DynamoDB Dynomite TTL
TTL support is built into DynamoDB already. It’s just a matter of setting it up.
Migration
Create a migration with a ttl:number field. We’re adding a GSI index also so we can query it quickly. Also, making it a number data type ensures that numbers will be saved to the field, which is required for TTL: How it works: DynamoDB Time to Live (TTL)
class CreatePosts < Dynomite::Migration
def up
create_table :posts do |t|
t.partition_key :id
t.add_gsi "ttl:number"
end
end
end
Model
Set an expiration time for each item. The value needs to be in epoch time. For Ruby, that’s simply a .to_i on a Time object.
app/models/post.rb
class Post < ApplicationItem
field :ttl, type: :integer, default: -> { 1.hour.from_now.to_i }
end
Enable
Enable TTL on the AWS DynamoDB Side: Enabling Time to Live (TTL)
aws dynamodb update-time-to-live --table-name demo-dev_posts --time-to-live-specification "Enabled=true, AttributeName=ttl"
To confirm
$ aws dynamodb describe-time-to-live --table-name demo-dev_posts
{
"TimeToLiveDescription": {
"AttributeName": "ttl",
"TimeToLiveStatus": "ENABLED"
}
}
You can also use a migration to update the table time to live setting, see: Dynomite Migrations Time to Live.