Configurar o Discourse para usar um servidor PostgreSQL separado

[Discourse]

Digamos que você esteja usando o AWS RDS, ou um servidor PostgreSQL existente gerenciado em outro lugar. É bem simples fazer o Discourse usar essa configuração, sem a necessidade de conceder privilégios de superusuário a nada que o próprio Discourse execute. Veja como:

Pré-requisitos

O Discourse exige que a versão principal do PostgreSQL corresponda à que enviamos em nossas imagens docker; se você tentar executar em uma versão mais nova ou mais antiga, pode funcionar, mas não garantimos, e se algo quebrar no futuro, a responsabilidade é sua. Também exigimos algumas extensões que são distribuídas no pacote postgresql-contrib (ou seu equivalente). Você também precisará da extensão pgvector (pacote postgresql-<versão>-pgvector), que é exigida pelo plugin Discourse AI que acompanha o núcleo do Discourse.

Gere aleatoriamente uma senha para a conexão (mais de 20 caracteres). Neste guia, usaremos s3kr1t como um espaço reservado.

Configuração do DB

Como superusuário do banco de dados, execute o seguinte:

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;

Isso é tudo que precisa ser feito para preparar o DB para uso pelo Discourse.

Configurar o Discourse

Configure o Discourse da maneira usual e, em seguida, edite containers/app.yml da seguinte forma:

1. Remova a linha - "templates/postgres.template.yml" sob a chave de nível superior templates (perto do topo do arquivo);

2. Sob a chave de nível superior env, defina o seguinte:

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

3. Você também precisa definir o seguinte se o seu banco de dados não usar a porta padrão (5432):

   DISCOURSE_DB_PORT: <porta>
   DISCOURSE_DB_BACKUP_PORT: <porta>
   

4. Reconstrua com ./launcher rebuild app, e você estará pronto para começar.

[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)