Rails setup on WSL: db:create results in “cannot connect to server error”

Question

I'm trying to setup Rails to work in WSL 2. I have followed this guide to do so. On executing the command rails db:create I get the following error:

could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
Couldn't create 'myapp_development' database. Please check your configuration.
rails aborted!
ActiveRecord::NoDatabaseError: could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
/home/ke/rails/myapp/bin/rails:9:in `<top (required)>'
/home/ke/rails/myapp/bin/spring:15:in `<top (required)>'
bin/rails:3:in `load'
bin/rails:3:in `<main>'

Caused by:
PG::ConnectionBad: could not connect to server: No such file or directory
        Is the server running locally and accepting
        connections on Unix domain socket "/var/run/postgresql/.s.PGSQL.5432"?
/home/ke/rails/myapp/bin/rails:9:in `<top (required)>'
/home/ke/rails/myapp/bin/spring:15:in `<top (required)>'
bin/rails:3:in `load'
bin/rails:3:in `<main>'
Tasks: TOP => db:create
(See full trace by running task with --trace)

As per the instructions I have installed postgresql using the interactive installer by Enterprise DB. Is there some way the WSL installation isn't able to see the postgres installation on Windows?

Answer 1

I followed the same guide and had the same problem. Fixed it by explicitly specifying the host, username and password for accessing postgres database like so in database.yml:

default: &default
  adapter: postgresql
  encoding: unicode
  host: 127.0.0.1 # or localhost
  username: postgres # or your username
  password: ENV['POSTGRESQL_PASSWORD'] # or your password
  pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>

The problem was that WSL (ubuntu) was trying to connect to postgres on windows via a Unix socket, which did not exist. Just like using --host option while running psql --host=127.0.0.1 database_name , we have set a default for rails here.

Answer 2

If you want to install and use postgres in your windows environment than what are you using WSL for? You should install postgres on ubuntu(or any other distro that you use).

I also use WSL and have ruby, rails, postgres etc all installed on ubuntu and it works great.