Class: Impaler::Manager

Inherits:
Object
  • Object
show all
Defined in:
lib/impaler/manager.rb

Instance Method Summary collapse

Constructor Details

#initialize(impala_servers, hivethrift_servers, logger = Impaler::DEFAULT_LOGGER) ⇒ Manager

Returns a new instance of Manager.



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# File 'lib/impaler/manager.rb', line 12

def initialize(impala_servers, hivethrift_servers, logger=Impaler::DEFAULT_LOGGER)
  if impala_servers.nil? and hivethrift_servers.nil? 
    raise Impaler::ConnectionError.new("No impaler or hive servers were specified, at least one is required")
  end

  if !impala_servers.nil?
    if impala_servers.respond_to?(:choice)
      @impala_servers=impala_servers
    else 
      @impala_servers=[impala_servers]
    end

    impala_server = @impala_servers.choice.split(":")
    @impala_host = impala_server[0]
    @impala_port = impala_server[1]
  end

  if !hivethrift_servers.nil?
    if hivethrift_servers.respond_to?(:choice)
      @hivethrift_servers=hivethrift_servers
    else
      @hivethrift_servers=[hivethrift_servers]
    end
    hivethrift_server = @hivethrift_servers.choice.split(":")
    @hivethrift_host = hivethrift_server[0]
    @hivethrift_port = hivethrift_server[1]
  end

  @logger = logger
  open
end

Instance Method Details

#close ⇒ Object 



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# File 'lib/impaler/manager.rb', line 70

def close
  if !@impala_connection.nil?
    @impala_connection.close
    @impala_connection = nil
  end

  if !@hivethrift_connection.nil?
    @hivethrift_connection.close
    @hivethrift_connection = nil
  end
end

#columns(tablename) ⇒ Object

########################################################################### Metadata methods



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# File 'lib/impaler/manager.rb', line 144

def columns(tablename)
  desc = {}
  (query "describe #{tablename}").each { |col|
    cname=col[:name] || col[:col_name]
    ctype=col[:type] || col[:data_type]
    desc[cname.intern] = ctype.intern
  }
  desc
end

#open ⇒ Object 



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# File 'lib/impaler/manager.rb', line 44

def open
  connected=false
  if !@impala_host.nil? && !@impala_port.nil?
    @logger.debug "Impala connection #{@impala_host}:#{@impala_port}"
    @impala_connection = Impala.connect(@impala_host, @impala_port)
    @impala_connection.open
    @impala_connection.refresh
    connected=true
  else
    @impala_connection = nil
  end

  if !@hivethrift_host.nil? && !@hivethrift_port.nil?
    @logger.debug "Hivethrift connection #{@hivethrift_host}:#{@hivethrift_port}"
    @hivethrift_connection = RBHive::Connection.new(@hivethrift_host, @hivethrift_port)
    @hivethrift_connection.open
    connected=true
  else
    @hivethrift_connection = nil
  end

  if !connected
    raise Impaler::ConnectionError.new("All connections failed")
  end
end

#query(sql, query_mode = Impaler::IMPALA_THEN_HIVE) ⇒ Object

########################################################################### General use methods



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# File 'lib/impaler/manager.rb', line 86

def query(sql, query_mode = Impaler::IMPALA_THEN_HIVE)
  ret = nil
  error = nil
  success = false
  unless query_mode == Impaler::HIVE_ONLY or @impala_connection.nil? 
    begin
      @logger.debug "Trying query in impala"
      ret = @impala_connection.query(sql)
      @logger.debug "Successful query in impala"
      success = true
    rescue StandardError => e
      error = e
      @logger.warn "Impala error: #{e}"
    end
  end

  unless @hivethrift_connection.nil? || success || query_mode == Impaler::IMPALA_ONLY 
    begin
      @logger.debug "Trying query in hive"
      ret = @hivethrift_connection.fetch(sql)
      @logger.debug "Successful query in hive"
      success = true
    rescue StandardError => e
      error = e
      @logger.warn "Hive error: #{e}"
    end
  end

  if !success && !error.nil? 
    raise error
  elsif !success 
    raise Impaler::QueryError.new("Query did not run due to no connections being available")
  end
  return ret
end

#row_count(tablename) ⇒ Object

########################################################################### Helper query methods



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# File 'lib/impaler/manager.rb', line 133

def row_count(tablename)
    query("SELECT COUNT(1) c FROM #{tablename}").first[:c]
end

#set(key, value) ⇒ Object 



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# File 'lib/impaler/manager.rb', line 122

def set(key, value)
  # Only run on hive since that's the only one that supports set for now
  if !@hivethrift_connection.nil?
    @hivethrift_connection.set(key, value)
  end
end

#tables(pattern = nil) ⇒ Object 



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# File 'lib/impaler/manager.rb', line 154

def tables(pattern=nil)
  q = "SHOW TABLES" + ((pattern.nil?) ? "" : " '#{pattern}'")
  query(q).collect { |table|
    table[:name] || table[:tab_name]
  }
end