paulperegud / confetti

Erlang configuration provider / application:get_env/2 on steroids

Confetti

Confetti is configuration provider for your Erlang applications.

Basically it's application:get_env/2 on steroids.

Features

1. Management console (accessible via telnet) - maintenance department will love you for this:

   • Configuration reload in runtime (designated processes receive notifications on reload)

   • Easily extensible with your own management commands (plugins!)

   • (TODO) broadcast working configuration across the Erlang cluster

      ![Confetti management console](http://mtod.org/assets/c3/w92p4radk4wg8.png)
     

2. Configuration supervision:

   • Increase your system's uptime - previous working configuration is DETS-cached in case someone messes up the configuration files

   • Broken config for process_a can not break process_b

     

3. Easy to use

   application:start(confetti).

   then

   %% your process
   %% (...)
   init([]) ->
       confetti:use(my_foo),   %% reads configuration terms
                               %% from "conf/my_foo.conf",
                               %% spawns new configuration provider
                               %% if needed...
   
       confetti:fetch(my_foo),  %% fetches the configuration terms
       {ok, #state{}}.
   
   %% (...)
   %% react to configuration changes
   handle_info({config_reloaded, NewConf}, State) -> (...)

4. Customizable

   • Write configuration validators and more:

     confetti:use(foo, [
         %% Specify config file location
         {location, {"conf/bar", "foo.cnf"},
     
         %% Make sure it's more than just correct Erlang term
         %% or even transform the terms into something!
         %% Validator funs should accept Config and return {ok, NewConf}
         %% on success, error otherwise.
         {validators, [fun validate_foo_config/1]},
     
         %% ignore notifications for current process
         {subscribe, false}
     ]).

   • Expose any module via the management console:

     -module(my_commands).
     export([foo/1, foo/3]).
     
     foo(help) ->
         "Foo does bar two times!".
     foo(Param1, Param2, Param3) ->
         %% perform command logic
         "bar bar".

     Let confetti know about it:

     %% conf/mgmt_conf.conf
     {port, 50000}.
     {plugins, [my_commands]}.

     Assuming your application is already running, perform live management configruation reload:

     $ telnet localhost 50000
     
     ...
     
     (nonode@nohost)> reload mgmt_conf
     ok
     

   • Provide your own welcome screen to the management console, i.e.:

     $ figlet MyApp > priv/helo.txt
     

Try it out quickly

1. Obtain the source code
2. rebar compile; erl -pa ebin -boot start_sasl -s confetti_app
3. 1> example_srv:start_link().
4. telnet localhost 50000
5. Type help for available commands, and help COMMAND for command usage details.

License

BSD License. See LICENSE file for details.

Authors

Adam Rutkowski <[email protected]>

Contribute!

Feel encouraged to spot bugs/poor code and implement new sexy features.

Also, make sure, you add yourself to the authors where appropriate! Thanks.