heat/heat/common/utils.py
Angus Salkeld 3b9c41fb6c Initial commit (basics copied from glance)
Signed-off-by: Angus Salkeld <asalkeld@redhat.com>
2012-03-13 21:48:07 +11:00

373 lines
10 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# All Rights Reserved.
#
# 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.
"""
System-level utilities and helper functions.
"""
import datetime
import errno
import inspect
import logging
import os
import platform
import random
import subprocess
import socket
import sys
import uuid
import iso8601
from heat.common import exception
logger = logging.getLogger(__name__)
TIME_FORMAT = "%Y-%m-%dT%H:%M:%S"
def chunkreadable(iter, chunk_size=65536):
"""
Wrap a readable iterator with a reader yielding chunks of
a preferred size, otherwise leave iterator unchanged.
:param iter: an iter which may also be readable
:param chunk_size: maximum size of chunk
"""
return chunkiter(iter, chunk_size) if hasattr(iter, 'read') else iter
def chunkiter(fp, chunk_size=65536):
"""
Return an iterator to a file-like obj which yields fixed size chunks
:param fp: a file-like object
:param chunk_size: maximum size of chunk
"""
while True:
chunk = fp.read(chunk_size)
if chunk:
yield chunk
else:
break
def image_meta_to_http_headers(image_meta):
"""
Returns a set of image metadata into a dict
of HTTP headers that can be fed to either a Webob
Request object or an httplib.HTTP(S)Connection object
:param image_meta: Mapping of image metadata
"""
headers = {}
for k, v in image_meta.items():
if v is not None:
if k == 'properties':
for pk, pv in v.items():
if pv is not None:
headers["x-image-meta-property-%s"
% pk.lower()] = unicode(pv)
else:
headers["x-image-meta-%s" % k.lower()] = unicode(v)
return headers
def add_features_to_http_headers(features, headers):
"""
Adds additional headers representing heat features to be enabled.
:param headers: Base set of headers
:param features: Map of enabled features
"""
if features:
for k, v in features.items():
if v is not None:
headers[k.lower()] = unicode(v)
def get_image_meta_from_headers(response):
"""
Processes HTTP headers from a supplied response that
match the x-image-meta and x-image-meta-property and
returns a mapping of image metadata and properties
:param response: Response to process
"""
result = {}
properties = {}
if hasattr(response, 'getheaders'): # httplib.HTTPResponse
headers = response.getheaders()
else: # webob.Response
headers = response.headers.items()
for key, value in headers:
key = str(key.lower())
if key.startswith('x-image-meta-property-'):
field_name = key[len('x-image-meta-property-'):].replace('-', '_')
properties[field_name] = value or None
elif key.startswith('x-image-meta-'):
field_name = key[len('x-image-meta-'):].replace('-', '_')
result[field_name] = value or None
result['properties'] = properties
if 'size' in result:
try:
result['size'] = int(result['size'])
except ValueError:
raise exception.Invalid
for key in ('is_public', 'deleted', 'protected'):
if key in result:
result[key] = bool_from_header_value(result[key])
return result
def bool_from_header_value(value):
"""
Returns True if value is a boolean True or the
string 'true', case-insensitive, False otherwise
"""
if isinstance(value, bool):
return value
elif isinstance(value, (basestring, unicode)):
if str(value).lower() == 'true':
return True
return False
def bool_from_string(subject):
"""
Interpret a string as a boolean.
Any string value in:
('True', 'true', 'On', 'on', '1')
is interpreted as a boolean True.
Useful for JSON-decoded stuff and config file parsing
"""
if isinstance(subject, bool):
return subject
elif isinstance(subject, int):
return subject == 1
if hasattr(subject, 'startswith'): # str or unicode...
if subject.strip().lower() in ('true', 'on', '1'):
return True
return False
def import_class(import_str):
"""Returns a class from a string including module and class"""
mod_str, _sep, class_str = import_str.rpartition('.')
