include simplemodule.app.src in simplemod template

[marianoguerra]

rebar fix

let's create a simple erlang module using rebar::

    # create module folder
    mkdir modulo

    # go to it
    cd modulo

    # download and set it to executable
    wget http://cloud.github.com/downloads/basho/rebar/rebar && chmod u+x rebar

    # create the module skeleton
    ./rebar create template=simplemod modid=modulo

now let's try to compile it::

    ➜  modulo  ./rebar compile
    ==> modulo (compile)
    ➜  modulo  tree
    .
    ├── rebar
    ├── src
    │   └── modulo.erl
    └── test
        └── modulo_tests.erl

        2 directories, 3 files

nothing happened :(

it seems something is missing, let's add the app.src file::

    ➜  modulo  vim src/modulo.app.src
    ➜  modulo  cat src/modulo.app.src
    {application, modulo, [
      {description, "super useful module."},
      {vsn, "0.0.1"},
      {env, []}
    ]}.

and try again::

    ➜  modulo  ./rebar compile
    ==> modulo (compile)
    Compiled src/modulo.erl
    ➜  modulo  tree
    .
    ├── ebin
    │   ├── modulo.app
    │   └── modulo.beam
    ├── rebar
    ├── src
    │   ├── modulo.app.src
    │   └── modulo.erl
    └── test
        └── modulo_tests.erl

    3 directories, 6 files

success!

then the simplemod template needs the app.src file to be complete.

let's try fixing that, first fork rebar from github.com/basho/rebar.

then clone it::

    git clone git@github.com:marianoguerra/rebar.git

    cd rebar

let's see where the templates are::

    ➜  rebar git:(master) find -name simplemod\*
    ./priv/templates/simplemod_tests.erl
    ./priv/templates/simplemod.erl
    ./priv/templates/simplemod.template

    ➜  rebar git:(master) cd priv/templates

now let's be a nice git citizen and create a branch for this fix::

    git checkout -b simplemod-app-src-missing

looking at the other templates they have a file like simpleapp.app.src

where simpleapp is the name of the template.

looking at the content::

    {application, {{appid}},
     [
      {description, ""},
      {vsn, "1"},
      {registered, []},
      {applications, [
                      kernel,
                      stdlib
                     ]},
      {mod, { {{appid}}_app, []}},
      {env, []}
     ]}.

seems to be a template were appid is the variable to be replaced, let's try
with that::

    # copy the file
    cp simpleapp.app.src simplemod.app.src
    # some sed spells
    sed -i 's/appid/modid/g' simplemod.app.src

let's see the content with cat simplemod.app.src::

    {application, {{modid}},
     [
      {description, ""},
      {vsn, "1"},
      {registered, []},
      {applications, [
                      kernel,
                      stdlib
                     ]},
      {mod, { {{modid}}_app, []}},
      {env, []}
     ]}.

and add the new file to the template definition::

    echo '{template, "simplemod.app.src", "src/{{modid}}.app.src"}.' >> simplemod.template

and see the new content::

    cat simplemod.template

    {variables, [{modid, "mymod"}]}.
    {template, "simplemod.erl", "src/{{modid}}.erl"}.
    {template, "simplemod_tests.erl", "test/{{modid}}_tests.erl"}.
    {template, "simplemod.app.src", "src/{{modid}}.app.src"}.

let's build the new version (inside the base rebar folder)::

    ./bootstrap

now let's try our new version::

    mkdir /tmp/modulo
    cp rebar /tmp/modulo
    cd /tmp/modulo

    ./rebar create template=simplemod modid=modulo

    ==> modulo (create)
    Writing src/modulo.erl
    Writing test/modulo_tests.erl
    Writing src/modulo.app.src

    ➜  modulo  ./rebar compile
    ==> modulo (compile)
    Compiled src/modulo.erl

    ➜  modulo  tree
    .
    ├── ebin
    │   ├── modulo.app
    │   └── modulo.beam
    ├── rebar
    ├── src
    │   ├── modulo.app.src
    │   └── modulo.erl
    └── test
        └── modulo_tests.erl

    3 directories, 6 files

success!

[marianoguerra]

complete formatted guide to the fix can be found here: https://github.com/marianoguerra/me/blob/master/guides/rebar-fix.rst

it includes the last git steps to commit and push the branch

[ghost]

This was meant to be used together with simpleapp.
Maybe we should reconsider some of the templates.
@dizzyd, @joewilliams thoughts?

[dizzyd]

Yes, we should reconsider the templates, I think. However, this specific PR will be closed, since the point of simple mod is to provide a module, not a full app.