SERVER-28342 Ensure session bookkeeping happens

Ensure we properly vivify session records on ingress.

1 files changed, 154 insertions, 0 deletions

diff --git a/src/mongo/db/logical_session_cache_impl.h b/src/mongo/db/logical_session_cache_impl.h
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+++ b/src/mongo/db/logical_session_cache_impl.h
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+/**
+ * Copyright (C) 2017 MongoDB Inc.
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * As a special exception, the copyright holders give permission to link the
+ * code of portions of this program with the OpenSSL library under certain
+ * conditions as described in each individual source file and distribute
+ * linked combinations including the program with the OpenSSL library. You
+ * must comply with the GNU Affero General Public License in all respects
+ * for all of the code used other than as permitted herein. If you modify
+ * file(s) with this exception, you may extend this exception to your
+ * version of the file(s), but you are not obligated to do so. If you do not
+ * wish to do so, delete this exception statement from your version. If you
+ * delete this exception statement from all source files in the program,
+ * then also delete it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/db/logical_session_cache.h"
+#include "mongo/db/logical_session_id.h"
+#include "mongo/db/refresh_sessions_gen.h"
+#include "mongo/db/service_liason.h"
+#include "mongo/db/sessions_collection.h"
+#include "mongo/db/time_proof_service.h"
+#include "mongo/platform/atomic_word.h"
+#include "mongo/stdx/thread.h"
+#include "mongo/util/lru_cache.h"
+
+namespace mongo {
+
+class Client;
+class OperationContext;
+class ServiceContext;
+
+extern int logicalSessionRecordCacheSize;
+extern int logicalSessionRefreshMinutes;
+
+/**
+ * A thread-safe cache structure for logical session records.
+ *
+ * The cache takes ownership of the passed-in ServiceLiason and
+ * SessionsCollection helper types.
+ */
+class LogicalSessionCacheImpl final : public LogicalSessionCache {
+public:
+    static constexpr int kLogicalSessionCacheDefaultCapacity = 10000;
+    static constexpr Minutes kLogicalSessionDefaultRefresh = Minutes(5);
+
+    /**
+     * An Options type to support the LogicalSessionCacheImpl.
+     */
+    struct Options {
+        Options(){};
+
+        /**
+         * The number of session records to keep in the cache.
+         *
+         * May be set with --setParameter logicalSessionRecordCacheSize=X.
+         */
+        int capacity = logicalSessionRecordCacheSize;
+
+        /**
+         * A timeout value to use for sessions in the cache, in minutes.
+         *
+         * By default, this is set to 30 minutes.
+         *
+         * May be set with --setParameter localLogicalSessionTimeoutMinutes=X.
+         */
+        Minutes sessionTimeout = Minutes(localLogicalSessionTimeoutMinutes);
+
+        /**
+         * The interval over which the cache will refresh session records.
+         *
+         * By default, this is set to every 5 minutes. If the caller is
+         * setting the sessionTimeout by hand, it is suggested that they
+         * consider also setting the refresh interval accordingly.
+         *
+         * May be set with --setParameter logicalSessionRefreshMinutes=X.
+         */
+        Minutes refreshInterval = Minutes(logicalSessionRefreshMinutes);
+    };
+
+    /**
+     * Construct a new session cache.
+     */
+    explicit LogicalSessionCacheImpl(std::unique_ptr<ServiceLiason> service,
+                                     std::unique_ptr<SessionsCollection> collection,
+                                     Options options = Options{});
+
+    LogicalSessionCacheImpl(const LogicalSessionCacheImpl&) = delete;
+    LogicalSessionCacheImpl& operator=(const LogicalSessionCacheImpl&) = delete;
+
+    ~LogicalSessionCacheImpl();
+
+    Status promote(LogicalSessionId lsid) override;
+
+    Status startSession(OperationContext* opCtx, LogicalSessionRecord record) override;
+
+    Status refreshSessions(OperationContext* opCtx,
+                           const RefreshSessionsCmdFromClient& cmd) override;
+    Status refreshSessions(OperationContext* opCtx,
+                           const RefreshSessionsCmdFromClusterMember& cmd) override;
+
+    void vivify(OperationContext* opCtx, const LogicalSessionId& lsid) override;
+
+    void clear() override;
+
+    Status refreshNow(Client* client) override;
+
+    Date_t now() override;
+
+    size_t size() override;
+
+private:
+    /**
+     * Internal methods to handle scheduling and perform refreshes for active
+     * session records contained within the cache.
+     */
+    void _periodicRefresh(Client* client);
+    Status _refresh(Client* client);
+
+    /**
+     * Returns true if a record has passed its given expiration.
+     */
+    bool _isDead(const LogicalSessionRecord& record, Date_t now) const;
+
+    /**
+     * Takes the lock and inserts the given record into the cache.
+     */
+    boost::optional<LogicalSessionRecord> _addToCache(LogicalSessionRecord record);
+
+    const Minutes _refreshInterval;
+    const Minutes _sessionTimeout;
+
+    std::unique_ptr<ServiceLiason> _service;
+    std::unique_ptr<SessionsCollection> _sessionsColl;
+
+    stdx::mutex _cacheMutex;
+    LRUCache<LogicalSessionId, LogicalSessionRecord, LogicalSessionIdHash> _cache;
+};
+
+}  // namespace mongo