rebar3/src/rebar_templater.erl

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2021-12-27 19:09:21 +00:00
%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ts=4 sw=4 et
%% -------------------------------------------------------------------
%%
%% rebar: Erlang Build Tools
%%
%% Copyright (c) 2009 Dave Smith (dizzyd@dizzyd.com)
%%
%% Permission is hereby granted, free of charge, to any person obtaining a copy
%% of this software and associated documentation files (the "Software"), to deal
%% in the Software without restriction, including without limitation the rights
%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
%% copies of the Software, and to permit persons to whom the Software is
%% furnished to do so, subject to the following conditions:
%%
%% The above copyright notice and this permission notice shall be included in
%% all copies or substantial portions of the Software.
%%
%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
%% THE SOFTWARE.
%% -------------------------------------------------------------------
-module(rebar_templater).
-export([new/4,
list_templates/1,
render/2]).
-ifdef(TEST).
-export([consult_template/3]).
-endif.
-include("rebar.hrl").
-define(TEMPLATE_RE, "^(?!\\._).*\\.template\$").
%% ===================================================================
%% Public API
%% ===================================================================
%% Apply a template
new(Template, Vars, Force, State) ->
{AvailTemplates, Files} = find_templates(State),
?DEBUG("Looking for ~p", [Template]),
case lists:keyfind(Template, 1, AvailTemplates) of
false -> {not_found, Template};
TemplateTup -> create(TemplateTup, Files, Vars, Force, State)
end.
%% Give a list of templates with their expanded content
list_templates(State) ->
{AvailTemplates, Files} = find_templates(State),
[list_template(Files, Template, State) || Template <- AvailTemplates].
%% ===================================================================
%% Internal Functions
%% ===================================================================
%% Expand a single template's value
list_template(Files, {Name, Type, File}, State) ->
case consult_template(Files, Type, File) of
{error, Reason} ->
{error, {consult, File, Reason}};
TemplateTerms ->
{Name, Type, File,
get_template_description(TemplateTerms),
get_template_vars(TemplateTerms, State)}
end.
%% Load up the template description out from a list of attributes read in
%% a .template file.
get_template_description(TemplateTerms) ->
case lists:keyfind(description, 1, TemplateTerms) of
{_, Desc} -> Desc;
false -> undefined
end.
%% Load up the variables out from a list of attributes read in a .template file
%% and return them merged with the globally-defined and default variables.
get_template_vars(TemplateTerms, State) ->
Vars = case lists:keyfind(variables, 1, TemplateTerms) of
{_, Value} -> Value;
false -> []
end,
override_vars(Vars, override_vars(global_variables(State), default_variables())).
%% Provide a way to merge a set of variables with another one. The left-hand
%% set of variables takes precedence over the right-hand set.
2022-01-08 14:36:34 +00:00
%% In the case where left-hand variable description contains overridden defaults, but
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%% the right-hand one contains additional data such as documentation, the resulting
%% variable description will contain the widest set of information possible.
override_vars([], General) -> General;
override_vars([{Var, Default} | Rest], General) ->
case lists:keytake(Var, 1, General) of
{value, {Var, _Default, Doc}, NewGeneral} ->
[{Var, Default, Doc} | override_vars(Rest, NewGeneral)];
{value, {Var, _Default}, NewGeneral} ->
[{Var, Default} | override_vars(Rest, NewGeneral)];
false ->
[{Var, Default} | override_vars(Rest, General)]
end;
override_vars([{Var, Default, Doc} | Rest], General) ->
[{Var, Default, Doc} | override_vars(Rest, lists:keydelete(Var, 1, General))].
%% Default variables, generated dynamically.
default_variables() ->
{DefaultAuthor, DefaultEmail} = default_author_and_email(),
{{Y,M,D},{H,Min,S}} = calendar:universal_time(),
[{date, lists:flatten(io_lib:format("~4..0w-~2..0w-~2..0w",[Y,M,D]))},
{datetime, lists:flatten(io_lib:format("~4..0w-~2..0w-~2..0wT~2..0w:~2..0w:~2..0w+00:00",[Y,M,D,H,Min,S]))},
{author_name, DefaultAuthor},
{author_email, DefaultEmail},
{copyright_year, integer_to_list(Y)},
{apps_dir, "apps", "Directory where applications will be created if needed"}].
