Using sockets for database#

Mattermost requires a database back-end, and PostgreSQL is our database of choice. In this document let’s understand how you can use sockets for setting up the database.

Install and configure PostgreSQL.
Choose between TCP or UNIX Socket, and jump to the corresponding section.

With TCP socket#

Create the new user while connecting to the server as postgres user (you will be prompted for a password for the new user):

sudo -u postgres createuser -P mmuser
Create the Mattermost database, owned by mmuser user:

sudo -u postgres createdb -O mmuser mattermostdb
In the connections and authentications section, set the listen_address list line per your needs:
/var/lib/postgres/data/postgresql.conf listen_address = 'localhost,my_local_ip_address'
You can use ‘*’ to listen on all available addresses.

Then add a line like the following to the authentication config:

/var/lib/postgres/data/pg_hba.conf
# TYPE  DATABASE        USER            ADDRESS                 METHOD
# IPv4 local connections:
host    all             all             ip_address/32   md5

Run the setup using:

$ psql --host=ip_address --dbname=mattermostdb --username=mmuser --password

With Unix socket#

Create the new user while connecting to the server as postgres user:
```
sudo -u postgres createuser mattermost
```

Create the Mattermost database, owned by mattermost user:

sudo -u postgres createdb -O mattermost mattermostdb

Setup the Unix socket by adding the following line to /var/lib/postgres/data/pg_hba.conf:
```
local    mattermostdb    mattermost    peer
```
Restart postgresql.service.

Run the setup using:

sudo -u mattermost psql --dbname=mattermostdb

Configuring Mattermost#

Mattermost is configured in /etc/webapps/mattermost/config.json. Strings need to be quoted.
Set DriverName to postgres.

Set DataSource:
- TCP socket: postgres://mmuser:mmuser_password@127.0.0.1:5432/mattermostdb?sslmode=disable&connect_timeout=10
- Unix socket: postgres:///mattermostdb?host=/run/postgresql, where mattermostdb is the name of the database and /run/postgresql is the directory containing the Unix socket.