The mysql-proxy administration interface can be accessed using any MySQL client using the standard protocols. You can use the administration interface to gain information about the proxy server as a whole - standard connections to the proxy are isolated to operate as if you were connected directly to the backend MySQL server.
In mysql-proxy 0.8.0 and earlier, a rudimentary interface was built into the proxy. In later versions this was replaced so that you must specify an administration script to be used when users connect to the administration interface.
To use the administration interface, you should specify the user
name and password required to connect to the admin service
(using the --admin-username
and --admin-password
options). You must also specify the Lua script to be used as the
interface to the administration service by using the
admin-lua-script script
option to point to a Lua script.
For example, you can create a basic interface to the internal components of the mysql-proxy system using the following script, written by Diego Medina:
--[[
Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
--]]
-- admin.lua
--[[
See http://forge.mysql.com/tools/tool.php?id=78
(Thanks to Jan Kneschke)
See http://www.chriscalender.com/?p=41
(Thanks to Chris Calender)
See http://datacharmer.blogspot.com/2009/01/mysql-proxy-is-back.html
(Thanks Giuseppe Maxia)
--]]
function set_error(errmsg)
proxy.response = {
type = proxy.MYSQLD_PACKET_ERR,
errmsg = errmsg or "error"
}
end
function read_query(packet)
if packet:byte() ~= proxy.COM_QUERY then
set_error("[admin] we only handle text-based queries (COM_QUERY)")
return proxy.PROXY_SEND_RESULT
end
local query = packet:sub(2)
local rows = { }
local fields = { }
-- try to match the string up to the first non-alphanum
local f_s, f_e, command = string.find(packet, "^%s*(%w+)", 2)
local option
if f_e then
-- if that match, take the next sub-string as option
f_s, f_e, option = string.find(packet, "^%s+(%w+)", f_e + 1)
end
-- we got our commands, execute it
if command == "show" and option == "querycounter" then
---
-- proxy.PROXY_SEND_RESULT requires
--
-- proxy.response.type to be either
-- * proxy.MYSQLD_PACKET_OK or
-- * proxy.MYSQLD_PACKET_ERR
--
-- for proxy.MYSQLD_PACKET_OK you need a resultset
-- * fields
-- * rows
--
-- for proxy.MYSQLD_PACKET_ERR
-- * errmsg
proxy.response.type = proxy.MYSQLD_PACKET_OK
proxy.response.resultset = {
fields = {
{ type = proxy.MYSQL_TYPE_LONG, name = "query_counter", },
},
rows = {
{ proxy.global.query_counter }
}
}
-- we have our result, send it back
return proxy.PROXY_SEND_RESULT
elseif command == "show" and option == "myerror" then
proxy.response.type = proxy.MYSQLD_PACKET_ERR
proxy.response.errmsg = "my first error"
return proxy.PROXY_SEND_RESULT
elseif string.sub(packet, 2):lower() == 'select help' then
return show_process_help()
elseif string.sub(packet, 2):lower() == 'show proxy processlist' then
return show_process_table()
elseif query == "SELECT * FROM backends" then
fields = {
{ name = "backend_ndx",
type = proxy.MYSQL_TYPE_LONG },
{ name = "address",
type = proxy.MYSQL_TYPE_STRING },
{ name = "state",
type = proxy.MYSQL_TYPE_STRING },
{ name = "type",
type = proxy.MYSQL_TYPE_STRING },
}
for i = 1, #proxy.global.backends do
local b = proxy.global.backends[i]
rows[#rows + 1] = {
i, b.dst.name, b.state, b.type
}
end
else
set_error()
return proxy.PROXY_SEND_RESULT
end
proxy.response = {
type = proxy.MYSQLD_PACKET_OK,
resultset = {
fields = fields,
rows = rows
}
}
return proxy.PROXY_SEND_RESULT
end
function make_dataset (header, dataset)
proxy.response.type = proxy.MYSQLD_PACKET_OK
proxy.response.resultset = {
fields = {},
rows = {}
}
for i,v in pairs (header) do
table.insert(proxy.response.resultset.fields, {type = proxy.MYSQL_TYPE_STRING, name = v})
end
for i,v in pairs (dataset) do
table.insert(proxy.response.resultset.rows, v )
end
return proxy.PROXY_SEND_RESULT
end
function show_process_table()
local dataset = {}
local header = { 'Id', 'IP Address', 'Time' }
local rows = {}
for t_i, t_v in pairs (proxy.global.process) do
for s_i, s_v in pairs ( t_v ) do
table.insert(rows, { t_i, s_v.ip, os.date('%c',s_v.ts) })
end
end
return make_dataset(header,rows)
end
function show_process_help()
local dataset = {}
local header = { 'command', 'description' }
local rows = {
{'SELECT HELP', 'This command.'},
{'SHOW PROXY PROCESSLIST', 'Show all connections and their true IP Address.'},
}
return make_dataset(header,rows)
end
function dump_process_table()
proxy.global.initialize_process_table()
print('current contents of process table')
for t_i, t_v in pairs (proxy.global.process) do
print ('session id: ', t_i)
for s_i, s_v in pairs ( t_v ) do
print ( '\t', s_i, s_v.ip, s_v.ts )
end
end
print ('---END PROCESS TABLE---')
end
--[[ Help
we use a simple string-match to split commands are word-boundaries
mysql> show querycounter
is split into
command = "show"
option = "querycounter"
spaces are ignored, the case has to be as is.
