/server/impl/RaftLeaderMetrics.java
 
b/ratis-server/src/main/java/org/apache/ratis/server/impl/RaftLeaderMetrics.java
index 44f6b2f..245aa39 100644
--- 
a/ratis-server/src/main/java/org/apache/ratis/server/impl/RaftLeaderMetrics.java
+++ 
b/ratis-server/src/main/java/org/apache/ratis/server/impl/RaftLeaderMetrics.java
@@ -26,7 +26,9 @@ import java.util.Map;
 import java.util.SortedMap;
 
 import com.codahale.metrics.Gauge;
+
 import org.apache.ratis.metrics.RatisMetricRegistry;
+import org.apache.ratis.proto.RaftProtos;
 import org.apache.ratis.protocol.RaftPeer;
 import org.apache.ratis.server.metrics.RatisMetrics;
 import 
org.apache.ratis.thirdparty.com.google.common.annotations.VisibleForTesting;
@@ -82,8 +84,13 @@ public final class RaftLeaderMetrics {
   public void addPeerCommitIndexGauge(RaftPeer peer) {
     String followerCommitIndexKey = String.format(
         LEADER_METRIC_PEER_COMMIT_INDEX, peer.getId().toString());
-    registry.gauge(followerCommitIndexKey,
-        () -> () -> commitInfoCache.get(peer.getId()).getCommitIndex());
+    registry.gauge(followerCommitIndexKey, () -> () -> {
+      RaftProtos.CommitInfoProto commitInfoProto = 
commitInfoCache.get(peer.getId());
+      if (commitInfoProto != null) {
+        return commitInfoProto.getCommitIndex();
+      }
+      return 0L;
+    });
   }
 
   /**