rebar3/src/rebar_agent.erl

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2021-12-27 19:09:21 +00:00
%%% @doc Runs a process that holds a rebar3 state and can be used
%%% to statefully maintain loaded project state into a running VM.
-module(rebar_agent).
-export([start_link/1, do/1, do/2, do/3, async_do/1, async_do/2, async_do/3]).
-export(['$handle_undefined_function'/2]).
-export([init/1,
handle_call/3, handle_cast/2, handle_info/2,
code_change/3, terminate/2]).
-include("rebar.hrl").
-record(state, {state,
cwd,
show_warning=true}).
%% @doc boots an agent server; requires a full rebar3 state already.
%% By default (within rebar3), this isn't called; `rebar_prv_shell'
%% enters and transforms into this module
-spec start_link(rebar_state:t()) -> {ok, pid()}.
start_link(State) ->
gen_server:start_link({local, ?MODULE}, ?MODULE, State, []).
%% @doc runs a given command in the agent's context.
-spec do(atom() | string()) -> ok | {error, term()}.
do(Command) when is_atom(Command) ->
gen_server:call(?MODULE, {cmd, Command}, infinity);
do(Args) when is_list(Args) ->
gen_server:call(?MODULE, {cmd, default, do, Args}, infinity).
%% @doc runs a given command in the agent's context, under a given
%% namespace.
-spec do(atom(), atom() | string()) -> ok | {error, term()}.
do(Namespace, Command) when is_atom(Namespace), is_atom(Command) ->
gen_server:call(?MODULE, {cmd, Namespace, Command}, infinity);
do(Namespace, Args) when is_atom(Namespace), is_list(Args) ->
gen_server:call(?MODULE, {cmd, Namespace, do, Args}, infinity).
-spec do(atom(), atom(), string()) -> ok | {error, term()}.
do(Namespace, Command, Args) when is_atom(Namespace), is_atom(Command), is_list(Args) ->
gen_server:call(?MODULE, {cmd, Namespace, Command, Args}, infinity).
-spec async_do(atom()) -> ok.
async_do(Command) when is_atom(Command) ->
gen_server:cast(?MODULE, {cmd, Command});
async_do(Args) when is_list(Args) ->
gen_server:cast(?MODULE, {cmd, default, do, Args}).
-spec async_do(atom(), atom()) -> ok.
async_do(Namespace, Command) when is_atom(Namespace), is_atom(Command) ->
gen_server:cast(?MODULE, {cmd, Namespace, Command});
async_do(Namespace, Args) when is_atom(Namespace), is_list(Args) ->
gen_server:cast(?MODULE, {cmd, Namespace, do, Args}).
-spec async_do(atom(), atom(), string()) -> ok.
async_do(Namespace, Command, Args) when is_atom(Namespace), is_atom(Command), is_list(Args) ->
gen_server:cast(?MODULE, {cmd, Namespace, Command, Args}).
'$handle_undefined_function'(Cmd, [Namespace, Args]) ->
gen_server:call(?MODULE, {cmd, Namespace, Cmd, Args}, infinity);
'$handle_undefined_function'(Cmd, [Args]) ->
gen_server:call(?MODULE, {cmd, default, Cmd, Args}, infinity);
'$handle_undefined_function'(Cmd, []) ->
gen_server:call(?MODULE, {cmd, default, Cmd}, infinity).
%%%%%%%%%%%%%%%%%
%%% CALLBACKS %%%
%%%%%%%%%%%%%%%%%
%% @private
init(State) ->
Cwd = rebar_dir:get_cwd(),
{ok, #state{state=State, cwd=Cwd}}.
%% @private
handle_call({cmd, Command}, _From, State=#state{state=RState, cwd=Cwd}) ->
MidState = maybe_show_warning(State),
put(cmd_type, sync),
{Res, NewRState} = run(default, Command, "", RState, Cwd),
put(cmd_type, undefined),
{reply, Res, MidState#state{state=NewRState}, hibernate};
handle_call({cmd, Namespace, Command}, _From, State = #state{state=RState, cwd=Cwd}) ->
MidState = maybe_show_warning(State),
put(cmd_type, sync),
{Res, NewRState} = run(Namespace, Command, "", RState, Cwd),
put(cmd_type, undefined),
{reply, Res, MidState#state{state=NewRState}, hibernate};
handle_call({cmd, Namespace, Command, Args}, _From, State = #state{state=RState, cwd=Cwd}) ->
MidState = maybe_show_warning(State),
put(cmd_type, sync),
{Res, NewRState} = run(Namespace, Command, Args, RState, Cwd),
put(cmd_type, undefined),
{reply, Res, MidState#state{state=NewRState}, hibernate};
handle_call(_Call, _From, State) ->
{noreply, State}.
