Init two instances of maxminddb

[sergeydi]

I try to copy maxminddb.lua as discussed in (https://github.com/anjia0532/lua-resty-maxminddb/issues/11) for creating additional instance for other maxmind db. But got error:

23030#23030: *18 lua entry thread aborted: runtime error: /usr/local/openresty/lualib/maxminddb2.lua:120: attempt to redefine 'MMDB_entry_s' at line 4

My code:

local geoip = require "maxminddb"
local orgip = require "maxminddb2"
if not geoip.initted() then
    geoip.init("/usr/share/GeoIP/GeoIP2-Country.mmdb")
end

if not orgip.initted() then
    orgip.init("/usr/share/GeoIP/GeoIP2-ISP.mmdb")
end

[anjia0532]

paste your maxminddb2.lua code

[sergeydi]

I just copy https://github.com/anjia0532/lua-resty-maxminddb/raw/master/lib/resty/maxminddb.lua

root@clickhouse-api:/usr/local/openresty/lualib# md5sum maxminddb.lua 
9926c22ff8027399c53f770ed8810de6  maxminddb.lua
root@clickhouse-api:/usr/local/openresty/lualib# md5sum maxminddb2.lua 
9926c22ff8027399c53f770ed8810de6  maxminddb2.lua
root@clickhouse-api:/usr/local/openresty/lualib# 

[maxminddb2.zip](https://github.com/anjia0532/lua-resty-maxminddb/files/3841921/maxminddb2.zip)

[sergeydi]

maxminddb2.zip

[anjia0532]

can you try to init two /path/to/GeoIP/GeoLite2-City.mmdb ?

ref my comment https://github.com/anjia0532/lua-resty-maxminddb/issues/11#issuecomment-420953393

BTW,this lib only support city db(official 😊 ),not asn db.

[Stiff91x]

I have the same problem, i should take infos from 3db, Country, ISP and Connection-Type, but always the first initialized wins...

I tried with 3 objects like @sergeydi and experienced same "redefine 'MMDB_entry_s' at line 4", any suggests? Thanks

PS: i'm using _M._VERSION = '1.3.2'

[anjia0532]

@Stiff91x this lib only support city db.

[joelsdc]

Hi, today I went down this rabbit hole and I'd like to add my findings:

1. I don't think "this lib only supports city db" is completely accurate, I have tried country and asn, and both work perfectly. In fact, I've been using this lib with ASN db in prod for a long time now with 0 issues.
2. The problem where you cannot load both at the same time does exist, but I've managed to work around it with minimal hacks to the code.
3. In my usacase, I load the maxmind databases in init_by_lua* so on each request I can just do the lookup, I think this should be faster but I haven't verified with load tests.

The hack (ugly, but works):

--- maxminddb.lua	2021-02-23 18:27:21.000000000 -0800
+++ maxminddb.lua_new	2021-02-23 17:20:20.000000000 -0800
@@ -1,3 +1,5 @@
+-- {{ ansible_managed }}
+
 --[[
 	Copyright 2017-now anjia ([email protected])

@@ -165,6 +167,7 @@
 local maxm                                          = ffi.load('libmaxminddb')
 --https://github.com/maxmind/libmaxminddb
 local mmdb                                          = ffi_new('MMDB_s')
+local mmdb_asn                                      = ffi_new('MMDB_s')
 local initted                                       = false

 local function mmdb_strerror(rc)
@@ -175,17 +178,23 @@
     return ffi_str(C.gai_strerror(rc))
 end

-function _M.init(dbfile)
+function _M.init(dbfile,dbfile_asn)
   if not initted then
     local maxmind_ready   = maxm.MMDB_open(dbfile,0,mmdb)
+    local maxmind_ready_asn   = maxm.MMDB_open(dbfile_asn,0,mmdb_asn)

     if maxmind_ready ~= MMDB_SUCCESS then
         return nil, mmdb_strerror(maxmind_ready)
     end

+    if maxmind_ready_asn ~= MMDB_SUCCESS then
+        return nil, mmdb_strerror(maxmind_ready_asn)
+    end
+
     initted = true

     ffi_gc(mmdb, maxm.MMDB_close)
+    ffi_gc(mmdb_asn, maxm.MMDB_close)
   end
   return initted
 end
@@ -356,6 +365,51 @@
   return result
 end

