summaryrefslogtreecommitdiff
path: root/src/rebar_templater.erl
blob: 4aa5ed6b02bb17815c48ad09325acbab61cf5aca (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
%% -*- tab-width: 4;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(['create-app'/2,
         'create-node'/2,
         'list-templates'/2,
         create/2]).

-include("rebar.hrl").

-define(TEMPLATE_RE, ".*\\.template\$").

%% ===================================================================
%% Public API
%% ===================================================================

'create-app'(Config, File) ->
    %% Alias for create w/ template=simpleapp
    rebar_config:set_global(template, "simpleapp"),
    create(Config, File).

'create-node'(Config, File) ->
    %% Alias for create w/ template=simplenode
    rebar_config:set_global(template, "simplenode"),
    create(Config, File).

'list-templates'(_Config, _File) ->
    %% Load a list of all the files in the escript -- cache it in the pdict
    %% since we'll potentially need to walk it several times over the course
    %% of a run.
    cache_escript_files(),

    %% Build a list of available templates
    AvailTemplates = find_disk_templates() ++ find_escript_templates(),
    ?CONSOLE("Available templates:\n", []),
    _ = [begin
             BaseName = filename:basename(F, ".template"),
             ?CONSOLE("\t* ~s: ~s (~p)\n", [BaseName, F, Type])
         end || {Type, F} <- AvailTemplates],
    ok.


create(_Config, _) ->
    %% Load a list of all the files in the escript -- cache it in the pdict
    %% since we'll potentially need to walk it several times over the course
    %% of a run.
    cache_escript_files(),

    %% Build a list of available templates
    AvailTemplates = find_disk_templates() ++ find_escript_templates(),
    ?DEBUG("Available templates: ~p\n", [AvailTemplates]),

    %% Using the specified template id, find the matching template file/type.
    %% Note that if you define the same template in both ~/.rebar/templates
    %% that is also present in the escript, the one on the file system will
    %% be preferred.
    {Type, Template} = select_template(AvailTemplates, template_id()),

    %% Load the template definition as is and get the list of variables the
    %% template requires.
    TemplateTerms = consult(load_file(Type, Template)),
    case lists:keyfind(variables, 1, TemplateTerms) of
        {variables, Vars} ->
            case parse_vars(Vars, dict:new()) of
                {error, Entry} ->
                    Context0 = undefined,
                    ?ABORT("Failed while processing variables from template ~p."
                           "Variable definitions must follow form of "
                           "[{atom(), term()}]. Failed at: ~p\n",
                           [template_id(), Entry]);
                Context0 ->
                    ok
            end;
        false ->
            ?WARN("No variables section found in template ~p; using empty context.\n",
                  [template_id()]),
            Context0 = dict:new()
    end,

    %% For each variable, see if it's defined in global vars -- if it is, prefer that
    %% value over the defaults
    Context = update_vars(dict:fetch_keys(Context0), Context0),
    ?DEBUG("Template ~p context: ~p\n", [template_id(), dict:to_list(Context)]),

    %% Now, use our context to process the template definition -- this permits us to
    %% use variables within the definition for filenames.
    FinalTemplate = consult(render(load_file(Type, Template), Context)),
    ?DEBUG("Final template def ~p: ~p\n", [template_id(), FinalTemplate]),

    %% Execute the instructions in the finalized template
    Force = rebar_config:get_global(force, "0"),
    execute_template(FinalTemplate, Type, Template, Context, Force, []).




%% ===================================================================
%% Internal functions
%% ===================================================================

%%
%% Scan the current escript for available files and cache in pdict.
%%
cache_escript_files() ->
    {ok, Files} = rebar_utils:escript_foldl(
                      fun(Name, _, GetBin, Acc) ->
                              [{Name, GetBin()} | Acc]
                      end,
                      [], rebar_config:get_global(escript, undefined)),
    erlang:put(escript_files, Files).


template_id() ->
    case rebar_config:get_global(template, undefined) of
        undefined ->
            ?ABORT("No template specified.\n", []);
        TemplateId ->
            TemplateId
    end.

find_escript_templates() ->
    [{escript, Name} || {Name, _Bin} <- erlang:get(escript_files),
                        re:run(Name, ?TEMPLATE_RE, [{capture, none}]) == match].

find_disk_templates() ->
    OtherTemplates = find_other_templates(),
    HomeFiles = rebar_utils:find_files(filename:join(os:getenv("HOME"),
                                                     ".rebar/templates"), ?TEMPLATE_RE),
    LocalFiles = rebar_utils:find_files(".", ?TEMPLATE_RE),
    [{file, F} || F <- OtherTemplates ++ HomeFiles ++ LocalFiles].

find_other_templates() ->
    case rebar_config:get_global(template_dir, undefined) of
        undefined ->
            [];
        TemplateDir ->
            rebar_utils:find_files(TemplateDir, ?TEMPLATE_RE)
    end.

select_template([], Template) ->
    ?ABORT("Template ~s not found.\n", [Template]);
select_template([{Type, Avail} | Rest], Template) ->
    case filename:basename(Avail, ".template") == Template of
        true ->
            {Type, Avail};
        false ->
            select_template(Rest, Template)
    end.

%%
%% Read the contents of a file from the appropriate source
%%
load_file(escript, Name) ->
    {Name, Bin} = lists:keyfind(Name, 1, erlang:get(escript_files)),
    Bin;
load_file(file, Name) ->
    {ok, Bin} = file:read_file(Name),
    Bin.

