[erlang-patches] add application:start_all/1-2 (recursive OTP app starting)

Siri Hansen <>
Thu Jul 11 09:22:28 CEST 2013

Hi Fred!

OTP technical board has discussed your patch and we find the functionality
useful. We would, however, like to see some adjustments:

1. Since the function behaves more like application:ensure_started/1,2 than
application:start/1,2 we would like the new name to be

2. On failure, the current implementation potentially leaves one or more
applications started. We would like it to clean up after itself in this

3. On success, we would like the function to return {ok,StartedApps}, where
StartedApps is the list of applications (names) that were actually started.

Would it be possible for you to update the patch accordingly?

Thanks for your contribution!

2013/6/24 Fredrik <>

> On 06/20/2013 08:16 PM, Fred Hebert wrote:
>> This adds two new functions to the application module that will
>> recursively look for missing dependencies to start the entire dependency
>> chain of a given application, and then the application itself, if
>> possible.
>> Its entire behavior is based on the currently existing 'start/1-2'
>> functions, which will report dependencies that have not yet been started
>> and other problems encountered. 'start_all/1-2' will use this
>> information the way any programmer would manually do it to automate the
>> process.
>> This kind of functionality, while not OTP-ish (releases do this start
>> sequence for the user), is still useful for testing purposes, quick
>> demonstrations, and programmers who do not wish or know how to use OTP
>> releases.
>> The function returns 'ok' for all started or already started
>> applications, and will return '{error, {AppName, Reason}}' on a failure
>> to allow users to rapidly know why the function failed.
>> I decided to call it start_all even though its semantics are somewhat
>> similar to ensure_start in how it ignores already_started applications,
>> but am open to changing the name if the OTP team prefers
>> 'ensure_all/1-2' as functions for this module.
>> Documentation has been added, and so were tests, looking for a few
>> simple case: simple app, app with a dependency, and apps with a
>> 3rd-level dependency not booting, all locally.
>> Note that no specific check is made for direct or indirect circular
>> dependencies between applications, and these will make the function go
>> in an infinite loop.
>> git fetch git://github.com/ferd/otp.git start-all
>> https://github.com/ferd/otp/**compare/erlang:maint...start-**all<https://github.com/ferd/otp/compare/erlang:maint...start-all>
>> https://github.com/ferd/otp/**compare/erlang:maint...start-**all.patch<https://github.com/ferd/otp/compare/erlang:maint...start-all.patch>
>> Regards,
>> Fred Hebert.
>> ______________________________**_________________
>> erlang-patches mailing list
>> http://erlang.org/mailman/**listinfo/erlang-patches<http://erlang.org/mailman/listinfo/erlang-patches>
> Hello Fred,
> I've fetched your patch and assigned it to be reviewed.
> Thanks,
> --
> BR Fredrik Gustafsson
> Erlang OTP Team
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> http://erlang.org/mailman/**listinfo/erlang-patches<http://erlang.org/mailman/listinfo/erlang-patches>
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