instance_manager.cc

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/*
 * Copyright (c) 2014 Juniper Networks, Inc. All rights reserved.
 */
 
#include "oper/instance_manager.h"
 
#include <boost/bind.hpp>
#include <boost/functional/hash.hpp>
#include <boost/filesystem.hpp>
#include <boost/tokenizer.hpp>
#include <sys/wait.h>
#include "cmn/agent.h"
#include "db/db.h"
#include "io/event_manager.h"
#include "oper/instance_task.h"
#include "oper/operdb_init.h"
#include "oper/service_instance.h"
#include "oper/vm.h"
#include "oper/docker_instance_adapter.h"
#include "oper/netns_instance_adapter.h"
#ifdef WITH_LIBVIRT
    #include "oper/libvirt_instance_adapter.h"
#endif
#include "base/util.h"
 
using boost::uuids::uuid;
SandeshTraceBufferPtr InstanceManagerTraceBuf(
        SandeshTraceBufferCreate("InstanceManager", 1000));
 
static const char loadbalancer_config_path_default[] =
        "/var/lib/contrail/loadbalancer/";
static const char namespace_store_path_default[] =
        "/var/run/netns";
static const char namespace_prefix[] = "vrouter-";
 
class InstanceManager::NamespaceStaleCleaner {
public:
    NamespaceStaleCleaner(Agent *agent, InstanceManager *manager)
            : agent_(agent), manager_(manager) {
    }
 
    void CleanStaleEntries() {
        namespace fs = boost::filesystem;
 
        //Read all the Namepaces in the system
        fs::path ns(manager_->namespace_store_path_);
        if ( !fs::exists(ns) || !fs::is_directory(ns)) {
            return;
        }
 
        typedef boost::tokenizer<boost::char_separator<char> > tokenizer;
        boost::char_separator<char> slash_sep("/");
        boost::char_separator<char> colon_sep(":");
        fs::directory_iterator end_iter;
        for(fs::directory_iterator iter(ns); iter != end_iter; iter++) {
 
            // Get to the name of namespace by removing complete path
            tokenizer tokens(iter->path().string(), slash_sep);
            std::string ns_name;
            for(tokenizer::iterator it=tokens.begin(); it!=tokens.end(); it++){
                ns_name = *it;
            }
 
            //We are interested only in namespaces starting with a given
            //prefix
            std::size_t vrouter_found;
            vrouter_found = ns_name.find(namespace_prefix);
            if (vrouter_found == std::string::npos) {
                continue;
            }
 
            //Remove the standard prefix
            ns_name.replace(vrouter_found, strlen(namespace_prefix), "");
 
            //Namespace might have a ":". Extract both left and right of
            //":" Left of ":" is the VM uuid. If not found in Agent's VM
            //DB, it can be deleted
            tokenizer tok(ns_name, colon_sep);
            boost::uuids::uuid vm_uuid = StringToUuid(*tok.begin());
            VmKey key(vm_uuid);
            if (agent_->vm_table()->Find(&key, true)) {
                continue;
            }
 
            ServiceInstance::Properties prop;
            prop.instance_id = vm_uuid;
            prop.service_type = ServiceInstance::SourceNAT;
            tokenizer::iterator next_tok = ++(tok.begin());
            //Loadbalancer namespace
            if (next_tok != tok.end()) {
                prop.loadbalancer_id = *next_tok;
                prop.service_type = ServiceInstance::LoadBalancer;
            }
 
            //Delete Namespace
            manager_->StopStaleNetNS(prop);
 
            //If Loadbalncer, delete the config files as well
            if (prop.service_type == ServiceInstance::LoadBalancer) {
                //Delete the complete directory
                std::stringstream pathgen;
                pathgen << manager_->loadbalancer_config_path_
                        << prop.loadbalancer_id << ".conf";
 
                boost::system::error_code error;
                if (fs::exists(pathgen.str())) {
                    fs::remove(pathgen.str(), error);
                    if (error) {
                        std::stringstream ss;
                        ss << "Stale loadbalancer cfg fle delete error ";
                        ss << error.message();
                        INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
                    }
                }
            }
        }
    }
 
private:
    Agent *agent_;
    InstanceManager *manager_;
};
 
