mirror of
https://github.com/correl/rebar.git
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68089c6297
ensure any processes with a reference to an old user process as their group leader are updated to use the new user process. this introduces a slight delay at startup as the system must wait for the new processes to be registered. there is a max wait period of three seconds (before the shell command gives up and throws a timeout error) fixes #314 ("rebar shell" somehow blocks using io:format in gen_server handle_call)
91 lines
No EOL
3.9 KiB
Erlang
91 lines
No EOL
3.9 KiB
Erlang
%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
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%% ex: ts=4 sw=4 et
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%% -------------------------------------------------------------------
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%%
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%% rebar: Erlang Build Tools
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%%
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%% Copyright (c) 2011 Trifork
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%%
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%% Permission is hereby granted, free of charge, to any person obtaining a copy
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%% of this software and associated documentation files (the "Software"), to deal
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%% in the Software without restriction, including without limitation the rights
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%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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%% copies of the Software, and to permit persons to whom the Software is
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%% furnished to do so, subject to the following conditions:
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%%
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%% The above copyright notice and this permission notice shall be included in
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%% all copies or substantial portions of the Software.
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%%
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%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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%% THE SOFTWARE.
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%% -------------------------------------------------------------------
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-module(rebar_shell).
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-author("Kresten Krab Thorup <krab@trifork.com>").
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-include("rebar.hrl").
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-export([shell/2, info/2]).
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%% NOTE:
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%% this is an attempt to replicate `erl -pa ./ebin -pa deps/*/ebin`. it is
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%% mostly successful but does stop and then restart the user io system to get
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%% around issues with rebar being an escript and starting in `noshell` mode.
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%% it also lacks the ctrl-c interrupt handler that `erl` features. ctrl-c will
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%% immediately kill the script. ctrl-g, however, works fine
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shell(_Config, _AppFile) ->
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true = code:add_pathz(rebar_utils:ebin_dir()),
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%% scan all processes for any with references to the old user and save them to
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%% update later
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NeedsUpdate = [Pid || Pid <- erlang:processes(),
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proplists:get_value(group_leader, erlang:process_info(Pid)) == whereis(user)
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],
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%% terminate the current user
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ok = supervisor:terminate_child(kernel_sup, user),
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%% start a new shell (this also starts a new user under the correct group)
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_ = user_drv:start(),
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%% wait until user_drv and user have been registered (max 3 seconds)
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ok = wait_until_user_started(3000),
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%% set any process that had a reference to the old user's group leader to the
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%% new user process
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_ = [erlang:group_leader(whereis(user), Pid) || Pid <- NeedsUpdate],
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%% enable error_logger's tty output
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ok = error_logger:swap_handler(tty),
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%% disable the simple error_logger (which may have been added multiple
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%% times). removes at most the error_logger added by init and the
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%% error_logger added by the tty handler
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ok = remove_error_handler(3),
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%% this call never returns (until user quits shell)
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timer:sleep(infinity).
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info(help, shell) ->
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?CONSOLE(
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"Start a shell with project and deps preloaded similar to~n"
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"'erl -pa ebin -pa deps/*/ebin'.~n",
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[]
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).
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remove_error_handler(0) ->
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?WARN("Unable to remove simple error_logger handler~n", []);
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remove_error_handler(N) ->
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case gen_event:delete_handler(error_logger, error_logger, []) of
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{error, module_not_found} -> ok;
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{error_logger, _} -> remove_error_handler(N-1)
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end.
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%% Timeout is a period to wait before giving up
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wait_until_user_started(0) ->
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?ABORT("Timeout exceeded waiting for `user` to register itself~n", []),
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erlang:error(timeout);
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wait_until_user_started(Timeout) ->
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case whereis(user) of
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%% if user is not yet registered wait a tenth of a second and try again
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undefined -> timer:sleep(100), wait_until_user_started(Timeout - 100);
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_ -> ok
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end. |