I don't want to load a seed file for every deployment, since it takes 2-3 mins.
I only want to load the seeds if it is needed.
I have the following code which will run a seed in the initializer of the application, so when the application starts, it will load the seeds. But is there a way to only do it if it is needed (i.e. something has changed?)
For migrations we have: if ActiveRecord::Migrator.needs_migration?
But what about seeds?
if ENV_PROPS['run_seeds_at_startup']
Common::Log.info 'Starting seed load'
seed_file = File.join('db/seeds.rb')
load(seed_file) if File.exist?(seed_file)
Common::Log.info 'Seed data loaded'
else
Common::Log.info 'Automatic Seeds are shutdown in the env-props.yml...'
end
Generally if there's data I only need to create once, I try to setup a custom rake task that can either be run on the server directly post deploy, or one can setup a capistrano recipe to run it once. If you want to use seeds.rb, really the only way I've found to do this is to check if the records exist already. But i'm not aware of any global check or wrapper around executing the seeds file.
Related
I’m using Rials 4.2.5. I want to create some seed data for a new model, user_images, I just created in an existing project. However, I already have a db/seeds.rb file that has been run on my database. Where do I put the seed data for this new model? I assume i can’t use db/seeds.rb because it has already been run. It is not an option to blow away the database and start again.
Thanks, - Dave
You can use seeds.. I use, for example:
Person.find_or_create_by(name: 'Bob')
Lots of them, as required, then run as many times as I like.. I run seeds on each auto deployment for example, so I don't forget..
Link to command: http://apidock.com/rails/v4.2.1/ActiveRecord/Relation/find_or_create_by
create a custom rake task in lib/tasks. The file should end in .rake. Then you run it by the name. For example:
task :do_something => :environment do
p "do something"
end
You'd run this task by calling rake do_something in terminal.
My seeds file runs through quite a few csv files, does a few checks and creates various ActiveRecord records accordingly. While testing all these files, I finally think I have it and run rake db:seed but if something fails, I want what has been created so far to rollback.
Scenario that has already happened:
Seeds file requires 4 different CSV's
Only 3 of the 4 CSV's were uploaded to staging server
rake db:seed was run and the seeds file blew up half way through because it couldn't find a file, but over 1000 AR objects were created prior to that.
Ideally I'd like to do something like:
begin
CSV.readlines(file1)
CSV.readlines(file2)
CSV.readlines(file3)
CSV.readlines(file4)
rescue
# raise an error
# rollback all objects created prior to error
end
I suppose I could implement something custom but I can't find anything on the rails guides regarding this.
This is the purpose of Active Record Transactions:
Transactions are protective blocks where SQL statements are only
permanent if they can all succeed as one atomic action. The classic
example is a transfer between two accounts where you can only have a
deposit if the withdrawal succeeded and vice versa. Transactions
enforce the integrity of the database and guard the data against
program errors or database break-downs. So basically you should use
transaction blocks whenever you have a number of statements that must
be executed together or not at all.
Try this
ActiveRecord::Base.transaction do
...
end
If I have the following code defined inside db/seeds.rb,
default_car=Car.create({:name=>'TOYOTA'})
User.create({:username=>'default_user', car_id=>default_car.id})
I know the default_car and the user instances will be stored into Database when I run "rake db:seed".
My question is, if I run 'rake db:seed' again, again and again(multiple times), will the same instances be stored to database with multiple copies or it only save the instance once into database no matter how many times I run rake db:seed?
Better solution:
default_car = Car.find_or_create_by_name 'TOYOTA'
user = User.find_or_create_by_username 'default_user'
user.car = default_car
user.save
That way you can run "rake db:seed" multiple times without having to drop the database manually every time.
This is a limitation of having a single seed file. I was finding this frustrating as the application grows you often want to add new seed data so you end up either doing what Pascal suggests or creating either migrations with data in them or rake tasks to load the seeds. To get round this I knocked up seedbank. So I combine this with Pascals approach so I can re-run the seeds but can also target specific ones if I want to.
depends on your models if you allow duplicate values. if you don't it will throw an error. what you do is to clear your db first before running seed via rake db:resetdb
I am trying out Rails engines by creating a classifieds engine where users can view/post/reply to classifieds.
