115 lines
3.7 KiB
Ruby
115 lines
3.7 KiB
Ruby
# frozen_string_literal: true
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module Gitlab
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module Database
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module LoadBalancing
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class SidekiqServerMiddleware
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JobReplicaNotUpToDate = Class.new(StandardError)
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MINIMUM_DELAY_INTERVAL_SECONDS = 0.8
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def call(worker, job, _queue)
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worker_class = worker.class
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strategy = select_load_balancing_strategy(worker_class, job)
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job['load_balancing_strategy'] = strategy.to_s
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if use_primary?(strategy)
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::Gitlab::Database::LoadBalancing::Session.current.use_primary!
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elsif strategy == :retry
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raise JobReplicaNotUpToDate, "Sidekiq job #{worker_class} JID-#{job['jid']} couldn't use the replica."\
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" Replica was not up to date."
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else
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# this means we selected an up-to-date replica, but there is nothing to do in this case.
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end
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yield
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ensure
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clear
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end
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private
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def clear
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::Gitlab::Database::LoadBalancing.release_hosts
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::Gitlab::Database::LoadBalancing::Session.clear_session
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end
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def use_primary?(strategy)
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strategy.start_with?('primary')
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end
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def select_load_balancing_strategy(worker_class, job)
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return :primary unless load_balancing_available?(worker_class)
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wal_locations = get_wal_locations(job)
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return :primary_no_wal if wal_locations.blank?
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# Happy case: we can read from a replica.
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return replica_strategy(worker_class, job) if databases_in_sync?(wal_locations)
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sleep_if_needed(job)
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if databases_in_sync?(wal_locations)
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replica_strategy(worker_class, job)
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elsif can_retry?(worker_class, job)
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# Optimistic case: The worker allows retries and we have retries left.
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:retry
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else
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# Sad case: we need to fall back to the primary.
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:primary
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end
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end
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def sleep_if_needed(job)
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remaining_delay = MINIMUM_DELAY_INTERVAL_SECONDS - (Time.current.to_f - job['created_at'].to_f)
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sleep remaining_delay if remaining_delay > 0 && remaining_delay < MINIMUM_DELAY_INTERVAL_SECONDS
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end
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def get_wal_locations(job)
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job['dedup_wal_locations'] || job['wal_locations']
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end
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def load_balancing_available?(worker_class)
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worker_class.include?(::ApplicationWorker) &&
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worker_class.utilizes_load_balancing_capabilities? &&
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worker_class.get_data_consistency_feature_flag_enabled?
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end
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def can_retry?(worker_class, job)
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worker_class.get_data_consistency == :delayed && not_yet_retried?(job)
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end
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def replica_strategy(worker_class, job)
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retried_before?(worker_class, job) ? :replica_retried : :replica
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end
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def retried_before?(worker_class, job)
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worker_class.get_data_consistency == :delayed && !not_yet_retried?(job)
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end
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def not_yet_retried?(job)
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# if `retry_count` is `nil` it indicates that this job was never retried
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# the `0` indicates that this is a first retry
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job['retry_count'].nil?
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end
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def databases_in_sync?(wal_locations)
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::Gitlab::Database::LoadBalancing.each_load_balancer.all? do |lb|
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if (location = wal_locations[lb.name])
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lb.select_up_to_date_host(location)
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else
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# If there's no entry for a load balancer it means the Sidekiq
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# job doesn't care for it. In this case we'll treat the load
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# balancer as being in sync.
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true
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end
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end
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end
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end
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end
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end
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end
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