Good afternoon! Newbie here, I’ve tried to install Lemmy using Ansible (Debian stable) and I ended up having an issue with the Postgresql connectivity (localhost via socket).

The error message I have is:

thread 'main' panicked at 'Error connecting to postgresql:///lemmy?user=lemmy&host=/var/run/postgresql: connection to server on socket "/var/run/postgresql/.s.PGSQL.5432" failed: No such file or directory

I have updated my /etc/postgresql/15/main/pg_hba.conf from peer to trust to md5 with no success (rebooting Postresql each time).

My config.hjson is:

database: {
 uri: "postgresql:///lemmy?user=lemmy&host=/var/run/postgresql"
 password: "{{ postgres\_password }}"
}

Any idea / suggestion? Thanks!

PS: cross-posted on the Matrix.org install support chat

  • @idefix@sh.itjust.worksOP
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    11 year ago

    The path is correct, my investigations directed me towards a docker access issue as suggested by your #2. Looking into it now, thanks!

    • @taaz@biglemmowski.win
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      1 year ago

      If lemmy is actually running in docker then you should rather use network instead of socket file - while it should work I would be afraid of docker shenanigans when it comes to mounting a socket file as volume into the container (it should work, but …).

      You should be able to access postgres over network on the host thru extra_hosts settings:

      extra_hosts:
          - "host.docker.internal:host-gateway"
      

      https://stackoverflow.com/a/43541732

      postgres://host.docker.internal:5432

      • @idefix@sh.itjust.worksOP
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        11 year ago

        My investigations so far have led me to the conclusion that the Ansible install creates multiple docker containers, including one for Lemmy and one for Postgresql. I need now to figure out how inter-container communications work but the host itself is not used.

        • @taaz@biglemmowski.win
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          1 year ago

          Ah right, I assumed you were trying to connect the lemmy container to postgres running outside of docker.

          One important thing to remember with all docker compose files - the service name (the first keys in the services: configuration) is also the hostname of that container so to ping lemmy (from some other container in that docker compose) you would do ping lemmy, same for postgres ping postgres - but if the postgres service was named db0 then it would be ping db0.
          You also do not have to expose ports - all containers in that compose share one network (exposing is for outside access).
          All together your postgres config for lemmy should like this:

           database: { 
            # name of the postgres database for lemmy
            database: "lemmy" 
            # username to connect to postgres 
            user: "postgres"
            # password to connect to postgres
            password: "xxxxxxx"
            # host where postgres is running
            host: "postgres" 
            # port where postgres can be accessed
            port: 5432
            # maximum number of active sql connections
            pool_size: 10
          }
          
            • @taaz@biglemmowski.win
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              11 year ago

              I don’t get what you mean here. Communication over (linux) socket file and TCP/IP is very different.

              • @idefix@sh.itjust.worksOP
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                21 year ago

                After reading your comment, I went back to investigate my install. I can’t remember having changed anything relevant but Lemmy started to function properly, connecting as it should the database. It’s been stable since, even after reboots.

                As you suggested, I am using “postgres” as the host, as the service is described in the docker-compose.yml file. The communication is then via TCP/IP and not socket.