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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.
*/
#define MONGO_LOGV2_DEFAULT_COMPONENT ::mongo::logv2::LogComponent::kDefault
#include "mongo/platform/basic.h"
#include "mongo/base/initializer.h"
#include <fmt/format.h>
#include <iostream>
#include <string>
#include <utility>
#include <vector>
#include "mongo/base/dependency_graph.h"
#include "mongo/base/status.h"
#include "mongo/logv2/log.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/quick_exit.h"
#include "mongo/util/str.h"
namespace mongo {
class Initializer::Graph {
public:
class Payload : public DependencyGraph::Payload {
public:
InitializerFunction initFn;
DeinitializerFunction deinitFn;
bool initialized = false;
};
/**
* Note that cycles in the dependency graph are not discovered by this
* function. Rather, they're discovered by `topSort`, below.
*/
void add(std::string name,
InitializerFunction initFn,
DeinitializerFunction deinitFn,
std::vector<std::string> prerequisites,
std::vector<std::string> dependents) {
auto data = std::make_unique<Payload>();
data->initFn = std::move(initFn);
data->deinitFn = std::move(deinitFn);
_graph.addNode(
std::move(name), std::move(prerequisites), std::move(dependents), std::move(data));
}
/**
* Returns the payload of the node that was added by `name`, or nullptr if no such node exists.
*/
Payload* find(const std::string& name) {
return static_cast<Payload*>(_graph.find(name));
}
/**
* Returns a topological sort of the dependency graph, represented
* as an ordered vector of node names.
*
* - Throws with `ErrorCodes::GraphContainsCycle` if the graph contains a cycle.
*
* - Throws with `ErrorCodes::BadValue` if the graph is incomplete.
* That is, a node named in a dependency edge was never added.
*/
std::vector<std::string> topSort() const {
return _graph.topSort();
}
private:
/**
* Map of all named nodes. Nodes named as dependency edges but not
* explicitly added will either be absent from this map or be present with
* a null-valude initFn.
*/
DependencyGraph _graph;
};
Initializer::Initializer() : _graph(std::make_unique<Graph>()) {}
Initializer::~Initializer() = default;
void Initializer::_transition(State expected, State next) {
if (_lifecycleState != expected)
uasserted(
ErrorCodes::IllegalOperation,
format(
FMT_STRING(
"Invalid initializer state transition. Expected {} -> {}, but currently at {}"),
expected,
next,
_lifecycleState));
_lifecycleState = next;
}
void Initializer::addInitializer(std::string name,
InitializerFunction initFn,
DeinitializerFunction deinitFn,
std::vector<std::string> prerequisites,
std::vector<std::string> dependents) {
uassert(ErrorCodes::BadValue, "Null-valued init function", initFn);
uassert(ErrorCodes::CannotMutateObject,
"Initializer dependency graph is frozen",
_lifecycleState == State::kNeverInitialized);
_graph->add(std::move(name),
std::move(initFn),
std::move(deinitFn),
std::move(prerequisites),
std::move(dependents));
}
void Initializer::executeInitializers(const std::vector<std::string>& args) {
if (_lifecycleState == State::kNeverInitialized)
_transition(State::kNeverInitialized, State::kUninitialized); // freeze
_transition(State::kUninitialized, State::kInitializing);
if (_sortedNodes.empty())
_sortedNodes = _graph->topSort();
InitializerContext context(args);
for (const auto& nodeName : _sortedNodes) {
auto* node = _graph->find(nodeName);
if (node->initialized)
continue; // Legacy initializer without re-initialization support.
uassert(ErrorCodes::InternalError,
format(FMT_STRING("node has no init function: \"{}\""), nodeName),
node->initFn);
node->initFn(&context);
node->initialized = true;
}
_transition(State::kInitializing, State::kInitialized);
// The order of the initializers is non-deterministic, so make it available.
// Must be after verbose has been parsed, or the Debug(2) severity won't be visible.
LOGV2_DEBUG_OPTIONS(4777800,
2,
{logv2::LogTruncation::Disabled},
"Ran initializers",
"nodes"_attr = _sortedNodes);
}
void Initializer::executeDeinitializers() {
_transition(State::kInitialized, State::kDeinitializing);
DeinitializerContext context{};
// Execute deinitialization in reverse order from initialization.
for (auto it = _sortedNodes.rbegin(), end = _sortedNodes.rend(); it != end; ++it) {
auto* node = _graph->find(*it);
if (node->deinitFn) {
node->deinitFn(&context);
node->initialized = false;
}
}
_transition(State::kDeinitializing, State::kUninitialized);
}
InitializerFunction Initializer::getInitializerFunctionForTesting(const std::string& name) {
auto node = _graph->find(name);
return node ? node->initFn : nullptr;
}
Initializer& getGlobalInitializer() {
static auto g = new Initializer;
return *g;
}
Status runGlobalInitializers(const std::vector<std::string>& argv) {
try {
getGlobalInitializer().executeInitializers(argv);
return Status::OK();
} catch (const DBException& ex) {
return ex.toStatus();
}
}
Status runGlobalDeinitializers() {
try {
getGlobalInitializer().executeDeinitializers();
return Status::OK();
} catch (const DBException& ex) {
return ex.toStatus();
}
}
void runGlobalInitializersOrDie(const std::vector<std::string>& argv) {
if (Status status = runGlobalInitializers(argv); !status.isOK()) {
std::cerr << "Failed global initialization: " << status << std::endl;
quickExit(1);
}
}
namespace {
// Make sure that getGlobalInitializer() is called at least once before main(), and so at least
// once in a single-threaded context. Otherwise, static initialization inside
// getGlobalInitializer() won't be thread-safe.
[[maybe_unused]] const auto earlyCaller = [] {
getGlobalInitializer();
return 0;
}();
} // namespace
} // namespace mongo
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