Creating a modal instance on the attribute update of another in Rails? - ruby-on-rails

Question

I'm building a Rails app that has modals Outage, Service, Note and User.
Service has a boolean attribute is_down. By default, is_down is false. When the attribute is updated to true meaning the service goes down, an Outage should be created and a Note should also be created with User, automated.
This all happens in one update of the is_down attribute. If Service goes back up, the outage remains intact but now has an end_time.
Here is the 'story line`:
Service model:
class Service < ApplicationRecord
has_many :outages
has_many :notes
# This is where I'm confused
is_down
if self.is_down
Outage.create(start_time: Time.now, reason: nil)
Note.create(user_id: 1, entry: "Outage began at #{Time.now}", service_id: self.id)
end
end
end
Outage model:
class Outage < ApplicationRecord
belongs_to :service
has_many :notes
has_many :users, through: :notes
end
Note modal (a join table between Outage and User)
class Note < ApplicationRecord
belongs_to :outage
belongs_to :user
end
and User model:
class User < ApplicationRecord
has_many :notes
has_many :outages, through: :notes
end
Outage is more like a story line where during the outage, users can enter notes about what they've learned.
Here is the schema:
enable_extension "plpgsql"
create_table "notes", force: :cascade do |t|
t.text "entry"
t.boolean "is_public", default: true
t.bigint "outage_id"
t.bigint "user_id"
t.datetime "created_at", precision: 6, null: false
t.datetime "updated_at", precision: 6, null: false
t.index ["outage_id"], name: "index_notes_on_outage_id"
t.index ["user_id"], name: "index_notes_on_user_id"
end
create_table "outages", force: :cascade do |t|
t.datetime "start_time"
t.datetime "end_time"
t.text "reason"
t.boolean "is_recurring", default: false
t.string "frequency", default: "None"
t.bigint "service_id"
t.index ["service_id"], name: "index_outages_on_service_id"
end
create_table "services", force: :cascade do |t|
t.string "name"
t.boolean "is_down", default: false
t.datetime "created_at", precision: 6, null: false
t.datetime "updated_at", precision: 6, null: false
end
create_table "users", force: :cascade do |t|
t.string "username"
t.datetime "created_at", precision: 6, null: false
t.datetime "updated_at", precision: 6, null: false
end
add_foreign_key "notes", "outages"
add_foreign_key "notes", "users"
add_foreign_key "outages", "services"
end
Besides the initial question of automated creation on update of Service attribute, is_down, is this also a good way to go about implementing this?

Answer 1

I would suggest looking into the lifecycle callbacks for ActiveRecord. You can add an after_save callback to your Service class that checks to see if is_down has changed and then create or close an Outage
class Service < ApplicationRecord
has_many :outages
...
after_save :create_or_update_outage, if: is_down_changed?
...
private
def create_or_update_outage
if is_down
outages.create
else
outages.where(end_time: nil).last.update(end_time: Time.now)
end
end