Mysql2::Error "Access denied for user" using env variable in database.yml

Question

My System is macOX Mojave 10.14
MySQL is MySQL:8.0.16
My database.yml is:

development:
  adapter: mysql2
  encoding: utf8
  database: dev_database
  reconnect: false
  pool: 5
  username: <%= ENV['RAILS_DEV_DB_USSERNAME'] %>
  password: <%= ENV['RAILS_DEV_DB_PASSWORD'] %>
  socket: /tmp/mysql.sock

and I have confirmed if the variable is valid. Using

Command-Line: erb config/database.yml

I can get:

development:
  adapter: mysql2
  encoding: utf8
  database: dev_database
  reconnect: false
  pool: 5
  username: root
  password: Wle3S#23sv
  socket: /tmp/mysql.sock

But when I start rails s -e developent, and browse to my page, I can not connect to my database.

What can I do now?

what is the result of `echo $RAILS_DEV_DB_USSERNAME` in the terminal(non rails — SoWhat, May 28 '19 at 05:02
`echo $RAILS_DEV_DB_USSERNAME` return `root` ,`echo $RAILS_DEV_DB_PASSWORD ` return my correct password.i checked — Karl Batbbb, May 28 '19 at 05:10
does changing the username to root work. In the database.yml file — SoWhat, May 28 '19 at 05:29
you mean change `<%= ENV['RAILS_DEV_DB_USSERNAME'] %>` to `root` in the database.yml? still not working — Karl Batbbb, May 28 '19 at 05:46
`spring stop` return `Spring is not running`,I can't find out the reason,I just created a new rails project,and everything is fine. — Karl Batbbb, May 29 '19 at 02:08

amit bhosale · Accepted Answer · 2019-05-28T07:57:22.800

As Author arpiagar suggested rails 3, how use an ENV config vars in a Settings.yml file? check his example (26)

when you introduce a scriptlet tag in .yml file, it is more of erb template. So read it as a erb template first and then load the yml

You can use dotenv or figaro gems (inspired by the Twelve-Factor App methodology) to loads environment variables.

For example if you use dotenv gem

By default, load will look for a file called .env in the current working directory. Pass in multiple files and they will be loaded in order. The first value set for a variable will win.

require 'dotenv'
Dotenv.load('file1.env', 'file2.env')
HOSTNAME = ENV['HOSTNAME']

More info please check below mentioned links

Mysql2::Error "Access denied for user" using env variable in database.yml

1 Answers1