Merge pull request #13636 from vespa-engine/hmusum/configserver-refactoring-13

Merge watcher classes for sessions into one class

11 files changed, 80 insertions, 144 deletions

diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/ApplicationRepository.java b/configserver/src/main/java/com/yahoo/vespa/config/server/ApplicationRepository.java
index c44a839d24d..becf01c191c 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/ApplicationRepository.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/ApplicationRepository.java
@@ -490,7 +490,7 @@ public class ApplicationRepository implements com.yahoo.config.provision.Deploye
             Tenant tenant = tenantRepository.getTenant(applicationId.tenant());
             if (tenant == null) throw new NotFoundException("Tenant '" + applicationId.tenant() + "' not found");
             long sessionId = getSessionIdForApplication(tenant, applicationId);
-            RemoteSession session = tenant.getSessionRepo().getRemoteSession(sessionId);
+            RemoteSession session = tenant.getSessionRepository().getRemoteSession(sessionId);
             if (session == null) throw new NotFoundException("Remote session " + sessionId + " not found");
             return session.ensureApplicationLoaded().getForVersionOrLatest(version, clock.instant());
         } catch (NotFoundException e) {
@@ -528,7 +528,7 @@ public class ApplicationRepository implements com.yahoo.config.provision.Deploye
     }
 
     private boolean localSessionHasBeenDeleted(ApplicationId applicationId, long sessionId, Duration waitTime) {
-        SessionRepository sessionRepository = tenantRepository.getTenant(applicationId.tenant()).getSessionRepo();
+        SessionRepository sessionRepository = tenantRepository.getTenant(applicationId.tenant()).getSessionRepository();
         Instant end = Instant.now().plus(waitTime);
         do {
             if (sessionRepository.getRemoteSession(sessionId) == null) return true;
@@ -690,7 +690,7 @@ public class ApplicationRepository implements com.yahoo.config.provision.Deploye
     public int deleteExpiredRemoteSessions(Clock clock, Duration expiryTime) {
         return tenantRepository.getAllTenants()
                 .stream()
-                .map(tenant -> tenant.getSessionRepo().deleteExpiredRemoteSessions(clock, expiryTime))
+                .map(tenant -> tenant.getSessionRepository().deleteExpiredRemoteSessions(clock, expiryTime))
                 .mapToInt(i -> i)
                 .sum();
     }
@@ -765,7 +765,7 @@ public class ApplicationRepository implements com.yahoo.config.provision.Deploye
     }
 
     private RemoteSession getRemoteSession(Tenant tenant, long sessionId) {
-        RemoteSession session = tenant.getSessionRepo().getRemoteSession(sessionId);
+        RemoteSession session = tenant.getSessionRepository().getRemoteSession(sessionId);
         if (session == null) throw new NotFoundException("Session " + sessionId + " was not found");
 
         return session;
@@ -816,7 +816,7 @@ public class ApplicationRepository implements com.yahoo.config.provision.Deploye
     private RemoteSession getActiveSession(Tenant tenant, ApplicationId applicationId) {
         TenantApplications applicationRepo = tenant.getApplicationRepo();
         if (applicationRepo.activeApplications().contains(applicationId)) {
-            return tenant.getSessionRepo().getRemoteSession(applicationRepo.requireActiveSessionOf(applicationId));
+            return tenant.getSessionRepository().getRemoteSession(applicationRepo.requireActiveSessionOf(applicationId));
         }
         return null;
     }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/Deployment.java b/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/Deployment.java
index def629f738c..0fb1407830a 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/Deployment.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/deploy/Deployment.java
@@ -63,10 +63,10 @@ public class Deployment implements com.yahoo.config.provision.Deployment {
     /** The (optional) Athenz domain this application should use */
     private final Optional<AthenzDomain> athenzDomain;
 
-    private boolean prepared = false;
-    
     /** Whether this model should be validated (only takes effect if prepared=false) */
-    private boolean validate;
+    private final boolean validate;
+
+    private boolean prepared = false;
 
     private boolean ignoreSessionStaleFailure = false;
 
