%%%----------------------------------------------------------------------------
%%% @doc Environment utils
%%% @author Serge Aleynikov <saleyn@gmail.com>
%%% @copyright 2012 Serge Aleynikov
%%% @end
%%%----------------------------------------------------------------------------
%%% Created: 2012-09-21
%%%----------------------------------------------------------------------------
-module(env).
-author('saleyn@gmail.com').
%% API
-export([subst_env_path/1, subst_env_path/2,
replace_env_vars/1, replace_env_vars/2,
get_env/3, home_dir/0,
normalize_path/1]).
-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").
-endif.
-deprecated([{subst_env_path,1,"use replace_env_vars/1 instead"}]).
-deprecated([{subst_env_path,2,"use replace_env_vars/2 instead"}]).
%%%----------------------------------------------------------------------------
%%% External API
%%%----------------------------------------------------------------------------
-spec subst_env_path(list() | binary()) -> list() | binary().
subst_env_path(OsPath) ->
replace_env_vars(OsPath, []).
-spec subst_env_path(list() | binary(), [{atom() | string(), string()}]) ->
list() | binary().
subst_env_path(OsPath, Bindings) when is_list(Bindings) ->
replace_env_vars(OsPath, Bindings).
%%------------------------------------------------------------------------
%% @doc Perform replacement of environment variable values in the OsPath.
%% ```
%% Example:
%% env:replace_env_vars("~/app") -> "/home/cuser/app"
%% env:replace_env_vars("${HOME}/app") -> "/home/cuser/app"
%% env:replace_env_vars("$USER/app") -> "cuser/app"
%% '''
%% @see os:getenv/1
%% @end
%%------------------------------------------------------------------------
-spec replace_env_vars(list() | binary()) -> list() | binary().
replace_env_vars(OsPath) ->
replace_env_vars(OsPath, []).
%%------------------------------------------------------------------------
%% @doc Perform replacement of environment variable values in the OsPath.
%% This function also allows to provide a list of `Bindings' that
%% override the environment (they are checked before environment
%% variables are looked up).
%% ```
%% Example:
%% env:replace_env_vars("~/", [{"HOME", "/home/cu"}]) -> "/home/cu/"
%% env:replace_env_vars("~/", [{home, "/home/cu"}]) -> "/home/cu/"
%% env:replace_env_vars("$A/", [{a, "/aaa"}]) -> "/aaa/"
%% env:replace_env_vars("${A}/",[{a, "/aaa"}]) -> "/aaa/"
%% '''
%% @see os:getenv/1
%% @end
%%------------------------------------------------------------------------
-spec replace_env_vars(list() | binary(), [{atom() | string(), string()}]) ->
list() | binary().
replace_env_vars(OsPath, Bindings) when is_list(Bindings) ->
element(2, env_subst(OsPath, Bindings)).
%%-----------------------------------------------------------------------------
%% @doc Get application configuration
%% @end
%%-----------------------------------------------------------------------------
-spec get_env(atom(), atom(), any()) -> any().
get_env(App, Key, Default) ->
case application:get_env(App, Key) of
{ok, Val} ->
Val;
_ ->
Default
end.
%%%----------------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------------
internal_var("RELEASES") -> {ok, get_rels_dir()};
internal_var("ROOTDIR") -> {ok, get_root_dir()};
internal_var("RELPATH") -> {ok, get_rel_path()}; % Releases/Version
internal_var(_) -> undefined.
env_var(OS, "$$", _) when OS==unix; OS==win ->
"$";
env_var(OS, [$~] = Key, Bindings) when OS==unix; OS==win ->
case get_var(OS, "HOME", Bindings) of
{ok, Value} -> {Key, Value};
_ -> Key
end;
env_var(OS, [$~ | User] = Word, Bindings) when OS==unix; OS==win ->
case get_var(OS, "HOME", Bindings) of
{ok, Value} -> {[$~], filename:join(filename:dirname(Value), User)};
_ -> Word
end;
env_var(OS, [$$, ${ | Env] = Word, Bindings) when OS==unix; OS==win ->
Key = string:strip(Env, right, $}),
case get_var(OS, Key, Bindings) of
{ok, Value} -> {Key, Value};
_ -> Word
end;
env_var(OS, [$$ | Key] = Word, Bindings) when OS==unix; OS==win ->
case get_var(OS, Key, Bindings) of
{ok, Value} -> {Key, Value};
_ -> Word
end;
env_var(win, "%%", _) ->
"%";
env_var(win, [$% | Env] = Word, Bindings) ->
Key = string:strip(Env, right, $%),
case get_var(win, Key, Bindings) of
{ok, Value} -> {Key, Value};
_ -> Word
end;
env_var(_, Other, _Bindings) ->
Other.
get_var(OS, Name, Bindings) ->
case try_get_binding(Name, Bindings) of
undefined when Name == "HOME" ->
{ok, home_dir(OS)};
undefined ->
case os:getenv(Name) of
false -> internal_var(Name);
Value -> {ok, Value}
end;
Value ->
{ok, Value}
end.