default_author_and_email() ->
%% See if we can get a git user and email to use as defaults
case rebar_utils:sh("git config --global user.name", [return_on_error]) of
{ok, Name} ->
case rebar_utils:sh("git config --global user.email", [return_on_error]) of
{ok, Email} ->
{rebar_string:trim(Name, both, "\n"),
rebar_string:trim(Email, both, "\n")};
{error, _} ->
%% Use neither if one doesn't exist
{"Anonymous", "anonymous@example.org"}
end;
{error, _} ->
%% Ok, try mecurial
case rebar_utils:sh("hg showconfig ui.username", [return_on_error]) of
{ok, NameEmail} ->
case re:run(NameEmail, "^(.*) <(.*)>$", [{capture, [1,2], list}, unicode]) of
{match, [Name, Email]} ->
{Name, Email};
_ ->
{"Anonymous", "anonymous@example.org"}
end;
{error, _} ->
{"Anonymous", "anonymous@example.org"}
end
end.
%% Load variable definitions from the 'Globals' file in the home template
%% directory
global_variables(State) ->
GlobalFile = rebar_dir:template_globals(State),
case file:consult(GlobalFile) of
{error, enoent} -> [];
{ok, Data} -> proplists:get_value(variables, Data, [])
end.
%% drop the documentation for variables when present
drop_var_docs([]) -> [];
drop_var_docs([{K,V,_}|Rest]) -> [{K,V} | drop_var_docs(Rest)];
drop_var_docs([{K,V}|Rest]) -> [{K,V} | drop_var_docs(Rest)].
%% Load the template index, resolve all variables, and then execute
%% the template.
create({Template, Type, File}, Files, UserVars, Force, State) ->
TemplateTerms = consult_template(Files, Type, File),
Vars0 = drop_var_docs(override_vars(UserVars, get_template_vars(TemplateTerms, State))),
Vars = maybe_handle_author_name(Vars0),
maybe_warn_about_name(Vars),
TemplateCwd = filename:dirname(File),
Result = execute_template(TemplateTerms, Files, {Template, Type, TemplateCwd}, Vars, Force),
maybe_print_final_message(proplists:get_value(message, TemplateTerms, undefined), Vars),
Result.
maybe_handle_author_name(Vars) ->
case lists:keyfind(author_name, 1, Vars) of
false -> Vars;
{author_name, Name0} ->
Name1 = unicode:characters_to_binary(Name0),
lists:keyreplace(author_name, 1, Vars, {author_name, Name1})
end.
maybe_print_final_message(undefined, _) ->
ok;
maybe_print_final_message(Message, Values) ->
io:format("~s~n", [render(Message, Values)]).
maybe_warn_about_name(Vars) ->
Name = proplists:get_value(name, Vars, "valid"),
case validate_atom(Name) of
invalid ->
?WARN("The 'name' variable is often associated with Erlang "
"module names and/or file names. The value submitted "
"(~ts) isn't an unquoted Erlang atom. Templates "
"generated may contain errors.",
[Name]);
valid ->
ok
end.
maybe_warn_about_name_clash(File) ->
case filename:extension(File) of
".erl" ->
Module0 = re:replace(filename:basename(File), "\\.erl$", "", [{return, list}]),
Module = list_to_atom(Module0),
try Module:module_info() of
_ -> ?WARN("The module definition of '~ts' in file ~ts "
"will clash with an existing Erlang module.",
[Module, File])
catch
_:_ -> ok
end;
_ -> ok
end.
validate_atom(Str) ->
case io_lib:fread("~a", unicode:characters_to_list(Str)) of
{ok, [Atom], ""} ->
case io_lib:write_atom(Atom) of
"'" ++ _ -> invalid; % quoted
_ -> valid % unquoted
end;
_ ->
invalid
end.
%% Run template instructions one at a time.