InstanceManager::~InstanceManager() {
    TimerManager::DeleteTimer(stale_timer_);
    STLDeleteValues(&adapters_);
}
 
InstanceManager::InstanceManager(Agent *agent)
        : si_listener_(DBTableBase::kInvalidId),
          netns_timeout_(-1),
          work_queue_(TaskScheduler::GetInstance()->GetTaskId(INSTANCE_MANAGER_TASK_NAME), 0,
                      boost::bind(&InstanceManager::DequeueEvent, this, _1)),
          loadbalancer_config_path_(loadbalancer_config_path_default),
          namespace_store_path_(namespace_store_path_default),
          stale_timer_interval_(5 * 60 * 1000),
          stale_timer_(TimerManager::CreateTimer(*(agent->event_manager()->io_service()),
                      "NameSpaceStaleTimer", TaskScheduler::GetInstance()->
                      GetTaskId(INSTANCE_MANAGER_TASK_NAME), 0)), agent_(agent) {
          if (agent->isMockMode()) {
              loadbalancer_config_path_ = "/tmp/" + agent->AgentGUID()
              + loadbalancer_config_path_default;
              namespace_store_path_ = "/tmp/" +  agent->AgentGUID()
              + namespace_store_path_default;
          }
          work_queue_.set_name("Instance Manager");
 
}
 
void InstanceManager::Initialize(DB *database, const std::string &netns_cmd,
                                 const std::string &docker_cmd,
                                 const int netns_workers,
                                 const int netns_timeout) {
    DBTableBase *si_table = agent_->service_instance_table();
    assert(si_table);
    si_listener_ = si_table->Register(
        boost::bind(&InstanceManager::EventObserver, this, _1, _2));
 
    netns_cmd_ = netns_cmd;
    if (netns_cmd_.length() == 0) {
        LOG(ERROR, "NetNS path for network namespace command not specified "
                   "in the config file, the namespaces won't be started");
    }
    if (docker_cmd.length() == 0) {
        LOG(ERROR, "Path for Docker starter command not specified "
                   "in the config file, the Docker instances won't be started");
    }
 
    std::stringstream pathgen;
    pathgen << loadbalancer_config_path_;
    boost::filesystem::path dir(pathgen.str());
    boost::system::error_code error;
    boost::filesystem::create_directories(dir, error);
    if (error) {
        LOG(ERROR, "Falied to create Loadbalancer Directory " << pathgen.str());
    }
 
    adapters_.push_back(new DockerInstanceAdapter(docker_cmd, agent_));
    adapters_.push_back(new NetNSInstanceAdapter(netns_cmd,
                        loadbalancer_config_path_, agent_));
#ifdef WITH_LIBVIRT
    adapters_.push_back(new LibvirtInstanceAdapter(agent_,
                        "qemu:///system"));
#endif
 
    netns_timeout_ = kTimeoutDefault;
    if (netns_timeout >= 1) {
        netns_timeout_ = netns_timeout;
    }
 
    netns_reattempts_ = kReattemptsDefault;
 
    int workers = kWorkersDefault;
    if (netns_workers > 0) {
       workers = netns_workers;
    }
 
    task_queues_.resize(workers);
    for (std::vector<InstanceTaskQueue *>::iterator iter = task_queues_.begin();
         iter != task_queues_.end(); ++iter) {
        InstanceTaskQueue *task_queue =
                new InstanceTaskQueue(agent_->event_manager());
        assert(task_queue);
        task_queue->set_on_timeout_cb(
                        boost::bind(&InstanceManager::OnTaskTimeout,
                                    this, _1));
        *iter = task_queue;
    }
    stale_timer_->Start(StaleTimerInterval(),
                        boost::bind(&InstanceManager::StaleTimeout, this));
 
