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/**
* Copyright (C) 2014 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.
*/
#include "mongo/platform/basic.h"
#include <boost/optional.hpp>
#include "mongo/client/read_preference.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/commands.h"
#include "mongo/db/matcher/extensions_callback_noop.h"
#include "mongo/db/query/cursor_response.h"
#include "mongo/db/stats/counters.h"
#include "mongo/db/views/resolved_view.h"
#include "mongo/rpc/get_status_from_command_result.h"
#include "mongo/s/commands/cluster_aggregate.h"
#include "mongo/s/commands/strategy.h"
#include "mongo/s/query/cluster_find.h"
namespace mongo {
namespace {
using std::unique_ptr;
using std::string;
using std::vector;
const char kTermField[] = "term";
/**
* Implements the find command on mongos.
*/
class ClusterFindCmd : public BasicCommand {
MONGO_DISALLOW_COPYING(ClusterFindCmd);
public:
ClusterFindCmd() : BasicCommand("find") {}
virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
return false;
}
bool slaveOk() const final {
return false;
}
bool slaveOverrideOk() const final {
return true;
}
bool maintenanceOk() const final {
return false;
}
bool adminOnly() const final {
return false;
}
bool shouldAffectCommandCounter() const final {
return false;
}
void help(std::stringstream& help) const final {
help << "query for documents";
}
/**
* In order to run the find command, you must be authorized for the "find" action
* type on the collection.
*/
Status checkAuthForCommand(Client* client,
const std::string& dbname,
const BSONObj& cmdObj) final {
const NamespaceString nss(parseNs(dbname, cmdObj));
auto hasTerm = cmdObj.hasField(kTermField);
return AuthorizationSession::get(client)->checkAuthForFind(nss, hasTerm);
}
Status explain(OperationContext* opCtx,
const std::string& dbname,
const BSONObj& cmdObj,
ExplainOptions::Verbosity verbosity,
BSONObjBuilder* out) const final {
const NamespaceString nss(parseNsCollectionRequired(dbname, cmdObj));
// Parse the command BSON to a QueryRequest.
bool isExplain = true;
auto qr = QueryRequest::makeFromFindCommand(std::move(nss), cmdObj, isExplain);
if (!qr.isOK()) {
return qr.getStatus();
}
auto result = Strategy::explainFind(
opCtx, cmdObj, *qr.getValue(), verbosity, ReadPreferenceSetting::get(opCtx), out);
if (result == ErrorCodes::CommandOnShardedViewNotSupportedOnMongod) {
auto resolvedView = ResolvedView::fromBSON(out->asTempObj());
out->resetToEmpty();
auto aggCmdOnView = qr.getValue().get()->asAggregationCommand();
if (!aggCmdOnView.isOK()) {
return aggCmdOnView.getStatus();
}
auto aggRequestOnView =
AggregationRequest::parseFromBSON(nss, aggCmdOnView.getValue(), verbosity);
if (!aggRequestOnView.isOK()) {
return aggRequestOnView.getStatus();
}
auto resolvedAggRequest =
resolvedView.asExpandedViewAggregation(aggRequestOnView.getValue());
auto resolvedAggCmd = resolvedAggRequest.serializeToCommandObj().toBson();
ClusterAggregate::Namespaces nsStruct;
nsStruct.requestedNss = std::move(nss);
nsStruct.executionNss = std::move(resolvedView.getNamespace());
auto status = ClusterAggregate::runAggregate(
opCtx, nsStruct, resolvedAggRequest, resolvedAggCmd, out);
appendCommandStatus(*out, status);
return status;
}
return result;
}
bool run(OperationContext* opCtx,
const std::string& dbname,
const BSONObj& cmdObj,
std::string& errmsg,
BSONObjBuilder& result) final {
// We count find command as a query op.
globalOpCounters.gotQuery();
const NamespaceString nss(parseNsCollectionRequired(dbname, cmdObj));
const bool isExplain = false;
auto qr = QueryRequest::makeFromFindCommand(nss, cmdObj, isExplain);
if (!qr.isOK()) {
return appendCommandStatus(result, qr.getStatus());
}
auto cq =
CanonicalQuery::canonicalize(opCtx, std::move(qr.getValue()), ExtensionsCallbackNoop());
if (!cq.isOK()) {
return appendCommandStatus(result, cq.getStatus());
}
// Do the work to generate the first batch of results. This blocks waiting to get responses
// from the shard(s).
std::vector<BSONObj> batch;
BSONObj viewDefinition;
auto cursorId = ClusterFind::runQuery(
opCtx, *cq.getValue(), ReadPreferenceSetting::get(opCtx), &batch, &viewDefinition);
if (!cursorId.isOK()) {
if (cursorId.getStatus() == ErrorCodes::CommandOnShardedViewNotSupportedOnMongod) {
auto aggCmdOnView = cq.getValue()->getQueryRequest().asAggregationCommand();
if (!aggCmdOnView.isOK()) {
return appendCommandStatus(result, aggCmdOnView.getStatus());
}
auto aggRequestOnView =
AggregationRequest::parseFromBSON(nss, aggCmdOnView.getValue());
if (!aggRequestOnView.isOK()) {
return appendCommandStatus(result, aggRequestOnView.getStatus());
}
auto resolvedView = ResolvedView::fromBSON(viewDefinition);
auto resolvedAggRequest =
resolvedView.asExpandedViewAggregation(aggRequestOnView.getValue());
auto resolvedAggCmd = resolvedAggRequest.serializeToCommandObj().toBson();
// We pass both the underlying collection namespace and the view namespace here. The
// underlying collection namespace is used to execute the aggregation on mongoD. Any
// cursor returned will be registered under the view namespace so that subsequent
// getMore and killCursors calls against the view have access.
ClusterAggregate::Namespaces nsStruct;
nsStruct.requestedNss = std::move(nss);
nsStruct.executionNss = std::move(resolvedView.getNamespace());
auto status = ClusterAggregate::runAggregate(
opCtx, nsStruct, resolvedAggRequest, resolvedAggCmd, &result);
appendCommandStatus(result, status);
return status.isOK();
}
return appendCommandStatus(result, cursorId.getStatus());
}
// Build the response document.
CursorResponseBuilder firstBatch(/*firstBatch*/ true, &result);
for (const auto& obj : batch) {
firstBatch.append(obj);
}
firstBatch.done(cursorId.getValue(), nss.ns());
return true;
}
} cmdFindCluster;
} // namespace
} // namespace mongo
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