simnode_config

#!/usr/bin/env escript

main([]) ->
    try
        {ok,DefaultDirName}=file:get_cwd(),
        Id = input_int("Please enter a node number", 1,99),
        NodeName = input("Please enter a node name", make_nodename(Id) ),
        Cookie = input("Please enter a network cookie", "oreo" ),
        DirName = input("Please enter a directory name", DefaultDirName ),
        file_substitute(filename:join(["priv","templates","simnode.config.template"]),
            filename:join(["config","sys.config"]),
            [{"$$PROJECT_HOME$$",DirName},
            {"$$NODE_ID$$",integer_to_list(Id)}]),
        file_substitute(filename:join(["priv","templates","simnode.args.template"]),
            filename:join(["config","vm.args"]),
            [{"$$NODE_NAME$$",NodeName},{"$$COOKIE$$",Cookie}])
    catch
        _:_ ->
            usage()
    end;
main(_) ->
    usage().

usage() ->
    io:format("usage: mqtt_config <project_home_prefix>~n"),
    halt(1).

find_hostname()->
    {ok,Hostname}=inet:gethostname(),
    {ok,{hostent,_RealHostname,_,inet,4,[A|_]}}=inet_res:gethostbyname(Hostname),
    {ok,{hostent,VerifiedHostName,_,inet,4,_}}=inet_res:gethostbyaddr(A),
    VerifiedHostName.

make_nodename(Id)->
    "simnode" ++ integer_to_list(Id) ++ "@" ++ find_hostname().

replace([],FinalBlob)->
    FinalBlob;
replace([{Variable,Value}|T],Blob) when is_integer(Value)->
    replace(T,string:replace(Blob,Variable,integer_to_list(Value),all));
replace([{Variable,Value}|T],Blob) when is_list(Value)->
    replace(T,string:replace(Blob,Variable,Value,all)).

file_substitute(FileNameIn,FileNameOut,VariableList)->
    {ok,FileBin}=file:read_file(FileNameIn),
    FileBlob=binary_to_list(FileBin),
    NewBlob=replace(VariableList,FileBlob),
    file:write_file(FileNameOut,list_to_binary(NewBlob)).

input_int(Prompt,Min,Max)->
    InputData=string:trim(io:get_line( Prompt ++ "(" ++ integer_to_list(Min) ++ ".." ++ integer_to_list(Max) ++ ") [" ++ integer_to_list(Min) ++ "] :")),
    case InputData=="" of
        true ->
            Min;
        false ->
            D = string:trim(InputData),
            try
                I = list_to_integer(D),
                case ((I >= Min) and (I =< Max)) of
                    true ->
                        I;
                    false ->
                        io:format("Must be a number between ~p and ~p.~n",[Min,Max]),
                        input_int(Prompt,Min,Max)
                end
            catch
                _:_ ->
                    io:format("Must be a number between ~p and ~p.~n",[Min,Max]),
                    input_int(Prompt,Min,Max)
            end
    end.

input(Prompt,Default)->
    InputData=string:trim(io:get_line( Prompt ++ " [" ++ Default ++ "] :")),
    case InputData=="" of
        true -> Default;
        false -> InputData
    end.