execute_template([], _, {Template,_,_}, _, _) ->
?DEBUG("Template ~ts applied", [Template]),
ok;
%% We can't execute the description
execute_template([{description, _} | Terms], Files, Template, Vars, Force) ->
execute_template(Terms, Files, Template, Vars, Force);
%% We can't execute variables
execute_template([{variables, _} | Terms], Files, Template, Vars, Force) ->
execute_template(Terms, Files, Template, Vars, Force);
%% We can't execute message
execute_template([{message, _} | Terms], Files, Template, Vars, Force) ->
execute_template(Terms, Files, Template, Vars, Force);
%% Create a directory
execute_template([{dir, Path} | Terms], Files, Template, Vars, Force) ->
?DEBUG("Creating directory ~p", [Path]),
case ec_file:mkdir_p(expand_path(Path, Vars)) of
ok ->
ok;
{error, Reason} ->
?ABORT("Failed while processing template instruction "
"{dir, ~p}: ~p", [Path, Reason])
end,
execute_template(Terms, Files, Template, Vars, Force);
%% Change permissions on a file
execute_template([{chmod, File, Perm} | Terms], Files, Template, Vars, Force) ->
Path = expand_path(File, Vars),
case file:change_mode(Path, Perm) of
ok ->
execute_template(Terms, Files, Template, Vars, Force);
{error, Reason} ->
?ABORT("Failed while processing template instruction "
"{chmod, ~.8#, ~p}: ~p", [Perm, File, Reason])
end;
%% Create a raw untemplated file
execute_template([{file, From, To} | Terms], Files, {Template, Type, Cwd}, Vars, Force) ->
?DEBUG("Creating file ~p", [To]),
In = expand_path(From, Vars),
Data = load_file(Files, Type, filename:join(Cwd, In)),
Out = expand_path(To,Vars),
case write_file(Out, Data, Force) of
ok -> ok;
{error, exists} -> ?INFO("File ~p already exists.", [Out])
end,
execute_template(Terms, Files, {Template, Type, Cwd}, Vars, Force);
%% Operate on a django template
execute_template([{template, From, To} | Terms], Files, {Template, Type, Cwd}, Vars, Force) ->
?DEBUG("Executing template file ~p", [From]),
In = expand_path(From, Vars),
Out = expand_path(To, Vars),
Tpl = load_file(Files, Type, filename:join(Cwd, In)),
maybe_warn_about_name_clash(Out),
case write_file(Out, render(Tpl, Vars), Force) of
ok ->
ok;
{error, exists} ->
?INFO("File ~p already exists", [Out])
end,
execute_template(Terms, Files, {Template, Type, Cwd}, Vars, Force);
%% Unknown
execute_template([Instruction|Terms], Files, Tpl={Template,_,_}, Vars, Force) ->
?WARN("Unknown template instruction ~p in template ~ts",
[Instruction, Template]),
execute_template(Terms, Files, Tpl, Vars, Force).
%% Workaround to allow variable substitution in path names without going
%% through the ErlyDTL compilation step. Parse the string and replace
%% as we go.
expand_path([], _) -> [];
expand_path("{{"++Rest, Vars) -> replace_var(Rest, [], Vars);
expand_path([H|T], Vars) -> [H | expand_path(T, Vars)].
%% Actual variable replacement.
replace_var("}}"++Rest, Acc, Vars) ->
Var = lists:reverse(Acc),
Val = proplists:get_value(list_to_atom(Var), Vars, ""),
Val ++ expand_path(Rest, Vars);
replace_var([H|T], Acc, Vars) ->
replace_var(T, [H|Acc], Vars).
%% Load a list of all the files in the escript and on disk
find_templates(State) ->
DiskTemplates = find_disk_templates(State),
PluginTemplates = find_plugin_templates(State),
{MainTemplates, Files} =
case rebar_state:escript_path(State) of
undefined -> % running in local install
{find_localinstall_templates(State), []};
_ ->
%% Cache the files since we'll potentially need to walk it several times
%% over the course of a run.
F = cache_escript_files(State),
{find_escript_templates(F), F}
end,
AvailTemplates = find_available_templates([MainTemplates,
PluginTemplates,
DiskTemplates]),
?DEBUG("Available templates: ~p\n", [AvailTemplates]),
{AvailTemplates, Files}.
find_available_templates(TemplateListList) ->
AvailTemplates = prioritize_templates(TemplateListList),
?DEBUG("Available templates: ~p\n", [AvailTemplates]),
AvailTemplates.
prioritize_templates([TemplateList]) ->
tag_names(TemplateList);
prioritize_templates([TemplateList | TemplateListList]) ->
prioritize_templates(tag_names(TemplateList),
prioritize_templates(TemplateListList)).
%% Scan the current escript for available files
cache_escript_files(State) ->
{ok, Files} = rebar_utils:escript_foldl(
fun(Name, _, GetBin, Acc) ->
[{Name, GetBin()} | Acc]
end,
[], rebar_state:escript_path(State)),
Files.
%% Find all the template indexes hiding in the rebar3 escript.
find_escript_templates(Files) ->
[{escript, Name}
|| {Name, _Bin} <- Files,
re:run(Name, ?TEMPLATE_RE, [{capture, none}, unicode]) == match].
find_localinstall_templates(_State) ->
Templates = rebar_utils:find_files(code:priv_dir(rebar), ?TEMPLATE_RE),
%% Pretend we're still running escripts; should work transparently.
[{builtin, F} || F <- Templates].
