echoteam / app_status

APP STATUS

The erlang library provides dependency tree with notifications useful for controlling of load process.

Example usage:

    app1:start() ->
        app_status:init(app1),
        % ... some init
        % ... 
        app_status:ready(app1).

    app2:start() ->
        ok = app_status:expect(app2, app1), % will wait for app1 ready up to 5m
        % ... some another init
        app_status:ready(app2).

APP STATUS does not stick to the OTP-application name, you could use any arbitrary term:

    app_status:dead({some_application, instance666}).

Every application could be in several states: init, ready and not_seen. You should manually change state of the applications by calling one of app_status:{init,ready,dead}/1. You could switch the application state many times if you need.

Every application could have dependencies. You could specify one or many by calling:

    app_status:expect(my_application, [dep1, dep2, dep3]).

If the application have unready dependencies (e.g. app_status:get_status(dep1) is not ready) then it goes to the special waiting state: app_status:get_status(my_application) is {waiting, [dep1]}.

APP STATUS also supports notifications via app_status:notify/1 functions.

    app_status:notify(my_application).

This statement will send message {app_status, my_application, NewStatus} to the Pid2 every time when my_application will switch from the ready state to another and back.

There are functions app_status:wait/{1,2} whose syncronically waits for some specified application will not be in status {waiting, ...}.

In order to obtain more information please refer the source code.