Check if lock owner is finished on lock acquisition

Sometimes requests "die" suddenly, without going through catch/finally blocks.
If this happens, any lock they own will remain locked until it times out (which
can take hours in some cases).

This cl implicitly unlocks any lock if the owner of the lock isn't running
anymore.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=168880938

javatests/google/registry/model/server/LockTest.java

@@ -15,13 +15,18 @@
 package google.registry.model.server;
 
 import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
+import com.google.common.base.Optional;
 import google.registry.model.ofy.Ofy;
 import google.registry.testing.AppEngineRule;
 import google.registry.testing.ExceptionRule;
 import google.registry.testing.FakeClock;
 import google.registry.testing.InjectRule;
+import google.registry.util.RequestStatusChecker;
 import org.joda.time.Duration;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -34,6 +39,7 @@ public class LockTest {
   private static final String RESOURCE_NAME = "foo";
   private static final Duration ONE_DAY = Duration.standardDays(1);
   private static final Duration TWO_MILLIS = Duration.millis(2);
+  private static final RequestStatusChecker requestStatusChecker = mock(RequestStatusChecker.class);
 
   @Rule
   public final AppEngineRule appEngine = AppEngineRule.builder()
@@ -46,49 +52,68 @@ public class LockTest {
   @Rule
   public final ExceptionRule thrown = new ExceptionRule();
 
+  private Optional<Lock> acquire(String tld, Duration leaseLength) {
+    return Lock.acquire(RESOURCE_NAME, tld, leaseLength, requestStatusChecker);
+  }
+
+  @Before public void setUp() {
+    when(requestStatusChecker.getLogId()).thenReturn("current-request-id");
+    when(requestStatusChecker.isRunning("current-request-id")).thenReturn(true);
+  }
+
   @Test
   public void testReleasedExplicitly() throws Exception {
-    Lock lock = Lock.acquire(RESOURCE_NAME, "", ONE_DAY);
-    assertThat(lock).isNotNull();
+    Optional<Lock> lock = acquire("", ONE_DAY);
+    assertThat(lock).isPresent();
     // We can't get it again at the same time.
-    assertThat(Lock.acquire(RESOURCE_NAME, "", ONE_DAY)).isNull();
+    assertThat(acquire("", ONE_DAY)).isAbsent();
     // But if we release it, it's available.
-    lock.release();
-    assertThat(Lock.acquire(RESOURCE_NAME, "", ONE_DAY)).isNotNull();
+    lock.get().release();
+    assertThat(acquire("", ONE_DAY)).isPresent();
   }
 
   @Test
   public void testReleasedAfterTimeout() throws Exception {
     FakeClock clock = new FakeClock();
     inject.setStaticField(Ofy.class, "clock", clock);
-    assertThat(Lock.acquire(RESOURCE_NAME, "", TWO_MILLIS)).isNotNull();
+    assertThat(acquire("", TWO_MILLIS)).isPresent();
     // We can't get it again at the same time.
-    assertThat(Lock.acquire(RESOURCE_NAME, "", TWO_MILLIS)).isNull();
+    assertThat(acquire("", TWO_MILLIS)).isAbsent();
     // A second later we still can't get the lock.
     clock.advanceOneMilli();
-    assertThat(Lock.acquire(RESOURCE_NAME, "", TWO_MILLIS)).isNull();
+    assertThat(acquire("", TWO_MILLIS)).isAbsent();
     // But two seconds later we can get it.
     clock.advanceOneMilli();
-    assertThat(Lock.acquire(RESOURCE_NAME, "", TWO_MILLIS)).isNotNull();
+    assertThat(acquire("", TWO_MILLIS)).isPresent();
+  }
+
+  @Test
+  public void testReleasedAfterRequestFinish() throws Exception {
+    assertThat(acquire("", ONE_DAY)).isPresent();
+    // We can't get it again while request is active
+    assertThat(acquire("", ONE_DAY)).isAbsent();
+    // But if request is finished, we can get it.
+    when(requestStatusChecker.isRunning("current-request-id")).thenReturn(false);
+    assertThat(acquire("", ONE_DAY)).isPresent();
   }
 
   @Test
   public void testTldsAreIndependent() throws Exception {
-    Lock lockA = Lock.acquire(RESOURCE_NAME, "a", ONE_DAY);
-    assertThat(lockA).isNotNull();
+    Optional<Lock> lockA = acquire("a", ONE_DAY);
+    assertThat(lockA).isPresent();
     // For a different tld we can still get a lock with the same name.
-    Lock lockB = Lock.acquire(RESOURCE_NAME, "b", ONE_DAY);
-    assertThat(lockB).isNotNull();
+    Optional<Lock> lockB = acquire("b", ONE_DAY);
+    assertThat(lockB).isPresent();
     // We can't get lockB again at the same time.
-    assertThat(Lock.acquire(RESOURCE_NAME, "b", ONE_DAY)).isNull();
+    assertThat(acquire("b", ONE_DAY)).isAbsent();
     // Releasing lockA has no effect on lockB (even though we are still using the "b" tld).
-    lockA.release();
-    assertThat(Lock.acquire(RESOURCE_NAME, "b", ONE_DAY)).isNull();
+    lockA.get().release();
+    assertThat(acquire("b", ONE_DAY)).isAbsent();
   }
 
   @Test
   public void testFailure_emptyResourceName() throws Exception {
     thrown.expect(IllegalArgumentException.class, "resourceName cannot be null or empty");
-    Lock.acquire("", "", TWO_MILLIS);
+    Lock.acquire("", "", TWO_MILLIS, requestStatusChecker);
   }
 }