try:
__import__(mod_str)
return getattr(sys.modules[mod_str], class_str)
except (ImportError, ValueError, AttributeError), e:
raise exception.ImportFailure(import_str=import_str,
reason=e)
def import_object(import_str):
"""Returns an object including a module or module and class"""
try:
__import__(import_str)
return sys.modules[import_str]
except ImportError:
cls = import_class(import_str)
return cls()
def generate_uuid():
return str(uuid.uuid4())
def is_uuid_like(value):
try:
uuid.UUID(value)
return True
except Exception:
return False
def isotime(at=None):
"""Stringify time in ISO 8601 format"""
if not at:
at = datetime.datetime.utcnow()
str = at.strftime(TIME_FORMAT)
tz = at.tzinfo.tzname(None) if at.tzinfo else 'UTC'
str += ('Z' if tz == 'UTC' else tz)
return str
def parse_isotime(timestr):
"""Parse time from ISO 8601 format"""
try:
return iso8601.parse_date(timestr)
except iso8601.ParseError as e:
raise ValueError(e.message)
except TypeError as e:
raise ValueError(e.message)
def normalize_time(timestamp):
"""Normalize time in arbitrary timezone to UTC"""
offset = timestamp.utcoffset()
return timestamp.replace(tzinfo=None) - offset if offset else timestamp
def safe_mkdirs(path):
try:
os.makedirs(path)
except OSError, e:
if e.errno != errno.EEXIST:
raise
def safe_remove(path):
try:
os.remove(path)
except OSError, e:
if e.errno != errno.ENOENT:
raise
class PrettyTable(object):
"""Creates an ASCII art table for use in bin/heat
Example:
ID Name Size Hits
--- ----------------- ------------ -----
122 image 22 0
"""
def __init__(self):
self.columns = []
def add_column(self, width, label="", just='l'):
"""Add a column to the table
:param width: number of characters wide the column should be
:param label: column heading
:param just: justification for the column, 'l' for left,
'r' for right
"""
self.columns.append((width, label, just))
def make_header(self):
label_parts = []
break_parts = []
for width, label, _ in self.columns:
# NOTE(sirp): headers are always left justified
label_part = self._clip_and_justify(label, width, 'l')
label_parts.append(label_part)
break_part = '-' * width
break_parts.append(break_part)
label_line = ' '.join(label_parts)
break_line = ' '.join(break_parts)
return '\n'.join([label_line, break_line])
def make_row(self, *args):
row = args
row_parts = []
for data, (width, _, just) in zip(row, self.columns):
row_part = self._clip_and_justify(data, width, just)
row_parts.append(row_part)
row_line = ' '.join(row_parts)
return row_line
@staticmethod
def _clip_and_justify(data, width, just):
# clip field to column width
clipped_data = str(data)[:width]
if just == 'r':
# right justify
justified = clipped_data.rjust(width)
else:
# left justify
justified = clipped_data.ljust(width)
return justified
def get_terminal_size():
def _get_terminal_size_posix():
import fcntl
import struct
import termios
height_width = None
try:
height_width = struct.unpack('hh', fcntl.ioctl(sys.stderr.fileno(),
termios.TIOCGWINSZ,
struct.pack('HH', 0, 0)))
except:
pass
if not height_width:
try:
p = subprocess.Popen(['stty', 'size'],
shell=false,
stdout=subprocess.PIPE)
return tuple(int(x) for x in p.communicate()[0].split())
except:
pass
return height_width
def _get_terminal_size_win32():
try:
from ctypes import windll, create_string_buffer
handle = windll.kernel32.GetStdHandle(-12)
csbi = create_string_buffer(22)
res = windll.kernel32.GetConsoleScreenBufferInfo(handle, csbi)
except:
return None
if res:
import struct
unpack_tmp = struct.unpack("hhhhHhhhhhh", csbi.raw)
(bufx, bufy, curx, cury, wattr,
left, top, right, bottom, maxx, maxy) = unpack_tmp
height = bottom - top + 1
width = right - left + 1
return (height, width)
else:
return None
def _get_terminal_size_unknownOS():
raise NotImplementedError
func = {'posix': _get_terminal_size_posix,
'win32': _get_terminal_size_win32}
height_width = func.get(platform.os.name, _get_terminal_size_unknownOS)()
if height_width == None:
raise exception.Invalid()
for i in height_width:
if not isinstance(i, int) or i <= 0:
raise exception.Invalid()
return height_width[0], height_width[1]