Event directives

This page covers samb event directives. Syntax examples will be displayed for YAML and samb (.se) files. Each directive will have a table, the table will display the directive's name, type and parent. The parent of a directive specifies the directive it is nested in.

• Events
  • App start
  • App stop
  • Request panic

Events

Event directives allows users to have custom code run on pre-defined samb events.

App start

Event App start runs on application start. You can use this event to initialize the variables your application will use, this can be composed of database connections, flag variables, caches etc...

Directive name	Type	Parent
start	Go	Server

YAML sample :

...
  start:
    do:
      - println("HelloWorld")
      - println("Starting...")
...

.SE sample :

    start {
    	do println("HelloWorld");
    	do println("HelloWorld2");
    }

App stop

Event App stop runs on application exit. You can use this event to clean up the variables your application was using, this can be composed of closing database connections, clearing caches etc...

Directive name	Type	Parent
shutdown	Go	Server

YAML sample :

...
  shutdown:
    do:
      - println("HelloWorld")
      - println("Starting...")
...

.SE sample :

    shutdown {
    	do println("HelloWorld");
    	do println("HelloWorld2");
    }

Request panic

Event Request panic runs when a handler invokes builtin Go function panic, with a string as the only parameter. You can use this event to catch and process errors. You must generate the function responsible for handling a request panic. Use command samb-medic, provided in this repository, to generate a request panic (recovery) function. The generated function will have parameters:

• r : the current request
• w : response writer
• m : error string, supplied as a parameter to invocation of builtin function panic.

Directive name	Type	Parent
recover	Go	Server

YAML sample :

...
  recover:
    do:
	  # only specify function identifier,
	  # parameters will be appended.
      - jsonPanic
...

.SE sample :

    recover {
    	do jsonPanic;
    }