Module: Quandl::Cassandra::Base::Connection::ClassMethods

Defined in:
lib/quandl/cassandra/base/connection.rb

Instance Method Summary collapse

Instance Method Details

#connection ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 71

def connection
  @@connection ||= establish_connection
end

#consistency ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 75

def consistency
  Quandl::Cassandra.configuration.consistency
end

#delete(*ids) ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 11

def delete(*ids)
  statement = prepare("DELETE FROM #{table_name} WHERE id = ?")
  Array(ids).flatten.
    collect{|id| statement.async.execute(id, consistency) }.
    collect(&:value)
end

#establish_connection ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 85

def establish_connection
  c = Cql::Client.connect(
    hosts:        Quandl::Cassandra.configuration.hosts, 
    consistency:  Quandl::Cassandra.configuration.consistency )
  # switch keyspace
  c.use( Quandl::Cassandra.configuration.keyspace ) if Quandl::Cassandra.configuration.keyspace.present?
  @@connection = c
  c
end

#execute(statement, consist = nil) ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 35

def execute(statement, consist = nil)
  consist = consistency unless consist.present?
  with_connection do |c|
    c.execute( statement, consist )
  end
rescue Cql::QueryError
  raise $!, "#{$!}\n  statement: #{statement}", $!.backtrace
end

#execute_async(statement, consist = nil) ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 26

def execute_async(statement, consist = nil)
  consist = consistency unless consist.present?
  with_connection do |c|
    c.async.execute( statement, consist )
  end
rescue Cql::QueryError
  raise $!, "#{$!}\n  statement: #{statement}", $!.backtrace
end

#prepare(statement) ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 18

def prepare(statement)
  with_connection do |c|
    c.prepare(statement)
  end
rescue Cql::QueryError
  raise $!, "#{$!}\n  statement: #{statement}", $!.backtrace
end

#rescue_and_retry(times, &block) ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 50

def rescue_and_retry(times, &block)

  block.call(connection)
  
rescue Cql::QueryError => err
  #puts "ERROR: #{err.code} #{err}\n  cql: '#{err.cql}'"
  Quandl::Logger.error("#{err.code} '#{err.cql}' #{$!}")
  # raise error if it's failed three times
  raise( $!, "#{err.code} '#{err.cql}' #{$!}", $!.backtrace ) if times <= 1
  # otherwise rescue and retry
  rescue_and_retry(times - 1, &block)
  
rescue Cql::Io::ConnectionError, Cql::NotConnectedError => err
  #puts "ERROR: #{err}"
  Quandl::Logger.error(err)
  reset_connection
  raise if times <= 1
  rescue_and_retry(times - 1, &block)
  
end

#reset_connection ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 79

def reset_connection
  connection.close
  @@connection = establish_connection
  true
end

#truncate ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 7

def truncate
  execute("TRUNCATE #{table_name}")
end

#with_connection(&block) ⇒ Object 



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# File 'lib/quandl/cassandra/base/connection.rb', line 44

def with_connection(&block)
  rescue_and_retry(2) do
    block.call(connection)
  end
end