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# frozen_string_literal: true
module Gitlab
module Database
# A class for reflecting upon a database and its settings, such as the
# adapter name, PostgreSQL version, and the presence of tables or columns.
class Reflection
attr_reader :model
def initialize(model)
@model = model
@version = nil
end
def config
# The result of this method must not be cached, as other methods may use
# it after making configuration changes and expect those changes to be
# present. For example, `disable_prepared_statements` expects the
# configuration settings to always be up to date.
#
# See the following for more information:
#
# - https://gitlab.com/gitlab-org/release/retrospectives/-/issues/39
# - https://gitlab.com/gitlab-com/gl-infra/production/-/issues/5238
model.connection_db_config.configuration_hash.with_indifferent_access
end
def username
config[:username] || ENV['USER']
end
def database_name
config[:database]
end
def adapter_name
config[:adapter]
end
def human_adapter_name
if postgresql?
'PostgreSQL'
else
'Unknown'
end
end
def postgresql?
adapter_name.casecmp('postgresql') == 0
end
# Check whether the underlying database is in read-only mode
def db_read_only?
pg_is_in_recovery =
connection
.execute('SELECT pg_is_in_recovery()')
.first
.fetch('pg_is_in_recovery')
Gitlab::Utils.to_boolean(pg_is_in_recovery)
end
def db_read_write?
!db_read_only?
end
def version
@version ||= database_version.match(/\A(?:PostgreSQL |)([^\s]+).*\z/)[1]
end
def database_version
connection.execute("SELECT VERSION()").first['version']
end
def postgresql_minimum_supported_version?
version.to_f >= MINIMUM_POSTGRES_VERSION
end
def cached_column_exists?(column_name)
connection
.schema_cache.columns_hash(model.table_name)
.has_key?(column_name.to_s)
end
def cached_table_exists?
exists? && connection.schema_cache.data_source_exists?(model.table_name)
end
def exists?
# We can't _just_ check if `connection` raises an error, as it will
# point to a `ConnectionProxy`, and obtaining those doesn't involve any
# database queries. So instead we obtain the database version, which is
# cached after the first call.
connection.schema_cache.database_version
true
rescue StandardError
false
end
def system_id
row = connection
.execute('SELECT system_identifier FROM pg_control_system()')
.first
row['system_identifier']
end
def flavor
{
# Based on https://aws.amazon.com/premiumsupport/knowledge-center/aurora-version-number/
'Amazon Aurora PostgreSQL' => { statement: 'SELECT AURORA_VERSION()', error: /PG::UndefinedFunction/ },
# Based on https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_PostgreSQL.html#PostgreSQL.Concepts.General.FeatureSupport.Extensions,
# this is also available for both Aurora and RDS, so we need to check for the former first.
'PostgreSQL on Amazon RDS' => { statement: 'SHOW rds.extensions', error: /PG::UndefinedObject/ },
# Based on https://cloud.google.com/sql/docs/postgres/flags#postgres-c this should be specific
# to Cloud SQL for PostgreSQL
'Cloud SQL for PostgreSQL' => { statement: 'SHOW cloudsql.iam_authentication', error: /PG::UndefinedObject/ },
# Based on
# - https://docs.microsoft.com/en-us/azure/postgresql/flexible-server/concepts-extensions
# - https://docs.microsoft.com/en-us/azure/postgresql/concepts-extensions
# this should be available only for Azure Database for PostgreSQL - Flexible Server.
'Azure Database for PostgreSQL - Flexible Server' => { statement: 'SHOW azure.extensions', error: /PG::UndefinedObject/ },
# Based on
# - https://docs.microsoft.com/en-us/azure/postgresql/flexible-server/concepts-servers
# - https://docs.microsoft.com/en-us/azure/postgresql/concepts-servers#managing-your-server
# this database is present on both Flexible and Single server, so we should check the former first.
'Azure Database for PostgreSQL - Single Server' => { statement: "SELECT datname FROM pg_database WHERE datname = 'azure_maintenance'" }
}.each do |flavor, conditions|
return flavor if connection.execute(conditions[:statement]).to_a.present?
rescue ActiveRecord::StatementInvalid => e
raise if conditions[:error] && !e.message.match?(conditions[:error])
end
nil
end
private
def connection
model.connection
end
end
end
end
|
