Class ImpalaShell

shell/impala_shell/impala_shell.py:143–1995

Simple Impala Shell. Implements the context manager interface to ensure client connections and sessions are cleanly torn down. ImpalaShell instances should be used within a "with" statement to ensure correct teardown. Basic usage: type connect to connect to an impalad Then i

# Py3 method resolution order requires 'object' to be last w/ multiple inheritance
class ImpalaShell(cmd.Cmd, object):
  """ Simple Impala Shell.

  Implements the context manager interface to ensure client connections and sessions
  are cleanly torn down. ImpalaShell instances should be used within a "with" statement
  to ensure correct teardown.

  Basic usage: type connect <host:port> to connect to an impalad
  Then issue queries or other commands. Tab-completion should show the set of
  available commands.
  Methods that implement shell commands return a boolean tuple (stop, status)
  stop is a flag the command loop uses to continue/discontinue the prompt.
  Status tells the caller that the command completed successfully.
  """

  # NOTE: These variables are centrally defined for reuse, but they are also
  # used directly in several tests to verify shell behavior (e.g. to
  # verify that the shell remained connected or the shell connected
  # successfully).

  # If not connected to an impalad, the server version is unknown.
  UNKNOWN_SERVER_VERSION = "Not Connected"
  PROMPT_FORMAT = "[{host}:{port}] {db}> "
  DISCONNECTED_PROMPT = "[Not connected] > "
  # Message to display when the connection failed and it is reconnecting.
  CONNECTION_LOST_MESSAGE = 'Connection lost, reconnecting...'
  # Message to display when there is an exception when connecting.
  ERROR_CONNECTING_MESSAGE = "Error connecting "
  # Message to display when there is a socket error.
  SOCKET_ERROR_MESSAGE = "Socket error"
  # Message to display upon successful connection to an Impalad
  CONNECTED_TO_MESSAGE = "Connected to"
  # Message to display in shell when cancelling a query
  CANCELLATION_MESSAGE = ' Cancelling Query'
  # Number of times to attempt cancellation before giving up.
  CANCELLATION_TRIES = 3
  # Commands are terminated with the following delimiter.
  CMD_DELIM = ';'
  # Valid variable name pattern
  VALID_VAR_NAME_PATTERN = r'[A-Za-z][A-Za-z0-9_]*'
  # Pattern for removal of comments preceding SET commands
  COMMENTS_BEFORE_SET_PATTERN = r'^(\s*/\*(.|\n)*?\*/|\s*--.*\n)*\s*((un)?set)'
  COMMENTS_BEFORE_SET_REPLACEMENT = r'\3'
  # Variable names are prefixed with the following string
  VAR_PREFIXES = ['VAR', 'HIVEVAR']
  DEFAULT_DB = 'default'
  # Regex applied to all tokens of a query to detect DML statements.
  DML_REGEX = re.compile("^(insert|upsert|update|delete)$", re.I)
  # Seperator for queries in the history file.
  HISTORY_FILE_QUERY_DELIM = '_IMP_DELIM_'
  # Strings that are interpreted as True for some shell options.
  TRUE_STRINGS = ("true", "TRUE", "True", "1")
  # List of quit commands
  QUIT_COMMANDS = ("quit", "exit")

  VALID_SHELL_OPTIONS = {
    'LIVE_PROGRESS': (lambda x: x in ImpalaShell.TRUE_STRINGS, "live_progress"),
    'LIVE_SUMMARY': (lambda x: x in ImpalaShell.TRUE_STRINGS, "live_summary"),