Auto-starting a custom service after DHCP server

HI Nithin patet,

yes we can register our own service to run as soon as the particular service is initialized by using sysevents.
Sysevent utility will activate respective handlers upon events.

syntax:
sysevent async event_name $HANDLER

example:
sysevent async new_event_name /etc/utopia/service.d/new_service_handler.sh

sysevent async ethwan-initialized /etc/utopia/service.d/service_crond.sh


Note:
1. Register for $HANDLER to be activated whenever <event_name> changes value. Ensure that if multiple value changes occur, then only one instance of $HANDLER will be run at a time.
sysevent async event_name $HANDLER

2. Register for $HANDLER to be activated whenever any value is SET for <event_name>
sysevent async event_name $HANDLER
sysevent setoptions event_name $TUPLE_FLAG_EVENT

The files with numbers(15_dhcp_server) is used because there is a execute_dir programs will execute all files in the sysevent registration directory  /etc/utopia/registration.d in lexicographic order. This is useful as the shell scripts should be called in certain order .


Thanks and Regards

Srinivas

HI Nitin Patet, 

We can either execute on the console or we can add it in the code. 
since you are invoking your application after  dhcp is getting initialized, you can find a place in the code where the dhcp initialization is done successfully and  then invoke your application

e.g,,  get the dhcp_server_status and then invoke your application
sysevent get dhcp_server-status  // started
sysevent async event_name $HANDLER


For your reference, you can refer the below files on how to use the sysevent async to invoke a service.
1. service_dhcp_server.sh
2. service_crond.sh

Thanks and Regards
Srinivas