PostgreSQL unix socket will not connect and crashes

[Jieiku]

Environment

• ejabberd version: 21.07
• Erlang version: erl +V: Erlang (SMP,ASYNC_THREADS) (BEAM) emulator version 10.6.4
• OS: Linux Ubuntu 20.04.3 LTS (GNU/Linux 5.4.143-1-pve x86_64)
• Installed from: official deb ( https://static.process-one.net/ejabberd/downloads/21.07/ejabberd_21.07-0_amd64.deb )

Configuration:

loglevel: 5

host_config:
  "example.com":
    sql_type: pgsql
    sql_server: "/run/postgresql"
    sql_database: "ejabberd"
    sql_username: "ejabberd"
    sql_password: ""
    auth_method: sql
    auth_password_format: scram

Errors from error.log/crash.log

ejabberd.log:

2021-11-26 19:27:50.986 [warning] <0.622.0>@ejabberd_sql:handle_reconnect:472 pgsql connection failed:
** Reason: {init,{error,nxdomain}}
** Retry after: 30 seconds

crash.log:

2021-11-26 19:27:50 =CRASH REPORT====
  crasher:
    initial call: pgsql_proto:init/1
    pid: <0.769.0>
    registered_name: []
    exception exit: {{init,{error,nxdomain}},[{gen_server,init_it,6,[{file,"gen_server.erl"},{line,358}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,249}]}]}
    ancestors: ['ejabberd_sql_example.com_2','ejabberd_sql_sup_example.com',ejabberd_db_sup,ejabberd_sup,<0.107.0>]
    message_queue_len: 0
    messages: []
    links: []
    dictionary: []
    trap_exit: false
    status: running
    heap_size: 610
    stack_size: 27
    reductions: 765
  neighbours:

error.log:

2021-11-26 19:27:50.987 [error] <0.766.0> CRASH REPORT Process <0.766.0> with 0 neighbours exited with reason: {init,{error,nxdomain}} in gen_server:init_it/6 line 358

Bug description

If you configure ejabberd.yaml (as shown above) to use pgsql via unix socket then it will not connect. Crashes are generated in the crash log as well.

[licaon-kter]

/close as duplicate #3165 ?

[Jieiku]

I don't see any resolution in that issue report, only that it was closed, and that was over a year ago, so I am hoping it is worth revisiting this?

[licaon-kter]

Did the issue got fixed in the lib?

[Jieiku]

mmm I found this project: https://github.com/saleyn/euds the opening readme of the page says this:

This project implements a NIF library to support Unix Domain Sockets.

UPDATE: this project will be deprecated beginning with Erlang 19RC2, which will include native support for Unix Domain Sockets.

That to me says that if we are on Erlang 19RC2 or later then yes native support for Unix sockets should be in the Erlang Library.

EDIT: here is relevant info: http://erlang.org/download/otp_src_19.0.readme

OTP-13572 Application(s): erts, kernel
Related Id(s): PR-612

           Experimental support for Unix Domain Sockets has been
           implemented. Read the sources if you want to try it
           out. Example: gen_udp:open(0,
           [{ifaddr,{local,"/tmp/socket"}}]). Documentation will
           be written after user feedback on the experimental API.

[badlop]

if we are on Erlang 19RC2 or later then yes native support for Unix sockets should be in the Erlang Library.

ejabberd uses p1_pgsql

ejabberd/src/ejabberd_sql.erl

Line 954 in 5506b83

case pgsql:connect([{host, Server},

and that library expects a host and a port
https://github.com/processone/p1_pgsql/blob/4c42903f91cbb2840b8a5266e6e3b5cdc82b702e/src/pgsql_proto.erl#L99

and that's the only it supports:
https://github.com/processone/p1_pgsql/blob/4c42903f91cbb2840b8a5266e6e3b5cdc82b702e/src/pgsql_util.erl#L48

[Jieiku]

hey hey, thanks for the reply! would still love to be able to use unix socket.

[Jieiku]

This is possible now?

[badlop]

Not possible yet, and apparently no plan; in that case the Milestone field should indicate in what version it is supported, expected or possible.

As months have passed and it seems there's no specific plan to implement it or general interest, during the periodic issue cleaning this has been marked for the "Parking lot", tagged "To reconsider", and temporarily closed.

[jeroenhabets]

FYI: @badlop wrote a patch 🥇 (see processone/p1_pgsql#7 (comment)) that I successfully (smoke)tested. @Jieiku perhaps you want to test https://github.com/badlop/ejabberd/tree/pgsql-unix-socket as well?

[jeroenhabets]

Thanks again @badlop 🥇! Now that it's committed we only need to be patience for it to be released.