Check when created_at, datetime, etc. are not saved in Japan time in Docker and Rails

Conclusion

If the time such as created_at and datetime is not saved in Japan time with Docker and Rails, check the timezone in the ruby ​​container.

If you write it in config like this, a lot will come out. This seems to work if the environment is homebrew.

With docker, it is necessary to set the timezone in the container to Asia/Tokyo.

config/application.rb

module App
  class Application < Rails::Application
    # Initialize configuration defaults for originally generated Rails version.
    config.load_defaults 5.2

    config.time_zone = 'Asia/Tokyo'
    config.active_record.default_timezone = :local

So add this.

ruby Dockerfile

ENV TZ Asia/Tokyo <=Add here(docker-comopse.yml may be better)

If this doesn't work, you may need to check the timezone of the DB container and set it to'Asia/Tokyo'.

Reference page Change the Docker container timezone setting -Box programming diary.

Check TZ when Time \ .now is not Japan time in Rails \ | TOMILOG

Differences between Time, Date, DateTime, TimeWithZone between Ruby and Rails -Qiita

Organize Rails and surrounding TimeZone settings \ (active \ _record \ .default \ _timezone trap ) -Qiita

How to change TimeZone from UTC to JST with Docker \ + Rails6! The setting method is very easy! – Himakuro Blog

MySQL :: MySQL 5 \ .6 Reference Manual :: 10 \ .6 Time Zone Support on MySQL Server