Merge changes from topic "revert-283559-currentuser-remove-cache-key-ZXSAZPLOCM"
* changes:
Revert "Remove PerThreadCache"
Revert "Remove unused CurrentUser#cacheKey method"
diff --git a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
index a1197ef..404f5e4 100644
--- a/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
+++ b/java/com/google/gerrit/httpd/restapi/RestApiServlet.java
@@ -108,6 +108,7 @@
import com.google.gerrit.server.RequestInfo;
import com.google.gerrit.server.RequestListener;
import com.google.gerrit.server.audit.ExtendedHttpAuditEvent;
+import com.google.gerrit.server.cache.PerThreadCache;
import com.google.gerrit.server.change.ChangeFinder;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.gerrit.server.group.GroupAuditService;
@@ -327,7 +328,7 @@
try (TraceContext traceContext = enableTracing(req, res)) {
List<IdString> path = splitPath(req);
- try {
+ try (PerThreadCache ignored = PerThreadCache.create()) {
RequestInfo requestInfo = createRequestInfo(traceContext, requestUri(req), path);
globals.requestListeners.runEach(l -> l.onRequest(requestInfo));
diff --git a/java/com/google/gerrit/server/AnonymousUser.java b/java/com/google/gerrit/server/AnonymousUser.java
index c96d61a..91d2d05 100644
--- a/java/com/google/gerrit/server/AnonymousUser.java
+++ b/java/com/google/gerrit/server/AnonymousUser.java
@@ -27,6 +27,12 @@
}
@Override
+ public Object getCacheKey() {
+ // Treat all anonymous users as a single user
+ return "anonymous";
+ }
+
+ @Override
public String toString() {
return "ANONYMOUS";
}
diff --git a/java/com/google/gerrit/server/CurrentUser.java b/java/com/google/gerrit/server/CurrentUser.java
index 43d3c7b..825b34f 100644
--- a/java/com/google/gerrit/server/CurrentUser.java
+++ b/java/com/google/gerrit/server/CurrentUser.java
@@ -91,6 +91,12 @@
*/
public abstract GroupMembership getEffectiveGroups();
+ /**
+ * Returns a unique identifier for this user that is intended to be used as a cache key. Returned
+ * object should to implement {@code equals()} and {@code hashCode()} for effective caching.
+ */
+ public abstract Object getCacheKey();
+
/** Unique name of the user on this server, if one has been assigned. */
public Optional<String> getUserName() {
return Optional.empty();
diff --git a/java/com/google/gerrit/server/IdentifiedUser.java b/java/com/google/gerrit/server/IdentifiedUser.java
index ec2eb81..75c7cda 100644
--- a/java/com/google/gerrit/server/IdentifiedUser.java
+++ b/java/com/google/gerrit/server/IdentifiedUser.java
@@ -413,6 +413,11 @@
return effectiveGroups;
}
+ @Override
+ public Object getCacheKey() {
+ return getAccountId();
+ }
+
public PersonIdent newRefLogIdent() {
return newRefLogIdent(new Date(), TimeZone.getDefault());
}
diff --git a/java/com/google/gerrit/server/InternalUser.java b/java/com/google/gerrit/server/InternalUser.java
index 821a0c6..381819d 100644
--- a/java/com/google/gerrit/server/InternalUser.java
+++ b/java/com/google/gerrit/server/InternalUser.java
@@ -36,6 +36,11 @@
}
@Override
+ public String getCacheKey() {
+ return "internal";
+ }
+
+ @Override
public boolean isInternalUser() {
return true;
}
diff --git a/java/com/google/gerrit/server/PeerDaemonUser.java b/java/com/google/gerrit/server/PeerDaemonUser.java
index 8a8b67a..b27e05c 100644
--- a/java/com/google/gerrit/server/PeerDaemonUser.java
+++ b/java/com/google/gerrit/server/PeerDaemonUser.java
@@ -40,6 +40,11 @@
return GroupMembership.EMPTY;
}
+ @Override
+ public Object getCacheKey() {
+ return getRemoteAddress();
+ }
+
public SocketAddress getRemoteAddress() {
return peer;
}
diff --git a/java/com/google/gerrit/server/cache/PerThreadCache.java b/java/com/google/gerrit/server/cache/PerThreadCache.java
new file mode 100644
index 0000000..b4f79d1
--- /dev/null
+++ b/java/com/google/gerrit/server/cache/PerThreadCache.java
@@ -0,0 +1,146 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cache;
+
+import static com.google.common.base.Preconditions.checkState;
+
+import com.google.common.base.Objects;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Maps;
+import com.google.gerrit.common.Nullable;
+import java.util.Map;
+import java.util.function.Supplier;
+
+/**
+ * Caches object instances for a request as {@link ThreadLocal} in the serving thread.
