root / lib / qlang.py @ 670e954a
History | View | Annotate | Download (9.6 kB)
1 |
#
|
---|---|
2 |
#
|
3 |
|
4 |
# Copyright (C) 2010, 2011, 2012 Google Inc.
|
5 |
#
|
6 |
# This program is free software; you can redistribute it and/or modify
|
7 |
# it under the terms of the GNU General Public License as published by
|
8 |
# the Free Software Foundation; either version 2 of the License, or
|
9 |
# (at your option) any later version.
|
10 |
#
|
11 |
# This program is distributed in the hope that it will be useful, but
|
12 |
# WITHOUT ANY WARRANTY; without even the implied warranty of
|
13 |
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
14 |
# General Public License for more details.
|
15 |
#
|
16 |
# You should have received a copy of the GNU General Public License
|
17 |
# along with this program; if not, write to the Free Software
|
18 |
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
19 |
# 02110-1301, USA.
|
20 |
|
21 |
|
22 |
"""Module for a simple query language
|
23 |
|
24 |
A query filter is always a list. The first item in the list is the operator
|
25 |
(e.g. C{[OP_AND, ...]}), while the other items depend on the operator. For
|
26 |
logic operators (e.g. L{OP_AND}, L{OP_OR}), they are subfilters whose results
|
27 |
are combined. Unary operators take exactly one other item (e.g. a subfilter for
|
28 |
L{OP_NOT} and a field name for L{OP_TRUE}). Binary operators take exactly two
|
29 |
operands, usually a field name and a value to compare against. Filters are
|
30 |
converted to callable functions by L{query._CompileFilter}.
|
31 |
|
32 |
"""
|
33 |
|
34 |
import re |
35 |
import string # pylint: disable=W0402 |
36 |
import logging |
37 |
|
38 |
import pyparsing as pyp |
39 |
|
40 |
from ganeti import errors |
41 |
from ganeti import utils |
42 |
from ganeti import compat |
43 |
|
44 |
|
45 |
# Logic operators with one or more operands, each of which is a filter on its
|
46 |
# own
|
47 |
OP_OR = "|"
|
48 |
OP_AND = "&"
|
49 |
|
50 |
|
51 |
# Unary operators with exactly one operand
|
52 |
OP_NOT = "!"
|
53 |
OP_TRUE = "?"
|
54 |
|
55 |
|
56 |
# Binary operators with exactly two operands, the field name and an
|
57 |
# operator-specific value
|
58 |
OP_EQUAL = "="
|
59 |
OP_NOT_EQUAL = "!="
|
60 |
OP_LT = "<"
|
61 |
OP_LE = "<="
|
62 |
OP_GT = ">"
|
63 |
OP_GE = ">="
|
64 |
OP_REGEXP = "=~"
|
65 |
OP_CONTAINS = "=[]"
|
66 |
|
67 |
|
68 |
#: Characters used for detecting user-written filters (see L{_CheckFilter})
|
69 |
FILTER_DETECTION_CHARS = frozenset("()=/!~'\"\\<>" + string.whitespace) |
70 |
|
71 |
#: Characters used to detect globbing filters (see L{_CheckGlobbing})
|
72 |
GLOB_DETECTION_CHARS = frozenset("*?") |
73 |
|
74 |
|
75 |
def MakeSimpleFilter(namefield, values): |
76 |
"""Builds simple a filter.
|
77 |
|
78 |
@param namefield: Name of field containing item name
|
79 |
@param values: List of names
|
80 |
|
81 |
"""
|
82 |
if values:
|
83 |
return [OP_OR] + [[OP_EQUAL, namefield, i] for i in values] |
84 |
|
85 |
return None |
86 |
|
87 |
|
88 |
def _ConvertLogicOp(op): |
89 |
"""Creates parsing action function for logic operator.
|
90 |
|
91 |
@type op: string
|
92 |
@param op: Operator for data structure, e.g. L{OP_AND}
|
93 |
|
94 |
"""
|
95 |
def fn(toks): |
96 |
"""Converts parser tokens to query operator structure.
|
97 |
|
98 |
@rtype: list
|
99 |
@return: Query operator structure, e.g. C{[OP_AND, ["=", "foo", "bar"]]}
|
100 |
|
101 |
"""
|
102 |
operands = toks[0]
|
103 |
|
104 |
if len(operands) == 1: |
105 |
return operands[0] |
106 |
|
107 |
# Build query operator structure
|
108 |
return [[op] + operands.asList()]
|
109 |
|
110 |
return fn
|
111 |
|
112 |
|
113 |
_KNOWN_REGEXP_DELIM = "/#^|"
|
114 |
_KNOWN_REGEXP_FLAGS = frozenset("si") |
115 |
|
116 |
|
117 |
def _ConvertRegexpValue(_, loc, toks): |
118 |
"""Regular expression value for condition.
