SERVER-30534 Create a _configsvrDropCollection command

3 files changed, 147 insertions, 0 deletions

diff --git a/jstests/core/views/views_all_commands.js b/jstests/core/views/views_all_commands.js
index 61e209f789c..03b1695ac32 100644
--- a/jstests/core/views/views_all_commands.js
+++ b/jstests/core/views/views_all_commands.js
@@ -67,6 +67,7 @@
         _configsvrCommitChunkMigration: {skip: isAnInternalCommand},
         _configsvrCommitChunkSplit: {skip: isAnInternalCommand},
         _configsvrCreateDatabase: {skip: isAnInternalCommand},
+        _configsvrDropCollection: {skip: isAnInternalCommand},
         _configsvrEnableSharding: {skip: isAnInternalCommand},
         _configsvrMoveChunk: {skip: isAnInternalCommand},
         _configsvrMovePrimary: {skip: isAnInternalCommand},
diff --git a/src/mongo/db/s/SConscript b/src/mongo/db/s/SConscript
index baa5f344a41..86292a29021 100644
--- a/src/mongo/db/s/SConscript
+++ b/src/mongo/db/s/SConscript
@@ -167,6 +167,7 @@ env.Library(
         'config/configsvr_commit_chunk_migration_command.cpp',
         'config/configsvr_control_balancer_command.cpp',
         'config/configsvr_create_database_command.cpp',
+        'config/configsvr_drop_collection_command.cpp',
         'config/configsvr_enable_sharding_command.cpp',
         'config/configsvr_merge_chunk_command.cpp',
         'config/configsvr_move_chunk_command.cpp',
diff --git a/src/mongo/db/s/config/configsvr_drop_collection_command.cpp b/src/mongo/db/s/config/configsvr_drop_collection_command.cpp
new file mode 100644
index 00000000000..33b78b8c2ba
--- /dev/null
+++ b/src/mongo/db/s/config/configsvr_drop_collection_command.cpp
@@ -0,0 +1,145 @@
+/**
+ *    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.
+ */
+#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/base/status.h"
+#include "mongo/db/auth/authorization_session.h"
+#include "mongo/db/commands.h"
+#include "mongo/db/operation_context.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_helpers.h"
+#include "mongo/s/grid.h"
+#include "mongo/s/stale_exception.h"
+#include "mongo/util/log.h"
+
+namespace mongo {
+namespace {
+
+class ConfigSvrDropCollectionCommand : public BasicCommand {
+public:
+    ConfigSvrDropCollectionCommand() : BasicCommand("_configsvrDropCollection") {}
+
+    bool slaveOk() const override {
+        return false;
+    }
+
+    bool adminOnly() const override {
+        return true;
+    }
+
+    bool supportsWriteConcern(const BSONObj& cmd) const override {
+        return true;
+    }
+
+    void help(std::stringstream& help) const override {
+        help << "Internal command, which is exported by the sharding config server. Do not call "
+                "directly. Drops a collection.";
+    }
+
+    Status checkAuthForCommand(Client* client,
+                               const std::string& dbname,
+                               const BSONObj& cmdObj) override {
+        if (!AuthorizationSession::get(client)->isAuthorizedForActionsOnResource(
+                ResourcePattern::forClusterResource(), ActionType::internal)) {
+            return Status(ErrorCodes::Unauthorized, "Unauthorized");
+        }
+        return Status::OK();
+    }
+
+    bool run(OperationContext* opCtx,
+             const std::string& dbname,
+             const BSONObj& cmdObj,
+             BSONObjBuilder& result) override {
+        return true;
+    }
+
+private:
+    /**
+     * Sends the 'drop' command for the specified collection to the specified shard. Throws
+     * DBException on failure.
+     */
+    static void _dropUnshardedCollectionFromShard(OperationContext* opCtx,
+                                                  const ShardId& shardId,
+                                                  const NamespaceString& nss,
+                                                  BSONObjBuilder* result) {
+        const auto catalogClient = Grid::get(opCtx)->catalogClient();
+        const auto shardRegistry = Grid::get(opCtx)->shardRegistry();
+
+        auto scopedDistLock = uassertStatusOK(catalogClient->getDistLockManager()->lock(
+            opCtx, nss.ns(), "drop", DistLockManager::kDefaultLockTimeout));
+
+        const auto dropCommandBSON = [shardRegistry, opCtx, &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 (!opCtx->getWriteConcern().usedDefault) {
+                builder.append(WriteConcernOptions::kWriteConcernField,
+                               opCtx->getWriteConcern().toBSON());
+            }
+
+            return builder.obj();
+        }();
+
+        const auto shard = uassertStatusOK(shardRegistry->getShard(opCtx, shardId));
+        auto cmdDropResult = uassertStatusOK(shard->runCommandWithFixedRetryAttempts(
+            opCtx,
+            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);
+
+        if (!cmdDropResult.writeConcernStatus.isOK()) {
+            appendWriteConcernErrorToCmdResponse(
+                shardId, cmdDropResult.response["writeConcernError"], *result);
+        }
+    }
+
+} configsvrDropCollectionCmd;
+
+}  // namespace
+}  // namespace mongo