LDAP auth no longer working after upgrade to Ejabberd Docker 20.07

[budbay]

Issue

After upgrading Ejabberd Docker container from 20.04 to 20.07 LDAP has completely stopped working, reverting back to 20.04 everything works normally. No changes have been made to configuration, and no other errors or warnings show up in logs other than below. Have been running and upgrading Ejabberd docker since 19.xx version without issues.

Environment

• Ejabberd 20.07 Docker Container (using tag: latest)
• OS: Ubuntu 18.04
• Docker installed from repos and up to date

LDAP Config

auth_method: [ldap]
ldap_servers: [IP]
ldap_encrypt: none
ldap_port: 389
ldap_base: "dc=example,dc=com" 

Error from log

   crasher:
     initial call: ejabberd_auth_ldap:init/1
     pid: <0.645.0>
     registered_name: []
     exception error: undefined function pg:start_link/0
       in function  eldap_pool:start_link/7 (src/eldap_pool.erl, line 69)
       in call from ejabberd_auth_ldap:init/1 (src/ejabberd_auth_ldap.erl, line 103)
       in call from gen_server:init_it/2 (gen_server.erl, line 374)
       in call from gen_server:init_it/6 (gen_server.erl, line 342)
    ancestors: [ejabberd_backend_sup,ejabberd_sup,<0.126.0>]
    message_queue_len: 0
    messages: []
    links: [<0.537.0>]
    dictionary: []
    trap_exit: true
    status: running
    heap_size: 610
    stack_size: 27
    reductions: 16544
  neighbours:

[badlop]

Do you know what Erlang version is used by ejabberd?

Looking at the error message and the source code, ejabberd's rebar.config thinks it is using Erlang 23.0 or newer. But apparently the Erlang library pg (which is included with Erlang/OTP 23.0 and newer, was not found.

$ erl
Erlang/OTP 23 [erts-11.0.2] [source] [64-bit] [smp:2:2] [ds:2:2:10] [async-threads:1]

Eshell V11.0.2  (abort with ^G)
1> pg:start_link().
{ok,<0.90.0>}

For example, in Debian, the library pg.beam is included in the package erlang-base:
https://packages.debian.org/search?searchon=contents&keywords=pg.beam&mode=path&suite=unstable&arch=amd64

[budbay]

I opened a debug shell and it states that it is using Erlang/OTP 22, so is this a bug with the docker container that it is not supplying the correct version?

[badlop]

Um, maybe Docker is missing some of the changes done in rebar.config

Can you please apply this patch to ejabberd and comment if it helps?

diff --git a/mix.exs b/mix.exs
index afc645eb3..00d7e0a57 100644
--- a/mix.exs
+++ b/mix.exs
@@ -66,7 +66,10 @@ defmodule Ejabberd.Mixfile do
              cond_options() ++
              Enum.map(includes, fn (path) -> {:i, path} end) ++
              if_version_above('20', [{:d, :DEPRECATED_GET_STACKTRACE}]) ++
+             if_version_below('21', [{:d, :USE_OLD_HTTP_URI}]) ++
              if_version_below('22', [{:d, :LAGER}]) ++
+             if_version_below('23', [{:d, :USE_OLD_CRYPTO_HMAC}]) ++
+             if_version_below('23', [{:d, :USE_OLD_PG2}]) ++
              if_function_exported(:erl_error, :format_exception, 6, [{:d, :HAVE_ERL_ERROR}])
     defines = for {:d, value} <- result, do: {:d, value}
     result ++ [{:d, :ALL_DEFS, defines}]

[budbay]

I applied the patch and rebuilt the docker image and LDAP auth is working as expected now, sorry but I only now had the time to test.

[badlop]

Thanks! I've applied the changes to ejabberd's git repo.