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