+ *
+ * <p>This class is intended to cache objects that have a high instantiation cost, are specific to
+ * the current request and potentially need to be instantiated multiple times while serving a
+ * request.
+ *
+ * <p>This is different from the key-value storage in {@code CurrentUser}: {@code CurrentUser}
+ * offers a key-value storage by providing thread-safe {@code get} and {@code put} methods. Once the
+ * value is retrieved through {@code get} there is not thread-safety anymore - apart from the
+ * retrieved object guarantees. Depending on the implementation of {@code CurrentUser}, it might be
+ * shared between the request serving thread as well as sub- or background treads.
+ *
+ * <p>In comparison to that, this class guarantees thread safety even on non-thread-safe objects as
+ * its cache is tied to the serving thread only. While allowing to cache non-thread-safe objects, it
+ * has the downside of not sharing any objects with background threads or executors.
+ *
+ * <p>Lastly, this class offers a cache, that requires callers to also provide a {@code Supplier} in
+ * case the object is not present in the cache, while {@code CurrentUser} provides a storage where
+ * just retrieving stored values is a valid operation.
+ *
+ * <p>To prevent OOM errors on requests that would cache a lot of objects, this class enforces an
+ * internal limit after which no new elements are cached. All {@code get} calls are served by
+ * invoking the {@code Supplier} after that.
+ */
+public class PerThreadCache implements AutoCloseable {
+ private static final ThreadLocal<PerThreadCache> CACHE = new ThreadLocal<>();
+ /**
+ * Cache at maximum 25 values per thread. This value was chosen arbitrarily. Some endpoints (like
+ * ListProjects) break the assumption that the data cached in a request is limited. To prevent
+ * this class from accumulating an unbound number of objects, we enforce this limit.
+ */
+ private static final int PER_THREAD_CACHE_SIZE = 25;
+
+ /**
+ * Unique key for key-value mappings stored in PerThreadCache. The key is based on the value's
+ * class and a list of identifiers that in combination uniquely set the object apart form others
+ * of the same class.
+ */
+ public static final class Key<T> {
+ private final Class<T> clazz;
+ private final ImmutableList<Object> identifiers;
+
+ /**
+ * Returns a key based on the value's class and an identifier that uniquely identify the value.
+ * The identifier needs to implement {@code equals()} and {@hashCode()}.
+ */
+ public static <T> Key<T> create(Class<T> clazz, Object identifier) {
+ return new Key<>(clazz, ImmutableList.of(identifier));
+ }
+
+ /**
+ * Returns a key based on the value's class and a set of identifiers that uniquely identify the
+ * value. Identifiers need to implement {@code equals()} and {@hashCode()}.
+ */
+ public static <T> Key<T> create(Class<T> clazz, Object... identifiers) {
+ return new Key<>(clazz, ImmutableList.copyOf(identifiers));
+ }
+
+ private Key(Class<T> clazz, ImmutableList<Object> identifiers) {
+ this.clazz = clazz;
+ this.identifiers = identifiers;
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hashCode(clazz, identifiers);
+ }
+
+ @Override
+ public boolean equals(Object o) {
+ if (!(o instanceof Key)) {
+ return false;
+ }
+ Key<?> other = (Key<?>) o;
+ return this.clazz == other.clazz && this.identifiers.equals(other.identifiers);
+ }
+ }
+
+ public static PerThreadCache create() {
+ checkState(CACHE.get() == null, "called create() twice on the same request");
+ PerThreadCache cache = new PerThreadCache();
+ CACHE.set(cache);
+ return cache;
+ }
+
+ @Nullable
+ public static PerThreadCache get() {
+ return CACHE.get();
+ }
+
+ public static <T> T getOrCompute(Key<T> key, Supplier<T> loader) {
+ PerThreadCache cache = get();
+ return cache != null ? cache.get(key, loader) : loader.get();
+ }
+
+ private final Map<Key<?>, Object> cache = Maps.newHashMapWithExpectedSize(PER_THREAD_CACHE_SIZE);
+
+ private PerThreadCache() {}
+
+ /**
+ * Returns an instance of {@code T} that was either loaded from the cache or obtained from the
+ * provided {@link Supplier}.
