From Rails to Erlyweb - Part II Manage Project - Reloaded

The migrating from Rails to Erlyweb of our project is going to be finished. I got more experience on how to deal with Erlyweb. First, the project management can be more straightforward. Here is it:

2. Manage project - Reloaded

Erlyweb provides erlyweb:compile(App, ..) to compile the source files under app directory. To start an app, you usually should erlydb:start(mysql, ....) and compile app files first. To make life easy, you can put some scripting like code under myproject\script directory. Here's my project source tree:

myproject
  + apps
  |   + myapp
  |       + ebin   
  |       + include
  |       + nbproject
  |       + src
  |           + components
  |           + lib
  |           + services
  |       + test
  |       + www
  + config
  |   * yaws.conf
  |   * erlyweb.conf
  + script
      + ebin
      + src
           * erlyweb_app.erl

Where, config/yaws.conf contains the yaws' configuration. Here's mine:

ebin_dir = D:/myapp/trunk/script/ebin

<server localhost>
	port = 8000
	listen = 0.0.0.0
	docroot = D:/myapp/trunk/apps/myapp/www
	appmods = </myapp, erlyweb>
        start_mod = erlyweb_app
	<opaque>
		appname = myapp
                environment = development
        </opaque>
</server>

You may have noticed, all beams under D:/myapp/trunk/script/ebin will be auto-loaded when yaws starts up. And you can prepare another yaws.conf for test or production environment by change the environment var in opaque

Now the config/erlyweb.conf:

{pa, ["script/ebin", 
      "apps/myapp/ebin", 
      "vendor/erlyweb/ebin", 
      "vendor/eunit/ebin"]}.

{i, ["vendor", 
     "apps/myapp/include",
     "/usr/local/lib/yaws"]}.

{production,  [{dbdriver, mysql},
               {database, "mydb_production"},
               {hostname, "localhost"}, 
               {username, "mememe"},
               {password, "pwpwpw"}]}.

{development, [{dbdriver, mysql},
               {database, "mydb_development"},
               {hostname, "localhost"}, 
               {username, "mememe"},
               {password, "pwpwpw"}]}.

{test,        [{dbdriver, mysql},
               {database, "mydb_test"},
               {hostname, "localhost"}, 
               {username, "mememe"},
               {password, "pwpwpw"}]}.

erlyweb_app.erl is the boot scripting code, which will be used to start db connection and compile the code. Currently I run these scripts manually. I'll talk later.

Notice: erlyweb 0.6.2 needed, which contains Haoboy's logfun patch.

%% @doc Main entrance to the entire erlyweb application.
-module(erlyweb_app).

-export([start/1]).

-export([get_conf/1,
         build/1,
         build_test/1, 
	 build_product/1,
	 environment/1,
	 decompile/2,
	 db_log/4,
	 db_dummy_log/4
        ]).

-include("yaws/include/yaws.hrl").
-include("yaws/include/yaws_api.hrl").

db_log(Module, Line, Level, FormatFun) ->
    mysql:log(Module, Line, Level, FormatFun).
db_dummy_log(_Mod, _Line, _Level, _FormatFun) ->
    empty.

%% @doc call back function when yaws start an app  
%% @see man yaws.conf
%%      start_mod = Module
%%          Defines  a  user  provided  callback  module.  At startup of the
%%          server, Module:start/1 will  be  called.   The  #sconf{}  record
%%          (defined  in  yaws.hrl) will be used as the input argument. This
%%          makes it possible for  a  user  application  to  syncronize  the
%%          startup  with  the  yaws  server as well as getting hold of user
%%          specific  configuration  data,  see  the  explanation  for   the
%%          

To build it,

> erlc -I /opt/local/lib/yaws/include erlyweb_app.erl -o ebin

The erlyweb_app.erl is almost escript ready, but I use it as module functions currently. It's pre-compiled and erlyweb_app.beam is placed under script/ebin

So, I start myapp by steps:

cd \myproject
yaws -sname myapp -i --conf config/yaws.conf --erlang "-smp auto"
1> erlyweb_app:build(myapp).

The erlyweb_app.erl is almost escript ready, but I use it as module functions currently. It's pre-compiled and erlyweb_app.beam is placed under script/ebin

After I made changes to myapp, I run above erlyweb_app:build(myapp). again, then everything is up to date.

And if you'd like to build it from another erl shell, try this:

erl -sname erlybird
(erlybird@myhost)1> rpc:call(myapp@myhost, erlyweb_app, build, [myapp])

Yes, next version of ErlyBird will support building erlyweb apps remotely in ErlyBird's Erlang shell.