ZOOKEEPER-4284: Add metrics for observer sync time

Motivation

- With enabling the feature of followers hosting observers, we would need a metric to measure the observer sync time just like what we have for the follower sync time.

Changes

- Added the "observer_sync_time" metrics
- Added unit test on the metrics

Author: liwang <liwang@apple.com>

Reviewers: Enrico Olivelli <eolivelli@apache.org>, Michael Han <hanm@apache.org>, Damien Diederen <ddiederen@apache.org>

Closes #1691 from li4wang/ZOOKEEPER-4284

1 files changed, 14 insertions, 0 deletions

diff --git a/zookeeper-server/src/test/java/org/apache/zookeeper/test/ObserverMasterTest.java b/zookeeper-server/src/test/java/org/apache/zookeeper/test/ObserverMasterTest.java
index 2d2bea768..4ba33c7a8 100644
--- a/zookeeper-server/src/test/java/org/apache/zookeeper/test/ObserverMasterTest.java
+++ b/zookeeper-server/src/test/java/org/apache/zookeeper/test/ObserverMasterTest.java
@@ -55,6 +55,7 @@ import org.apache.zookeeper.ZooKeeper.States;
 import org.apache.zookeeper.admin.ZooKeeperAdmin;
 import org.apache.zookeeper.jmx.MBeanRegistry;
 import org.apache.zookeeper.jmx.ZKMBeanInfo;
+import org.apache.zookeeper.metrics.MetricsUtils;
 import org.apache.zookeeper.server.admin.Commands;
 import org.apache.zookeeper.server.quorum.QuorumPeerConfig;
 import org.apache.zookeeper.server.util.PortForwarder;
@@ -85,6 +86,8 @@ public class ObserverMasterTest extends ObserverMasterTestBase {
         assertTrue(ClientBase.waitForServerUp("127.0.0.1:" + CLIENT_PORT_OBS, CONNECTION_TIMEOUT),
                 "waiting for server 3 being up");
 
+        validateObserverSyncTimeMetrics();
+
         if (testObserverMaster) {
             int masterPort = q3.getQuorumPeer().observer.getSocket().getPort();
             LOG.info("port {} {}", masterPort, OM_PORT);
@@ -522,4 +525,15 @@ public class ObserverMasterTest extends ObserverMasterTestBase {
 
     }
 
+    private void validateObserverSyncTimeMetrics() {
+        final String name = "observer_sync_time";
+        final Map<String, Object> metrics = MetricsUtils.currentServerMetrics();
+
+        assertEquals(5, metrics.keySet().stream().filter(key -> key.contains(name)).count());
+        assertNotNull(metrics.get(String.format("avg_%s", name)));
+        assertNotNull(metrics.get(String.format("min_%s", name)));
+        assertNotNull(metrics.get(String.format("max_%s", name)));
+        assertNotNull(metrics.get(String.format("cnt_%s", name)));
+        assertNotNull(metrics.get(String.format("sum_%s", name)));
+    }
 }