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/LocalSessionStateWatcher.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/LocalSessionStateWatcher.java
deleted file mode 100644
index acbb1dc81ce..00000000000
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/LocalSessionStateWatcher.java
+++ /dev/null
@@ -1,74 +0,0 @@
-// Copyright 2018 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
-package com.yahoo.vespa.config.server.session;
-
-import java.util.logging.Level;
-import com.yahoo.text.Utf8;
-import com.yahoo.vespa.curator.Curator;
-import org.apache.curator.framework.recipes.cache.ChildData;
-
-import java.util.concurrent.Executor;
-import java.util.logging.Logger;
-
-/**
- * Watches one particular local session (/config/v2/tenants/&lt;tenantName&gt;/sessions/&lt;n&gt;/sessionState in ZooKeeper)
- * to pick up when an application is deleted (the delete might be done on any config server in the cluster)
- *
- * @author Harald Musum
- */
-public class LocalSessionStateWatcher {
-
-    private static final Logger log = Logger.getLogger(LocalSessionStateWatcher.class.getName());
-
-    private final Curator.FileCache fileCache;
-    private final LocalSession session;
-    private final SessionRepository sessionRepository;
-    private final Executor zkWatcherExecutor;
-
-    LocalSessionStateWatcher(Curator.FileCache fileCache, LocalSession session,
-                             SessionRepository sessionRepository, Executor zkWatcherExecutor) {
-        this.fileCache = fileCache;
-        this.session = session;
-        this.sessionRepository = sessionRepository;
-        this.zkWatcherExecutor = zkWatcherExecutor;
-        this.fileCache.start();
-        this.fileCache.addListener(this::nodeChanged);
-    }
-
-    // Will delete session if it exists in local session repo
-    private void sessionChanged(Session.Status status) {
-        long sessionId = session.getSessionId();
-        log.log(status == Session.Status.DELETE ? Level.INFO : Level.FINE,
-                session.logPre() + "Session change: Local session " + sessionId + " changed status to " + status);
-
-        if (status.equals(Session.Status.DELETE) && sessionRepository.getLocalSession(sessionId) != null) {
-            log.log(Level.FINE, session.logPre() + "Deleting session " + sessionId);
-            sessionRepository.deleteLocalSession(session);
-        }
-    }
-
-    public long getSessionId() {
-        return session.getSessionId();
-    }
-
-    public void close() {
-        try {
-            fileCache.close();
-        } catch (Exception e) {
-            log.log(Level.WARNING, "Exception when closing watcher", e);
-        }
-    }
-
-    public void nodeChanged() {
-        zkWatcherExecutor.execute(() -> {
-            try {
-                ChildData node = fileCache.getCurrentData();
-                if (node != null) {
-                    sessionChanged(Session.Status.parse(Utf8.toString(node.getData())));
-                }
-            } catch (Exception e) {
-                log.log(Level.WARNING, session.logPre() + "Error handling session changed for session " + getSessionId(), e);
-            }
-        });
-    }
-
-}
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/Session.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/Session.java
index 1e832548342..77058d8d6d9 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/Session.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/Session.java
@@ -20,6 +20,7 @@ import java.util.Optional;
  * system ({@link LocalSession}s) and sessions working on zookeeper {@link RemoteSession}s.
  *
  * @author Ulf Lilleengen
+ * @author hmusum
  */
 public abstract class Session implements Comparable<Session>  {
 
@@ -32,6 +33,7 @@ public abstract class Session implements Comparable<Session>  {
         this.sessionId = sessionId;
         this.sessionZooKeeperClient = sessionZooKeeperClient;
     }
+
     /**
      * Retrieve the session id for this session.
      * @return the session id.
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java
index c7dc295c42d..392c5e93122 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionRepository.java
@@ -72,8 +72,7 @@ public class SessionRepository {
 
     private final SessionCache<LocalSession> localSessionCache = new SessionCache<>();
     private final SessionCache<RemoteSession> remoteSessionCache = new SessionCache<>();
-    private final Map<Long, LocalSessionStateWatcher> localSessionStateWatchers = new HashMap<>();
-    private final Map<Long, RemoteSessionStateWatcher> remoteSessionStateWatchers = new HashMap<>();
+    private final Map<Long, SessionStateWatcher> sessionStateWatchers = new HashMap<>();
     private final Duration sessionLifetime;
     private final Clock clock;
     private final Curator curator;
@@ -120,10 +119,11 @@ public class SessionRepository {
 
