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Name

lua-resty-oceanbase - Lua OceanBase client driver for ngx_lua based on the cosocket API

Status

This library is considered not production ready.

Description

This Lua library is a OceanBase client driver for the ngx_lua nginx module:

https://wiki.nginx.org/HttpLuaModule

This Lua library takes advantage of ngx_lua's cosocket API, which ensures 100% nonblocking behavior.

Note that at least ngx_lua 0.5.7 or ngx_openresty 1.2.1.7 is required.

Also, the bit library is also required. If you're using LuaJIT 2.0 with ngx_lua, then the bit library is already available by default.

Synopsis

lua_package_path "/path/to/lua-resty-oceanbase/lib/?.lua;;";

server {
    location /test {
        content_by_lua '
            local oceanbase = require "resty.oceanbase"
            local db, err = oceanbase:new()

            local ok, err, errno, sqlstate = db:connect{
                host = "127.0.0.1",
                port = 5432,
            }

            if ok then
                local sql = [[select * from test limit 100 offset 0]]
                db:query(sql, function(i, row, err)
                    if err then
                        ngx.header["X-API-Error"] = err["M"] -- readable error message
                        --ngx.exit(500)            
                        ngx.say(err["M"])            
                    else
                        ngx.say(i..", "..table.concat(row, ", "))    
                    end
                end)
            end

            db:close()                
        ';
    }
}

Limitations

  • This library cannot be used in code contexts like set_by_lua*, log_by_lua*, and header_filter_by_lua* where the ngx_lua cosocket API is not available.
  • The resty.oceanbase object instance cannot be stored in a Lua variable at the Lua module level, because it will then be shared by all the concurrent requests handled by the same nginx worker process (see https://wiki.nginx.org/HttpLuaModule#Data_Sharing_within_an_Nginx_Worker ) and result in bad race conditions when concurrent requests are trying to use the same resty.mysql instance. You should always initiate resty.mysql objects in function local variables or in the ngx.ctx table. These places all have their own data copies for each request.

TODO

  • add the OB connection pool support.

Author

Hugo Zhu [email protected]

Copyright and License

This module is licensed under the BSD license.

Copyright (C) 2012, by Hugo Zhu [email protected].

All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

See Also