|
119 |
|
120 |
"""
|
121 |
(regexp, flags) = toks[0]
|
122 |
|
123 |
# Ensure only whitelisted flags are used
|
124 |
unknown_flags = (frozenset(flags) - _KNOWN_REGEXP_FLAGS)
|
125 |
if unknown_flags:
|
126 |
raise pyp.ParseFatalException("Unknown regular expression flags: '%s'" % |
127 |
"".join(unknown_flags), loc)
|
128 |
|
129 |
if flags:
|
130 |
re_flags = "(?%s)" % "".join(sorted(flags)) |
131 |
else:
|
132 |
re_flags = ""
|
133 |
|
134 |
re_cond = re_flags + regexp |
135 |
|
136 |
# Test if valid
|
137 |
try:
|
138 |
re.compile(re_cond) |
139 |
except re.error, err:
|
140 |
raise pyp.ParseFatalException("Invalid regular expression (%s)" % err, loc) |
141 |
|
142 |
return [re_cond]
|
143 |
|
144 |
|
145 |
def BuildFilterParser(): |
146 |
"""Builds a parser for query filter strings.
|
147 |
|
148 |
@rtype: pyparsing.ParserElement
|
149 |
|
150 |
"""
|
151 |
field_name = pyp.Word(pyp.alphas, pyp.alphanums + "_/.")
|
152 |
|
153 |
# Integer
|
154 |
num_sign = pyp.Word("-+", exact=1) |
155 |
number = pyp.Combine(pyp.Optional(num_sign) + pyp.Word(pyp.nums)) |
156 |
number.setParseAction(lambda toks: int(toks[0])) |
157 |
|
158 |
quoted_string = pyp.quotedString.copy().setParseAction(pyp.removeQuotes) |
159 |
|
160 |
# Right-hand-side value
|
161 |
rval = (number | quoted_string) |
162 |
|
163 |
# Boolean condition
|
164 |
bool_cond = field_name.copy() |
165 |
bool_cond.setParseAction(lambda (fname, ): [[OP_TRUE, fname]])
|
166 |
|
167 |
# Simple binary conditions
|
168 |
binopstbl = { |
169 |
"==": OP_EQUAL,
|
170 |
"!=": OP_NOT_EQUAL,
|
171 |
"<": OP_LT,
|
172 |
"<=": OP_LE,
|
173 |
">": OP_GT,
|
174 |
">=": OP_GE,
|
175 |
} |
176 |
|
177 |
binary_cond = (field_name + pyp.oneOf(binopstbl.keys()) + rval) |
178 |
binary_cond.setParseAction(lambda (lhs, op, rhs): [[binopstbl[op], lhs, rhs]])
|
179 |
|
180 |
# "in" condition
|
181 |
in_cond = (rval + pyp.Suppress("in") + field_name)
|
182 |
in_cond.setParseAction(lambda (value, field): [[OP_CONTAINS, field, value]])
|
183 |
|
184 |
# "not in" condition
|
185 |
not_in_cond = (rval + pyp.Suppress("not") + pyp.Suppress("in") + field_name) |
186 |
not_in_cond.setParseAction(lambda (value, field): [[OP_NOT, [OP_CONTAINS,
|
187 |
field, value]]]) |
188 |
|
189 |
# Regular expression, e.g. m/foobar/i
|
190 |
regexp_val = pyp.Group(pyp.Optional("m").suppress() +
|
191 |
pyp.MatchFirst([pyp.QuotedString(i, escChar="\\")
|
192 |
for i in _KNOWN_REGEXP_DELIM]) + |
193 |
pyp.Optional(pyp.Word(pyp.alphas), default=""))
|
194 |
regexp_val.setParseAction(_ConvertRegexpValue) |
195 |
regexp_cond = (field_name + pyp.Suppress("=~") + regexp_val)
|
196 |
regexp_cond.setParseAction(lambda (field, value): [[OP_REGEXP, field, value]])
|
197 |
|
198 |
not_regexp_cond = (field_name + pyp.Suppress("!~") + regexp_val)
|
199 |
not_regexp_cond.setParseAction(lambda (field, value):
|
200 |
[[OP_NOT, [OP_REGEXP, field, value]]]) |
201 |
|
202 |
# Globbing, e.g. name =* "*.site"
|
203 |
glob_cond = (field_name + pyp.Suppress("=*") + quoted_string)
|
204 |
glob_cond.setParseAction(lambda (field, value):
|
205 |
[[OP_REGEXP, field, |
206 |
utils.DnsNameGlobPattern(value)]]) |
207 |
|
208 |
not_glob_cond = (field_name + pyp.Suppress("!*") + quoted_string)
|
209 |
not_glob_cond.setParseAction(lambda (field, value):
