79 lines
2.0 KiB
Ruby
79 lines
2.0 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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# A host that wraps the primary database connection.
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#
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# This class is used to always enable load balancing as if replicas exist,
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# without the need for extra database connections. This ensures that code
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# using the load balancer doesn't have to handle the case where load
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# balancing is enabled, but no replicas have been configured (= the
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# default case).
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class PrimaryHost
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WAL_ERROR_MESSAGE = <<~MSG.strip
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Obtaining WAL information when not using any replicas results in
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redundant queries, and may break installations that don't support
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streaming replication (e.g. AWS' Aurora database).
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MSG
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def initialize(load_balancer)
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@load_balancer = load_balancer
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end
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def release_connection
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# no-op as releasing primary connections isn't needed.
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nil
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end
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def enable_query_cache!
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# This could mess up the primary connection, so we make this a no-op
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nil
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end
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def disable_query_cache!
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# This could mess up the primary connection, so we make this a no-op
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nil
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end
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def query_cache_enabled
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@load_balancer.pool.query_cache_enabled
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end
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def connection
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@load_balancer.pool.connection
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end
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def disconnect!(timeout: 120)
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nil
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end
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def offline!
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::Gitlab::Database::LoadBalancing::Logger.warn(
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event: :host_offline,
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message: 'Marking primary host as offline'
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)
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nil
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end
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def online?
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true
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end
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def primary_write_location
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raise NotImplementedError, WAL_ERROR_MESSAGE
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end
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def database_replica_location
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raise NotImplementedError, WAL_ERROR_MESSAGE
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end
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def caught_up?(_location)
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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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