%% @private
handle_cast({cmd, Command}, State=#state{state=RState, cwd=Cwd}) ->
MidState = maybe_show_warning(State),
put(cmd_type, async),
{_, NewRState} = run(default, Command, "", RState, Cwd),
put(cmd_type, undefined),
{noreply, MidState#state{state=NewRState}, hibernate};
handle_cast({cmd, Namespace, Command}, State = #state{state=RState, cwd=Cwd}) ->
MidState = maybe_show_warning(State),
put(cmd_type, async),
{_, NewRState} = run(Namespace, Command, "", RState, Cwd),
put(cmd_type, undefined),
{noreply, MidState#state{state=NewRState}, hibernate};
handle_cast({cmd, Namespace, Command, Args}, State = #state{state=RState, cwd=Cwd}) ->
MidState = maybe_show_warning(State),
put(cmd_type, async),
{_, NewRState} = run(Namespace, Command, Args, RState, Cwd),
put(cmd_type, undefined),
{noreply, MidState#state{state=NewRState}, hibernate};
handle_cast(_Cast, State) ->
{noreply, State}.
%% @private
handle_info(_Info, State) ->
{noreply, State}.
%% @private
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
%% @private
terminate(_Reason, _State) ->
ok.
%%%%%%%%%%%%%%%
%%% PRIVATE %%%
%%%%%%%%%%%%%%%
%% @private runs the actual command and maintains the state changes
-spec run(atom(), atom(), string(), rebar_state:t(), file:filename()) ->
{ok, rebar_state:t()} | {{error, term()}, rebar_state:t()}.
run(Namespace, Command, StrArgs, RState, Cwd) ->
try
case rebar_dir:get_cwd() of
Cwd ->
PArgs = getopt:tokenize(StrArgs),
Args = [atom_to_list(Namespace), atom_to_list(Command)] ++ PArgs,
CmdState0 = refresh_state(RState, Cwd),
CmdState1 = rebar_state:set(CmdState0, task, atom_to_list(Command)),
CmdState = rebar_state:set(CmdState1, caller, api),
case rebar3:run(CmdState, Args) of
{ok, TmpState} ->
refresh_paths(TmpState),
{ok, CmdState};
{error, Err} when is_list(Err) ->
refresh_paths(CmdState),
{{error, lists:flatten(Err)}, CmdState};
{error, Err} ->
refresh_paths(CmdState),
{{error, Err}, CmdState}
end;
_ ->
{{error, cwd_changed}, RState}
end
catch
?WITH_STACKTRACE(Type, Reason, Stacktrace)
?DIAGNOSTIC("Agent Stacktrace: ~p", [Stacktrace]),
{{error, {Type, Reason}}, RState}
end.
%% @private function to display a warning for the feature only once
-spec maybe_show_warning(#state{}) -> #state{}.
maybe_show_warning(S=#state{show_warning=true}) ->
?WARN("This feature is experimental and may be modified or removed at any time.", []),
S#state{show_warning=false};
maybe_show_warning(State) ->
State.
%% @private based on a rebar3 state term, reload paths in a way
%% that makes sense.
-spec refresh_paths(rebar_state:t()) -> ok.
refresh_paths(RState) ->
RefreshPaths = application:get_env(rebar, refresh_paths, [all_deps, test]),
ToRefresh = parse_refresh_paths(RefreshPaths, RState, []),
%% Modules from apps we can't reload without breaking functionality
ShellOpts = rebar_state:get(RState, shell, []),
ShellBlacklist = proplists:get_value(app_reload_blacklist, ShellOpts, []),
Blacklist = lists:usort(
application:get_env(rebar, refresh_paths_blacklist, ShellBlacklist)
++ [rebar, erlware_commons, providers, cf, cth_readable]),
%% Similar to rebar_utils:update_code/1, but also forces a reload
%% of used modules. Also forces to reload all of ebin/ instead
%% of just the modules in the .app file, because 'extra_src_dirs'
%% allows to load and compile files that are not to be kept
%% in the app file.
[refresh_path(Path, Blacklist) || Path <- ToRefresh],
ok.
refresh_path(Path, Blacklist) ->
Name = filename:basename(Path, "/ebin"),
App = list_to_atom(Name),
case App of
test -> % skip
code:add_patha(Path),
ok;
_ ->
application:load(App),
case application:get_key(App, modules) of
undefined ->
code:add_patha(Path);
{ok, _Mods} ->
case lists:member(App, Blacklist) of
false ->
refresh_path_do(Path, App);
true ->
refresh_path_blacklisted(Path)
end
end
end.
refresh_path_do(Path, App) ->
Modules = mods_in_path(Path),
?DIAGNOSTIC("reloading ~p from ~ts", [Modules, Path]),
code:replace_path(App, Path),
reload_modules(Modules).
%% @private blacklisted paths are not reloaded, but if they were not loaded
%% already, we try and ensure they are loaded once. This is a soft operation
%% that does not provoke crashes in existing processes, but hides issues
%% as seen in issue #2013 comments where some loaded modules that are currently
%% run by no processes get unloaded by rebar_paths, without being loaded back in.
refresh_path_blacklisted(Path) ->
Modules = [M || M <- mods_in_path(Path), not is_loaded(M)],
?DIAGNOSTIC("ensure ~p loaded", [Modules]),
code:add_pathz(Path), % in case the module is only in a new non-clashing path
_ = [code:ensure_loaded(M) || M <- Modules],
ok.
