background-jobs

require "csv"

class PeopleCsvStream
  include Enumerable

  HEADERS = %w[id full_name email signed_up_at plan].freeze

class CreateTopSellersMv < ActiveRecord::Migration[7.0]
  def up
    execute <<~SQL
      CREATE MATERIALIZED VIEW top_sellers AS
        SELECT p.id            AS product_id,
               p.name          AS product_name,

class CreateDeadJobs < ActiveRecord::Migration[7.1]
  def change
    create_table :dead_jobs do |t|
      t.string  :jid, null: false
      t.string  :queue, null: false
      t.string  :klass, null: false

type AsyncTask = () => Promise<void>;

export interface GuardOptions {
  name: string;
  logger?: Pick<Console, "info" | "warn" | "error">;
}

CREATE TABLE outbox (
    id             BIGSERIAL PRIMARY KEY,
    aggregate_type TEXT        NOT NULL,
    aggregate_id   TEXT        NOT NULL,
    event_type     TEXT        NOT NULL,
    payload        JSONB       NOT NULL,

class CreateProcessedEvents < ActiveRecord::Migration[7.1]
  def change
    create_table :processed_events do |t|
      t.string :event_key, null: false
      t.string :job_class, null: false
      t.jsonb :metadata, null: false, default: {}

class ShardedCounter
  SHARDS = 16
  SNAPSHOT_TTL = 10 # seconds

  def initialize(name, redis: REDIS)
    @name = name

class ReindexCheckpoint < ApplicationRecord
  enum status: { idle: 0, running: 1, done: 2, failed: 3 }

  validates :index_name, presence: true, uniqueness: true

  def self.for(index_name)

class CreateInventoryReservations < ActiveRecord::Migration[7.1]
  def change
    create_table :inventory_items do |t|
      t.string  :sku, null: false
      t.integer :quantity_on_hand,  null: false, default: 0
      t.integer :quantity_reserved, null: false, default: 0

class ProcessUploadJob < ApplicationJob
  queue_as :default

  retry_on StandardError, wait: :exponentially_longer, attempts: 5
  discard_on ActiveJob::DeserializationError

module RetryableTransaction
  module_function

  RETRIABLE = [ActiveRecord::Deadlocked, ActiveRecord::LockWaitTimeout].freeze

  def run(max_retries: 3, base_delay: 0.05, &block)

class CreateMaintenanceTasks < ActiveRecord::Migration[7.0]
  def change
    create_table :maintenance_tasks do |t|
      t.string :name, null: false
      t.string :state, null: false, default: "pending"
      t.datetime :started_at