%% Fetch template indexes that sit on disk in the user's HOME
find_disk_templates(State) ->
OtherTemplates = find_other_templates(State),
HomeFiles = rebar_utils:find_files(rebar_dir:template_dir(State),
?TEMPLATE_RE, true), % recursive
[{file, F} || F <- OtherTemplates ++ HomeFiles].
%% Fetch template indexes that sit on disk in custom areas
find_other_templates(State) ->
case rebar_state:get(State, template_dir, undefined) of
undefined ->
[];
TemplateDir ->
rebar_utils:find_files(TemplateDir, ?TEMPLATE_RE, true) % recursive
end.
%% Fetch template indexes that sit on disk in plugins
find_plugin_templates(State) ->
[{plugin, File}
|| App <- rebar_state:all_plugin_deps(State),
Priv <- [rebar_app_info:priv_dir(App)],
Priv =/= undefined,
File <- rebar_utils:find_files(Priv, ?TEMPLATE_RE)]
++ %% and add global plugins too
[{plugin, File}
|| PSource <- rebar_state:get(State, {plugins, global}, []),
Plugin <- [plugin_provider(PSource)],
is_atom(Plugin),
Priv <- [code:priv_dir(Plugin)],
Priv =/= undefined,
File <- rebar_utils:find_files(Priv, ?TEMPLATE_RE)].
plugin_provider(P) when is_atom(P) -> P;
plugin_provider(T) when is_tuple(T) -> element(1, T).
%% Take an existing list of templates and tag them by name the way
%% the user would enter it from the CLI
tag_names(List) ->
[{filename:basename(File, ".template"), Type, File}
|| {Type, File} <- List].
%% If multiple templates share the same name, those in the escript (built-in)
%% take precedence. Otherwise, the on-disk order is the one to win.
prioritize_templates([], Acc) -> Acc;
prioritize_templates([{Name, Type, File} | Rest], Valid) ->
case lists:keyfind(Name, 1, Valid) of
false ->
prioritize_templates(Rest, [{Name, Type, File} | Valid]);
{_, escript, _} ->
?DEBUG("Skipping template ~p, due to presence of a built-in "
"template with the same name", [Name]),
prioritize_templates(Rest, Valid);
{_, builtin, _} ->
?DEBUG("Skipping template ~p, due to presence of a built-in "
"template with the same name", [Name]),
prioritize_templates(Rest, Valid);
{_, plugin, _} ->
?DEBUG("Skipping template ~p, due to presence of a plugin "
"template with the same name", [Name]),
prioritize_templates(Rest, Valid);
{_, file, _} ->
?DEBUG("Skipping template ~p, due to presence of a custom "
"template at ~ts", [Name, File]),
prioritize_templates(Rest, Valid)
end.
%% Read the contents of a file from the appropriate source
load_file(Files, escript, Name) ->
{Name, Bin} = lists:keyfind(Name, 1, Files),
Bin;
load_file(_Files, builtin, Name) ->
{ok, Bin} = file:read_file(Name),
Bin;
load_file(_Files, plugin, Name) ->
{ok, Bin} = file:read_file(Name),
Bin;
load_file(_Files, file, Name) ->
case file:read_file(Name) of
{ok, Bin} -> Bin;
{error, Reason} ->
?ABORT("Failed to load file ~p: ~p\n", [Name, Reason])
end.
write_file(Output, Data, Force) ->
%% determine if the target file already exists
FileExists = filelib:is_regular(Output),
%% perform the function if we're allowed,
%% otherwise just process the next template
case Force orelse FileExists =:= false of
true ->
ok = filelib:ensure_dir(Output),
case {Force, FileExists} of
{true, true} ->
?INFO("Writing ~ts (forcibly overwriting)",
[Output]);
_ ->
?INFO("Writing ~ts", [Output])
end,
case file:write_file(Output, Data) of
ok ->
ok;
{error, Reason} ->
?ABORT("Failed to write output file ~p: ~p\n",
[Output, Reason])
end;
false ->
{error, exists}
end.
%% Render a binary to a string, using mustache and the specified context
render(Bin, Context) ->
bbmustache:render(
rebar_utils:to_binary(Bin),
Context,
[{key_type, atom},
{escape_fun, fun(X) -> X end}] % disable HTML-style escaping
).
consult_template(Files, Type, File) ->
TemplateBin = load_file(Files, Type, File),
Encoding =
case epp:read_encoding_from_binary(TemplateBin) of
none -> epp:default_encoding();
X -> X
end,
rebar_string:consult(unicode:characters_to_list(TemplateBin, Encoding)).