+ */
+ public <T> T get(Key<T> key, Supplier<T> loader) {
+ @SuppressWarnings("unchecked")
+ T value = (T) cache.get(key);
+ if (value == null) {
+ value = loader.get();
+ if (cache.size() < PER_THREAD_CACHE_SIZE) {
+ cache.put(key, value);
+ }
+ }
+ return value;
+ }
+
+ @Override
+ public void close() {
+ CACHE.remove();
+ }
+}
diff --git a/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java b/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java
index 7934d60..d10c139 100644
--- a/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java
+++ b/java/com/google/gerrit/server/permissions/DefaultPermissionBackend.java
@@ -34,6 +34,7 @@
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.PeerDaemonUser;
import com.google.gerrit.server.account.CapabilityCollection;
+import com.google.gerrit.server.cache.PerThreadCache;
import com.google.gerrit.server.project.ProjectCache;
import com.google.gerrit.server.project.ProjectState;
import com.google.inject.Inject;
@@ -108,7 +109,11 @@
public ForProject project(Project.NameKey project) {
try {
ProjectState state = projectCache.get(project).orElseThrow(illegalState(project));
- return projectControlFactory.create(user, state).asForProject();
+ ProjectControl control =
+ PerThreadCache.getOrCompute(
+ PerThreadCache.Key.create(ProjectControl.class, project, user.getCacheKey()),
+ () -> projectControlFactory.create(user, state));
+ return control.asForProject();
} catch (Exception e) {
Throwable cause = e.getCause() != null ? e.getCause() : e;
return FailedPermissionBackend.project(
diff --git a/java/com/google/gerrit/server/query/change/GroupBackedUser.java b/java/com/google/gerrit/server/query/change/GroupBackedUser.java
index dac555d..3960813 100644
--- a/java/com/google/gerrit/server/query/change/GroupBackedUser.java
+++ b/java/com/google/gerrit/server/query/change/GroupBackedUser.java
@@ -64,4 +64,9 @@
public String getLoggableName() {
return "GroupBackedUser with memberships: " + groups.getKnownGroups();
}
+
+ @Override
+ public Object getCacheKey() {
+ return groups.getKnownGroups();
+ }
}
diff --git a/javatests/com/google/gerrit/server/cache/PerThreadCacheTest.java b/javatests/com/google/gerrit/server/cache/PerThreadCacheTest.java
new file mode 100644
index 0000000..5d420d3
--- /dev/null
+++ b/javatests/com/google/gerrit/server/cache/PerThreadCacheTest.java
@@ -0,0 +1,103 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.cache;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.gerrit.testing.GerritJUnit.assertThrows;
+
+import java.util.function.Supplier;
+import org.junit.Test;
+
+public class PerThreadCacheTest {
+
+ @SuppressWarnings("TruthIncompatibleType")
+ @Test
+ public void key_respectsClass() {
+ assertThat(PerThreadCache.Key.create(String.class))
+ .isEqualTo(PerThreadCache.Key.create(String.class));
+ assertThat(PerThreadCache.Key.create(String.class))
+ .isNotEqualTo(
+ /* expected: Key<String>, actual: Key<Integer> */ PerThreadCache.Key.create(
+ Integer.class));
+ }
+
+ @Test
+ public void key_respectsIdentifiers() {
+ assertThat(PerThreadCache.Key.create(String.class, "id1"))
+ .isEqualTo(PerThreadCache.Key.create(String.class, "id1"));
+ assertThat(PerThreadCache.Key.create(String.class, "id1"))
+ .isNotEqualTo(PerThreadCache.Key.create(String.class, "id2"));
+ }
+
+ @Test
