discourse/lib/export/exporter.rb

334 lines
9.6 KiB
Ruby

module Export
class Exporter
def initialize(user_id, publish_to_message_bus = false)
@user_id, @publish_to_message_bus = user_id, publish_to_message_bus
ensure_no_operation_is_running
ensure_we_have_a_user
initialize_state
end
def run
log "[STARTED]"
log "'#{@user.username}' has started the backup!"
mark_export_as_running
listen_for_shutdown_signal
ensure_directory_exists(@tmp_directory)
ensure_directory_exists(@archive_directory)
write_metadata
### READ-ONLY / START ###
enable_readonly_mode
pause_sidekiq
wait_for_sidekiq
dump_public_schema
disable_readonly_mode
### READ-ONLY / END ###
log "Finalizing backup..."
update_dump
create_archive
after_create_hook
remove_old
rescue SystemExit
log "Backup process was cancelled!"
rescue Exception => ex
log "EXCEPTION: " + ex.message
log ex.backtrace.join("\n")
else
@success = true
"#{@archive_basename}.tar.gz"
ensure
notify_user rescue nil
clean_up
@success ? log("[SUCCESS]") : log("[FAILED]")
end
protected
def ensure_no_operation_is_running
raise BackupRestore::OperationRunningError if BackupRestore.is_operation_running?
end
def ensure_we_have_a_user
@user = User.find_by(id: @user_id)
raise Discourse::InvalidParameters.new(:user_id) unless @user
end
def initialize_state
@success = false
@current_db = RailsMultisite::ConnectionManagement.current_db
@timestamp = Time.now.strftime("%Y-%m-%d-%H%M%S")
@tmp_directory = File.join(Rails.root, "tmp", "backups", @current_db, @timestamp)
@dump_filename = File.join(@tmp_directory, BackupRestore::DUMP_FILE)
@meta_filename = File.join(@tmp_directory, BackupRestore::METADATA_FILE)
@archive_directory = File.join(Rails.root, "public", "backups", @current_db)
@archive_basename = File.join(@archive_directory, "#{SiteSetting.title.parameterize}-#{@timestamp}")
@logs = []
@readonly_mode_was_enabled = Discourse.readonly_mode?
end
def listen_for_shutdown_signal
Thread.new do
while BackupRestore.is_operation_running?
exit if BackupRestore.should_shutdown?
sleep 0.1
end
end
end
def mark_export_as_running
log "Marking backup as running..."
BackupRestore.mark_as_running!
end
def enable_readonly_mode
return if @readonly_mode_was_enabled
log "Enabling readonly mode..."
Discourse.enable_readonly_mode
end
def pause_sidekiq
log "Pausing sidekiq..."
Sidekiq.pause!
end
def wait_for_sidekiq
log "Waiting for sidekiq to finish running jobs..."
iterations = 1
while sidekiq_has_running_jobs?
log "Waiting for sidekiq to finish running jobs... ##{iterations}"
sleep 5
iterations += 1
raise "Sidekiq did not finish running all the jobs in the allowed time!" if iterations > 6
end
end
def sidekiq_has_running_jobs?
Sidekiq::Workers.new.each do |process_id, thread_id, worker|
payload = worker.try(:payload)
return true if payload.try(:all_sites)
return true if payload.try(:current_site_id) == @current_db
end
false
end
def write_metadata
log "Writing metadata to '#{@meta_filename}'..."
metadata = {
source: "discourse",
version: BackupRestore.current_version
}
File.write(@meta_filename, metadata.to_json)
end
def dump_public_schema
log "Dumping the public schema of the database..."
logs = Queue.new
pg_dump_running = true
Thread.new do
RailsMultisite::ConnectionManagement::establish_connection(db: @current_db)
while pg_dump_running
message = logs.pop.strip
log(message) unless message.blank?
end
end
IO.popen("#{pg_dump_command} 2>&1") do |pipe|
begin
while line = pipe.readline
logs << line
end
rescue EOFError
# finished reading...
ensure
pg_dump_running = false
logs << ""
end
end
raise "pg_dump failed" unless $?.success?
end
def pg_dump_command
db_conf = BackupRestore.database_configuration
password_argument = "PGPASSWORD=#{db_conf.password}" if db_conf.password.present?
host_argument = "--host=#{db_conf.host}" if db_conf.host.present?
username_argument = "--username=#{db_conf.username}" if db_conf.username.present?
