Class: Gitlab::Database::QueryAnalyzers::PreventCrossDatabaseModification

Inherits:
Base
  • Object
show all
Defined in:
lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb

Constant Summary collapse

CrossDatabaseModificationAcrossUnsupportedTablesError = 
Class.new(QueryAnalyzerError)
QUERY_LIMIT = 
10

Constants inherited from Base

Base::QueryAnalyzerError

Class Method Summary collapse

Methods inherited from Base

analyzer_key, context, context_key, end!, suppress=, suppress_key, suppressed?, with_suppressed

Class Method Details

.add_to_queries(sql) ⇒ Object 



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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 178

def self.add_to_queries(sql)
  return unless dev_or_test_env?

  context[:queries].push(sql)
end

.allow_cross_database_modification_within_transaction(url:, &blk) ⇒ Object

This method will allow cross database modifications within the block Example:

allow_cross_database_modification_within_transaction(url: ‘url-to-an-issue’) do

create(:build) # inserts ci_build and project record in one transaction

end



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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 16

def self.allow_cross_database_modification_within_transaction(url:, &blk)
  self.with_suppressed(true, &blk)
end

.analyze(parsed) ⇒ Object

rubocop:disable Metrics/AbcSize



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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 62

def self.analyze(parsed)
  database = ::Gitlab::Database.db_config_name(parsed.connection)
  sql = parsed.sql

  # We ignore BEGIN in tests as this is the outer transaction for
  # DatabaseCleaner
  if self.transaction_begin?(parsed)
    context[:transaction_depth_by_db][database] += 1

    return
  elsif self.transaction_end?(parsed)
    context[:transaction_depth_by_db][database] -= 1
    if context[:transaction_depth_by_db][database] == 0
      context[:modified_tables_by_db][database].clear
      clear_queries

      # Attempt to troubleshoot https://gitlab.com/gitlab-org/gitlab/-/issues/351531
      ::CrossDatabaseModification::TransactionStackTrackRecord.log_gitlab_transactions_stack(action: :end_of_transaction)
    elsif context[:transaction_depth_by_db][database] < 0
      context[:transaction_depth_by_db][database] = 0
      raise CrossDatabaseModificationAcrossUnsupportedTablesError, "Misaligned cross-DB transactions discovered at query #{sql}. This could be a bug in #{self.class} or a valid issue to investigate. Read more at https://docs.gitlab.com/ee/development/database/multiple_databases.html#removing-cross-database-transactions ."
    end

    return
  end

  return unless self.in_transaction?
  return if in_factory_bot_create?

  # PgQuery might fail in some cases due to limited nesting:
  # https://github.com/pganalyze/pg_query/issues/209
  tables = sql.downcase.include?(' for update') ? parsed.pg.tables : parsed.pg.dml_tables

  # We have some code where plans and gitlab_subscriptions are lazily
  # created and this causes lots of spec failures
  # https://gitlab.com/gitlab-org/gitlab/-/issues/343394
  tables -= %w[plans gitlab_subscriptions]

  # Ignore some tables
  tables -= context[:ignored_tables].to_a

  return if tables.empty?

  # All migrations will write to schema_migrations in the same transaction.
  # It's safe to ignore this since schema_migrations exists in all
  # databases
  return if tables == ['schema_migrations']

  add_to_queries(sql)
  context[:modified_tables_by_db][database].merge(tables)
  all_tables = context[:modified_tables_by_db].values.flat_map(&:to_a)
  schemas = ::Gitlab::Database::GitlabSchema.table_schemas!(all_tables)
  schemas += ApplicationRecord.gitlab_transactions_stack

  unless ::Gitlab::Database::GitlabSchema.cross_transactions_allowed?(schemas)
    messages = []
    messages << "Cross-database data modification of '#{schemas.to_a.join(", ")}' were detected within " \
                "a transaction modifying the '#{all_tables.to_a.join(", ")}' tables. "
    messages << "Please refer to https://docs.gitlab.com/ee/development/database/multiple_databases.html#removing-cross-database-transactions " \
                "for details on how to resolve this exception."
    messages += cleaned_queries

    raise CrossDatabaseModificationAcrossUnsupportedTablesError, messages.join("\n\n")
  end
rescue CrossDatabaseModificationAcrossUnsupportedTablesError => e
  ::Gitlab::ErrorTracking.track_exception(e, { gitlab_schemas: schemas, tables: all_tables, query: parsed.sql })
  raise if dev_or_test_env?
end

.begin! ⇒ Object 



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

def self.begin!
  super

  context.merge!({
    transaction_depth_by_db: Hash.new { |h, k| h[k] = 0 },
    modified_tables_by_db: Hash.new { |h, k| h[k] = Set.new },
    ignored_tables: [],
    queries: []
  })
end

