When trying to access my app locally, I am given: "could not translate host name ... to address" and "Temporary failure in name resolution"

Question

I am going through Heroku's getting started tutorial. As far as I know, Postgres is fully updated and everything is installed appropriately. Interestingly, the app works online when I deploy it to heroku, but when I try to run the app locally, not so much! I am getting a:

PG::ConnectionBad

could not translate host name "myname" to address: Temporary failure in name resolution

    ### Convenience alias for PG::Connection.new.
def self::connect( *args )
    return PG::Connection.new( *args )
end

I have not touched any information in the files created by Heroku for this tutorial - so what could be wrong?

The following commands were run:

heroku login
git clone https://github.com/heroku/ruby-getting-started.git
cd ruby-getting-started

heroku create

git push heroku main

heroku open (this gets to the app okay)
heroku logs --tail
which psql

bundle install

export DATABASE_URL=postgres://$(whoami)
bundle exec rake db:create db:migrate (Here is where the error is)

heroku local web
(Error here) http://localhost:5000/

Answer 1

DATABASE_URL=postgres://$(whoami)

This is trying to connect to a computer which happens to have the same name as your local user account. Unsurprisingly, it doesn't exist, hence the error.

Answer 2

Debug Postgres connection

Confirm that Postgres exists in yout local machine, is running and it have a user that maches with you machine username.

Try to run this command in your local machine:

psql -U $(whoami) -d postgres

The output should be something like this:

psql (9.2.24, server 10.14)
WARNING: psql version 9.2, server version 10.0.
        Some psql features might not work.
Type "help" for help.

postgres=#

Then, confirm that a database matching with your username exists with "\l".

postgres=#\l
                                   List of databases
      Name      |  Owner   | Encoding |   Collate   |    Ctype    |   Access privileges
----------------+----------+----------+-------------+-------------+-----------------------
 myuser       | odoo     | UTF8     | en_US.UTF-8 | en_US.UTF-8 |

tip: you can close with "\q"

postgres=#\q

if no error, try replacing the value of DATABASE_URL with one of the following...

postgresql://
postgresql://localhost
postgresql://localhost:5433
postgresql://localhost/mydb 
postgresql://user@localhost

If this is not successful, then you must review the way that postgres is installed.

...Or manually create a superadmin User with a password inside Postgres.

The conection string pattern is postgres://user:password@host:port

example...

export DATABASE_URL=postgres://db_user:123456@localhost:5432