[ password_argument, # pass the password to pg_dump (if any)
"pg_dump", # the pg_dump command
"--schema=public", # only public schema
"--file='#{@dump_filename}'", # output to the dump.sql file
"--no-owner", # do not output commands to set ownership of objects
"--no-privileges", # prevent dumping of access privileges
"--verbose", # specifies verbose mode
host_argument, # the hostname to connect to (if any)
username_argument, # the username to connect as (if any)
db_conf.database # the name of the database to dump
].join(" ")
end
def update_dump
log "Updating dump for more awesomeness..."
`#{sed_command}`
end
def sed_command
# in order to limit the downtime when restoring as much as possible
# we force the restoration to happen in the "restore" schema
# during the restoration, this make sure we
# - drop the "restore" schema if it exists
# - create the "restore" schema
# - prepend the "restore" schema into the search_path
regexp = "SET search_path = public, pg_catalog;"
replacement = [ "DROP SCHEMA IF EXISTS restore CASCADE;",
"CREATE SCHEMA restore;",
"SET search_path = restore, public, pg_catalog;",
].join(" ")
# we only want to replace the VERY first occurence of the search_path command
expression = "1,/^#{regexp}$/s/#{regexp}/#{replacement}/"
# I tried to use the --in-place argument but it was SLOOOWWWWwwwwww
# so I output the result into another file and rename it back afterwards
[ "sed -e '#{expression}' < #{@dump_filename} > #{@dump_filename}.tmp",
"&&",
"mv #{@dump_filename}.tmp #{@dump_filename}",
].join(" ")
end
def create_archive
log "Creating archive: #{File.basename(@archive_basename)}.tar.gz"
tar_filename = "#{@archive_basename}.tar"
log "Making sure archive does not already exist..."
`rm -f #{tar_filename}`
`rm -f #{tar_filename}.gz`
log "Creating empty archive..."
`tar --create --file #{tar_filename} --files-from /dev/null`
log "Archiving metadata..."
FileUtils.cd(File.dirname(@meta_filename)) do
`tar --append --dereference --file #{tar_filename} #{File.basename(@meta_filename)}`
end
log "Archiving data dump..."
FileUtils.cd(File.dirname(@dump_filename)) do
`tar --append --dereference --file #{tar_filename} #{File.basename(@dump_filename)}`
end
upload_directory = "uploads/" + @current_db
log "Archiving uploads..."
FileUtils.cd(File.join(Rails.root, "public")) do
`tar --append --dereference --file #{tar_filename} #{upload_directory}`
end
log "Gzipping archive..."
`gzip --best #{tar_filename}`
end
def after_create_hook
log "Executing the after_create_hook for the backup"
backup = Backup.create_from_filename("#{File.basename(@archive_basename)}.tar.gz")
backup.after_create_hook
end
def remove_old
log "Removing old backups..."
Backup.remove_old
end
def notify_user
log "Notifying '#{@user.username}' of the end of the backup..."
if @success
SystemMessage.create_from_system_user(@user, :export_succeeded)
else
SystemMessage.create_from_system_user(@user, :export_failed, logs: @logs.join("\n"))
end
end
def clean_up
log "Cleaning stuff up..."
remove_tmp_directory
unpause_sidekiq
disable_readonly_mode if Discourse.readonly_mode?
mark_export_as_not_running
log "Finished!"
end
def remove_tmp_directory
log "Removing tmp '#{@tmp_directory}' directory..."
FileUtils.rm_rf(@tmp_directory) if Dir[@tmp_directory].present?
rescue
log "Something went wrong while removing the following tmp directory: #{@tmp_directory}"
end
def unpause_sidekiq
log "Unpausing sidekiq..."
Sidekiq.unpause!
rescue
log "Something went wrong while unpausing Sidekiq."
end
def disable_readonly_mode
return if @readonly_mode_was_enabled
log "Disabling readonly mode..."
Discourse.disable_readonly_mode
end
def mark_export_as_not_running
log "Marking backup as finished..."
BackupRestore.mark_as_not_running!
end
def ensure_directory_exists(directory)
log "Making sure '#{directory}' exists..."
FileUtils.mkdir_p(directory)
end
def log(message)
puts(message) rescue nil
publish_log(message) rescue nil
save_log(message)
end
def publish_log(message)
return unless @publish_to_message_bus
data = { timestamp: Time.now, operation: "backup", message: message }
MessageBus.publish(BackupRestore::LOGS_CHANNEL, data, user_ids: [@user_id])
end
def save_log(message)
@logs << "[#{Time.now}] #{message}"
end
end
end