PostgreSQL requires password after changing Rails DB setup from database name to url

Question

Changed the DB setup of Rails ( config/database.yml ) from:

development:
  <<: *default
  database: my_app_development

to:

development:
  <<: *default
  url: postgres://postgres@localhost:5432/my_app_development

Started getting the following error:

rails db:migrate:reset
=> rails aborted!
=> PG::ConnectionBad: fe_sendauth: no password supplied

OS: Ubuntu 18.04 LTS

Answer 1

The issue was that pg_hba.conf has different rules for this scenario. The following line might look like it enables all connections

# TYPE  DATABASE        USER            ADDRESS                 METHOD
local   all             all                                     peer (or trust)

But there can be other offending ones, in my case:

# TYPE  DATABASE        USER            ADDRESS                 METHOD
host    all             all             127.0.0.1/32            md5

Changing this line from md5 to trust resolved the issue. Keep in mind that this is not safe.