5

Does anyone know the easiest way to run a rake task for a Rails app on an Elastic Beanstalk environment?

I have some data that I want to reset every once in a while (timeline TBD). I've seen other posts talking about creating a cron task, but I just want to be able to execute the task on a one-off basis for now.

Dennis
  • 998
  • 7
  • 19
  • Does this answer your question? [Can you run a rails console or rake command in the elastic beanstalk environment?](https://stackoverflow.com/questions/19620897/can-you-run-a-rails-console-or-rake-command-in-the-elastic-beanstalk-environment) – Yuki Inoue Mar 08 '20 at 08:00

3 Answers3

9

You'd need to login to the box in order to run a rake task.
simply run eb ssh <env-name>
your app is at /var/app/current

Tal
  • 7,827
  • 6
  • 38
  • 61
  • oh - just saw you found an answer. I think "eb ssh" would serve you better than plain ssh. – Tal Nov 12 '15 at 08:32
  • Yea, thanks for the tip on the "eb ssh." One thing I had to do was create a "known_hosts" folder in my .ssh directory and move a copy of my .pem key there to get it to work – Dennis Dec 03 '15 at 19:13
1

Figured out a way.

  • SSH into your EC2 instance using the following instructions: SSH Instructions (I used option 3)
  • Navigate to the /var/app/current directory once you're logged in
  • Run your rake task (rake db:migrate or whatever task you're trying to run)
Dennis
  • 998
  • 7
  • 19
1

For Amazon Linux 2 you need to export your Elastic Beanstalk variables to the shell profile so that they can be used to invoke your rails command from inside the /var/app/current directory.

This approach might look scary to some of you, but it's really nothing special. Basically the root-protected /etc/profile.d/sh.local file will contain all of your Elastic Beanstalk environment's variables. This includes passwords and master keys ... lots of sensitive stuff. If a bad guy (or girl or bot) compromises your app by somehow ssh'ing into your Elastic Beanstalk instance, they WILL be able mess with your app. If that terrifies you, stop reading. If you still want to run your rails tasks or console from inside your Elastic Beanstalk instance, read on ...

The modern Amazon Linux 2 way to accomplish this is to create a prebuild hook file that will write all the Elastic Beanstalk environment variables to /etc/profile.d/sh.local. This way when you eb ssh <YOUR-ENVIRONMENT-NAME> into your Elastic Beanstalk instance, all of the Elastic Beanstalk variables will be included in YOUR shell session.

In your Rails app, create a new script file precisely at: <YOUR_RAILS_APP_ROOT>/.platform/hooks/prebuild/set-vars.sh. The file's will be:

#!/bin/bash

# put envars into /etc/profile.d/sh.local so that they an be used to `bundle exec rails c`
# see https://aws.amazon.com/premiumsupport/knowledge-center/elastic-beanstalk-env-variables-shell/

# installs `jq` to transform the json representation of the env vars
# into shell-happy looking env-vars
yum install -y jq

# write your eb environment variables to /etc/profile.d/sh.local
/opt/elasticbeanstalk/bin/get-config environment | jq -r 'to_entries | .[] | "export \(.key)=\"\(.value)\""' > /etc/profile.d/sh.local

Commit this file to your project and deploy your application to Elastic Beanstalk.

Once the deployment has successfully concluded, ssh into your Elastic Beanstalk instance and try to run some rails commands from your application directory:

$ eb ssh <YOUR-ENVIRONMENT-NAME>

 _____ _           _   _      ____                       _        _ _
| ____| | __   ___| |_(_) ___| __ )  ___  __ _ _ __  ___| |_ __ _| | | __
|  _| | |/ _ \/ __| __| |/ __|  _ \ / _ \/ _\ | '_ \/ __| __/ _\ | | |/ /
| |___| | (_| \__ \ |_| | (__| |_) |  __/ (_| | | | \__ \ || (_| | |   <
|_____|_|\__,_|___/\__|_|\___|____/ \___|\__,_|_| |_|___/\__\__,_|_|_|\_\

Amazon Linux 2 AMI

$ cd /var/app/current

$ bundle exec rails --version
Rails 7.#.#

$ bundle exec rails -T
rails about                                                   # List versions of all Rails frameworks and the environment
...

$ bundle exec rails c
Loading ... environment (Rails 7.#.#)
irb(main):001:0>

Inspiration came from: https://aws.amazon.com/premiumsupport/knowledge-center/elastic-beanstalk-env-variables-shell/

Learn extending Linux 2 Elastic Beanstalk docs here: https://docs.aws.amazon.com/elasticbeanstalk/latest/dg/platforms-linux-extend.html

...press the up arrow, mark as modern answer/solution so the rest of us can find this...

Dan
  • 1,955
  • 17
  • 21