The main application contains code for user authentication and profiles while there is an engine which I have created which will deal with the classifieds functionality.
Now I want to add some sample data to the database for the classifieds engine. So I created a rake file called 'sample_classifieds_data.rake' in 'vendor/plugins/classifieds/lib/tasks' and I added the yml files in 'vendor/plugins/classifieds/lib/tasks/sample_classifieds_data'
The code of the rake file and a sample yml file can be found here: http://gist.github.com/216776
Now the problem is that when I run the rake task, no error is being thrown but the values are not getting populated in the database.
Any ideas? BTW, it is development environment and the database is the development database.
I ran a similar rake task to populate sample users in the database which worked. the location of that rake file 'sample_data.rake' was located in 'lib/tasks'.
In rails edge, you can use the rake db:seed feature to add datas to your base. See the commit.
The use is pretty simple.
Create a db/seeds.rb file.
And put whatever code you want to seed your database in it.
For example :
Category.create!(:name => 'My Category')
Country.create!(:name => 'Cassoulet Land')
And when you want to seed your database, you could do a rake db:seed
If, for any reason, you do not wish to use edge (which would be comprehensible in a production environment), you can use the Seed Fu plugin, which quite does the trick for you.
Your task looks good. About the only thing would cause your task to fail silently is that the file you're passing to Fixture.new does not point to a yml or csv file.
Double check by modifying the put statement to print the full path of the file it imported, and compare what it prints against your directory structure.
For example, things will fail silently if your fixture files start with a capital letter? Categories.yml instead of categories.yml
The db:seed task was added in Rails 2.3.4. So no need to run edge.
http://weblog.rubyonrails.org/2009/9/4/ruby-on-rails-2-3-4
In a Rails application, I need a table in my database to contain constant data.
This table content is not intended to change for the moment but I do not want to put the content in the code, to be able to change it whenever needed.
I tried filling this table in the migration that created it, but this does not seem to work with the test environment and breaks my unit tests. In test environment, my model is never able to return any value while it is ok in my development environment.
Is there a way to fill that database correctly even in test environment ? Is there another way of handling these kind of data that should not be in code ?
edit
Thanks all for your answers and especially Vlad R for explaining the problem.
I now understand why my data are not loaded in test. This is because the test environment uses the db:load rake command which directly loads the schema instead of running the migrations. Having put my values in the migration only and not in the schema, these values are not loaded for test.
What you are probably observing is that the test framework is not running the migrations (db:migrate), but loading db/schema.rb directly (db:load) instead.
You have two options:
continue to use the migration for production and development; for the test environment, add your constant data to the corresponding yml files in db/fixtures
leave the existing db/fixtures files untouched, and create another set of yml files (containing the constant data) in the same vein as db/fixtures, but usable by both test and production/development environments when doing a rake db:load schema initialization
To cover those scenarios that use db:load (instead of db:migrate - e.g. test, bringing up a new database on a new development machine using the faster db:load instead of db:migrate, etc.) is create a drop-in rakefile in RAILS_APP/lib/tasks to augment the db:load task by loading your constant intialization data from "seed" yml files (one for each model) into the database.
Use the db:seed rake task as an example. Put your seed data in db/seeds/.yml
#the command is: rake:db:load
namespace :db do
desc 'Initialize data from YAML.'
task :load => :environment do
require 'active_record/fixtures'
Dir.glob(RAILS_ROOT + '/db/seeds/*.yml').each do |file|
Fixtures.create_fixtures('db/seeds', File.basename(file, '.*'))
end
end
end
To cover the incremental scenarios (db:migrate), define one migration that does the same thing as the task defined above.
If your seed data ever changes, you will need to add another migration to remove the old seed data and load the new one instead, which may be non-trivial in case of foreign-key dependencies etc.
Take a look at my article on loading seed data.
There's a number of ways to do this. I like a rake task called db:populate which lets you specify your fixed data in normal ActiveRecord create statements. For getting the data into tests, I've just be loading this populate file in my test_helper. However, I think I am going to switch to a test database that already has the seed data populated.
There's also plugin called SeedFu that helps with this problem.
Whatever you do, I recommend against using fixtures for this, because they don't validate your data, so it's very easy to create invalid records.