|
210 |
[[OP_NOT, [OP_REGEXP, field, |
211 |
utils.DnsNameGlobPattern(value)]]]) |
212 |
|
213 |
# All possible conditions
|
214 |
condition = (binary_cond ^ bool_cond ^ |
215 |
in_cond ^ not_in_cond ^ |
216 |
regexp_cond ^ not_regexp_cond ^ |
217 |
glob_cond ^ not_glob_cond) |
218 |
|
219 |
# Associativity operators
|
220 |
filter_expr = pyp.operatorPrecedence(condition, [ |
221 |
(pyp.Keyword("not").suppress(), 1, pyp.opAssoc.RIGHT, |
222 |
lambda toks: [[OP_NOT, toks[0][0]]]), |
223 |
(pyp.Keyword("and").suppress(), 2, pyp.opAssoc.LEFT, |
224 |
_ConvertLogicOp(OP_AND)), |
225 |
(pyp.Keyword("or").suppress(), 2, pyp.opAssoc.LEFT, |
226 |
_ConvertLogicOp(OP_OR)), |
227 |
]) |
228 |
|
229 |
parser = pyp.StringStart() + filter_expr + pyp.StringEnd() |
230 |
parser.parseWithTabs() |
231 |
|
232 |
# Originally C{parser.validate} was called here, but there seems to be some
|
233 |
# issue causing it to fail whenever the "not" operator is included above.
|
234 |
|
235 |
return parser
|
236 |
|
237 |
|
238 |
def ParseFilter(text, parser=None): |
239 |
"""Parses a query filter.
|
240 |
|
241 |
@type text: string
|
242 |
@param text: Query filter
|
243 |
@type parser: pyparsing.ParserElement
|
244 |
@param parser: Pyparsing object
|
245 |
@rtype: list
|
246 |
|
247 |
"""
|
248 |
logging.debug("Parsing as query filter: %s", text)
|
249 |
|
250 |
if parser is None: |
251 |
parser = BuildFilterParser() |
252 |
|
253 |
try:
|
254 |
return parser.parseString(text)[0] |
255 |
except pyp.ParseBaseException, err:
|
256 |
raise errors.QueryFilterParseError("Failed to parse query filter" |
257 |
" '%s': %s" % (text, err), err)
|
258 |
|
259 |
|
260 |
def _CheckFilter(text): |
261 |
"""CHecks if a string could be a filter.
|
262 |
|
263 |
@rtype: bool
|
264 |
|
265 |
"""
|
266 |
return bool(frozenset(text) & FILTER_DETECTION_CHARS) |
267 |
|
268 |
|
269 |
def _CheckGlobbing(text): |
270 |
"""Checks if a string could be a globbing pattern.
|
271 |
|
272 |
@rtype: bool
|
273 |
|
274 |
"""
|
275 |
return bool(frozenset(text) & GLOB_DETECTION_CHARS) |
276 |
|
277 |
|
278 |
def _MakeFilterPart(namefield, text, isnumeric=False): |
279 |
"""Generates filter for one argument.
|
280 |
|
281 |
"""
|
282 |
if isnumeric:
|
283 |
try:
|
284 |
number = int(text)
|
285 |
except (TypeError, ValueError), err: |
286 |
raise errors.OpPrereqError("Invalid job ID passed: %s" % str(err), |
287 |
errors.ECODE_INVAL) |
288 |
return [OP_EQUAL, namefield, number]
|
289 |
elif _CheckGlobbing(text):
|
290 |
return [OP_REGEXP, namefield, utils.DnsNameGlobPattern(text)]
|
291 |
else:
|
292 |
return [OP_EQUAL, namefield, text]
|
293 |
|
294 |
|
295 |
def MakeFilter(args, force_filter, namefield=None, isnumeric=False): |
296 |
"""Try to make a filter from arguments to a command.
|
297 |
|
298 |
If the name could be a filter it is parsed as such. If it's just a globbing
|
299 |
pattern, e.g. "*.site", such a filter is constructed. As a last resort the
|
300 |
names are treated just as a plain name filter.
|
301 |
|
302 |
@type args: list of string
|
303 |
@param args: Arguments to command
|
304 |
@type force_filter: bool
|
305 |
@param force_filter: Whether to force treatment as a full-fledged filter
|
306 |
@type namefield: string
|
307 |
@param namefield: Name of field to use for simple filters (use L{None} for
|
308 |
a default of "name")
|
309 |
@type isnumeric: bool
|
310 |
@param isnumeric: Whether the namefield type is numeric, as opposed to
|
311 |
the default string type; this influences how the filter is built
|
312 |
@rtype: list
|
313 |
@return: Query filter
|
314 |
|
315 |
"""
|
316 |
if namefield is None: |
317 |
namefield = "name"
|
318 |
|
319 |
if (force_filter or |
320 |
(args and len(args) == 1 and _CheckFilter(args[0]))): |
321 |
try:
|
322 |
(filter_text, ) = args |
323 |
except (TypeError, ValueError): |
324 |
raise errors.OpPrereqError("Exactly one argument must be given as a" |
325 |
" filter", errors.ECODE_INVAL)
|
326 |
|
327 |
result = ParseFilter(filter_text) |
328 |
elif args:
|
329 |
result = [OP_OR] + map(compat.partial(_MakeFilterPart, namefield,
|
330 |
isnumeric=isnumeric), args) |
331 |
else:
|
332 |
result = None
|
333 |
|
334 |
return result
|