.cleaned_queries ⇒ Object 



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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 184

def self.cleaned_queries
  return [] unless dev_or_test_env?

  context[:queries].last(QUERY_LIMIT).each_with_index.map do |sql, i|
    "#{i}: #{sql}"
  end
end

.clear_queries ⇒ Object 



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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 172

def self.clear_queries
  return unless dev_or_test_env?

  context[:queries].clear
end

.dev_or_test_env? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 168

def self.dev_or_test_env?
  Gitlab.dev_or_test_env?
end

.enabled? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 51

def self.enabled?
  ::Feature::FlipperFeature.table_exists? &&
    Feature.enabled?(:detect_cross_database_modification, type: :ops)
end

.in_factory_bot_create? ⇒ Boolean

We ignore execution in the #create method from FactoryBot because it is not representative of real code we run in production. There are far too many false positives caused by instantiating objects in different ‘gitlab_schema` in a FactoryBot `create`.

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 201

def self.in_factory_bot_create?
  Rails.env.test? && caller_locations.any? do |l|
    l.path.end_with?('lib/factory_bot/evaluation.rb') && l.label == 'create' ||
      l.path.end_with?('lib/factory_bot/strategy/create.rb') ||
      l.path.end_with?('lib/factory_bot/strategy/build.rb') ||
      l.path.end_with?('shoulda/matchers/active_record/validate_uniqueness_of_matcher.rb') && l.label == 'create_existing_record'
  end
end

.in_transaction? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 192

def self.in_transaction?
  context[:transaction_depth_by_db].values.any?(&:positive?)
end

.requires_tracking?(parsed) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 56

def self.requires_tracking?(parsed)
  # The transaction boundaries always needs to be tracked regardless of suppress behavior
  self.transaction_begin?(parsed) || self.transaction_end?(parsed)
end

.temporary_ignore_tables_in_transaction(tables, url:, &blk) ⇒ Object

This method will temporary ignore the given tables in a current transaction This is meant to disable ‘PreventCrossDB` check for some well known failures



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

def self.temporary_ignore_tables_in_transaction(tables, url:, &blk)
  return yield unless context&.dig(:ignored_tables)

  begin
    prev_ignored_tables = context[:ignored_tables]
    context[:ignored_tables] = prev_ignored_tables + tables
    yield
  ensure
    context[:ignored_tables] = prev_ignored_tables
  end
end

.transaction_begin?(parsed) ⇒ Boolean

rubocop:enable Metrics/AbcSize

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 132

def self.transaction_begin?(parsed)
  # We ignore BEGIN or START in tests
  unless Rails.env.test?
    return true if transaction_stmt?(parsed, :TRANS_STMT_BEGIN)
    return true if transaction_stmt?(parsed, :TRANS_STMT_START)
  end

  # SAVEPOINT
  return true if transaction_stmt?(parsed, :TRANS_STMT_SAVEPOINT)

  false
end

.transaction_end?(parsed) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 145

def self.transaction_end?(parsed)
  # We ignore ROLLBACK or COMMIT in tests
  unless Rails.env.test?
    return true if transaction_stmt?(parsed, :TRANS_STMT_COMMIT)
    return true if transaction_stmt?(parsed, :TRANS_STMT_COMMIT_PREPARED)
    return true if transaction_stmt?(parsed, :TRANS_STMT_ROLLBACK)
    return true if transaction_stmt?(parsed, :TRANS_STMT_ROLLBACK_PREPARED)
  end

  # RELEASE (SAVEPOINT) or ROLLBACK TO (SAVEPOINT)
  return true if transaction_stmt?(parsed, :TRANS_STMT_RELEASE)
  return true if transaction_stmt?(parsed, :TRANS_STMT_ROLLBACK_TO)

  false
end

.transaction_stmt?(parsed, kind) ⇒ Boolean

Known kinds: github.com/pganalyze/pg_query/blob/f6588703deb9d7a94b87b34b7c3bab240087fbc4/ext/pg_query/include/nodes/parsenodes.h#L3050

Returns:

  • (Boolean) 


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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 162

def self.transaction_stmt?(parsed, kind)
  parsed.pg.tree.stmts.map(&:stmt).any? do |stmt|
    stmt.node == :transaction_stmt && stmt.transaction_stmt.kind == kind
  end
end

.with_cross_database_modification_prevented(&blk) ⇒ Object

This method will prevent cross database modifications within the block if it was allowed previously



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# File 'lib/gitlab/database/query_analyzers/prevent_cross_database_modification.rb', line 22

def self.with_cross_database_modification_prevented(&blk)
  self.with_suppressed(false, &blk)
end