Following rebar instructions in section-2 branch results in error

[quantumproducer]

Following section 2 instructions.

RROR: generate failed while processing /Users/quantum/code/cowboy_tutorial_webchat/rel: {'EXIT',{{badmatch,{error,"appmon: Missing application directory."}},
         [{rebar_reltool,generate,2,
                         [{file,"src/rebar_reltool.erl"},{line,53}]},
          {rebar_core,run_modules,4,[{file,"src/rebar_core.erl"},{line,493}]},
          {rebar_core,execute,6,[{file,"src/rebar_core.erl"},{line,418}]},
          {rebar_core,maybe_execute,8,
                      [{file,"src/rebar_core.erl"},{line,302}]},
          {rebar_core,process_dir1,7,[{file,"src/rebar_core.erl"},{line,261}]},
          {rebar_core,process_each,5,[{file,"src/rebar_core.erl"},{line,351}]},
          {rebar_core,process_dir1,7,[{file,"src/rebar_core.erl"},{line,253}]},
          {rebar_core,process_commands,2,
                      [{file,"src/rebar_core.erl"},{line,93}]}]}}
~/code/cowboy_tutorial_webchat:.

[hcs42]

Since this tutorial was written, the appmon application has been removed from Erlang. It can be replaced with observer.

These steps might help:

• Delete the "{app, gs, [{incl_cond, include}]}" and "{app, observer,
  [{incl_cond, include}]}" lines from reltool.config and add a "{app, observer,
  [{incl_cond, include}]}" line instead. (So that we use observer instead of
  appmon.)
• Change the {incl_cond, exclude} line to {incl_cond, derived}, so that the
  dependencies of observer are automatically calculated.

Nowadays even rebar is being replaced by its newer version (http://www.rebar3.org/).

[fiodinggo]

{sys, [
{lib_dirs, ["../apps", "../deps"]},
{erts, [{mod_cond, derived}, {app_file, strip}]},
{app_file, strip},
{rel, "chat", "1",
[
kernel,
gs,
stdlib,
sasl,
runtime_tools,
crypto,
mimetypes,
ranch,
cowboy,
chat
]},
{rel, "start_clean", "",
[
kernel,
stdlib
]},
{boot_rel, "chat"},
{profile, embedded},
{incl_cond, exclude},
{excl_archive_filters, ["."]}, %% Do not archive built libs
{excl_sys_filters, ["^bin/.", "^erts./bin/(dialyzer|typer)",
"^erts./(doc|info|include|lib|man|src)"]},
{excl_app_filters, [".gitignore"]},
{app, sasl, [{incl_cond, include}]},
{app, stdlib, [{incl_cond, include}]},
{app, kernel, [{incl_cond, include}]},
{app, gs, [{incl_cond, include}]},
{app, runtime_tools, [{incl_cond, include}]},
{app, crypto, [{incl_cond, include}]},
{app, mimetypes, [{incl_cond, include}]},
{app, ranch, [{incl_cond, include}]},
{app, cowboy, [{incl_cond, include}]},
{app, chat, [{incl_cond, include}]}
]}.

{target_dir, "chat"}.

{overlay, [
{mkdir, "log/sasl"},
{copy, "files/erl", "{{erts_vsn}}/bin/erl"},
{copy, "files/nodetool", "{{erts_vsn}}/bin/nodetool"},
{copy, "files/chat", "bin/chat"},
{copy, "files/chat.cmd", "bin/chat.cmd"},
{copy, "files/start_erl.cmd", "bin/start_erl.cmd"},
{copy, "files/install_upgrade.escript", "bin/install_upgrade.escript"},
{copy, "files/sys.config", "releases/{{rel_vsn}}/sys.config"},
{copy, "files/vm.args", "releases/{{rel_vsn}}/vm.args"}
]}.