}
 
void InstanceManager::SetNetNSCmd(const std::string &netns_cmd) {
    ServiceInstance::Properties prop;
    prop.virtualization_type =
        ServiceInstance::ServiceInstance::NetworkNamespace;
    NetNSInstanceAdapter *adapter = static_cast<NetNSInstanceAdapter
        *>(FindApplicableAdapter(prop));
    if (adapter)
        adapter->set_cmd(netns_cmd);
}
 
void InstanceManager::SetStaleTimerInterval(int minutes) {
    stale_timer_interval_ = minutes * 60 * 1000;
}
 
void InstanceManager::OnTaskTimeout(InstanceTaskQueue *task_queue) {
    InstanceManagerChildEvent event;
    event.type = OnTaskTimeoutEvent;
    event.task_queue = task_queue;
 
    work_queue_.Enqueue(event);
}
 
void InstanceManager::OnTaskTimeoutEventHandler(InstanceManagerChildEvent event) {
    std::stringstream ss;
    ss << "TaskTimeOut for the TaskQ " << event.task_queue;
    INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
 
    ScheduleNextTask(event.task_queue);
}
 
void InstanceManager::OnErrorEventHandler(InstanceManagerChildEvent event) {
    ServiceInstance *svc_instance = GetSvcInstance(event.task);
    if (!svc_instance) {
       return;
    }
 
    std::stringstream ss;
    ss << "Error for the Task " << event.task << " " << event.errors;
    INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
 
    InstanceState *state = GetState(svc_instance);
    if (state != NULL) {
       state->set_errors(event.errors);
    }
}
 
void InstanceManager::OnExitEventHandler(InstanceManagerChildEvent event) {
    ServiceInstance *svc_instance = GetSvcInstance(event.task);
    if (!svc_instance) {
       return;
    }
 
    std::stringstream ss;
    ss << "Exit event for the Task " << event.task;
    INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
 
    UpdateStateStatusType(event);
    for (std::vector<InstanceTaskQueue *>::iterator iter =
                  task_queues_.begin();
          iter != task_queues_.end(); ++iter) {
         InstanceTaskQueue *task_queue = *iter;
         if (!task_queue->Empty()) {
             if (task_queue->Front() == event.task) {
                 task_queue->Pop();
                 delete event.task;
                 task_queue->StopTimer();
                 DeleteState(svc_instance);
                 ScheduleNextTask(task_queue);
                 return;
             }
         }
    }
 
}
 
bool InstanceManager::DequeueEvent(InstanceManagerChildEvent event) {
    if (event.type == OnErrorEvent) {
        OnErrorEventHandler(event);
    } else if (event.type == OnTaskTimeoutEvent) {
        OnTaskTimeoutEventHandler(event);
    } else if (event.type == OnExitEvent) {
        OnExitEventHandler(event);
    }
 
    return true;
}
 
void InstanceManager::UpdateStateStatusType(InstanceManagerChildEvent event) {
    ServiceInstance* svc_instance = UnregisterSvcInstance(event.task);
    if (svc_instance) {
        InstanceState *state = GetState(svc_instance);
 
        // The below code might not really capture the errors that
        // occured in the child process. As we are relying on the pipe
        // status to identify child exit, even if child process ends up
        // in error state, pipe might return "success" because pipe is
        // closed without erros. But what we want to reflect is the
        // error of child process. If there is any error in the pipe
        // status, we show that as is. If not, if there is any error string
        // in error_, we mark the error status as -1.
        // pipe returning boost::system::errc::no_such_file_or_directory
        // error is considered as no pipe errors
 
        if (state != NULL) {
            int error_status = event.error_val;
            if (error_status ==
                        boost::system::errc::no_such_file_or_directory) {
                error_status = 0;
            }
            if (!state->errors().empty()) {
                if (error_status == 0) {
                    error_status = -1;
                }
            }
 
            state->set_status(error_status);
 
            if (error_status != 0) {
                if (state->status_type() != InstanceState::Timeout) {
                    state->set_status_type(InstanceState::Error);
                }
            } else if (state->status_type() == InstanceState::Starting) {
                state->set_status_type(InstanceState::Started);
            } else if (state->status_type() == InstanceState::Stopping) {
                state->set_status_type(InstanceState::Stopped);
            }
 
            std::stringstream ss;
            ss << "For the task " << event.task << " error status " <<
                error_status << " status type " << state->status_type();
            INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
        }
    }
}
 