     public synchronized void addSession(LocalSession session) {
         localSessionCache.addSession(session);
-        Path sessionsPath = TenantRepository.getSessionsPath(session.getTenantName());
         long sessionId = session.getSessionId();
-        Curator.FileCache fileCache = curator.createFileCache(sessionsPath.append(String.valueOf(sessionId)).append(ConfigCurator.SESSIONSTATE_ZK_SUBPATH).getAbsolute(), false);
-        localSessionStateWatchers.put(sessionId, new LocalSessionStateWatcher(fileCache, session, this, zkWatcherExecutor));
+        Curator.FileCache fileCache = curator.createFileCache(getSessionStatePath(sessionId).getAbsolute(), false);
+        RemoteSession remoteSession = new RemoteSession(tenantName, sessionId, componentRegistry, createSessionZooKeeperClient(sessionId));
+        sessionStateWatchers.put(sessionId, new SessionStateWatcher(fileCache, reloadHandler, remoteSession,
+                                                                    Optional.of(session), metrics, zkWatcherExecutor, this));
     }
 
     public LocalSession getLocalSession(long sessionId) {
@@ -208,7 +208,7 @@ public class SessionRepository {
     public void deleteLocalSession(LocalSession session) {
         long sessionId = session.getSessionId();
         log.log(Level.FINE, "Deleting local session " + sessionId);
-        LocalSessionStateWatcher watcher = localSessionStateWatchers.remove(sessionId);
+        SessionStateWatcher watcher = sessionStateWatchers.remove(sessionId);
         if (watcher != null)  watcher.close();
         localSessionCache.removeSession(sessionId);
         NestedTransaction transaction = new NestedTransaction();
@@ -318,21 +318,22 @@ public class SessionRepository {
      */
     public void sessionAdded(long sessionId) {
         log.log(Level.FINE, () -> "Adding session to SessionRepository: " + sessionId);
-        RemoteSession session = createRemoteSession(sessionId);
-        Path sessionPath = sessionsPath.append(String.valueOf(sessionId));
-        Curator.FileCache fileCache = curator.createFileCache(sessionPath.append(ConfigCurator.SESSIONSTATE_ZK_SUBPATH).getAbsolute(), false);
+        RemoteSession remoteSession = createRemoteSession(sessionId);
+        Curator.FileCache fileCache = curator.createFileCache(getSessionStatePath(sessionId).getAbsolute(), false);
         fileCache.addListener(this::nodeChanged);
-        loadSessionIfActive(session);
-        addRemoteSession(session);
-        remoteSessionStateWatchers.put(sessionId, new RemoteSessionStateWatcher(fileCache, reloadHandler, session, metrics, zkWatcherExecutor));
+        loadSessionIfActive(remoteSession);
+        addRemoteSession(remoteSession);
+        Optional<LocalSession> localSession = Optional.empty();
         if (distributeApplicationPackage.value()) {
-            Optional<LocalSession> localSession = createLocalSessionUsingDistributedApplicationPackage(sessionId);
+            localSession = createLocalSessionUsingDistributedApplicationPackage(sessionId);
             localSession.ifPresent(this::addSession);
         }
+        sessionStateWatchers.put(sessionId, new SessionStateWatcher(fileCache, reloadHandler, remoteSession, localSession,
+                                                                    metrics, zkWatcherExecutor, this));
     }
 
     private void sessionRemoved(long sessionId) {
-        RemoteSessionStateWatcher watcher = remoteSessionStateWatchers.remove(sessionId);
+        SessionStateWatcher watcher = sessionStateWatchers.remove(sessionId);
         if (watcher != null)  watcher.close();
         remoteSessionCache.removeSession(sessionId);
         metrics.incRemovedSessions();
@@ -571,10 +572,13 @@ public class SessionRepository {
         return new SessionCounter(componentRegistry.getConfigCurator(), tenantName).nextSessionId();
     }
 
-    private Path getSessionPath(long sessionId) {
+    public Path getSessionPath(long sessionId) {
         return sessionsPath.append(String.valueOf(sessionId));
     }
 
