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# frozen_string_literal: true
require 'spec_helper'
RSpec.describe Gitlab::Database::LockWritesManager do
let(:connection) { ApplicationRecord.connection }
let(:test_table) { '_test_table' }
let(:logger) { instance_double(Logger) }
subject(:lock_writes_manager) do
described_class.new(
table_name: test_table,
connection: connection,
database_name: 'main',
logger: logger
)
end
before do
allow(logger).to receive(:info)
connection.execute(<<~SQL)
CREATE TABLE #{test_table} (id integer NOT NULL, value integer NOT NULL DEFAULT 0);
INSERT INTO #{test_table} (id, value)
VALUES (1, 1), (2, 2), (3, 3)
SQL
end
describe '#lock_writes' do
it 'prevents any writes on the table' do
subject.lock_writes
expect do
connection.execute("delete from #{test_table}")
end.to raise_error(ActiveRecord::StatementInvalid, /Table: "#{test_table}" is write protected/)
end
it 'prevents truncating the table' do
subject.lock_writes
expect do
connection.execute("truncate #{test_table}")
end.to raise_error(ActiveRecord::StatementInvalid, /Table: "#{test_table}" is write protected/)
end
it 'adds 3 triggers to the ci schema tables on the main database' do
expect do
subject.lock_writes
end.to change {
number_of_triggers_on(connection, test_table)
}.by(3) # Triggers to block INSERT / UPDATE / DELETE
# Triggers on TRUNCATE are not added to the information_schema.triggers
# See https://www.postgresql.org/message-id/16934.1568989957%40sss.pgh.pa.us
end
it 'logs the write locking' do
expect(logger).to receive(:info).with("Database: 'main', Table: '_test_table': Lock Writes")
subject.lock_writes
end
it 'retries again if it receives a statement_timeout a few number of times' do
error_message = "PG::QueryCanceled: ERROR: canceling statement due to statement timeout"
call_count = 0
allow(connection).to receive(:execute) do |statement|
if statement.include?("CREATE TRIGGER")
call_count += 1
raise(ActiveRecord::QueryCanceled, error_message) if call_count.even?
end
end
subject.lock_writes
end
it 'raises the exception if it happened many times' do
error_message = "PG::QueryCanceled: ERROR: canceling statement due to statement timeout"
allow(connection).to receive(:execute) do |statement|
if statement.include?("CREATE TRIGGER")
raise(ActiveRecord::QueryCanceled, error_message)
end
end
expect do
subject.lock_writes
end.to raise_error(ActiveRecord::QueryCanceled)
end
end
describe '#unlock_writes' do
before do
subject.lock_writes
end
it 'allows writing on the table again' do
subject.unlock_writes
expect do
connection.execute("delete from #{test_table}")
end.not_to raise_error
end
it 'removes the write protection triggers from the gitlab_main tables on the ci database' do
expect do
subject.unlock_writes
end.to change {
number_of_triggers_on(connection, test_table)
}.by(-3) # Triggers to block INSERT / UPDATE / DELETE
# Triggers on TRUNCATE are not added to the information_schema.triggers
# See https://www.postgresql.org/message-id/16934.1568989957%40sss.pgh.pa.us
end
it 'logs the write unlocking' do
expect(logger).to receive(:info).with("Database: 'main', Table: '_test_table': Allow Writes")
subject.unlock_writes
end
end
def number_of_triggers_on(connection, table_name)
connection
.select_value("SELECT count(*) FROM information_schema.triggers WHERE event_object_table=$1", nil, [table_name])
end
end
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