InstanceState *InstanceManager::GetState(ServiceInstance *svc_instance) const {
    return static_cast<InstanceState *>(
        svc_instance->GetState(agent_->service_instance_table(),
                               si_listener_));
}
 
InstanceState *InstanceManager::GetState(InstanceTask* task) const {
    ServiceInstance* svc_instance = GetSvcInstance(task);
    if (svc_instance) {
        InstanceState *state = GetState(svc_instance);
        return state;
    }
    return NULL;
}
 
void InstanceManager::SetState(ServiceInstance *svc_instance,
                                InstanceState *state) {
    svc_instance->SetState(agent_->service_instance_table(),
                           si_listener_,state);
}
 
void InstanceManager::ClearState(ServiceInstance *svc_instance) {
    svc_instance->ClearState(agent_->service_instance_table(), si_listener_);
}
 
bool InstanceManager::DeleteState(ServiceInstance *svc_instance) {
 
    if (!svc_instance || !svc_instance->IsDeleted()) {
        return false;
    }
 
    InstanceState *state = GetState(svc_instance);
    if (state && !state->tasks_running()) {
        ClearState(svc_instance);
        delete state;
        ClearLastCmdType(svc_instance);
        return true;
    }
 
    return false;
}
 
 
void InstanceManager::StateClear() {
    DBTablePartition *partition = static_cast<DBTablePartition *>(
        agent_->service_instance_table()->GetTablePartition(0));
 
    if (!partition)
        return;
 
    DBEntryBase *next = NULL;
    for (DBEntryBase *entry = partition->GetFirst(); entry; entry = next) {
        next = partition->GetNext(entry);
        DBState *state =
            entry->GetState(agent_->service_instance_table(), si_listener_);
        if (state != NULL) {
            entry->ClearState(agent_->service_instance_table(), si_listener_);
            delete state;
            ClearLastCmdType(static_cast<ServiceInstance *>(entry));
        }
    }
}
 
void InstanceManager::Terminate() {
    StateClear();
    agent_->service_instance_table()->Unregister(si_listener_);
    agent_->service_instance_table()->Clear();
 
    InstanceTaskQueue *task_queue;
    for (std::vector<InstanceTaskQueue *>::iterator iter = task_queues_.begin();
         iter != task_queues_.end(); ++iter) {
        if ((task_queue = *iter) == NULL) {
            continue;
        }
        task_queue->Clear();
 
        delete task_queue;
    }
    work_queue_.Shutdown();
}
 
void InstanceManager::Enqueue(InstanceTask *task,
                              const boost::uuids::uuid &uuid) {
    std::stringstream ss;
    ss << uuid;
    InstanceTaskQueue *task_queue = GetTaskQueue(ss.str());
    task_queue->Push(task);
    ScheduleNextTask(task_queue);
}
 
InstanceTaskQueue *InstanceManager::GetTaskQueue(const std::string &str) {
    boost::hash<std::string> hash;
    int index = hash(str) % task_queues_.size();
    return task_queues_[index];
}
 
//After Run(), if child process is running, we keep the task status as
//"Starting" or "Stopping". We start a timer to track TaskTimeout time.
//if process is not runnning, we verify how many times we already attempted
//to run. If netns_reattempts_ are already crossed, we return false,
// so that caller deletes the task without running any further.
//If required reattempts are not done, we start a timer and return true
// so that same task is run again after the timeout. The task status is set to
//"reattempt" to track reattempt case
bool InstanceManager::StartTask(InstanceTaskQueue *task_queue,
                                InstanceTask *task) {
 
