96 lines
3 KiB
Ruby
96 lines
3 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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# The exceptions raised for connection errors.
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CONNECTION_ERRORS = if defined?(PG)
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[
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PG::ConnectionBad,
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PG::ConnectionDoesNotExist,
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PG::ConnectionException,
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PG::ConnectionFailure,
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PG::UnableToSend,
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# During a failover this error may be raised when
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# writing to a primary.
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PG::ReadOnlySqlTransaction
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].freeze
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else
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[].freeze
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end
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ProxyNotConfiguredError = Class.new(StandardError)
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# The connection proxy to use for load balancing (if enabled).
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def self.proxy
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unless load_balancing_proxy = ActiveRecord::Base.load_balancing_proxy
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Gitlab::ErrorTracking.track_exception(
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ProxyNotConfiguredError.new(
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"Attempting to access the database load balancing proxy, but it wasn't configured.\n" \
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"Did you forget to call '#{self.name}.configure_proxy'?"
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))
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end
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load_balancing_proxy
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end
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# Returns a Hash containing the load balancing configuration.
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def self.configuration
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@configuration ||= Configuration.for_model(ActiveRecord::Base)
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end
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# Returns true if load balancing is to be enabled.
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def self.enable?
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return false if Gitlab::Runtime.rake?
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configured?
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end
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def self.configured?
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configuration.load_balancing_enabled? ||
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configuration.service_discovery_enabled?
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end
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def self.start_service_discovery
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return unless configuration.service_discovery_enabled?
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ServiceDiscovery
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.new(proxy.load_balancer, **configuration.service_discovery)
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.start
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end
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# Configures proxying of requests.
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def self.configure_proxy
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lb = LoadBalancer.new(configuration, primary_only: !enable?)
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ActiveRecord::Base.load_balancing_proxy = ConnectionProxy.new(lb)
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# Populate service discovery immediately if it is configured
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if configuration.service_discovery_enabled?
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ServiceDiscovery
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.new(lb, **configuration.service_discovery)
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.perform_service_discovery
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end
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end
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DB_ROLES = [
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ROLE_PRIMARY = :primary,
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ROLE_REPLICA = :replica,
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ROLE_UNKNOWN = :unknown
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].freeze
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# Returns the role (primary/replica) of the database the connection is
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# connecting to.
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def self.db_role_for_connection(connection)
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db_config = Database.db_config_for_connection(connection)
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return ROLE_UNKNOWN unless db_config
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if db_config.name.ends_with?(LoadBalancer::REPLICA_SUFFIX)
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ROLE_REPLICA
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else
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ROLE_PRIMARY
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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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