Configura Discourse per usare un server PostgreSQL separato

[Discourse]

Supponiamo che tu stia utilizzando AWS RDS o un server PostgreSQL esistente gestito altrove. È abbastanza semplice far sì che Discourse utilizzi una tale configurazione, senza la necessità di concedere privilegi di superutente a qualsiasi cosa Discourse stesso esegua. Ecco come.

Prerequisiti

Discourse richiede che la versione principale di PostgreSQL corrisponda a quella che forniamo nelle nostre immagini docker; se si tenta di eseguire su una versione più recente o precedente, potrebbe funzionare, ma non lo garantiamo, e se qualcosa si rompe in futuro, terranno entrambi i pezzi. Richiediamo anche alcune estensioni che sono distribuite nel pacchetto postgresql-contrib (o il suo equivalente). Avrai anche bisogno dell’estensione pgvector (pacchetto postgresql-<versione>-pgvector), richiesta dal plugin Discourse AI fornito con il core di Discourse.

Genera casualmente una password per la connessione (20+ caratteri). In questa guida, useremo s3kr1t come segnaposto.

Configurazione del DB

Come superutente del database, esegui quanto segue:

CREATE USER discourse PASSWORD 's3kr1t';
CREATE DATABASE discourse OWNER discourse;
\c discourse
CREATE EXTENSION hstore;
CREATE EXTENSION pg_trgm;
CREATE EXTENSION unaccent;
CREATE EXTENSION vector;

Tutto ciò che deve essere fatto per preparare il DB all’uso da parte di Discourse è questo.

Configurazione di Discourse

Configura Discourse nel modo abituale, quindi modifica containers/app.yml come segue:

1. Rimuovi la riga - "templates/postgres.template.yml" sotto la chiave di primo livello templates (verso l’alto del file);

2. Sotto la chiave di primo livello env, imposta quanto segue:

    DISCOURSE_DB_USERNAME: discourse
    DISCOURSE_DB_PASSWORD: s3kr1t
    DISCOURSE_DB_HOST: <IP o nome host>
    DISCOURSE_DB_NAME: discourse
   

3. Devi anche impostare quanto segue se il tuo database non utilizza la porta predefinita (5432):

   DISCOURSE_DB_PORT: <porta>
   DISCOURSE_DB_BACKUP_PORT: <porta>
   

4. Ricostruisci con ./launcher rebuild app, e dovresti essere pronto per partire.

[alexweej (Alexander “Weej” Jones)]

There is an additional setting, DISCOURSE_DB_PORT, which can, naturally, configure the TCP port number. @mpalmer please update the post?

Thanks

[mpalmer (Matt Palmer)]

This isn’t supposed to be a comprehensive description of every possible way you can configure your database connection, rather it’s a quick howto to make things a bit easier.

[alexweej (Alexander “Weej” Jones)]

Is there somewhere more authoritative for this documentation? I even tried (unsuccessfully) to track down the source code for this…!

Thanks

[mpalmer (Matt Palmer)]

The discourse_docker repo is where all that lives.

[alexweej (Alexander “Weej” Jones)]

Thanks for the pointer, I’m embarrassed to admit I’ve gone through almost an entire setup without realising the wealth of documentation on that page.

That said, the only reference to DISCOURSE_DB_PORT is in web.template.yml: https://github.com/discourse/discourse_docker/search?utf8=✓&q=DISCOURSE_DB_PORT&type=

[mpalmer (Matt Palmer)]

Yes, it could probably stand to be promoted into the default “web_only” template, with a suitably explanatory comment. PRs welcome!

[Ivan_Rapekas]

Hi, first thanks for this guide. I try to setup external postgresql on the same machine, where docker installed. Do I need to bind port of my external postgresql 5432 to docker? Could anybody assist how to do it, using Discourse configuration file?

[mpalmer (Matt Palmer)]

Your question doesn’t make any sense. You don’t bind external listening ports to Docker.

[Ivan_Rapekas]

I follow the instruction a the top. First I set up an ordinary docker, it works. Then I want to switch the application to external postgres. When I rebuild the app, I get an error

Is the server running on host "127.0.0.1" and accepting TCP/IP connections on port 5432?

My server has not a FQDN yet, I use 127.0.0.1 as a DB host. The database is listening on 127.0.0.1:5432, I am able to connect with psql. Where am I wrong? I tried to play with pg_hba.conf but no success, of course.

[Ivan_Rapekas]

Hi guys, possible of my personal server configuration or what else… But I found a solution by running a docker in hosted mode (not bridged as default):

/var/discourse/launcher rebuild app --docker-args --net=host --skip-mac-address

After that the discourse engine could connect to external postgres database, run at 127.0.0.1:5432. Default bridged mode does not allow docker to access ports listening at the host without tricks.

Hope this might help somebody.

[davedogs]

When I run ./launcher rebuild app, I get this error PG::ConnectionBad: timeout expired during the bundle exec rake db:migrate. Has anyone comes across this issue? I can successfully access the database with a postgres client.

[jpsayshello (Jaimin)]

I have not tried this yet.
Here it is suggested to remove web.template.yml but i see bunch of other stuff happening in discourse_docker/templates/web.template.yml at master · discourse/discourse_docker · GitHub

What about that ?

[schleifer (Andrew Schleifer)]

@jpsayshello

Here it is suggested to remove web.template.yml

No it doesn’t. 

@mpalmer

Remove the line - "templates/postgres.template.yml"

[Tango]

Can you take the same approach for Redis?

remove “templates/redis.template.yml” & add a line in the app.yml file for DISCOURSE_REDIS_HOST

Thanks in advance

Todd

[itsbhanusharma (Bhanu Sharma)]

Is there an obvious benefit that I’m maybe missing?

(I assume running redis on a separate machine will just add unwanted latency if nothing else)

[Tango]

Just that its managed & 1 less thing to worry about

[itsbhanusharma (Bhanu Sharma)]

You don’t have to worry about redis that ships with discourse. I haven’t seen it failing on me in the last 1 year of self hosting discourse.

[Tango]

Thanks @itsbhanusharma,

Do you know what the process would be even if I did?

This article, albeit a little old says to add

DISCOURSE_REDIS_HOST

which is the same format as the article you so kindly mentioned, so that all makes sense.

Just not sure where to put it (maybe underneath other changes made to the app.yml file or maybe in the "templates/redis.template.yml")

and also

what if any lines or files need to be deleted

Thanks

Todd

[itsbhanusharma (Bhanu Sharma)]

That variable should go into the file where you declared postgres variables. Just be warned that exposing redis for a production environment is lethal. (Because of poor security practices of redis itself)