Class: Gitlab::Database::Reflection

Inherits:
Object
  • Object
show all
Defined in:
lib/gitlab/database/reflection.rb

Overview

A class for reflecting upon a database and its settings, such as the adapter name, PostgreSQL version, and the presence of tables or columns.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(model) ⇒ Reflection

Returns a new instance of Reflection.



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# File 'lib/gitlab/database/reflection.rb', line 10

def initialize(model)
  @model = model
  @version = nil
end

Instance Attribute Details

#model ⇒ Object (readonly)

Returns the value of attribute model.



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# File 'lib/gitlab/database/reflection.rb', line 8

def model
  @model
end

Instance Method Details

#adapter_name ⇒ Object 



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# File 'lib/gitlab/database/reflection.rb', line 36

def adapter_name
  config[:adapter]
end

#cached_column_exists?(column_name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/reflection.rb', line 79

def cached_column_exists?(column_name)
  connection
    .schema_cache.columns_hash(model.table_name)
    .has_key?(column_name.to_s)
end

#cached_table_exists? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/reflection.rb', line 85

def cached_table_exists?
  exists? && connection.schema_cache.data_source_exists?(model.table_name)
end

#config ⇒ Object 



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# File 'lib/gitlab/database/reflection.rb', line 15

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

#database_name ⇒ Object 



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# File 'lib/gitlab/database/reflection.rb', line 32

def database_name
  config[:database]
end

#database_version ⇒ Object 



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# File 'lib/gitlab/database/reflection.rb', line 71

def database_version
  connection.execute("SELECT VERSION()").first['version']
end

#db_read_only? ⇒ Boolean

Check whether the underlying database is in read-only mode

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/reflection.rb', line 53

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

#db_read_write? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/reflection.rb', line 63

def db_read_write?
  !db_read_only?
end

#exists? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/reflection.rb', line 89

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

#flavor ⇒ Object 



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# File 'lib/gitlab/database/reflection.rb', line 108

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'" },
    # Based on
    #   - https://cloud.google.com/sql/docs/postgres/flags
    # running a query to detect flag names that begin with 'alloydb
    'AlloyDB for PostgreSQL' => { statement: "SELECT name FROM pg_settings WHERE name LIKE 'alloydb%'" }
  }.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

#human_adapter_name ⇒ Object 



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# File 'lib/gitlab/database/reflection.rb', line 40

def human_adapter_name
  if postgresql?
    'PostgreSQL'
  else
    'Unknown'
  end
end

#postgresql? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/reflection.rb', line 48

def postgresql?
  adapter_name.casecmp('postgresql') == 0
end

#postgresql_minimum_supported_version? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/reflection.rb', line 75

def postgresql_minimum_supported_version?
  version.to_f >= MINIMUM_POSTGRES_VERSION
end

#system_id ⇒ Object 



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# File 'lib/gitlab/database/reflection.rb', line 100

def system_id
  row = connection
    .execute('SELECT system_identifier FROM pg_control_system()')
    .first

  row['system_identifier']
end

#username ⇒ Object 



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# File 'lib/gitlab/database/reflection.rb', line 28

def username
  config[:username] || ENV['USER']
end

#version ⇒ Object 



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# File 'lib/gitlab/database/reflection.rb', line 67

def version
  @version ||= database_version.match(/\A(?:PostgreSQL |)([^\s]+).*\z/)[1]
end