+    Path getSessionStatePath(long sessionId) {
+        return getSessionPath(sessionId).append(ConfigCurator.SESSIONSTATE_ZK_SUBPATH);
+    }
 
     private SessionZooKeeperClient createSessionZooKeeperClient(long sessionId) {
         String serverId = componentRegistry.getConfigserverConfig().serverId();
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionStateWatcher.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionStateWatcher.java
index 68345d3862d..14f2ef6f271 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/RemoteSessionStateWatcher.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SessionStateWatcher.java
@@ -1,6 +1,7 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.config.server.session;
 
+import java.util.Optional;
 import java.util.logging.Level;
 import com.yahoo.text.Utf8;
 import com.yahoo.vespa.config.server.ReloadHandler;
@@ -16,47 +17,61 @@ import java.util.logging.Logger;
  * The session must be in the session repo.
  *
  * @author Vegard Havdal
+ * @author hmusum
  */
-public class RemoteSessionStateWatcher {
+public class SessionStateWatcher {
 
-    private static final Logger log = Logger.getLogger(RemoteSessionStateWatcher.class.getName());
+    private static final Logger log = Logger.getLogger(SessionStateWatcher.class.getName());
 
     private final Curator.FileCache fileCache;
     private final ReloadHandler reloadHandler;
-    private final RemoteSession session;
+    private final RemoteSession remoteSession;
+    private final Optional<LocalSession> localSession;
     private final MetricUpdater metrics;
     private final Executor zkWatcherExecutor;
+    private final SessionRepository sessionRepository;
 
-    RemoteSessionStateWatcher(Curator.FileCache fileCache,
-                              ReloadHandler reloadHandler,
-                              RemoteSession session,
-                              MetricUpdater metrics,
-                              Executor zkWatcherExecutor) {
+    SessionStateWatcher(Curator.FileCache fileCache,
+                        ReloadHandler reloadHandler,
+                        RemoteSession remoteSession,
+                        Optional<LocalSession> localSession,
+                        MetricUpdater metrics,
+                        Executor zkWatcherExecutor,
+                        SessionRepository sessionRepository) {
         this.fileCache = fileCache;
         this.reloadHandler = reloadHandler;
-        this.session = session;
+        this.remoteSession = remoteSession;
+        this.localSession = localSession;
         this.metrics = metrics;
         this.fileCache.start();
         this.fileCache.addListener(this::nodeChanged);
         this.zkWatcherExecutor = zkWatcherExecutor;
+        this.sessionRepository = sessionRepository;
     }
 
     private void sessionChanged(Session.Status status) {
+        long sessionId = remoteSession.getSessionId();
+
         // valid for NEW -> PREPARE transitions, not ACTIVATE -> PREPARE.
         if (status.equals(Session.Status.PREPARE)) {
-            log.log(Level.FINE, session.logPre() + "Loading prepared session: " + session.getSessionId());
-            session.loadPrepared();
+            log.log(Level.FINE, remoteSession.logPre() + "Loading prepared session: " + remoteSession.getSessionId());
+            remoteSession.loadPrepared();
         } else if (status.equals(Session.Status.ACTIVATE)) {
-            session.makeActive(reloadHandler);
+            remoteSession.makeActive(reloadHandler);
         } else if (status.equals(Session.Status.DEACTIVATE)) {
-            session.deactivate();
+            remoteSession.deactivate();
         } else if (status.equals(Session.Status.DELETE)) {
-            session.deactivate();
+            remoteSession.deactivate();
+            log.log(Level.INFO, remoteSession.logPre() + "Session change: Local session " + sessionId + " changed status to " + status);
+            localSession.ifPresent(session -> {
+                 log.log(Level.FINE, session.logPre() + "Deleting session " + sessionId);
+                 sessionRepository.deleteLocalSession(session);
+             });
         }
     }
 
     public long getSessionId() {
-        return session.getSessionId();
+        return remoteSession.getSessionId();
     }
 
     public void close() {
@@ -69,18 +84,18 @@ public class RemoteSessionStateWatcher {
 
