SERVER-34145 Persist database version on shard

4 files changed, 266 insertions, 4 deletions

diff --git a/src/mongo/s/SConscript b/src/mongo/s/SConscript
index 57e488774b3..b815dc7b38e 100644
--- a/src/mongo/s/SConscript
+++ b/src/mongo/s/SConscript
@@ -116,6 +116,7 @@ env.Library(
         'catalog/type_mongos.cpp',
         'catalog/type_shard.cpp',
         'catalog/type_shard_collection.cpp',
+        'catalog/type_shard_database.cpp',
         'catalog/type_tags.cpp',
         'chunk_version.cpp',
         'request_types/add_shard_request_type.cpp',
diff --git a/src/mongo/s/catalog/type_shard_database.cpp b/src/mongo/s/catalog/type_shard_database.cpp
new file mode 100644
index 00000000000..5be668cceae
--- /dev/null
+++ b/src/mongo/s/catalog/type_shard_database.cpp
@@ -0,0 +1,132 @@
+/**
+ *    Copyright (C) 2018 10gen 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.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/s/catalog/type_shard_database.h"
+
+#include "mongo/base/status_with.h"
+#include "mongo/bson/bsonobj.h"
+#include "mongo/bson/bsonobjbuilder.h"
+#include "mongo/bson/util/bson_extract.h"
+#include "mongo/s/catalog/type_database.h"
+#include "mongo/util/assert_util.h"
+
+namespace mongo {
+
+using std::string;
+
+const NamespaceString ShardDatabaseType::ConfigNS(
+    NamespaceString::kShardConfigDatabasesCollectionName);
+
+const BSONField<std::string> ShardDatabaseType::name("_id");
+const BSONField<DatabaseVersion> ShardDatabaseType::version("version");
+const BSONField<std::string> ShardDatabaseType::primary("primary");
+const BSONField<bool> ShardDatabaseType::partitioned("partitioned");
+const BSONField<int> ShardDatabaseType::enterCriticalSectionCounter("enterCriticalSectionCounter");
+
+ShardDatabaseType::ShardDatabaseType(const std::string dbName,
+                                     boost::optional<DatabaseVersion> version,
+                                     const ShardId primary,
+                                     bool partitioned)
+    : _name(dbName), _version(version), _primary(primary), _partitioned(partitioned) {}
+
+StatusWith<ShardDatabaseType> ShardDatabaseType::fromBSON(const BSONObj& source) {
+    std::string dbName;
+    {
+        Status status = bsonExtractStringField(source, name.name(), &dbName);
+        if (!status.isOK())
+            return status;
+    }
+
+    boost::optional<DatabaseVersion> dbVersion = boost::none;
+    {
+        BSONObj versionField = source.getObjectField("version");
+        // TODO: Parse this unconditionally once featureCompatibilityVersion 3.6 is no longer
+        // supported.
+        if (!versionField.isEmpty()) {
+            dbVersion = DatabaseVersion::parse(IDLParserErrorContext("DatabaseType"), versionField);
+        }
+    }
+
+    std::string dbPrimary;
+    {
+        Status status = bsonExtractStringField(source, primary.name(), &dbPrimary);
+        if (!status.isOK())
+            return status;
+    }
+
+    bool dbPartitioned;
+    {
+        Status status =
+            bsonExtractBooleanFieldWithDefault(source, partitioned.name(), false, &dbPartitioned);
+        if (!status.isOK())
+            return status;
+    }
+
+    ShardDatabaseType shardDatabaseType(dbName, dbVersion, dbPrimary, dbPartitioned);
+
+    return shardDatabaseType;
+}
+
+BSONObj ShardDatabaseType::toBSON() const {
+    BSONObjBuilder builder;
+
+    builder.append(name.name(), _name);
+    if (_version) {
+        builder.append(version.name(), _version->toBSON());
+    }
+    builder.append(primary.name(), _primary.toString());
+    builder.append(partitioned.name(), _partitioned);
+
+    return builder.obj();
+}
+
+std::string ShardDatabaseType::toString() const {
+    return toBSON().toString();
+}
+
+void ShardDatabaseType::setDbVersion(boost::optional<DatabaseVersion> version) {
+    _version = version;
+}
+
+void ShardDatabaseType::setDbName(const std::string& dbName) {
+    invariant(!dbName.empty());
+    _name = dbName;
+}
+
+void ShardDatabaseType::setPrimary(const ShardId& primary) {
+    invariant(primary.isValid());
+    _primary = primary;
+}
+
+void ShardDatabaseType::setPartitioned(bool partitioned) {
+    _partitioned = partitioned;
+}
+
+}  // namespace mongo
diff --git a/src/mongo/s/catalog/type_shard_database.h b/src/mongo/s/catalog/type_shard_database.h
