Files
grecia/lib/tasks/migrate_milestones_and_statuses.rake
2019-03-15 10:29:07 +01:00

107 lines
4.2 KiB
Ruby

namespace :milestones do
def generate_table_migration_sql(new_table:, old_table:, columns:)
from_cols = ["id", *columns.keys]
to_cols = ["id", *columns.values]
<<~SQL
INSERT INTO #{new_table} (#{to_cols.join(", ")})
SELECT #{from_cols.join(", ")} FROM #{old_table};
SQL
end
def migrate_table!(new_table:, old_table:, columns:)
puts "Migrating data from '#{old_table}' to '#{new_table}'..."
result = ActiveRecord::Base.connection.execute(
generate_table_migration_sql(old_table: old_table,
new_table: new_table,
columns: columns)
)
puts "#{result.cmd_tuples} rows affected"
end
def populate_column!(table:, column:, value:)
puts "Populating column '#{column}' from table '#{table}' with '#{value}'..."
result = ActiveRecord::Base.connection.execute(
"UPDATE #{table} SET #{column} = '#{value}';"
)
puts "#{result.cmd_tuples} rows affected"
end
def count_rows(table)
ActiveRecord::Base.connection.query("SELECT COUNT(*) FROM #{table};")[0][0].to_i
end
desc "Migrate milestones and milestone status data after making the model polymorphic"
task migrate: :environment do
# This script copies all milestone-related data from the old tables to
# the new ones (preserving all primary keys). All 3 of the new tables
# must be empty.
#
# To clear the new tables to test this script:
#
# DELETE FROM milestone_statuses;
# DELETE FROM milestones;
# DELETE FROM milestone_translations;
#
start = Time.now
ActiveRecord::Base.transaction do
migrate_table! old_table: "budget_investment_statuses",
new_table: "milestone_statuses",
columns: {"name" => "name",
"description" => "description",
"hidden_at" => "hidden_at",
"created_at" => "created_at",
"updated_at" => "updated_at"}
migrate_table! old_table: "budget_investment_milestones",
new_table: "milestones",
columns: {"investment_id" => "milestoneable_id",
"title" => "title",
"description" => "description",
"created_at" => "created_at",
"updated_at" => "updated_at",
"publication_date" => "publication_date",
"status_id" => "status_id"}
populate_column! table: "milestones",
column: "milestoneable_type",
value: "Budget::Investment"
migrate_table! old_table: "budget_investment_milestone_translations",
new_table: "milestone_translations",
columns: {"budget_investment_milestone_id" => "milestone_id",
"locale" => "locale",
"created_at" => "created_at",
"updated_at" => "updated_at",
"title" => "title",
"description" => "description"}
Image.where(imageable_type: "Budget::Investment::Milestone").
update_all(imageable_type: "Milestone")
Document.where(documentable_type: "Budget::Investment::Milestone").
update_all(documentable_type: "Milestone")
puts "Verifying that all rows were copied..."
{
"budget_investment_milestones" => "milestones",
"budget_investment_statuses" => "milestone_statuses",
"budget_investment_milestone_translations" => "milestone_translations"
}.each do |original_table, migrated_table|
ActiveRecord::Base.connection.execute(
"select setval('#{migrated_table}_id_seq', (select max(id) from #{migrated_table}));"
)
unless count_rows(original_table) == count_rows(migrated_table)
raise "Number of rows of old and new tables do not match! Rolling back transaction..."
end
end
end
puts "Finished in %.3f seconds" % (Time.now - start)
end
end