+
+function _M.lookup_asn(ip)
+
+  if not initted then
+      return nil, "not initialized"
+  end
+
+  -- copy from https://github.com/lilien1010/lua-resty-maxminddb/blob/f96633e2428f8f7bcc1e2a7a28b747b33233a8db/resty/maxminddb.lua#L159-L176
+  local gai_error = ffi_new('int[1]')
+  local mmdb_error = ffi_new('int[1]')
+
+  local result = maxm.MMDB_lookup_string(mmdb_asn,ip,gai_error,mmdb_error)
+
+  if mmdb_error[0] ~= MMDB_SUCCESS then
+    return nil,'lookup failed: ' .. mmdb_strerror(mmdb_error[0])
+  end
+
+  if gai_error[0] ~= MMDB_SUCCESS then
+    return nil,'lookup failed: ' .. gai_strerror(gai_error[0])
+  end
+
+  if true ~= result.found_entry then
+    return nil,'not found'
+  end
+
+  local entry_data_list = ffi_cast('MMDB_entry_data_list_s **const',ffi_new("MMDB_entry_data_list_s"))
+
+  local status = maxm.MMDB_get_entry_data_list(result.entry,entry_data_list)
+
+  if status ~= MMDB_SUCCESS then
+    return nil,'get entry data failed: ' .. mmdb_strerror(status)
+  end
+
+  local head = entry_data_list[0] -- Save so this can be passed to free fn.
+  local _,status,result = _dump_entry_data_list(entry_data_list)
+  maxm.MMDB_free_entry_data_list(head)
+
+  if status ~= MMDB_SUCCESS then
+    return nil,'dump entry data failed: ' .. mmdb_strerror(status)
+  end
+
+
+  return result
+end
+
 -- copy from https://github.com/lilien1010/lua-resty-maxminddb/blob/master/resty/maxminddb.lua#L208
 -- https://www.maxmind.com/en/geoip2-databases  you should download  the mmdb file from maxmind

Basically I'm duplicating what I need to be able to have 2 databases open at the same time in without the second one using the same resource as the first, and without running into the problem described attempt to redefine 'MMDB_entry_s' at line 4 when you copy/duplicate the maxminddb.lua lib.

I load it in init_by_lua* in nginx.conf passing both databases as args:

  init_by_lua_block {
    -- Load MaxMind ASN DB here so we don't have to load it per request in content_by_lua_*
    MMDB = require("maxminddb")
    MMDB.init("/var/lib/GeoIP/GeoLite2-Country.mmdb","/var/lib/GeoIP/GeoLite2-ASN.mmdb")
  }

And then later in the http server blocks, I can do:

      set_by_lua_block $request_country {
        local res, err = MMDB.lookup(ngx.var.remote_addr)
        if res then
            ngx.req.set_header("X-Client-Geo-Region", res.country.iso_code)
            return res.country.iso_code
        end
        return ""
      }

Or if I need info from the ASN:

      set_by_lua_block $request_asn {
        local res, err = MMDB.lookup_asn(ngx.var.remote_addr)
        if res then
            ngx.req.set_header("X-Client-ASN", res.autonomous_system_number)
            return res.autonomous_system_number
        end
        return ""
      }

This patch solves my use case, I need country and asn, but it should be pretty straight forward to adapt for other use cases.

I hope this helps anyone else that gets stuck with this.

[anjia0532]

@joelsdc thanks for your job, do you create a PR to commit this?

[onyon]

I needed this same functionality but with additional MMDBs and not just ASN. I solved this by sending a table into init and mapping them out internally.

geo.init({
  city = "/usr/local/maxmind/GeoIP2-City.mmdb",
  isp  = "/usr/local/maxmind/GeoIP2-ISP.mmdb",
  asn  = "/usr/local/maxmind/GeoLite2-ASN.mmdb",
  conn = "/usr/local/maxmind/GeoIP2-Connection-Type.mmdb"
})

geo.lookup("city", "8.8.8.8")
geo.lookup("isp", "8.8.8.8")
geo.lookup("asn", "8.8.8.8")
geo.lookup("conn", "8.8.8.8")

In the future I'll overload the input so it's backwards compatible and open up a PR to upstream. For now, if anyone else needs the code it's available here.

[anjia0532]

Expect ! @cebollia