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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* 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
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* 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 Server Side 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 <functional>
#include <tuple>
#include <type_traits>
#include <vector>
#include "mongo/executor/network_interface_mock.h"
#include "mongo/executor/task_executor.h"
#include "mongo/stdx/future.h"
#include "mongo/stdx/thread.h"
#include "mongo/unittest/unittest.h"
#include "mongo/util/time_support.h"
namespace mongo {
namespace executor {
/**
* A network infrastructure for testing that provides helpers (onCommand*, onFind*) to extract
* pending requests from the NetworkInterface in this NetworkTestEnv and set a response for it.
* Note that these helpers are synchronous and the code that is being tested that uses the
* TaskExecutor will typically be also synchronously waiting for the response from the network.
* Therefore, the test will not make progress if it is ran on a single thread. To get around this,
* the launchAsync helper can be used to create a new thread that will be used to initiate the
* network call.
*
* Example usage:
*
* auto future = netTestEnv.launchAsync([](){
* return methodWithNetCallToTest();
* });
*
*
* netTestEnv.OnCommandFunction([](const RemoteCommandRequest& request){
* // check contents of request
* return BSON("ok" << 1); // return desired response
* });
*
* // Add as many onCommand/onFind calls to match the number of network calls by the
* // methodWithNetCallToTest in the order they are going to be called.
*
* checkResult(future.timed_get(...));
*/
class NetworkTestEnv {
public:
// Common timeout for tests to use for any work scheduled through launchAsync to complete.
static constexpr Minutes kDefaultLaunchAsyncFutureTimeout{5};
/**
* Wraps a std::future but will cancel any pending network operations in its destructor if
* the future wasn't successfully waited on in the main test thread.
* Without this behavior any operations launched asynchronously might never terminate if they
* are waiting for network operations to complete.
*/
template <class T>
class FutureHandle {
public:
FutureHandle(stdx::future<T> future,
executor::TaskExecutor* executor,
executor::NetworkInterfaceMock* network)
: _future(std::move(future)), _executor(executor), _network(network) {}
FutureHandle(FutureHandle&& other) = default;
FutureHandle& operator=(FutureHandle&& other) {
// Assigning to initialized FutureHandle is banned because of the work required prior to
// waiting on the future.
invariant(!_future.valid());
_future = std::move(other._future);
_executor = other._executor;
_network = other._network;
return *this;
}
~FutureHandle() {
if (_future.valid()) {
_network->exitNetwork();
_executor->shutdown();
_future.wait();
}
}
template <class Rep, class Period>
T timed_get(const stdx::chrono::duration<Rep, Period>& timeout_duration) {
auto status = _future.wait_for(timeout_duration);
ASSERT(status == stdx::future_status::ready);
return _future.get();
}
template <class Period>
T timed_get(const Duration<Period>& timeout_duration) {
return timed_get(timeout_duration.toSystemDuration());
}
T default_timed_get() {
return timed_get(kDefaultLaunchAsyncFutureTimeout);
}
private:
stdx::future<T> _future;
executor::TaskExecutor* _executor;
executor::NetworkInterfaceMock* _network;
};
/**
* Helper method for launching an asynchronous task in a way that will guarantees that the
* task will finish even if the task depends on network traffic via the mock network and there's
* an exception that prevents the main test thread from scheduling responses to the network
* operations. It does this by returning a FutureHandle that wraps std::future and cancels
* all pending network operations in its destructor.
* Must be defined in the header because of its use of templates.
*/
template <typename Lambda>
FutureHandle<typename std::invoke_result<Lambda>::type> launchAsync(Lambda&& func) const {
auto future = async(stdx::launch::async, std::forward<Lambda>(func));
return NetworkTestEnv::FutureHandle<typename std::invoke_result<Lambda>::type>{
std::move(future), _executor, _mockNetwork};
}
using OnCommandFunction = std::function<StatusWith<BSONObj>(const RemoteCommandRequest&)>;
using OnCommandWithMetadataFunction =
std::function<RemoteCommandResponse(const RemoteCommandRequest&)>;
using OnFindCommandFunction =
std::function<StatusWith<std::vector<BSONObj>>(const RemoteCommandRequest&)>;
// Function that accepts a find request and returns a tuple of resulting documents and response
// metadata.
using OnFindCommandWithMetadataFunction =
std::function<StatusWith<std::tuple<std::vector<BSONObj>, BSONObj>>(
const RemoteCommandRequest&)>;
/**
* Create a new test environment based on an existing executor and network.
*/
NetworkTestEnv(TaskExecutor* executor, NetworkInterfaceMock* network);
/**
* Blocking methods, which receive one message from the network and respond using the
* responses returned from the input function. This is a syntactic sugar for simple,
* single request + response or find tests.
*/
void onCommand(OnCommandFunction func);
void onCommands(std::vector<OnCommandFunction> funcs);
void onCommandWithMetadata(OnCommandWithMetadataFunction func);
void onFindCommand(OnFindCommandFunction func);
void onFindWithMetadataCommand(OnFindCommandWithMetadataFunction func);
private:
// Task executor used for running asynchronous operations.
TaskExecutor* _executor;
// Mocked out network under the task executor.
NetworkInterfaceMock* _mockNetwork;
};
} // namespace executor
} // namespace mongo
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