Add metrics for replication delay and retries

Change-Id: I22c55de32636bcf19f5723477c603e6450b3479b

2 files changed, 33 insertions, 2 deletions

diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
index 002361a..316c8df 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/PushOne.java
@@ -289,10 +289,11 @@ class PushOne implements ProjectRunnable {
     Timer1.Context context = metrics.start(config.getName());
     try {
       long startedAt = context.getStartTime();
+      long delay = NANOSECONDS.toMillis(startedAt - createdAt);
+      metrics.record(config.getName(), delay, retryCount);
       git = gitManager.openRepository(projectName);
       runImpl();
       long elapsed = NANOSECONDS.toMillis(context.stop());
-      long delay = NANOSECONDS.toMillis(startedAt - createdAt);
       repLog.info("Replication to " + uri + " completed in "
           + (elapsed) + "ms, "
           + (delay) + "ms delay, " + retryCount + " retries");
diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationMetrics.java b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationMetrics.java
index ebfda33..e02084d 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationMetrics.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/ReplicationMetrics.java
@@ -16,6 +16,7 @@ package com.googlesource.gerrit.plugins.replication;
 
 import com.google.gerrit.metrics.Description;
 import com.google.gerrit.metrics.Field;
+import com.google.gerrit.metrics.Histogram1;
 import com.google.gerrit.metrics.MetricMaker;
 import com.google.gerrit.metrics.Timer1;
 import com.google.inject.Inject;
@@ -24,15 +25,33 @@ import com.google.inject.Singleton;
 @Singleton
 public class ReplicationMetrics {
   Timer1<String> executionTime;
+  Histogram1<String> executionDelay;
+  Histogram1<String> executionRetries;
 
   @Inject
   ReplicationMetrics(MetricMaker metricMaker) {
+    Field<String> DEST_FIELD = Field.ofString("destination");
+
     executionTime = metricMaker.newTimer(
         "replication_latency",
         new Description("Time spent pushing to remote destination.")
           .setCumulative()
           .setUnit(Description.Units.MILLISECONDS),
-        Field.ofString("destination"));
+        DEST_FIELD);
+
+    executionDelay = metricMaker.newHistogram(
+        "replication_delay",
+        new Description("Time spent waiting before pushing to remote destination")
+          .setCumulative()
+          .setUnit(Description.Units.MILLISECONDS),
+        DEST_FIELD);
+
+    executionRetries = metricMaker.newHistogram(
+        "replication_retries",
+        new Description("Number of retries when pushing to remote destination")
+          .setCumulative()
+          .setUnit("retries"),
+        DEST_FIELD);
   }
 
   /**
@@ -44,4 +63,15 @@ public class ReplicationMetrics {
     return executionTime.start(name);
   }
 
+  /**
+   * Record the replication delay and retry metrics for a destination.
+   * @param name the destination name.
+   * @param delay replication delay in milliseconds.
+   * @param retries number of retries.
+   */
+  void record(String name, long delay, long retries) {
+    executionDelay.record(name, delay);
+    executionRetries.record(name, retries);
+  }
+
 }