%% @private fetch module names from a given directory that contains
%% pre-build beam files.
mods_in_path(Path) ->
Files = filelib:wildcard(filename:join([Path, "*.beam"])),
[list_to_atom(filename:basename(F, ".beam")) || F <- Files].
%% @private check that a module is already loaded
is_loaded(Mod) ->
code:is_loaded(Mod) =/= false.
%% @private parse refresh_paths option
%% no_deps means only project_apps's ebin path
%% no_test means no test path
%% OtherPath.
parse_refresh_paths([all_deps | RefreshPaths], RState, Acc) ->
Paths = rebar_state:code_paths(RState, all_deps),
parse_refresh_paths(RefreshPaths, RState, Paths ++ Acc);
parse_refresh_paths([project_apps | RefreshPaths], RState, Acc) ->
Paths = [filename:join([rebar_app_info:out_dir(App), "ebin"])
|| App <- rebar_state:project_apps(RState)],
parse_refresh_paths(RefreshPaths, RState, Paths ++ Acc);
parse_refresh_paths([test | RefreshPaths], RState, Acc) ->
Paths = [filename:join([rebar_app_info:out_dir(App), "test"])
|| App <- rebar_state:project_apps(RState)],
parse_refresh_paths(RefreshPaths, RState, Paths ++ Acc);
parse_refresh_paths([RefreshPath0 | RefreshPaths], RState, Acc) when is_list(RefreshPath0) ->
case filelib:is_dir(RefreshPath0) of
true ->
RefreshPath0 =
case filename:basename(RefreshPath0) of
"ebin" -> RefreshPath0;
_ -> filename:join([RefreshPath0, "ebin"])
end,
parse_refresh_paths(RefreshPaths, RState, [RefreshPath0 | Acc]);
false ->
parse_refresh_paths(RefreshPaths, RState, Acc)
end;
parse_refresh_paths([_ | RefreshPaths], RState, Acc) ->
parse_refresh_paths(RefreshPaths, RState, Acc);
parse_refresh_paths([], _RState, Acc) ->
lists:usort(Acc).
%% @private from a disk config, reload and reapply with the current
%% profiles; used to find changes in the config from a prior run.
-spec refresh_state(rebar_state:t(), file:filename()) -> rebar_state:t().
refresh_state(RState, _Dir) ->
lists:foldl(
fun(F, State) -> F(State) end,
rebar3:init_config(),
[fun(S) -> rebar_state:apply_profiles(S, rebar_state:current_profiles(RState)) end]
).
%% @private takes a list of modules and reloads them
-spec reload_modules([module()]) -> term().
reload_modules([]) -> noop;
reload_modules(Modules0) ->
Modules = [M || M <- Modules0, is_changed(M)],
reload_modules(Modules, erlang:function_exported(code, prepare_loading, 1)).
%% @spec is_changed(atom()) -> boolean()
%% @doc true if the loaded module is a beam with a vsn attribute
%% and does not match the on-disk beam file, returns false otherwise.
is_changed(M) ->
try
module_vsn(M:module_info(attributes)) =/= module_vsn(code:get_object_code(M))
catch _:_ ->
false
end.
module_vsn({M, Beam, _Fn}) ->
% Because the vsn can set by -vsn(X) in module.
% So didn't use beam_lib:version/1 to get the vsn.
% So if set -vsn(X) in module, it will always reload the module.
{ok, {M, <<Vsn:128>>}} = beam_lib:md5(Beam),
Vsn;
module_vsn(Attrs) when is_list(Attrs) ->
{_, Vsn} = lists:keyfind(vsn, 1, Attrs),
Vsn.
%% @private reloading modules, when there are modules to actually reload
reload_modules(Modules, true) ->
%% OTP 19 and later -- use atomic loading and ignore unloadable mods
case code:prepare_loading(Modules) of
{ok, Prepared} ->
[code:purge(M) || M <- Modules],
code:finish_loading(Prepared);
{error, ModRsns} ->
Blacklist =
lists:foldr(fun({ModError, Error}, Acc) ->
case Error of
% perhaps cover other cases of failure?
on_load_not_allowed ->
reload_modules([ModError], false),
[ModError|Acc];
_ ->
?DIAGNOSTIC("Module ~p failed to atomic load because ~p", [ModError, Error]),
[ModError|Acc]
end
end,
[], ModRsns
),
reload_modules(Modules -- Blacklist, true)
end;
reload_modules(Modules, false) ->
%% Older versions, use a more ad-hoc mechanism.
lists:foreach(fun(M) ->
code:delete(M),
code:purge(M),
case code:load_file(M) of
{module, M} -> ok;
{error, Error} ->
?DIAGNOSTIC("Module ~p failed to load because ~p", [M, Error])
end
end, Modules
).