Files
impala/shell/shell_output.py
2014-01-08 10:50:55 -08:00

89 lines
3.1 KiB
Python

#!/usr/bin/env python
# Copyright 2012 Cloudera Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import csv
import sys
from cStringIO import StringIO
class PrettyOutputFormatter(object):
def __init__(self, prettytable):
self.prettytable = prettytable
def format(self, rows):
# Clear rows that already exist in the table.
self.prettytable.clear_rows()
try:
map(self.prettytable.add_row, rows)
return self.prettytable.get_string()
except Exception, e:
# beeswax returns each row as a tab separated string. If a string column
# value in a row has tabs, it will break the row split. Default to displaying
# raw results. This will change with a move to hiveserver2.
# Reference: https://issues.cloudera.org/browse/IMPALA-116
error_msg = ("Prettytable cannot resolve string columns values that have "
" embedded tabs. Reverting to tab delimited text output")
print >>sys.stderr, error_msg
return '\n'.join(['\t'.join(row) for row in rows])
class DelimitedOutputFormatter(object):
def __init__(self, field_delim="\t"):
if field_delim:
self.field_delim = field_delim.decode('string-escape')
if len(self.field_delim) != 1:
error_msg = ("Illegal delimiter %s, the delimiter "
"must be a 1-character string." % self.field_delim)
raise ValueError, error_msg
def format(self, rows):
# csv.writer expects a file handle to the input.
# cStringIO is used as the temporary buffer.
temp_buffer = StringIO()
writer = csv.writer(temp_buffer, delimiter=self.field_delim,
lineterminator='\n', quoting=csv.QUOTE_MINIMAL)
writer.writerows(rows)
rows = temp_buffer.getvalue().rstrip('\n')
temp_buffer.close()
return rows
class OutputStream(object):
def __init__(self, formatter, filename=None):
"""Helper class for writing query output.
User should invoke the `write(data)` method of this object.
`data` is a list of lists.
"""
self.formatter = formatter
self.handle = sys.stdout
self.filename = filename
if self.filename:
try:
self.handle = open(self.filename, 'ab')
except IOError, err:
print >>sys.stderr, "Error opening file %s: %s" % (self.filename, str(err))
print >>sys.stderr, "Writing to stdout"
def write(self, data):
print >>self.handle, self.formatter.format(data)
self.handle.flush()
def __del__(self):
# If the output file cannot be opened, OutputStream defaults to sys.stdout.
# Don't close the file handle if it points to sys.stdout.
if self.filename and self.handle != sys.stdout:
self.handle.close()