 
    InstanceState *state = GetState(task);
    if (state) {
        state->reset_errors();
    }
 
    pid_t pid;
    bool status = task->Run();
 
    std::stringstream ss;
    ss << "Run status for the task " << task << " " << status;
    ss << " With running status " << task->is_running();
    INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
 
    if (status || task->is_running()) {
        pid = task->pid();
        if (state != NULL) {
            state->set_pid(pid);
            state->set_cmd(task->cmd());
            if (task->cmd_type() == Start) {
                state->set_status_type(InstanceState::Starting);
            } else {
                state->set_status_type(InstanceState::Stopping);
            }
        }
    } else {
 
        ss.str(std::string());
        ss << "Run failure for the task " << task << " attempt " << task->reattempts();
        INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
 
        if (state) {
            state->set_status_type(InstanceState::Reattempt);
            state->set_cmd(task->cmd());
        }
        if (task->incr_reattempts() > netns_reattempts_) {
            ss.str(std::string());
            ss << "Run failure for the task " << task << " attempts exceeded";
            INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
            return false;
        }
    }
 
    task_queue->StartTimer(netns_timeout_ * 1000);
 
    return true;
}
 
//If Starting the task succeds we wait for another event on that task.
//If not the task is removed from the front of the queue and is delted.
void InstanceManager::ScheduleNextTask(InstanceTaskQueue *task_queue) {
    while (!task_queue->Empty()) {
 
        InstanceTask *task = task_queue->Front();
        InstanceState *state = GetState(task);
 
        if (!task->is_running()) {
            bool status = StartTask(task_queue, task);
            if (status) {
                return;
            }
        } else {
            int delay = time(NULL) - task->start_time();
            if (delay < netns_timeout_) {
               return;
            }
            if (state) {
                state->set_status_type(InstanceState::Timeout);
            }
 
            std::stringstream ss;
            ss << "Timeout for the Task " << task << " delay " << delay;
            ss << " netns timeout " << netns_timeout_ << " ";
            ss << task->cmd();
            INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
 
            if (delay >= (netns_timeout_ * 2)) {
               task->Terminate();
               if (task->IsSetup())
                   return;
            } else {
               task->Stop();
               return;
            }
        }
 
        task_queue->StopTimer();
        task_queue->Pop();
 
        ServiceInstance* svc_instance = GetSvcInstance(task);
        if (state && svc_instance)
            state->decr_tasks_running();
 
        task_svc_instances_.erase(task);
 
        std::stringstream ss;
        ss << "Delete of the Task " << task;
        INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
 
        DeleteState(svc_instance);
 
        delete task;
    }
}
 
ServiceInstance *InstanceManager::GetSvcInstance(InstanceTask *task) const {
    TaskSvcMap::const_iterator iter =
                    task_svc_instances_.find(task);
    if (iter != task_svc_instances_.end()) {
        return iter->second;
    }
    return NULL;
}
 
void InstanceManager::RegisterSvcInstance(InstanceTask *task,
                                          ServiceInstance *svc_instance) {
    pair<TaskSvcMap::iterator, bool> result =
         task_svc_instances_.insert(std::make_pair(task, svc_instance));
    assert(result.second);
 
    InstanceState *state = GetState(svc_instance);
    assert(state);
    state->incr_tasks_running();
}
 
ServiceInstance *InstanceManager::UnregisterSvcInstance(InstanceTask *task) {
    for (TaskSvcMap::iterator iter =
                    task_svc_instances_.begin();
         iter != task_svc_instances_.end(); ++iter) {
        if (task == iter->first) {
            ServiceInstance *svc_instance = iter->second;
            InstanceState *state = GetState(svc_instance);
            assert(state);
            state->decr_tasks_running();
            task_svc_instances_.erase(iter);
            return svc_instance;
        }
    }
 
    return NULL;
}
 
void InstanceManager::UnregisterSvcInstance(ServiceInstance *svc_instance) {
 
    InstanceState *state = GetState(svc_instance);
    assert(state);
 
    TaskSvcMap::iterator iter =
        task_svc_instances_.begin();
    while(iter != task_svc_instances_.end()) {
        if (svc_instance == iter->second) {
            task_svc_instances_.erase(iter++);
            state->decr_tasks_running();
        } else {
            ++iter;
        }
    }
}
 
