150 lines
4.8 KiB
Markdown
150 lines
4.8 KiB
Markdown
---
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stage: Enablement
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group: Distribution
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info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
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---
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# The Rails Console
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The [Rails console](https://guides.rubyonrails.org/command_line.html#rails-console).
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provides a way to interact with your GitLab instance from the command line.
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WARNING:
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The Rails console interacts directly with GitLab. In many cases,
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there are no handrails to prevent you from permanently modifying, corrupting
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or destroying production data. If you would like to explore the Rails console
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with no consequences, you are strongly advised to do so in a test environment.
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The Rails console is for GitLab system administrators who are troubleshooting
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a problem or need to retrieve some data that can only be done through direct
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access of the GitLab application.
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## Starting a Rails console session
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**For Omnibus installations**
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```shell
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sudo gitlab-rails console
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```
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**For installations from source**
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```shell
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sudo -u git -H bundle exec rails console -e production
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```
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**For Kubernetes deployments**
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The console is in the task-runner pod. Refer to our [Kubernetes cheat sheet](../troubleshooting/kubernetes_cheat_sheet.md#gitlab-specific-kubernetes-information) for details.
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To exit the console, type: `quit`.
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## Output Rails console session history
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Enter the following command on the rails console to display
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your command history.
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```ruby
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puts Readline::HISTORY.to_a
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```
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You can then copy it to your clipboard and save for future reference.
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## Using the Rails Runner
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If you need to run some Ruby code in the context of your GitLab production
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environment, you can do so using the [Rails Runner](https://guides.rubyonrails.org/command_line.html#rails-runner).
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When executing a script file, the script must be accessible by the `git` user.
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When the command or script completes, the Rails Runner process finishes.
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It is useful for running within other scripts or cron jobs for example.
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**For Omnibus installations**
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```shell
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sudo gitlab-rails runner "RAILS_COMMAND"
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# Example with a two-line Ruby script
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sudo gitlab-rails runner "user = User.first; puts user.username"
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# Example with a ruby script file (make sure to use the full path)
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sudo gitlab-rails runner /path/to/script.rb
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```
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**For installations from source**
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```shell
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sudo -u git -H bundle exec rails runner -e production "RAILS_COMMAND"
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# Example with a two-line Ruby script
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sudo -u git -H bundle exec rails runner -e production "user = User.first; puts user.username"
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# Example with a ruby script file (make sure to use the full path)
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sudo -u git -H bundle exec rails runner -e production /path/to/script.rb
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```
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Rails Runner does not produce the same output as the console.
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If you set a variable on the console, the console will generate useful debug output
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such as the variable contents or properties of referenced entity:
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```ruby
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irb(main):001:0> user = User.first
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=> #<User id:1 @root>
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```
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Rails Runner does not do this: you have to be explicit about generating
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output:
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```shell
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$ sudo gitlab-rails runner "user = User.first"
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$ sudo gitlab-rails runner "user = User.first; puts user.username ; puts user.id"
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root
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1
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```
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Some basic knowledge of Ruby will be very useful. Try [this
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30-minute tutorial](https://try.ruby-lang.org/) for a quick introduction.
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Rails experience is helpful but not essential.
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### Troubleshooting Rails Runner
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The `gitlab-rails` command executes Rails Runner using a non-root account and group, by default: `git:git`.
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If the non-root account cannot find the Ruby script filename passed to `gitlab-rails runner`
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you may get a syntax error, not an error that the file couldn't be accessed.
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A common reason for this is that the script has been put in the root account's home directory.
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`runner` tries to parse the path and file parameter as Ruby code.
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For example:
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```plaintext
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[root ~]# echo 'puts "hello world"' > ./helloworld.rb
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[root ~]# sudo gitlab-rails runner ./helloworld.rb
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Please specify a valid ruby command or the path of a script to run.
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Run 'rails runner -h' for help.
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/opt/gitlab/..../runner_command.rb:45: syntax error, unexpected '.'
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./helloworld.rb
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^
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[root ~]# sudo gitlab-rails runner /root/helloworld.rb
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Please specify a valid ruby command or the path of a script to run.
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Run 'rails runner -h' for help.
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/opt/gitlab/..../runner_command.rb:45: unknown regexp options - hllwrld
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[root ~]# mv ~/helloworld.rb /tmp
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[root ~]# sudo gitlab-rails runner /tmp/helloworld.rb
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hello world
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```
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A meaningful error should be generated if the directory can be accessed, but the file cannot:
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```plaintext
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[root ~]# chmod 400 /tmp/helloworld.rb
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[root ~]# sudo gitlab-rails runner /tmp/helloworld.rb
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Traceback (most recent call last):
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[traceback removed]
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/opt/gitlab/..../runner_command.rb:42:in `load': cannot load such file -- /tmp/helloworld.rb (LoadError)
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```
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