Handling OS signals

Default behavior

• SIGINT - return trace
• SIGTERM, SIGQUIT - shutdown service
• SIGUSR1 - reopen file descriptors for log (logrotate)

User behavior

The component os_signals::ProcessorComponent stores os_signals::Processor and listens to SIGUSR1 and SIGUSR2 signals. You can use AddListener function to subscribe to these signals.

For example, we use signal SIGUSR1 in components::Logging for reopening files after executing logrotate.

Example

1. Add in private field class

   os_signals::Subscriber signal_subscribe_

2. In in the component's constructor, register a signal listener. For example, components::Logging uses the following code:

   Logging::Logging(const ComponentConfig& config, const ComponentContext& context)
       : alert_storage_(context.FindComponent<alerts::StorageComponent>().GetStorage()),
         signal_subscriber_(context.FindComponent<os_signals::ProcessorComponent>()
                                .Get()
                                .AddListener(this, kName, os_signals::kSigUsr1, &Logging::OnLogRotate))

3. In the component's destructor, unsubscribe from the signal

    
       signal_subscriber_.Unsubscribe();
    

---

⇦ Controlling DNS | Deadline propagation ⇨