InstanceManagerAdapter* InstanceManager::FindApplicableAdapter(const ServiceInstance::Properties &props) {
    for (std::vector<InstanceManagerAdapter *>::iterator iter = adapters_.begin();
         iter != adapters_.end(); ++iter) {
         InstanceManagerAdapter *adapter = *iter;
        if (adapter != NULL && adapter->isApplicable(props)) {
            return adapter;
        }
    }
    return NULL;
}
 
void InstanceManager::StartServiceInstance(ServiceInstance *svc_instance,
                                 InstanceState *state, bool update) {
    const ServiceInstance::Properties &props = svc_instance->properties();
    InstanceManagerAdapter *adapter = this->FindApplicableAdapter(props);
    std::stringstream ss;
    if (adapter != NULL) {
        InstanceTask *task = adapter->CreateStartTask(props, update);
        if (task != NULL) {
            ss << "Starting the Task " << task << " " << task->cmd();
            ss << " for " << props.instance_id;
            INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
            task->set_on_data_cb(boost::bind(&InstanceManager::OnError,
                                              this, _1, _2));
            task->set_on_exit_cb(boost::bind(&InstanceManager::OnExit,
                        this, _1, _2));
            state->set_properties(props);
            RegisterSvcInstance(task, svc_instance);
            std::stringstream info;
            Enqueue(task, props.instance_id);
        } else {
            ss << "Error Starting the Task for " << props.instance_id;
            INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
        }
    } else {
        ss << "Unknown virtualization type " << props.virtualization_type;
        ss << " for " << svc_instance->ToString();
        INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
    }
}
 
 
void InstanceManager::StopServiceInstance(ServiceInstance *svc_instance,
                                InstanceState *state) {
    const ServiceInstance::Properties &props = state->properties();
    InstanceManagerAdapter *adapter = this->FindApplicableAdapter(props);
    std::stringstream ss;
    if (adapter != NULL) {
        InstanceTask *task = adapter->CreateStopTask(props);
        if (task != NULL) {
            ss << "Stopping the Task " << task << " " << task->cmd();
            ss << " for " << props.instance_id;
            INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
            task->set_on_data_cb(boost::bind(&InstanceManager::OnError,
                                              this, _1, _2));
            task->set_on_exit_cb(boost::bind(&InstanceManager::OnExit,
                        this, _1, _2));
            RegisterSvcInstance(task, svc_instance);
            std::stringstream info;
            Enqueue(task, props.instance_id);
        } else {
            std::stringstream ss;
            ss << "Error Stopping the Task for " << props.instance_id;
            INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
        }
    } else {
        ss << "Unknown virtualization type " << props.virtualization_type;
        ss << " for " << svc_instance->ToString();
        INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
    }
}
 
void InstanceManager::OnError(InstanceTask *task,
                              const std::string errors) {
 
    InstanceManagerChildEvent event;
    event.type = OnErrorEvent;
    event.task = task;
    event.errors = errors;
 
    work_queue_.Enqueue(event);
}
 
void InstanceManager::OnExit(InstanceTask *task,
                    const boost::system::error_code &ec) {
 
    InstanceManagerChildEvent event;
    event.type = OnExitEvent;
    event.task = task;
    event.error_val = ec.value();
 
    work_queue_.Enqueue(event);
}
 
void InstanceManager::StopStaleNetNS(ServiceInstance::Properties &props) {
    std::stringstream cmd_str;
 
    if (netns_cmd_.length() == 0) {
        return;
    }
    cmd_str << netns_cmd_ << " destroy";
 
    cmd_str << " " << props.ServiceTypeString();
    cmd_str << " " << UuidToString(props.instance_id);
    cmd_str << " " << UuidToString(boost::uuids::nil_uuid());
    cmd_str << " " << UuidToString(boost::uuids::nil_uuid());
    if (props.service_type == ServiceInstance::LoadBalancer) {
        if (props.loadbalancer_id.empty()) {
            LOG(ERROR, "loadbalancer id is missing for service instance: "
                        << UuidToString(props.instance_id));
            return;
        }
        cmd_str << " --loadbalancer-id " << props.loadbalancer_id;
    }
 
    std::string cmd = cmd_str.str();
    std::vector<std::string> argv;
    boost::split(argv, cmd, boost::is_any_of(" "), boost::token_compress_on);
    std::vector<const char *> c_argv(argv.size() + 1);
    for (std::size_t i = 0; i != argv.size(); ++i) {
        c_argv[i] = argv[i].c_str();
    }
 
    std::stringstream ss;
    ss << "StaleNetNS " << cmd;
    INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
 
    pid_t pid = vfork();
    if (pid == 0) {
        CloseTaskFds();
        execvp(c_argv[0], (char **) c_argv.data());
        perror("execvp");
 
