#!/usr/bin/env escript
%% -*- mode: erlang;erlang-indent-level: 4;indent-tabs-mode: nil -*-
%% ex: ft=erlang ts=4 sw=4 et
%% -------------------------------------------------------------------
%%
%% nodetool: Helper Script for interacting with live nodes
%%
%% -------------------------------------------------------------------
main(Args) ->
ok = start_epmd(),
%% Extract the args
{RestArgs, TargetNode} = process_args(Args, [], undefined),
%% See if the node is currently running -- if it's not, we'll bail
case {net_kernel:hidden_connect_node(TargetNode), net_adm:ping(TargetNode)} of
{true, pong} ->
ok;
{_, pang} ->
io:format("Node ~p not responding to pings.\n", [TargetNode]),
halt(1)
end,
case RestArgs of
["ping"] ->
%% If we got this far, the node already responsed to a ping, so just dump
%% a "pong"
io:format("pong\n");
["stop"] ->
io:format("~p\n", [rpc:call(TargetNode, init, stop, [], 60000)]);
["restart"] ->
io:format("~p\n", [rpc:call(TargetNode, init, restart, [], 60000)]);
["reboot"] ->
io:format("~p\n", [rpc:call(TargetNode, init, reboot, [], 60000)]);
["rpc", Module, Function | RpcArgs] ->
case rpc:call(TargetNode, list_to_atom(Module), list_to_atom(Function),
[RpcArgs], 60000) of
ok ->
ok;
{badrpc, Reason} ->
io:format("RPC to ~p failed: ~p\n", [TargetNode, Reason]),
halt(1);
_ ->
halt(1)
end;
["rpcterms", Module, Function | ArgsAsString] ->
case rpc:call(TargetNode, list_to_atom(Module), list_to_atom(Function),
consult(lists:flatten(ArgsAsString)), 60000) of
{badrpc, Reason} ->
io:format("RPC to ~p failed: ~p\n", [TargetNode, Reason]),
halt(1);
Other ->
io:format("~p\n", [Other])
end;
["eval" | ListOfArgs] ->
% shells may process args into more than one, and end up stripping
% spaces, so this converts all of that to a single string to parse
String = binary_to_list(
list_to_binary(
join(ListOfArgs," ")
)
),
% then just as a convenience to users, if they forgot a trailing
% '.' add it for them.
Normalized =
case lists:reverse(String) of
[$. | _] -> String;
R -> lists:reverse([$. | R])
end,
% then scan and parse the string
{ok, Scanned, _} = erl_scan:string(Normalized),
{ok, Parsed } = erl_parse:parse_exprs(Scanned),
% and evaluate it on the remote node
case rpc:call(TargetNode, erl_eval, exprs, [Parsed, [] ]) of
{value, Value, _} ->
io:format ("~p\n",[Value]);
{badrpc, Reason} ->
io:format("RPC to ~p failed: ~p\n", [TargetNode, Reason]),
halt(1)
end;
Other ->
io:format("Other: ~p\n", [Other]),
io:format("Usage: nodetool {ping|stop|restart|reboot|rpc|rpcterms|eval [Terms]} [RPC]\n")
end,
net_kernel:stop().
process_args([], Acc, TargetNode) ->
{lists:reverse(Acc), TargetNode};
process_args(["-setcookie", Cookie | Rest], Acc, TargetNode) ->
erlang:set_cookie(node(), list_to_atom(Cookie)),
process_args(Rest, Acc, TargetNode);
process_args(["-name", TargetName | Rest], Acc, _) ->
ThisNode = append_node_suffix(TargetName, "_maint_"),
{ok, _} = net_kernel:start([ThisNode, longnames]),
process_args(Rest, Acc, nodename(TargetName));
process_args(["-sname", TargetName | Rest], Acc, _) ->
ThisNode = append_node_suffix(TargetName, "_maint_"),
{ok, _} = net_kernel:start([ThisNode, shortnames]),
process_args(Rest, Acc, nodename(TargetName));
process_args([Arg | Rest], Acc, Opts) ->
process_args(Rest, [Arg | Acc], Opts).
start_epmd() ->
[] = os:cmd("\"" ++ epmd_path() ++ "\" -daemon"),
ok.
epmd_path() ->
ErtsBinDir = filename:dirname(escript:script_name()),
Name = "epmd",
case os:find_executable(Name, ErtsBinDir) of
false ->
case os:find_executable(Name) of
false ->
io:format("Could not find epmd.~n"),
halt(1);
GlobalEpmd ->
GlobalEpmd
end;
Epmd ->
Epmd
end.
nodename(Name) ->
case re:split(Name, "@", [{return, list}, unicode]) of
[_Node, _Host] ->
list_to_atom(Name);
[Node] ->
[_, Host] = re:split(atom_to_list(node()), "@", [{return, list}, unicode]),
list_to_atom(lists:concat([Node, "@", Host]))
end.
append_node_suffix(Name, Suffix) ->
case re:split(Name, "@", [{return, list}, unicode]) of
[Node, Host] ->
list_to_atom(lists:concat([Node, Suffix, os:getpid(), "@", Host]));
[Node] ->
list_to_atom(lists:concat([Node, Suffix, os:getpid()]))
end.
%%
%% 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.
%% string:join/2 copy; string:join/2 is getting obsoleted
%% and replaced by lists:join/2, but lists:join/2 is too new
%% for version support (only appeared in 19.0) so it cannot be
%% used. Instead we just adopt join/2 locally and hope it works
%% for most unicode use cases anyway.
join([], Sep) when is_list(Sep) ->
[];
join([H|T], Sep) ->
H ++ lists:append([Sep ++ X || X <- T]).