     private void nodeChanged() {
         zkWatcherExecutor.execute(() -> {
-            Session.Status currentStatus = session.getStatus();
+            Session.Status currentStatus = remoteSession.getStatus();
             Session.Status newStatus = Session.Status.NONE;
             try {
                 ChildData node = fileCache.getCurrentData();
                 if (node != null) {
                     newStatus = Session.Status.parse(Utf8.toString(node.getData()));
-                    log.log(Level.FINE, session.logPre() + "Session change: Remote session " + session.getSessionId() +
+                    log.log(Level.FINE, remoteSession.logPre() + "Session change: Remote session " + remoteSession.getSessionId() +
                                         " changed status from " + currentStatus.name() + " to " + newStatus.name());
                     sessionChanged(newStatus);
                 }
             } catch (Exception e) {
-                log.log(Level.WARNING, session.logPre() + "Error handling session change from " + currentStatus.name() +
+                log.log(Level.WARNING, remoteSession.logPre() + "Error handling session change from " + currentStatus.name() +
                                        " to " + newStatus.name() + " for session " + getSessionId(), e);
                 metrics.incSessionChangeErrors();
             }
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SilentDeployLogger.java b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SilentDeployLogger.java
index 92ab6b3fbf5..445837104d4 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/session/SilentDeployLogger.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/session/SilentDeployLogger.java
@@ -7,7 +7,7 @@ import java.util.logging.Logger;
 import com.yahoo.config.application.api.DeployLogger;
 
 /**
- * The purpose of this is to mute the log messages from model and application building in {@link RemoteSession} that is triggered by {@link RemoteSessionStateWatcher}, since those messages already
+ * The purpose of this is to mute the log messages from model and application building in {@link RemoteSession} that is triggered by {@link SessionStateWatcher}, since those messages already
  * have been emitted by the prepare handler, for the same prepare operation.
  * 
  * @author vegardh
diff --git a/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/Tenant.java b/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/Tenant.java
index f7c8ae9d5c3..cbcb96d0b36 100644
--- a/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/Tenant.java
+++ b/configserver/src/main/java/com/yahoo/vespa/config/server/tenant/Tenant.java
@@ -66,10 +66,6 @@ public class Tenant implements TenantHandlerProvider {
         return requestHandler;
     }
 
-    public SessionRepository getSessionRepo() {
-        return sessionRepository;
-    }
-
     public TenantName getName() {
         return name;
     }
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/ApplicationRepositoryTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/ApplicationRepositoryTest.java
index f0aa38a228e..8745a9bf596 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/ApplicationRepositoryTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/ApplicationRepositoryTest.java
@@ -4,7 +4,6 @@ package com.yahoo.vespa.config.server;
 import com.yahoo.cloud.config.ConfigserverConfig;
 import com.yahoo.component.Version;
 import com.yahoo.config.ConfigInstance;
-import com.yahoo.config.FileReference;
 import com.yahoo.config.SimpletypesConfig;
 import com.yahoo.config.application.api.ApplicationMetaData;
 import com.yahoo.config.model.NullConfigModelRegistry;
@@ -304,15 +303,16 @@ public class ApplicationRepositoryTest {
     public void delete() {
         TenantName tenantName = applicationId().tenant();
         Tenant tenant = tenantRepository.getTenant(tenantName);
+        SessionRepository sessionRepository = tenant.getSessionRepository();
         {
             PrepareResult result = deployApp(testApp);
             long sessionId = result.sessionId();
-            LocalSession applicationData = tenant.getSessionRepository().getLocalSession(sessionId);
+            LocalSession applicationData = sessionRepository.getLocalSession(sessionId);
             assertNotNull(applicationData);
             assertNotNull(applicationData.getApplicationId());
-            assertNotNull(tenant.getSessionRepo().getLocalSession(sessionId));
+            assertNotNull(sessionRepository.getLocalSession(sessionId));
             assertNotNull(applicationRepository.getActiveSession(applicationId()));
-            String sessionNode = TenantRepository.getSessionsPath(tenantName).append(String.valueOf(sessionId)).getAbsolute();
+            String sessionNode = sessionRepository.getSessionPath(sessionId).getAbsolute();
             assertTrue(configCurator.exists(sessionNode));
             TenantFileSystemDirs tenantFileSystemDirs = tenant.getApplicationRepo().getTenantFileSystemDirs();
             File sessionFile = new File(tenantFileSystemDirs.sessionsPath(), String.valueOf(sessionId));
@@ -321,8 +321,8 @@ public class ApplicationRepositoryTest {
             // Delete app and verify that it has been deleted from repos and provisioner
             assertTrue(applicationRepository.delete(applicationId()));
             assertNull(applicationRepository.getActiveSession(applicationId()));
-            assertNull(tenant.getSessionRepository().getLocalSession(sessionId));
-            assertNull(tenant.getSessionRepo().getLocalSession(sessionId));
+            assertNull(sessionRepository.getLocalSession(sessionId));
+            assertNull(sessionRepository.getLocalSession(sessionId));
             assertTrue(provisioner.removed);
             assertEquals(tenant.getName(), provisioner.lastApplicationId.tenant());
             assertEquals(applicationId(), provisioner.lastApplicationId);
@@ -364,7 +364,7 @@ public class ApplicationRepositoryTest {
             // A new delete should cleanup and be successful
             RemoteSession activeSession = applicationRepository.getActiveSession(applicationId());
             assertNull(activeSession);
-            assertNull(tenant.getSessionRepo().getLocalSession(prepareResult.sessionId()));
+            assertNull(sessionRepository.getLocalSession(prepareResult.sessionId()));
 