        _exit(127);
    }
}
 
void InstanceManager::SetLastCmdType(ServiceInstance *svc_instance,
                                     int last_cmd_type) {
    std::string uuid = UuidToString(svc_instance->uuid());
    std::map<std::string, int>::iterator iter =
            last_cmd_types_.find(uuid);
    if (iter != last_cmd_types_.end()) {
        iter->second = last_cmd_type;
    } else {
        last_cmd_types_.insert(std::make_pair(uuid, last_cmd_type));
    }
}
 
int InstanceManager::GetLastCmdType(ServiceInstance *svc_instance) const {
    std::string uuid = UuidToString(svc_instance->uuid());
    std::map<std::string, int>::const_iterator iter =
        last_cmd_types_.find(uuid);
    if (iter != last_cmd_types_.end()) {
        return iter->second;
    }
 
    return 0;
}
 
void InstanceManager::ClearLastCmdType(ServiceInstance *svc_instance) {
    std::string uuid = UuidToString(svc_instance->uuid());
        std::map<std::string, int>::iterator iter =
            last_cmd_types_.find(uuid);
    if (iter != last_cmd_types_.end()) {
        last_cmd_types_.erase(iter);
    }
}
 
void InstanceManager::EventObserver(
    DBTablePartBase *db_part, DBEntryBase *entry) {
    ServiceInstance *svc_instance = static_cast<ServiceInstance *>(entry);
 
    InstanceState *state = GetState(svc_instance);
    if (svc_instance->IsDeleted()) {
        if (state) {
            if (GetLastCmdType(svc_instance) == Start) {
                StopServiceInstance(svc_instance, state);
                SetLastCmdType(svc_instance, Stop);
            }
            if (DeleteState(svc_instance)) {
                return;
            }
        }
        ClearLastCmdType(svc_instance);
    } else {
        if (state == NULL) {
            state = new InstanceState();
            SetState(svc_instance, state);
        }
 
        bool usable = svc_instance->IsUsable();
 
        std::stringstream ss;
        ss << "NetNS event notification for uuid: " << svc_instance->ToString();
        ss << (usable ? " usable" : " not usable");
        INSTANCE_MANAGER_TRACE(Trace, ss.str().c_str());
 
        if (!usable && GetLastCmdType(svc_instance) == Start) {
            StopServiceInstance(svc_instance, state);
            SetLastCmdType(svc_instance, Stop);
        } else if (usable) {
            if (GetLastCmdType(svc_instance) == Start && state->properties().CompareTo(
                            svc_instance->properties()) != 0) {
                StartServiceInstance(svc_instance, state, true);
            } else if (GetLastCmdType(svc_instance) != Start) {
                StartServiceInstance(svc_instance, state, false);
                SetLastCmdType(svc_instance, Start);
            }
        }
    }
}
 
bool InstanceManager::StaleTimeout() {
 
    if (stale_cleaner_.get())
        return false;
    stale_cleaner_.reset(new NamespaceStaleCleaner(agent_, this));
    stale_cleaner_->CleanStaleEntries();
    stale_cleaner_.reset(NULL);
    return false;
}
 
void InstanceManager::SetNamespaceStorePath(std::string path) {
    namespace_store_path_ = path;
}
 
/*
 * InstanceState class
 */
InstanceState::InstanceState() : DBState(),
        pid_(0), status_(0), status_type_(0), tasks_running_(0) {
}
 
void InstanceState::Clear() {
    pid_ = 0;
    status_ = 0;
    errors_.empty();
    cmd_.empty();
}