Improve Inventory::SyncLoop to Avoid Blocking Agent Stop

[cborla]

Description

The current implementation of the Inventory::SyncLoop function in the Inventory module may cause unnecessary delays during the agent shutdown process. Specifically, the Scan() method is called after the stop condition (m_stopping) is triggered, leading to potential delays if Scan() is a time-consuming operation.

Problem Details

• The Scan() function is executed after the condition variable (m_cv.wait_for) returns, even if m_stopping is true.
• This behavior delays the shutdown of the agent when Scan() involves intensive operations or long-running tasks.
• This could lead to poor user experience during shutdown and inefficient resource handling.

Steps to Reproduce

• Start the agent with the Inventory module enabled.
• Trigger a stop request for the agent while SyncLoop is running.
• Observe that Scan() executes even after the stop request, delaying the shutdown.

Proposed Solution

Update the SyncLoop function to verify the m_stopping condition after the wait operation and before calling Scan(). This ensures that no unnecessary Scan() operation is performed after a stop request is issued.

Option

void Inventory::SyncLoop()
{
    LogInfo("Module started.");

    if (m_scanOnStart && !m_stopping)
    {
        Scan();
    }

    while (!m_stopping)
    {
        {
            std::unique_lock<std::mutex> lock{m_mutex};
            m_cv.wait_for(lock,
                std::chrono::milliseconds{m_intervalValue}, [&]() { return m_stopping; });
        }

        if (!m_stopping)
        {
            Scan();
        }
    }
    std::unique_lock<std::mutex> lock{m_mutex};
    m_spDBSync.reset(nullptr);
}

[jr0me]

As a note for when this issue goes into development, the first scan

    if (m_scanOnStart && !m_stopping)
    {
        Scan();
    }

Can happen while another threads calls Stop() on the Inventory, perhaps this scan should also try to capture the mutex before checking m_stopping, and block the Stop call until the scan finishes.