             assertTrue(applicationRepository.delete(applicationId()));
         }
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/HostHandlerTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/HostHandlerTest.java
index 37181abfcf4..d8724cb4db2 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/HostHandlerTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/http/v2/HostHandlerTest.java
@@ -38,8 +38,9 @@ import java.util.Collections;
  */
 // TODO: Try to move testing to ApplicationRepositoryTest and avoid all the low-level setup code here
 public class HostHandlerTest {
+
     private static final String urlPrefix = "http://myhost:14000/application/v2/host/";
-    private static File testApp = new File("src/test/apps/app");
+    private static final File testApp = new File("src/test/apps/app");
 
     private HostHandler handler;
     private final static TenantName mytenant = TenantName.from("mytenant");
@@ -55,7 +56,7 @@ public class HostHandlerTest {
         TestComponentRegistry componentRegistry = new TestComponentRegistry.Builder()
                 .modelFactoryRegistry(new ModelFactoryRegistry(Collections.singletonList(new VespaModelFactory(new NullConfigModelRegistry()))))
                 .build();
-        tenant.getSessionRepo().addRemoteSession(new RemoteSession(tenant.getName(), sessionId, componentRegistry, new MockSessionZKClient(app)));
+        tenant.getSessionRepository().addRemoteSession(new RemoteSession(tenant.getName(), sessionId, componentRegistry, new MockSessionZKClient(app)));
     }
 
     @Before
diff --git a/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionRepositoryTest.java b/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionRepositoryTest.java
index b9e872261c5..13a27e570c2 100644
--- a/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionRepositoryTest.java
+++ b/configserver/src/test/java/com/yahoo/vespa/config/server/session/SessionRepositoryTest.java
@@ -10,9 +10,7 @@ import com.yahoo.vespa.config.server.GlobalComponentRegistry;
 import com.yahoo.vespa.config.server.TestComponentRegistry;
 import com.yahoo.vespa.config.server.application.OrchestratorMock;
 import com.yahoo.vespa.config.server.http.SessionHandlerTest;
-import com.yahoo.vespa.config.server.tenant.Tenant;
 import com.yahoo.vespa.config.server.tenant.TenantRepository;
-import com.yahoo.vespa.config.server.zookeeper.ConfigCurator;
 import com.yahoo.vespa.curator.Curator;
 import com.yahoo.vespa.curator.mock.MockCurator;
 import com.yahoo.vespa.flags.FlagSource;
@@ -44,6 +42,7 @@ public class SessionRepositoryTest {
     private MockCurator curator;
     private TenantRepository tenantRepository;
     private ApplicationRepository applicationRepository;
+    private SessionRepository sessionRepository;
 
     @Rule
     public TemporaryFolder temporaryFolder = new TemporaryFolder();
@@ -71,6 +70,7 @@ public class SessionRepositoryTest {
                                                           new SessionHandlerTest.MockProvisioner(),
                                                           new OrchestratorMock(),
                                                           Clock.systemUTC());
+        sessionRepository = tenantRepository.getTenant(tenantName).getSessionRepository();
     }
 
