Erlang application supervisor - manage application crashes
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Makefile Update README description Jan 27, 2015


HardCore was created with the idea of creating an Erlang system with a 'hardened core'.

The problem: you have an Erlang system with multiple applications, some of which may fail completely. The system should continue to function and respond to users even if some of those applications crash.

One way to handle this problem is by means of a "circuit breaker" like Fuse:

The Hardcore application takes another approach: rather than monitor a single service, it monitors an entire application.

How it works

Once started with application:start(hardcore), you can start other applications like so:


If you're working with a release, you'd want to start some applications under HardCore management like so, in your sys.config file:

{hardcore, [{apps, [YourApp,
                    {AnotherApp, {Module, Function, []}}]}]},


When an application stops or starts, we need to be able to act on that. By default, the hardcore_backoff_server module handles restarts with an exponential backoff strategy. Using the callback argument to hardcore:start, it's possible to pass in a tuple like

{hardcore_backoff_server, state_change, []}

With a module, function, and optional arguments. When the state changes to one of stopped or started, the function is called like so:

Module:Function(stopped | started, AppName, Args)

As in the example above, the callback can also be passed in as part of the config file.