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%% Copyright (c) Meta Platforms, Inc. and affiliates. %% %% This source code is licensed under both the MIT license found in the %% LICENSE-MIT file in the root directory of this source tree and the Apache %% License, Version 2.0 found in the LICENSE-APACHE file in the root directory %% of this source tree. %% @format -module(release_variables_builder). -author("loscher@fb.com"). -moduledoc """ Reads a file containing a mapping from ENV variable to string value and outputs a shell file that can be included in other scripts. It always adds ERTS_VSN. The purpose is to forward information about the release, e.g. release name or version, to a release startup shell script. usage: release_variables_builder.escript release_variables """. -export([main/1]). -define(EXITSUCCESS, 0). -define(EXITERROR, 1). -spec main([string()]) -> ok. main([Spec, ReleaseVariablesFile]) -> try do(Spec, ReleaseVariablesFile), erlang:halt(?EXITSUCCESS) catch Type:{abort, Reason} -> io:format(standard_error, "~s:~s~n", [Type, Reason]), erlang:halt(?EXITERROR) end; main(_) -> usage(). -spec usage() -> ok. usage() -> io:format("release_variables_builder.escript release_variables"). -spec do(file:filename(), file:filename()) -> ok. do(Spec, ReleaseVariablesFile) -> {ok, Contents} = file:read_file(Spec, [raw]), Variables = json:decode(Contents), {ok, F} = file:open(ReleaseVariablesFile, [write, raw]), [ ok = file:write(F, io_lib:format("~s=\"~s\"~n", [Key, Value])) || Key := Value <- Variables#{"ERTS_VSN" => erlang:system_info(version)} ], ok = file:close(F), ok.