SERVER-27419 Move cluster 'drop' command to a separate file

Also renames DBConfig::invalidateNs to markNSNotSharded to better convey
the intent of the function.

1 files changed, 152 insertions, 0 deletions

diff --git a/src/mongo/s/commands/cluster_drop_cmd.cpp b/src/mongo/s/commands/cluster_drop_cmd.cpp
new file mode 100644
index 00000000000..86d1118a856
--- /dev/null
+++ b/src/mongo/s/commands/cluster_drop_cmd.cpp
@@ -0,0 +1,152 @@
+/**
+ *    Copyright (C) 2016 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.
+ */
+
+#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/base/status.h"
+#include "mongo/db/commands.h"
+#include "mongo/db/operation_context.h"
+#include "mongo/s/catalog/catalog_cache.h"
+#include "mongo/s/catalog/dist_lock_manager.h"
+#include "mongo/s/catalog/sharding_catalog_client.h"
+#include "mongo/s/catalog/type_database.h"
+#include "mongo/s/client/shard_registry.h"
+#include "mongo/s/commands/cluster_commands_common.h"
+#include "mongo/s/config.h"
+#include "mongo/s/grid.h"
+#include "mongo/s/sharding_raii.h"
+#include "mongo/s/stale_exception.h"
+#include "mongo/util/log.h"
+
+namespace mongo {
+namespace {
+
+class DropCmd : public Command {
+public:
+    DropCmd() : Command("drop") {}
+
+    bool slaveOk() const override {
+        return true;
+    }
+
+    bool adminOnly() const override {
+        return false;
+    }
+
+    bool supportsWriteConcern(const BSONObj& cmd) const override {
+        return true;
+    }
+
+    void addRequiredPrivileges(const std::string& dbname,
+                               const BSONObj& cmdObj,
+                               std::vector<Privilege>* out) override {
+        ActionSet actions;
+        actions.addAction(ActionType::dropCollection);
+        out->push_back(Privilege(parseResourcePattern(dbname, cmdObj), actions));
+    }
+
+    bool run(OperationContext* txn,
+             const std::string& dbname,
+             BSONObj& cmdObj,
+             int options,
+             std::string& errmsg,
+             BSONObjBuilder& result) override {
+        const NamespaceString nss(parseNsCollectionRequired(dbname, cmdObj));
+
+        auto scopedDbStatus = ScopedShardDatabase::getExisting(txn, dbname);
+        if (scopedDbStatus == ErrorCodes::NamespaceNotFound) {
+            return true;
+        }
+
+        uassertStatusOK(scopedDbStatus.getStatus());
+
+        auto const db = scopedDbStatus.getValue().db();
+
+        if (!db->isShardingEnabled() || !db->isSharded(nss.ns())) {
+            _dropUnshardedCollectionFromShard(txn, db->getPrimaryId(), nss);
+        } else {
+            uassertStatusOK(Grid::get(txn)->catalogClient(txn)->dropCollection(txn, nss));
+            db->markNSNotSharded(nss.ns());
+        }
+
+        return true;
+    }
+
+private:
+    /**
+     * Sends the 'drop' command for the specified collection to the specified shard. Throws
+     * DBException on failure.
+     */
+    static void _dropUnshardedCollectionFromShard(OperationContext* txn,
+                                                  const ShardId& shardId,
+                                                  const NamespaceString& nss) {
+        const auto shardRegistry = Grid::get(txn)->shardRegistry();
+
+        const auto dropCommandBSON = [shardRegistry, txn, &shardId, &nss] {
+            BSONObjBuilder builder;
+            builder.append("drop", nss.coll());
+
+            // Append the chunk version for the specified namespace indicating that we believe it is
+            // not sharded. Collections residing on the config server are never sharded so do not
+            // send the shard version.
+            if (shardId != shardRegistry->getConfigShard()->getId()) {
+                ChunkVersion::UNSHARDED().appendForCommands(&builder);
+            }
+
+            if (!txn->getWriteConcern().usedDefault) {
+                builder.append(WriteConcernOptions::kWriteConcernField,
+                               txn->getWriteConcern().toBSON());
+            }
+
+            return builder.obj();
+        }();
+
+        const auto shard = uassertStatusOK(Grid::get(txn)->shardRegistry()->getShard(txn, shardId));
+        auto cmdDropResult = uassertStatusOK(shard->runCommandWithFixedRetryAttempts(
+            txn,
+            ReadPreferenceSetting{ReadPreference::PrimaryOnly},
+            nss.db().toString(),
+            dropCommandBSON,
+            Shard::RetryPolicy::kIdempotent));
+
+        // Special-case SendStaleVersion errors
+        if (cmdDropResult.commandStatus == ErrorCodes::SendStaleConfig) {
+            throw RecvStaleConfigException(
+                str::stream() << "Stale config while dropping collection", cmdDropResult.response);
+        }
+
+        uassertStatusOK(cmdDropResult.commandStatus);
+        uassertStatusOK(cmdDropResult.writeConcernStatus);
+    }
+
+} clusterDropCmd;
+
+}  // namespace
+}  // namespace mongo