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# frozen_string_literal: true
# rubocop:todo all
require 'spec_helper'
describe 'Transactions examples' do
require_wired_tiger
require_transaction_support
let(:client) do
authorized_client.with(read_concern: {level: :majority}, write: {w: :majority})
end
before do
if SpecConfig.instance.client_debug?
Mongo::Logger.logger.level = 0
end
end
let(:hr) do
client.use(:hr).database
end
let(:reporting) do
client.use(:reporting).database
end
before(:each) do
hr[:employees].insert_one(employee: 3, status: 'Active')
# Sanity check since this test likes to fail
employee = hr[:employees].find({ employee: 3 }, limit: 1).first
expect(employee).to_not be_nil
reporting[:events].insert_one(employee: 3, status: { new: 'Active', old: nil})
end
after(:each) do
hr.drop
reporting.drop
# Work around https://jira.mongodb.org/browse/SERVER-53015
::Utils.mongos_each_direct_client do |client|
client.database.command(flushRouterConfig: 1)
end
end
context 'individual examples' do
let(:session) do
client.start_session
end
# Start Transactions Intro Example 1
def update_employee_info(session)
employees_coll = session.client.use(:hr)[:employees]
events_coll = session.client.use(:reporting)[:events]
session.start_transaction(read_concern: { level: :snapshot },
write_concern: { w: :majority })
employees_coll.update_one({ employee: 3 }, { '$set' => { status: 'Inactive'} },
session: session)
events_coll.insert_one({ employee: 3, status: { new: 'Inactive', old: 'Active' } },
session: session)
begin
session.commit_transaction
puts 'Transaction committed.'
rescue Mongo::Error => e
if e.label?('UnknownTransactionCommitResult')
puts "UnknownTransactionCommitResult, retrying commit operation..."
retry
else
puts 'Error during commit ...'
raise
end
end
end
# End Transactions Intro Example 1
context 'Transactions Intro Example 1' do
let(:run_transaction) do
update_employee_info(session)
end
it 'makes the changes to the database' do
run_transaction
employee = hr[:employees].find({ employee: 3 }, limit: 1).first
expect(employee).to_not be_nil
expect(employee['status']).to eq('Inactive')
end
end
context 'Transactions Retry Example 1' do
# Start Transactions Retry Example 1
def run_transaction_with_retry(session)
begin
yield session # performs transaction
rescue Mongo::Error => e
puts 'Transaction aborted. Caught exception during transaction.'
raise unless e.label?('TransientTransactionError')
puts "TransientTransactionError, retrying transaction ..."
retry
end
end
# End Transactions Retry Example 1
let(:run_transaction) do
run_transaction_with_retry(session) { |s| update_employee_info(s) }
end
it 'makes the changes to the database' do
run_transaction
employee = hr[:employees].find({ employee: 3 }, limit: 1).first
expect(employee).to_not be_nil
expect(employee['status']).to eq('Inactive')
end
end
context 'Transactions Retry Example 2' do
# Start Transactions Retry Example 2
def commit_with_retry(session)
begin
session.commit_transaction
puts 'Transaction committed.'
rescue Mongo::Error=> e
if e.label?('UnknownTransactionCommitResult')
puts "UnknownTransactionCommitResult, retrying commit operation..."
retry
else
puts 'Error during commit ...'
raise
end
end
end
# End Transactions Retry Example 2
let(:run_transaction) do
session.start_transaction
hr[:employees].insert_one({ employee: 4, status: 'Active' }, session: session)
reporting[:events].insert_one({ employee: 4, status: { new: 'Active', old: nil } },
session: session)
commit_with_retry(session)
end
it 'makes the changes to the database' do
run_transaction
employee = hr[:employees].find({ employee: 4 }, limit: 1).first
expect(employee).to_not be_nil
expect(employee['status']).to eq('Active')
end
end
end
context 'Transactions Retry Example 3 (combined example)' do
let(:run_transaction) do
# Start Transactions Retry Example 3
def run_transaction_with_retry(session)
begin
yield session # performs transaction
rescue Mongo::Error => e
puts 'Transaction aborted. Caught exception during transaction.'
raise unless e.label?('TransientTransactionError')
puts "TransientTransactionError, retrying transaction ..."
retry
end
end
def commit_with_retry(session)
begin
session.commit_transaction
puts 'Transaction committed.'
rescue Mongo::Error => e
if e.label?('UnknownTransactionCommitResult')
puts "UnknownTransactionCommitResult, retrying commit operation ..."
retry
else
puts 'Error during commit ...'
raise
end
end
end
# updates two collections in a transaction
def update_employee_info(session)
employees_coll = session.client.use(:hr)[:employees]
events_coll = session.client.use(:reporting)[:events]
session.start_transaction(read_concern: { level: :snapshot },
write_concern: { w: :majority },
read: {mode: :primary})
employees_coll.update_one({ employee: 3 }, { '$set' => { status: 'Inactive'} },
session: session)
events_coll.insert_one({ employee: 3, status: { new: 'Inactive', old: 'Active' } },
session: session)
commit_with_retry(session)
end
session = client.start_session
begin
run_transaction_with_retry(session) do
update_employee_info(session)
end
rescue StandardError => e
# Do something with error
raise
end
# End Transactions Retry Example 3
end
it 'makes the changes to the database' do
run_transaction
employee = hr[:employees].find({ employee: 3 }, limit: 1).first
expect(employee).to_not be_nil
expect(employee['status']).to eq('Inactive')
end
end
end
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