mysql> show myerror
returns a error-packet
--]]
The script works in combination with a main proxy script,
reporter.lua:
--[[
Copyright 2008, 2010, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
--]]
-- reporter.lua
--[[
See http://forge.mysql.com/tools/tool.php?id=78
(Thanks to Jan Kneschke)
See http://www.chriscalender.com/?p=41
(Thanks to Chris Calender)
See http://datacharmer.blogspot.com/2009/01/mysql-proxy-is-back.html
(Thanks Giuseppe Maxia)
--]]
proxy.global.query_counter = proxy.global.query_counter or 0
function proxy.global.initialize_process_table()
if proxy.global.process == nil then
proxy.global.process = {}
end
if proxy.global.process[proxy.connection.server.thread_id] == nil then
proxy.global.process[proxy.connection.server.thread_id] = {}
end
end
function read_auth_result( auth )
local state = auth.packet:byte()
if state == proxy.MYSQLD_PACKET_OK then
proxy.global.initialize_process_table()
table.insert( proxy.global.process[proxy.connection.server.thread_id],
{ ip = proxy.connection.client.src.name, ts = os.time() } )
end
end
function disconnect_client()
local connection_id = proxy.connection.server.thread_id
if connection_id then
-- client has disconnected, set this to nil
proxy.global.process[connection_id] = nil
end
end
---
-- read_query() can return a resultset
--
-- You can use read_query() to return a result-set.
--
-- @param packet the mysql-packet sent by the client
--
-- @return
-- * nothing to pass on the packet as is,
-- * proxy.PROXY_SEND_QUERY to send the queries from the proxy.queries queue
-- * proxy.PROXY_SEND_RESULT to send your own result-set
--
function read_query( packet )
-- a new query came in in this connection
-- using proxy.global.* to make it available to the admin plugin
proxy.global.query_counter = proxy.global.query_counter + 1
end
To use the script, save the first script to a file
(admin.lua in the following example) and
the other to reporter.lua, then run
mysql-proxy specifying the admin script and a
backend MySQL server:
shell>mysql-proxy --admin-lua-script=admin.lua --admin-password=password \ »--admin-username=root --proxy-backend-addresses=127.0.0.1:3306 -proxy-lua-script=reporter.lua
In a different window, connect to the MySQL server through the proxy:
shell> mysql --user=root --password=password --port=4040
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1798669
Server version: 5.0.70-log Gentoo Linux mysql-5.0.70-r1
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql>
In another different window, connect to the mysql-proxy admin service using the specified user name and password:
shell> mysql --user=root --password=password --port=4041 --host=localhost
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.0.99-agent-admin
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
mysql>
To monitor the status of the proxy, ask for a list of the current active processes:
mysql> show proxy processlist;
+---------+---------------------+--------------------------+
| Id | IP Address | Time |
+---------+---------------------+--------------------------+
| 1798669 | 192.168.0.112:52592 | Wed Jan 20 16:58:00 2010 |
+---------+---------------------+--------------------------+
1 row in set (0.00 sec)
mysql>
For more information on the example, see MySQL Proxy Admin Example.