Module: ForestAdminAgent::AuditTrail::Sql::Migrations

Defined in:

lib/forest_admin_agent/audit_trail/sql/migrations.rb

Overview

The audit table's schema, as an ordered, append-only list. Nothing has shipped yet, so this is still a single entry; once a release is out, never edit one — add another, since a database out there has already recorded the earlier ones as applied. Every statement tolerates being replayed (if_not_exists), which is what makes a lost race harmless.

Constant Summary

ALL =

[
  {
    name: '001-create-audit-logs',
    up: lambda do |connection, table|
      # if_not_exists: a non-PG race (no advisory lock) can let two instances both reach here.
      connection.create_table(table, if_not_exists: true) do |t|
        t.datetime :timestamp, null: false
        t.string :operation, null: false
        t.string :collection, null: false
        # Nullable, because a create's pending row has no id yet; text, because a packed composite id
        # outgrows a varchar.
        t.text :record_id
        # No default on purpose: every write sets it, so a row arriving without one is a bug worth
        # hearing about rather than a row that quietly claims to be done.
        t.string :status, null: false
        t.integer :user_id
        # Denormalised from the caller at write time: who acted then, not whoever holds that id today.
        t.text :user_first_name
        t.text :user_last_name
        t.text :user_email
        # Set only on an update that moved a writable primary key: the id the row was filed under
        # before. What lets a history query follow a record across a rename.
        t.text :previous_record_id
        # Smart-action rows only.
        t.text :action_name
        t.string :correlation_key
        t.json :previous_values
        t.json :new_values
      end

      base = table.split('.').last
      # MySQL cannot index unbounded TEXT, so that one index needs a length prefix.
      record_id_index = { name: "#{base}_record_id", if_not_exists: true }
      record_id_index[:length] = 255 if connection.adapter_name.downcase.match?(/mysql|maria/)

      connection.add_index(table, :record_id, **record_id_index)
      connection.add_index(table, :correlation_key, name: "#{base}_correlation_key", if_not_exists: true)
      connection.add_index(table, :user_id, name: "#{base}_user_id", if_not_exists: true)
    end
  }
].freeze