new file mode 100644
index 00000000000..f8b0209636d
--- /dev/null
+++ b/src/mongo/s/catalog/type_shard_database.h
@@ -0,0 +1,121 @@
+/**
+ *    Copyright (C) 2018 10gen 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 <boost/optional.hpp>
+#include <string>
+
+#include "mongo/db/jsobj.h"
+#include "mongo/s/database_version_gen.h"
+#include "mongo/s/shard_id.h"
+
+namespace mongo {
+
+class Status;
+template <typename T>
+class StatusWith;
+
+/**
+ * This class represents the layout and contents of documents contained in the shard server's
+ * config.databases collection. All manipulation of documents coming from that collection should
+ * be done with this class.
+ *
+ * Expected shard server config.databases collection format:
+ *   {
+ *      "_id" : "foo",
+ *      "version" : {
+ *          "uuid" : UUID
+ *          "lastMod" : 1
+ *      },
+ *      "primary": "shard0000",
+ *      "partitioned": true,
+ *      "enterCriticalSectionCounter" : 4                    // optional
+ *   }
+ *
+ * enterCriticalSectionCounter is currently just an OpObserver signal, thus otherwise ignored here.
+ */
+class ShardDatabaseType {
+public:
+    // Name of the database collection on the shard server.
+    static const NamespaceString ConfigNS;
+
+    static const BSONField<std::string> name;  // "_id"
+    static const BSONField<DatabaseVersion> version;
+    static const BSONField<std::string> primary;
+    static const BSONField<bool> partitioned;
+    static const BSONField<int> enterCriticalSectionCounter;
+
+    ShardDatabaseType(const std::string dbName,
+                      boost::optional<DatabaseVersion> version,
+                      const ShardId primary,
+                      bool partitioned);
+
+    /**
+     * Constructs a new ShardDatabaseType object from BSON. Also does validation of the contents.
+     */
+    static StatusWith<ShardDatabaseType> fromBSON(const BSONObj& source);
+
+    /**
+     * Returns the BSON representation of this shard database type object.
+     */
+    BSONObj toBSON() const;
+
+    /**
+     * Returns a std::string representation of the current internal state.
+     */
+    std::string toString() const;
+
+    const std::string& getDbName() const {
+        return _name;
+    }
+    void setDbName(const std::string& dbName);
+
+    const boost::optional<DatabaseVersion> getDbVersion() const {
+        return _version;
+    }
+    void setDbVersion(boost::optional<DatabaseVersion> version);
+
+    const ShardId& getPrimary() const {
+        return _primary;
+    }
+    void setPrimary(const ShardId& primary);
+
+    bool getPartitioned() const {
+        return _partitioned;
+    }
+    void setPartitioned(bool partitioned);
+
+private:
+    std::string _name;
+    boost::optional<DatabaseVersion> _version;
+    ShardId _primary;
+    bool _partitioned;
+};
+
+}  // namespace mongo
diff --git a/src/mongo/s/config_server_catalog_cache_loader.cpp b/src/mongo/s/config_server_catalog_cache_loader.cpp
index 68a6817ec83..eaa2669b072 100644
--- a/src/mongo/s/config_server_catalog_cache_loader.cpp
+++ b/src/mongo/s/config_server_catalog_cache_loader.cpp
@@ -200,13 +200,21 @@ void ConfigServerCatalogCacheLoader::getDatabase(
     stdx::function<void(OperationContext*, StatusWith<DatabaseType>)> callbackFn) {
 
     if (MONGO_FAIL_POINT(callShardServerCallbackFn)) {
-        uassertStatusOK(_threadPool.schedule([ dbName, callbackFn ]() noexcept {
+        uassertStatusOK(_threadPool.schedule([ name = dbName.toString(), callbackFn ]() noexcept {
             auto opCtx = Client::getCurrent()->makeOperationContext();
 
-            const auto dbVersion = Versioning::newDatabaseVersion();
-            DatabaseType dbt(dbName.toString(), ShardId("PrimaryShard"), false, dbVersion);
+            auto swDbt = [&]() -> StatusWith<DatabaseType> {
+                try {
 
-            callbackFn(opCtx.get(), dbt);
+                    const auto dbVersion = Versioning::newDatabaseVersion();
+                    DatabaseType dbt(std::move(name), ShardId("PrimaryShard"), false, dbVersion);
+                    return dbt;
+                } catch (const DBException& ex) {
+                    return ex.toStatus();
+                }
+            }();
+
+            callbackFn(opCtx.get(), swDbt);
         }));
     }
 }