From 8869814e96291242fad277991ce791e3fbdf4d31 Mon Sep 17 00:00:00 2001
From: mcilwain <mcilwain@google.com>
Date: Tue, 25 Jul 2017 14:31:19 -0700
Subject: [PATCH] Add logging statement for # of tasks in DNS queue

This will make DNS issues easier to debug retroactively as we will be
able to determine, by looking at the logs, if the queue size was growing
unbounded.

Also adds some logging helpers to allow programmatically choosing the level
of logging.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=163123783
---
 java/google/registry/dns/DnsQueue.java          | 15 +++++++++++++--
 java/google/registry/util/FormattingLogger.java | 11 ++++++++++-
 javatests/google/registry/dns/DnsQueueTest.java |  2 +-
 3 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/java/google/registry/dns/DnsQueue.java b/java/google/registry/dns/DnsQueue.java
index 51319e1ef..5776daadd 100644
--- a/java/google/registry/dns/DnsQueue.java
+++ b/java/google/registry/dns/DnsQueue.java
@@ -31,14 +31,17 @@ import com.google.appengine.api.taskqueue.TaskOptions;
 import com.google.appengine.api.taskqueue.TaskOptions.Method;
 import com.google.appengine.api.taskqueue.TransientFailureException;
 import com.google.apphosting.api.DeadlineExceededException;
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Optional;
 import com.google.common.collect.ImmutableList;
 import com.google.common.net.InternetDomainName;
 import google.registry.dns.DnsConstants.TargetType;
 import google.registry.model.registry.Registries;
 import google.registry.util.FormattingLogger;
+import google.registry.util.NonFinalForTesting;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
+import java.util.logging.Level;
 import javax.inject.Inject;
 import javax.inject.Named;
 import org.joda.time.Duration;
@@ -66,7 +69,9 @@ public class DnsQueue {
     return new DnsQueue(getQueue(DNS_PULL_QUEUE_NAME));
   }
 
-  long writeBatchSize = QueueConstants.maxLeaseCount();
+  @NonFinalForTesting
+  @VisibleForTesting
+  long leaseTasksBatchSize = QueueConstants.maxLeaseCount();
 
   /**
    * Enqueues the given task type with the given target name to the DNS queue.
@@ -107,7 +112,13 @@ public class DnsQueue {
   /** Returns handles for a batch of tasks, leased for the specified duration. */
   public List<TaskHandle> leaseTasks(Duration leaseDuration) {
     try {
-      return queue.leaseTasks(leaseDuration.getMillis(), MILLISECONDS, writeBatchSize);
+      int numTasks = queue.fetchStatistics().getNumTasks();
+      logger.logfmt(
+          (numTasks >= leaseTasksBatchSize) ? Level.WARNING : Level.INFO,
+          "There are %d tasks in the DNS queue '%s'.",
+          numTasks,
+          DNS_PULL_QUEUE_NAME);
+      return queue.leaseTasks(leaseDuration.getMillis(), MILLISECONDS, leaseTasksBatchSize);
     } catch (TransientFailureException | DeadlineExceededException e) {
       logger.severe(e, "Failed leasing tasks too fast");
       return ImmutableList.of();
diff --git a/java/google/registry/util/FormattingLogger.java b/java/google/registry/util/FormattingLogger.java
index 7a52f8966..48f046246 100644
--- a/java/google/registry/util/FormattingLogger.java
+++ b/java/google/registry/util/FormattingLogger.java
@@ -19,6 +19,7 @@ import com.google.common.collect.FluentIterable;
 import java.util.logging.Handler;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import javax.annotation.Nullable;
 
 /** Logging wrapper. */
 public class FormattingLogger {
@@ -34,7 +35,15 @@ public class FormattingLogger {
     this.logger = Logger.getLogger(name);
   }
 
-  private void log(Level level, Throwable cause, String msg) {
+  public void logfmt(Level level, Throwable cause, String fmt, Object... args) {
+    log(level, cause, String.format(fmt, args));
+  }
+
+  public void logfmt(Level level, String fmt, Object... args) {
+    log(level, null, String.format(fmt, args));
+  }
+
+  private void log(Level level, @Nullable Throwable cause, String msg) {
     StackTraceElement callerFrame = FluentIterable
         .from(new Exception().getStackTrace())
         .firstMatch(new Predicate<StackTraceElement>() {
diff --git a/javatests/google/registry/dns/DnsQueueTest.java b/javatests/google/registry/dns/DnsQueueTest.java
index 0b10f191d..5871240c2 100644
--- a/javatests/google/registry/dns/DnsQueueTest.java
+++ b/javatests/google/registry/dns/DnsQueueTest.java
@@ -45,7 +45,7 @@ public class DnsQueueTest {
   @Before
   public void init() {
     dnsQueue = DnsQueue.create();
-    dnsQueue.writeBatchSize = 10;
+    dnsQueue.leaseTasksBatchSize = 10;
   }
 
   @Test