     @Test
@@ -78,7 +78,6 @@ public class SessionRepositoryTest {
         setup();
         long firstSessionId = deploy();
         long secondSessionId = deploy();
-        SessionRepository sessionRepository = tenantRepository.getTenant(tenantName).getSessionRepository();
         assertNotNull(sessionRepository.getLocalSession(firstSessionId));
         assertNotNull(sessionRepository.getLocalSession(secondSessionId));
         assertNull(sessionRepository.getLocalSession(secondSessionId + 1));
@@ -96,7 +95,6 @@ public class SessionRepositoryTest {
 
         long firstSessionId = deploy();
         long secondSessionId = deploy();
-        SessionRepository sessionRepository = tenantRepository.getTenant(tenantName).getSessionRepository();
         assertNotNull(sessionRepository.getLocalSession(firstSessionId));
         assertNotNull(sessionRepository.getLocalSession(secondSessionId));
         assertNull(sessionRepository.getLocalSession(secondSessionId + 1));
@@ -130,7 +128,6 @@ public class SessionRepositoryTest {
         com.yahoo.path.Path session = TenantRepository.getSessionsPath(tenantName).append("" + sessionId);
         curator.delete(session);
         assertSessionRemoved(sessionId);
-        SessionRepository sessionRepository = tenantRepository.getTenant(tenantName).getSessionRepository();
         assertNull(sessionRepository.getRemoteSession(sessionId));
     }
 
@@ -145,21 +142,18 @@ public class SessionRepositoryTest {
         TenantName mytenant = TenantName.from("mytenant");
         curator.set(TenantRepository.getApplicationsPath(mytenant).append("mytenant:appX:default"), new byte[0]); // Invalid data
         tenantRepository.addTenant(mytenant);
-        Tenant tenant = tenantRepository.getTenant(mytenant);
         curator.create(TenantRepository.getSessionsPath(mytenant));
-        SessionRepository sessionRepository = tenant.getSessionRepo();
         assertThat(sessionRepository.getRemoteSessions().size(), is(0));
-        createSession(sessionId, true, mytenant);
+        createSession(sessionId, true);
         assertThat(sessionRepository.getRemoteSessions().size(), is(1));
     }
 
     private void createSession(long sessionId, boolean wait) {
-        createSession(sessionId, wait, tenantName);
+        createSession(sessionId, wait, sessionRepository);
     }
 
-    private void createSession(long sessionId, boolean wait, TenantName tenantName) {
-        com.yahoo.path.Path sessionsPath = TenantRepository.getSessionsPath(tenantName);
-        SessionZooKeeperClient zkc = new SessionZooKeeperClient(curator, sessionsPath.append(String.valueOf(sessionId)));
+    private void createSession(long sessionId, boolean wait, SessionRepository sessionRepository) {
+        SessionZooKeeperClient zkc = new SessionZooKeeperClient(curator, sessionRepository.getSessionPath(sessionId));
         zkc.createNewSession(Instant.now());
         if (wait) {
             Curator.CompletionWaiter waiter = zkc.getUploadWaiter();
@@ -168,14 +162,13 @@ public class SessionRepositoryTest {
     }
 
     private void assertStatusChange(long sessionId, Session.Status status) throws Exception {
-        com.yahoo.path.Path statePath = TenantRepository.getSessionsPath(tenantName).append("" + sessionId).append(ConfigCurator.SESSIONSTATE_ZK_SUBPATH);
+        com.yahoo.path.Path statePath = sessionRepository.getSessionStatePath(sessionId);
         curator.create(statePath);
         curator.framework().setData().forPath(statePath.getAbsolute(), Utf8.toBytes(status.toString()));
         assertRemoteSessionStatus(sessionId, status);
     }
 
     private void assertSessionRemoved(long sessionId) {
-        SessionRepository sessionRepository = tenantRepository.getTenant(tenantName).getSessionRepository();
         waitFor(p -> sessionRepository.getRemoteSession(sessionId) == null, sessionId);
         assertNull(sessionRepository.getRemoteSession(sessionId));
     }
@@ -185,7 +178,6 @@ public class SessionRepositoryTest {
     }
 
     private void assertRemoteSessionStatus(long sessionId, Session.Status status) {
-        SessionRepository sessionRepository = tenantRepository.getTenant(tenantName).getSessionRepository();
         waitFor(p -> sessionRepository.getRemoteSession(sessionId) != null &&
                      sessionRepository.getRemoteSession(sessionId).getStatus() == status, sessionId);
         assertNotNull(sessionRepository.getRemoteSession(sessionId));