From da5ca51bd3582c6f50c0f3306ed6ff5787d8433b Mon Sep 17 00:00:00 2001
From: Cyrill Gorcunov <gorcunov@gmail.com>
Date: Fri, 4 Oct 2019 10:49:24 +0300
Subject: [PATCH] box/console: Fix hang in remote console lua mode
If we change output mode on remote machine via
text-based session
node a (server)
------
require('console').listen('unix/:/tmp/X.sock')
...
node b (client)
------
require('console').connect('unix/:/tmp/X.sock')
connected to unix/:/tmp/X.sock
...
unix/:/tmp/X.sock> \set output lua
the client get stuck forever, it is because the text
wire protocol waits for yaml eos terminator which of
course never hit the peer, because lua mode uses own
one.
Thus to fix this problem we have to preprocess the text
we're passing to the server, just like we do in local
console. So we reuse command parsing code and remember
current output terminator in text_connection_mt instance.
Another problem is that named default output mode. There
could be a mixed environment where server operates in
default lua mode but client connects with yaml mode. To
break a tie we yield "\set output" command with current
output mode when establishing a connection. Since the
output format is per-session bound this doesn't affect
any other connections on a server.
Part-of #3834
Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
(cherry picked from commit c358398c7dc3777712c0dbec2c1b21e69bce2a4a)
---
src/box/lua/console.lua | 57 ++++++++++++++++++++++++++++++++++++++---
1 file changed, 54 insertions(+), 3 deletions(-)
diff --git a/src/box/lua/console.lua b/src/box/lua/console.lua
index a068d79a36..efd1cddd89 100644
--- a/src/box/lua/console.lua
+++ b/src/box/lua/console.lua
@@ -170,6 +170,24 @@ local function current_output()
return d
end
+--
+-- Return current EOS value for currently
+-- active output format.
+local function current_eos()
+ return output_eos[current_output()["fmt"]]
+end
+
+--
+-- Map output format descriptor into a "\set" command.
+local function output_to_cmd_string(desc)
+ if desc["opts"] then
+ string.format("\\set output %s,%s", desc["fmt"], desc["opts"])
+ else
+ string.format("\\set output %s", desc["fmt"])
+ end
+ return cmd
+end
+
local function format(status, ...)
local d = current_output()
return output_handlers[d["fmt"]](status, d["opts"], ...)
@@ -359,15 +377,39 @@ local text_connection_mt = {
-- @retval nil Error.
--
read = function(self)
- local ret = self._socket:read(output_eos["yaml"])
+ local ret = self._socket:read(self.eos)
if ret and ret ~= '' then
return ret
end
end,
--
+ -- The command might modify EOS so
+ -- we have to parse and preprocess it
+ -- first to not stuck in :read() forever.
+ --
+ -- Same time the EOS is per connection
+ -- value so we keep it inside the metatable
+ -- instace, and because we can't use same
+ -- name as output_eos() function we call
+ -- it simplier as self.eos.
+ preprocess_eval = function(self, text)
+ local command = get_command(text)
+ if command == nil then
+ return
+ end
+ local nr_items, items = parse_operators(command)
+ if nr_items == 3 then
+ local err, fmt, opts = output_parse(items[3])
+ if not err then
+ self.eos = output_eos[fmt]
+ end
+ end
+ end,
+ --
-- Write + Read.
--
eval = function(self, text)
+ self:preprocess_eval(text)
text = text..'$EOF$\n'
if not self:write(text) then
error(self:set_error())
@@ -422,9 +464,18 @@ local function wrap_text_socket(connection, url, print_f)
host = url.host or 'localhost',
port = url.service,
print_f = print_f,
+ eos = current_eos(),
}, text_connection_mt)
- if not conn:write('require("console").delimiter("$EOF$")\n') or
- not conn:read() then
+ --
+ -- Prepare the connection: setup EOS symbol
+ -- by executing the \set command on remote machine
+ -- explicitly, and then setup a delimiter.
+ local cmd_set_output = output_to_cmd_string(current_output()) .. '\n'
+ if not conn:write(cmd_set_output) or not conn:read() then
+ conn:set_error()
+ end
+ local cmd_delimiter = 'require("console").delimiter("$EOF$")\n'
+ if not conn:write(cmd_delimiter) or not conn:read() then
conn:set_error()
end
return conn
--
GitLab