try_get_binding(Name, Bindings) ->
case proplists:get_value(Name, Bindings) of
undefined when is_list(Name) ->
try
A = list_to_existing_atom(string:to_lower(Name)),
try_get_binding(A, Bindings)
catch _:_ ->
undefined
end;
Value ->
Value
end.
env_subst(Bin, Bindings) when is_binary(Bin) ->
{VarList, NewText} = env_subst(binary_to_list(Bin), Bindings),
{VarList, list_to_binary(NewText)};
env_subst(Text, Bindings) when is_list(Text) ->
env_subst(Text, os:type(), Bindings).
env_subst(Text, {unix, _}, Bindings) ->
env_subst(Text, unix,
"(?|(?:\\$\\$)|(?:~[^/$]*)|(?:\\${[A-Za-z][A-Za-z_0-9]*})|(?:\\$[A-Za-z][A-Za-z_0-9]*))",
Bindings);
env_subst(Text, {win32, _}, Bindings) ->
env_subst(Text, win, "(?|(?:\\%\\%)|(?:%[A-Za-z][A-Za-z_0-9]*%)|(?:~[^/$]*)|(?:\\${[A-Za-z][A-Za-z_0-9]*})|(?:\\$[A-Za-z][A-Za-z_0-9]*))", Bindings).
env_subst(Text, OsType, Pattern, Bindings) ->
case re:run(Text, Pattern, [global,{capture, all}]) of
{match, Matches} ->
{Vars, TextList, Last} =
lists:foldl(fun
([{Start, Length}], {Dict, List, Prev}) when Start >= 0 ->
Pos = Start+1,
Match = string:substr(Text, Pos, Length),
case env_var(OsType, Match, Bindings) of
{Key, Val} ->
case orddict:is_key(Key, Dict) of
true ->
NewDict = Dict;
false ->
NewDict = orddict:append(Key, Val, Dict)
end;
Val ->
NewDict = Dict
end,
NewList = [Val, string:substr(Text, Prev, Pos - Prev) | List],
NewPrev = Pos + Length,
{NewDict, NewList, NewPrev};
(_, Acc) -> Acc
end, {orddict:new(), [], 1}, Matches),
VarList = [{K, V} || {K, [V|_]} <- orddict:to_list(Vars)],
NewText = lists:concat(lists:reverse([string:substr(Text, Last) | TextList])),
{VarList, NewText};
nomatch ->
{[], Text}
end.
get_rel_ver() ->
% release and version
try [T || T <- release_handler:which_releases(), element(4, T) =:= permanent] of
[{Name, Vsn, _Apps, permanent} | _] ->
{Name, Vsn};
_Other ->
throw
catch _:_ ->
false
end.
get_root_dir() ->
case os:getenv("ROOTDIR") of
Str when is_list(Str) -> Str;
_ -> ""
end.
get_rels_dir() ->
case application:get_env(sasl, releases_dir) of
{ok, Path} ->
Path;
_ ->
filename:join(get_root_dir(), "releases")
end.
get_rel_path() ->
% version
{_, Ver} = get_rel_ver(),
% current release dir
filename:join(get_rels_dir(), Ver).
home_dir() ->
case os:type() of
{win32,_} -> home_dir(win);
{_,_} -> home_dir(linux)
end.
home_dir(win) ->
normalize_path(os:getenv("USERPROFILE"));
home_dir(_) ->
os:getenv("HOME").
normalize_path(Path) ->
case os:type() of
{win32,_} ->
F = fun Norm([$\\ | T]) -> [$/ | Norm(T)];
Norm([H | T]) -> [H | Norm(T)];
Norm([] ) -> []
end,
F(Path);
{_,_} ->
Path
end.
%%%----------------------------------------------------------------------------
%%% Test Cases
%%%----------------------------------------------------------------------------
-ifdef(EUNIT).
run_test_() ->
[
?_assertEqual("/abc/$/efg", replace_env_vars("/abc/$$/efg")),
?_assertEqual(true, os:putenv("X", "x")),
?_assertEqual("/" ++ os:getenv("X") ++ "/dir", replace_env_vars("/$X/dir")),
?_assertEqual(os:getenv("X") ++ "/dir", replace_env_vars("${X}/dir")),
?_assertEqual(os:getenv("HOME") ++ "/dir", replace_env_vars("~/dir")),
?_assertEqual("/aaa/dir", replace_env_vars("/$X/dir", [{"X", "aaa"}])),
?_assertEqual("/aaa/dir", replace_env_vars("/$X/dir", [{x, "aaa"}])),
?_assertEqual("/xxx/dir", replace_env_vars("$HOME/dir", [{"HOME", "/xxx"}])),
?_assertEqual("/xxx/dir", replace_env_vars("~/dir", [{"HOME", "/xxx"}])),
?_assertEqual("/xxx/dir", replace_env_vars("~/dir", [{home, "/xxx"}]))
].
-endif.
