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// Copyright Vespa.ai. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
/*
* File: AsyncInitializationPolicy.cpp
* Author: thomasg
*
* Created on July 17, 2012, 1:43 PM
*/
#include "asyncinitializationpolicy.h"
#include <vespa/vespalib/util/threadstackexecutor.h>
#include <vespa/messagebus/emptyreply.h>
#include <vespa/messagebus/error.h>
#include <vespa/documentapi/messagebus/documentprotocol.h>
#include <vespa/vespalib/text/stringtokenizer.h>
namespace {
VESPA_THREAD_STACK_TAG(async_init_policy);
}
namespace documentapi {
std::map<string, string>
AsyncInitializationPolicy::parse(string parameters) {
std::map<string, string> retVal;
vespalib::StringTokenizer tokenizer(parameters, ";");
for (uint32_t i = 0; i < tokenizer.size(); i++) {
string keyValue = tokenizer[i];
vespalib::StringTokenizer keyV(keyValue, "=");
if (keyV.size() == 1) {
retVal[keyV[0]] = "true";
} else {
retVal[keyV[0]] = keyV[1];
}
}
return retVal;
}
AsyncInitializationPolicy::AsyncInitializationPolicy(const std::map<string, string>&)
: _executor(std::make_unique<vespalib::ThreadStackExecutor>(1, async_init_policy)),
_state(State::NOT_STARTED),
_syncInit(true)
{
}
AsyncInitializationPolicy::~AsyncInitializationPolicy() = default;
void
AsyncInitializationPolicy::initSynchronous()
{
init();
_state = State::DONE;
}
namespace {
mbus::Error
currentPolicyInitError(vespalib::stringref error) {
// If an init error has been recorded for the last init attempt, report
// it back until we've managed to successfully complete the init step.
if (error.empty()) {
return mbus::Error(DocumentProtocol::ERROR_NODE_NOT_READY,
"Waiting to initialize policy");
} else {
return mbus::Error(DocumentProtocol::ERROR_POLICY_FAILURE,
"Error when creating policy: " + error);
}
}
}
void
AsyncInitializationPolicy::select(mbus::RoutingContext& context)
{
{
std::lock_guard lock(_lock);
if (_syncInit && _state != State::DONE) {
initSynchronous();
}
if (_state == State::NOT_STARTED || _state == State::FAILED) {
// Only 1 task may be queued to the executor at any point in time.
// This is maintained by only scheduling a task when either no task
// has been created before or the previous task has signalled it is
// entirely done with accessing the state of this policy (including
// the mutex). After setting _state == RUNNING, only the task
// is allowed to mutate _state.
_executor->execute(std::make_unique<Task>(*this));
_state = State::RUNNING;
}
if (_state != State::DONE) {
auto reply = std::make_unique<mbus::EmptyReply>();
reply->addError(currentPolicyInitError(_error));
context.setReply(std::move(reply));
return;
}
// We have the mutex in state DONE and since no task may be queued
// up for execution at this point, it's not possible for this to
// deadlock (executor will stall until all its tasks have finished
// executing, and any queued tasks would attempt to take the mutex
// we're currently holding, deadlocking both threads).
_executor.reset();
}
doSelect(context);
}
void
AsyncInitializationPolicy::Task::run()
{
string error;
try {
error = _owner.init();
} catch (const std::exception& e) {
error = e.what();
}
using State = AsyncInitializationPolicy::State;
std::lock_guard lock(_owner._lock);
_owner._error = error;
_owner._state = error.empty() ? State::DONE : State::FAILED;
}
}
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