+ public void endToEndCache() {
+ try (PerThreadCache ignored = PerThreadCache.create()) {
+ PerThreadCache cache = PerThreadCache.get();
+ PerThreadCache.Key<String> key1 = PerThreadCache.Key.create(String.class);
+
+ String value1 = cache.get(key1, () -> "value1");
+ assertThat(value1).isEqualTo("value1");
+
+ Supplier<String> neverCalled =
+ () -> {
+ throw new IllegalStateException("this method must not be called");
+ };
+ assertThat(cache.get(key1, neverCalled)).isEqualTo("value1");
+ }
+ }
+
+ @Test
+ public void cleanUp() {
+ PerThreadCache.Key<String> key = PerThreadCache.Key.create(String.class);
+ try (PerThreadCache ignored = PerThreadCache.create()) {
+ PerThreadCache cache = PerThreadCache.get();
+ String value1 = cache.get(key, () -> "value1");
+ assertThat(value1).isEqualTo("value1");
+ }
+
+ // Create a second cache and assert that it is not connected to the first one.
+ // This ensures that the cleanup is actually working.
+ try (PerThreadCache ignored = PerThreadCache.create()) {
+ PerThreadCache cache = PerThreadCache.get();
+ String value1 = cache.get(key, () -> "value2");
+ assertThat(value1).isEqualTo("value2");
+ }
+ }
+
+ @Test
+ public void doubleInstantiationFails() {
+ try (PerThreadCache ignored = PerThreadCache.create()) {
+ IllegalStateException thrown =
+ assertThrows(IllegalStateException.class, () -> PerThreadCache.create());
+ assertThat(thrown).hasMessageThat().contains("called create() twice on the same request");
+ }
+ }
+
+ @Test
+ public void enforceMaxSize() {
+ try (PerThreadCache cache = PerThreadCache.create()) {
+ // Fill the cache
+ for (int i = 0; i < 50; i++) {
+ PerThreadCache.Key<String> key = PerThreadCache.Key.create(String.class, i);
+ cache.get(key, () -> "cached value");
+ }
+ // Assert that the value was not persisted
+ PerThreadCache.Key<String> key = PerThreadCache.Key.create(String.class, 1000);
+ cache.get(key, () -> "new value");
+ String value = cache.get(key, () -> "directly served");
+ assertThat(value).isEqualTo("directly served");
+ }
+ }
+}
diff --git a/javatests/com/google/gerrit/server/extensions/webui/UiActionsTest.java b/javatests/com/google/gerrit/server/extensions/webui/UiActionsTest.java
index 1cdca1b..de23ef4 100644
--- a/javatests/com/google/gerrit/server/extensions/webui/UiActionsTest.java
+++ b/javatests/com/google/gerrit/server/extensions/webui/UiActionsTest.java
@@ -101,6 +101,11 @@
}
@Override
+ public Object getCacheKey() {
+ return new Object();
+ }
+
+ @Override
public boolean isIdentifiedUser() {
return true;
}
diff --git a/javatests/com/google/gerrit/server/permissions/RefControlTest.java b/javatests/com/google/gerrit/server/permissions/RefControlTest.java
index 64f9392..81cb732 100644
--- a/javatests/com/google/gerrit/server/permissions/RefControlTest.java
+++ b/javatests/com/google/gerrit/server/permissions/RefControlTest.java
@@ -1198,6 +1198,11 @@
}
@Override
+ public Object getCacheKey() {
+ return new Object();
+ }
+
+ @Override
public Optional<String> getUserName() {
return Optional.ofNullable(username);
}
diff --git a/plugins/replication b/plugins/replication
index 10b6162..a6a6ec5 160000
--- a/plugins/replication
+++ b/plugins/replication
@@ -1 +1 @@
-Subproject commit 10b616284a846dade09a330896ec76e80df1c68c
+Subproject commit a6a6ec5982e41a0ee9bfe24a46be96d4f13fcaaa
