[BUG] Error parsing config when using MQTT

Start by reproducing the error with the supplied /config/syslog-ng.conf and the MQTT destination on the documented Docker image and arm64 environment. Compare the reported parser location with the syslog-ng MQTT destination documentation. Done means the container starts without a parsing error and messages matching the DHCP filter are delivered to MQTT.

Is there an existing issue for this?

• I have searched the existing issues

Current Behavior

Attempting to set up an MQTT destination results in an error parsing config. I originally thought it was related to this issue, but I was able to eliminate the cloud_auth error by rolling back to version 4.1.1-r2-ls99 with no change to the MQTT error.

This is a new setup of syslog-ng, and I'm using the official documentation to set up a very basic log source & destination.

Expected Behavior

syslog-ng should start without an error parsing, and should log to an MQTT destination.

Steps To Reproduce

Set up syslog-ng with a basic configuration, and attempt to add an MQTT destination. Syslog-ng will then fail to start and will log a parsing error.

Environment

- OS: Raspbian
- How docker service was installed: sudo apt-get install docker-compose

syslog-ng.conf:

#############################################################################
# Default syslog-ng.conf file which collects all local logs into a
# single file called /var/log/messages tailored to container usage.

@version: 4.1
@include "scl.conf"

source s_local {
  internal();
};

source s_network_tcp {
  syslog(transport(tcp) port(6601));
};

source s_network_udp {
  syslog(transport(udp) port(5514));
};

destination d_local {
  file("/var/log/messages");
  file("/var/log/messages-kv.log" template("$ISODATE $HOST $(format-welf --scope all-nv-pairs)\n") frac-digits(3));
};

destination d_mqtt {
  mqtt(topic("router/dhcp/eth1"), address("tcp://myhost:1883"), username("myuser"), password("mypassword"));
};

log {
  source(s_local);
  source(s_network_tcp);
  source(s_network_udp);
  parser(panos-parser());
  destination(d_local);
  if (message("DHCP"))
  {
    destination(d_mqtt);
  };
};

### CPU architecture

arm64

### Docker creation

```bash
---
services:
  syslog-ng:
    image: lscr.io/linuxserver/syslog-ng:4.1.1-r2-ls99
    container_name: syslog-ng
    environment:
      - PUID=1000
      - PGID=1000
      - TZ='America/New_York'
    volumes:
      - /home/steve/docker/syslog-ng/config:/config
      - /home/steve/docker/syslog-ng/log:/var/log
    ports:
      - 514:5514/udp
      - 601:6601/tcp
      - 6514:6514/tcp
    restart: unless-stopped

Container logs

Logs from `docker logs syslog-ng`:

[migrations] started
[migrations] no migrations found
usermod: no changes
───────────────────────────────────────

      ██╗     ███████╗██╗ ██████╗
      ██║     ██╔════╝██║██╔═══██╗
      ██║     ███████╗██║██║   ██║
      ██║     ╚════██║██║██║   ██║
      ███████╗███████║██║╚██████╔╝
      ╚══════╝╚══════╝╚═╝ ╚═════╝

   Brought to you by linuxserver.io
───────────────────────────────────────

To support LSIO projects visit:
https://www.linuxserver.io/donate/

───────────────────────────────────────
GID/UID
───────────────────────────────────────

User UID:    1000
User GID:    1000
───────────────────────────────────────

[custom-init] No custom files found, skipping...
[ls.io-init] done.

Logs from syslog-ng itself (config/log/current):

2024-06-02 18:16:55.699826612  Error parsing config, syntax error, unexpected LL_IDENTIFIER, expecting '}' in /config/syslog-ng.conf:26:3-26:7:
2024-06-02 18:16:55.699999128  21        file("/var/log/messages");
2024-06-02 18:16:55.700063794  22        file("/var/log/messages-kv.log" template("$ISODATE $HOST $(format-welf --scope all-nv-pairs)\n") frac-digits(3));
2024-06-02 18:16:55.700070035  23      };
2024-06-02 18:16:55.700073868  24
2024-06-02 18:16:55.700078387  25      destination d_mqtt {
2024-06-02 18:16:55.700140627  26---->   mqtt(topic("router/dhcp/eth1"), address("tcp://myhost:1883"), username("myuser"), password("mypassword"));
2024-06-02 18:16:55.700198459  26---->   ^^^^
2024-06-02 18:16:55.700204126  27      };
2024-06-02 18:16:55.700207552  28
2024-06-02 18:16:55.700211107  29      log {
2024-06-02 18:16:55.700215200  30        source(s_local);
2024-06-02 18:16:55.700271329  31        source(s_network_tcp);
2024-06-02 18:16:55.700445938
2024-06-02 18:16:55.700452012
2024-06-02 18:16:55.700459827  syslog-ng documentation: https://www.syslog-ng.com/technical-documents/list/syslog-ng-open-source-edition
2024-06-02 18:16:55.700463364  contact:
2024-06-02 18:16:55.700468789   GitHub Project: https://github.com/syslog-ng/syslog-ng
2024-06-02 18:16:55.700474604   Chat with the Developers: https://gitter.im/syslog-ng/syslog-ng
2024-06-02 18:16:55.700480363   Mailing List: https://lists.balabit.hu/mailman/listinfo/syslog-ng