%%
%% Parse/validate variables out from the template definition
%%
parse_vars([], Dict) ->
    Dict;
parse_vars([{Key, Value} | Rest], Dict) when is_atom(Key) ->
    parse_vars(Rest, dict:store(Key, Value, Dict));
parse_vars([Other | _Rest], _Dict) ->
    {error, Other};
parse_vars(Other, _Dict) ->
    {error, Other}.

%%
%% Given a list of keys in Dict, see if there is a corresponding value defined
%% in the global config; if there is, update the key in Dict with it
%%
update_vars([], Dict) ->
    Dict;
update_vars([Key | Rest], Dict) ->
    Value = rebar_config:get_global(Key, dict:fetch(Key, Dict)),
    update_vars(Rest, dict:store(Key, Value, Dict)).


%%
%% Given a string or binary, parse it into a list of terms, ala file:consult/0
%%
consult(Str) when is_list(Str) ->
    consult([], Str, []);
consult(Bin) when is_binary(Bin)->
    consult([], binary_to_list(Bin), []).

consult(Cont, Str, Acc) ->
    case erl_scan:tokens(Cont, Str, 0) of
        {done, Result, Remaining} ->
            case Result of
                {ok, Tokens, _} ->
                    {ok, Term} = erl_parse:parse_term(Tokens),
                    consult([], Remaining, [Term | Acc]);
                {eof, _Other} ->
                    lists:reverse(Acc);
                {error, Info, _} ->
                    {error, Info}
            end;
        {more, Cont1} ->
            consult(Cont1, eof, Acc)
    end.


%%
%% Render a binary to a string, using mustache and the specified context
%%
render(Bin, Context) ->
    %% Be sure to escape any double-quotes before rendering...
    Str = re:replace(Bin, "\"", "\\\\\"", [global, {return,list}]),
    mustache:render(Str, Context).

write_file(Output, Data, Force) ->
    %% determine if the target file already exists
    FileExists = filelib:is_file(Output),

    %% perform the function if we're allowed,
    %% otherwise just process the next template
    if
        Force =:= "1"; FileExists =:= false ->
            ok = filelib:ensure_dir(Output),
            if
                {Force, FileExists} =:= {"1", true} ->
                    ?CONSOLE("Writing ~s (forcibly overwriting)~n",
                             [Output]);
                true ->
                    ?CONSOLE("Writing ~s~n", [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;
        true ->
            {error, exists}
    end.


%%
%% Execute each instruction in a template definition file.
%%
execute_template([], _TemplateType, _TemplateName, _Context, _Force, ExistingFiles) ->
    case ExistingFiles of
        [] ->
            ok;
        _ ->
            Msg = lists:flatten([io_lib:format("\t* ~p~n", [F]) || F <- lists:reverse(ExistingFiles)]),
            Help = "To force overwriting, specify force=1 on the command line.\n",
            ?ERROR("One or more files already exist on disk and were not generated:~n~s~s", [Msg , Help])
    end;
execute_template([{template, Input, Output} | Rest], TemplateType, TemplateName, Context, Force, ExistingFiles) ->
    InputName = filename:join(filename:dirname(TemplateName), Input),
    case write_file(Output, render(load_file(TemplateType, InputName), Context), Force) of
        ok ->
            execute_template(Rest, TemplateType, TemplateName, Context,
                             Force, ExistingFiles);
        {error, exists} ->
            execute_template(Rest, TemplateType, TemplateName, Context,
                             Force, [Output|ExistingFiles])
    end;
execute_template([{file, Input, Output} | Rest], TemplateType, TemplateName, Context, Force, ExistingFiles) ->
    InputName = filename:join(filename:dirname(TemplateName), Input),
    case write_file(Output, load_file(TemplateType, InputName), Force) of
        ok ->
            execute_template(Rest, TemplateType, TemplateName, Context,
                             Force, ExistingFiles);
        {error, exists} ->
            execute_template(Rest, TemplateType, TemplateName, Context,
                             Force, [Output|ExistingFiles])
    end;
execute_template([{dir, Name} | Rest], TemplateType, TemplateName, Context, Force, ExistingFiles) ->
    case filelib:ensure_dir(filename:join(Name, "dummy")) of
        ok ->
            execute_template(Rest, TemplateType, TemplateName, Context, Force, ExistingFiles);
        {error, Reason} ->
            ?ABORT("Failed while processing template instruction {dir, ~s}: ~p\n",
                   [Name, Reason])
    end;
execute_template([{chmod, Mod, File} | Rest], TemplateType, TemplateName, Context, Force, ExistingFiles) when is_integer(Mod) ->
    case file:change_mode(File, Mod) of
        ok ->
            execute_template(Rest, TemplateType, TemplateName, Context, Force, ExistingFiles);
        {error, Reason} ->
            ?ABORT("Failed while processing template instruction {cmod, ~b, ~s}: ~p~n",
                   [Mod, File, Reason])
    end;
execute_template([{variables, _} | Rest], TemplateType, TemplateName, Context, Force, ExistingFiles) ->
    execute_template(Rest, TemplateType, TemplateName, Context, Force, ExistingFiles);
execute_template([Other | Rest], TemplateType, TemplateName, Context, Force, ExistingFiles) ->
    ?WARN("Skipping unknown template instruction: ~p\n", [Other]),
    execute_template(Rest, TemplateType, TemplateName, Context, Force, ExistingFiles).