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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2016 John Spray <john.spray@redhat.com>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*/
#include "StandbyPyModules.h"
#include "common/Finisher.h"
#include "common/debug.h"
#include "common/errno.h"
#include "mgr/MgrContext.h"
#include "mgr/Gil.h"
// For ::mgr_store_prefix
#include "PyModuleRegistry.h"
#define dout_context g_ceph_context
#define dout_subsys ceph_subsys_mgr
#undef dout_prefix
#define dout_prefix *_dout << "mgr " << __func__ << " "
StandbyPyModules::StandbyPyModules(
const MgrMap &mgr_map_,
PyModuleConfig &module_config,
LogChannelRef clog_,
MonClient &monc_,
Finisher &f)
: state(module_config, monc_),
clog(clog_),
finisher(f)
{
state.set_mgr_map(mgr_map_);
}
// FIXME: completely identical to ActivePyModules
void StandbyPyModules::shutdown()
{
std::lock_guard locker(lock);
// Signal modules to drop out of serve() and/or tear down resources
for (auto &i : modules) {
auto module = i.second.get();
const auto& name = i.first;
dout(10) << "waiting for module " << name << " to shutdown" << dendl;
lock.unlock();
module->shutdown();
lock.lock();
dout(10) << "module " << name << " shutdown" << dendl;
}
// For modules implementing serve(), finish the threads where we
// were running that.
for (auto &i : modules) {
lock.unlock();
dout(10) << "joining thread for module " << i.first << dendl;
i.second->thread.join();
dout(10) << "joined thread for module " << i.first << dendl;
lock.lock();
}
modules.clear();
}
void StandbyPyModules::start_one(PyModuleRef py_module)
{
std::lock_guard l(lock);
const auto name = py_module->get_name();
auto standby_module = new StandbyPyModule(state, py_module, clog);
// Send all python calls down a Finisher to avoid blocking
// C++ code, and avoid any potential lock cycles.
finisher.queue(new LambdaContext([this, standby_module, name](int) {
int r = standby_module->load();
if (r != 0) {
derr << "Failed to run module in standby mode ('" << name << "')"
<< dendl;
delete standby_module;
} else {
std::lock_guard l(lock);
auto em = modules.emplace(name, standby_module);
ceph_assert(em.second); // actually inserted
dout(4) << "Starting thread for " << name << dendl;
standby_module->thread.create(standby_module->get_thread_name());
}
}));
}
int StandbyPyModule::load()
{
Gil gil(py_module->pMyThreadState, true);
// We tell the module how we name it, so that it can be consistent
// with us in logging etc.
auto pThisPtr = PyCapsule_New(this, nullptr, nullptr);
ceph_assert(pThisPtr != nullptr);
auto pModuleName = PyUnicode_FromString(get_name().c_str());
ceph_assert(pModuleName != nullptr);
auto pArgs = PyTuple_Pack(2, pModuleName, pThisPtr);
Py_DECREF(pThisPtr);
Py_DECREF(pModuleName);
pClassInstance = PyObject_CallObject(py_module->pStandbyClass, pArgs);
Py_DECREF(pArgs);
if (pClassInstance == nullptr) {
derr << "Failed to construct class in '" << get_name() << "'" << dendl;
derr << handle_pyerror() << dendl;
return -EINVAL;
} else {
dout(1) << "Constructed class from module: " << get_name() << dendl;
return 0;
}
}
bool StandbyPyModule::get_config(const std::string &key,
std::string *value) const
{
const std::string global_key = "mgr/" + get_name() + "/" + key;
dout(4) << __func__ << " key: " << global_key << dendl;
return state.with_config([global_key, value](const PyModuleConfig &config){
if (config.config.count(global_key)) {
*value = config.config.at(global_key);
return true;
} else {
return false;
}
});
}
bool StandbyPyModule::get_store(const std::string &key,
std::string *value) const
{
const std::string global_key = PyModule::mgr_store_prefix
+ get_name() + "/" + key;
dout(4) << __func__ << " key: " << global_key << dendl;
// Active modules use a cache of store values (kept up to date
// as writes pass through the active mgr), but standbys
// fetch values synchronously to get an up to date value.
// It's an acceptable cost because standby modules should not be
// doing a lot.
MonClient &monc = state.get_monc();
std::ostringstream cmd_json;
cmd_json << "{\"prefix\": \"config-key get\", \"key\": \""
<< global_key << "\"}";
bufferlist outbl;
std::string outs;
C_SaferCond c;
monc.start_mon_command(
{cmd_json.str()},
{},
&outbl,
&outs,
&c);
int r = c.wait();
if (r == -ENOENT) {
return false;
} else if (r != 0) {
// This is some internal error, not meaningful to python modules,
// so let them just see no value.
derr << __func__ << " error fetching store key '" << global_key << "': "
<< cpp_strerror(r) << " " << outs << dendl;
return false;
} else {
*value = outbl.to_str();
return true;
}
}
std::string StandbyPyModule::get_active_uri() const
{
std::string result;
state.with_mgr_map([&result, this](const MgrMap &mgr_map){
auto iter = mgr_map.services.find(get_name());
if (iter != mgr_map.services.end()) {
result = iter->second;
}
});
return result;
}
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