I'm trying to create a script to mess around with the db entries in my rails application, but I don't know how to properly set it up to gain access to all my models etc.
I can do this easily with scripts like seeds.rb using 'rake db:seed' to execute or in my application controllers, but I want to create scripts outside of these that I can run in the background or just once.
Do I need to include something, or call the script with a certain rails command? And as a second related question, is there any way for me to execute rails commands like 'rake db:seed' from within a ruby script? The only method I know of right now that works is running 'rails console' and executing commands there.
require 'config/environment.rb'
When the script is in your rails root...
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From within the Rails console, I would like to execute a ruby script, e.g. setup_for_experimenting.rb, that creates objects for and then executes the ruby program that I want to experiment with. The program I'm experimenting with is a service that is not yet completely written and has no tests yet, either, but I can execute it from within rails console.
How do I do give the command ruby setup_for_experimenting.rb from within the rails console?
You can add any plain ruby file inside the console with require
So in your case inside hte console
require "./setup_for_experimenting.rb"
When working with Rails, is there any way to customize the results from rake commands?
For instance, I use the rake dump task - rake db:dump - so that it gets all my locally produced database entries. I would want to expand that to a deployed app so that I can run one command and have a file that can reproduce my DB.
How can this be done?
What you could do is write a bash script that is just all the commands you need to dump and deploy.
You can also create an alias that runs multiple commands, which might be closer to what you want to do.
Here's a similar question that has answers explaining both:
How can I define a bash alias as a sequence of multiple commands?
How do you write a rake task outside the Rails application directory and make it run.
For example, say write a sample rake task
task :dummy do
puts User.first.first_name
end
this task is under ~/fun/sample.rake
And my rails application is located at ~/my_app/
Now I need to run the sample.rake. I know i need to load the environment, DB etc., etc., how do i do that? Stuck at this for the past hour.
I tried the one below, obviously it did not work because it did not know how to build it.
rake -f ~/my_app/Rakefile dummy
Note: I should not touch the files inside the Rails application but I can write whatever I want inside the fun directory
You need to create a Rakefile and load the rake gem. See this answer: Ruby: Accessing rake task from a gem without Rails
Out of pure curiosity, I am wondering if it's possible (no doubt it is) to 'hook into' a Rails Application's environment. So for example, say I want to create a cron script (I don't) that operates some sort of maintenance on a Rails app, and I want to write it in Ruby and using all of the nice code that I already have, for example, User.find etc.
Is this possible, and if so, how?
I'm just curious, as I feel I would eventually want to do this for some reason or other.
I'm currently on Rails 3 with Ruby 1.9.1, in case it matters.
This is certainly possible. Here is a good writeup on how to do that: How to run a rake task from cron
Take a look at the Rails::Railtie class. If you need to run code code when you start up your app, this is a way to do it. Here's a very simple example.
From the beginning of Rails there is ./script/runner, designed exactly for such kind of problems.
In Rails 3 you call it as: ./script/rails runner "puts User.find(:all).map(&:inspect)"
Try ./script/runner --help or ./script/rails runner --help
As the argument to the runner you provide a filename or just a code.
It's often more useful than preparing a Rake task, because you can execute just one-time actions:
ssh prod#example.com "cd rails/app && ./script/runner -e production 'puts User.count'"
You could either use script/rails runner as suggested by Arsen7 or you could write your own script in which you load the app environment in the beginning:
require 'config/environment'
is actually everything you need.
To have your script working in a cron job, make sure that it is executable (chmod u+x) and that it starts with a correct shebang line (#!/usr/bin/env ruby or whatever is appropriate for your situation).
yeah just require these file at top of your script file
require 'config/boot.rb'
require 'config/application.rb'
Rails.application.require_environment!
Now you'll have access to your models
For a RoR installation, is there any way to run rake commands without root access?
To put it another way, is there any way to get db:create and db:migrate to be run without root access (perhaps automatically or something)? Or can I run rake commands from a RoR controller?
Take a look at rails-2.X.X/lib/tasks/databases.rake and you can see the code called to create, drop, and migrate your database.
Once a rails environment is initialized, you can use the code inside the rake task file to create, drop, and migrate.
I do not know if you can do this at the controller level before it errors, but you can always try. You could also do it after rails has finished initializing in the environment file.
config/environment.rb
...
ActiveRecord::Migration.verbose = false
ActiveRecord::Migrator.migrate(File.join(Rails.root, 'db', 'migrate'))
Well, it is a bit of a chicken-egg problem, you may be able to start your RoR instance without the database created but I doubt it. If your hosting provider is able to host RoR apps, there must be a way for them to run rake for you or to let you run it somehow.
Since it sounds like you are running into troubles with creating the database, is there a way to do it from the hosting control panel? Still, how are you going to migrate your database? Sounds like you might need to look at a new host. I use Slicehost and think they are great :)
Give this code a try:
require 'rake'
require 'rake/testtask'
require 'rake/rdoctask'
require 'tasks/rails'
Rake::Task["db:version"].invoke
I just tried it in ./script/console and that worked. It wouldn't work without the require lines.
I use it to call other rake tasks from a rake task (when it's not a pre-req but something that has to happen in the middle).
Note, that won't get you any of the output from the command. If you want that you could just go with good old backticks and run the command like this:
output = `rake db:version`
That'll launch another process, but I don't think there's a problem with that.
Just to be clear, you do not need root access, you need just shell (ssh) access to that machine.
How are you deploying it without access ? If you're using capistrano than you already have shell access and it can run those tasks for you.