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39 """
40 Provides unit-testing utilities.
41
42 These utilities are kept here, separate from util.py, because they provide
43 common functionality that I do not want exported "publicly" once Cedar Backup
44 is installed on a system. They are only used for unit testing, and are only
45 useful within the source tree.
46
47 Many of these functions are in here because they are "good enough" for unit
48 test work but are not robust enough to be real public functions. Others (like
49 L{removedir} do what they are supposed to, but I don't want responsibility for
50 making them available to others.
51
52 @sort: findResources, commandAvailable,
53 buildPath, removedir, extractTar, changeFileAge,
54 getMaskAsMode, getLogin, failUnlessAssignRaises, runningAsRoot,
55 platformMacOsX, platformWindows, platformHasEcho,
56 platformSupportsLinks, platformSupportsPermissions,
57 platformRequiresBinaryRead
58
59 @author: Kenneth J. Pronovici <pronovic@ieee.org>
60 """
61
62
63
64
65
66
67 import sys
68 import os
69 import tarfile
70 import time
71 import getpass
72 import random
73 import string
74 import platform
75 import logging
76 from StringIO import StringIO
77
78 from CedarBackup2.util import encodePath, executeCommand
79
80
81
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83
84
85
86
87
88
90 """
91 Sets up a screen logger for debugging purposes.
92
93 Normally, the CLI functionality configures the logger so that
94 things get written to the right place. However, for debugging
95 it's sometimes nice to just get everything -- debug information
96 and output -- dumped to the screen. This function takes care
97 of that.
98 """
99 logger = logging.getLogger("CedarBackup2")
100 logger.setLevel(logging.DEBUG)
101 formatter = logging.Formatter(fmt="%(message)s")
102 handler = logging.StreamHandler(strm=sys.stdout)
103 handler.setFormatter(formatter)
104 handler.setLevel(logging.DEBUG)
105 logger.addHandler(handler)
106
107
108
109
110
111
113 """
114 Returns a dictionary of locations for various resources.
115 @param resources: List of required resources.
116 @param dataDirs: List of data directories to search within for resources.
117 @return: Dictionary mapping resource name to resource path.
118 @raise Exception: If some resource cannot be found.
119 """
120 mapping = { }
121 for resource in resources:
122 for resourceDir in dataDirs:
123 path = os.path.join(resourceDir, resource);
124 if os.path.exists(path):
125 mapping[resource] = path
126 break
127 else:
128 raise Exception("Unable to find resource [%s]." % resource)
129 return mapping
130
131
132
133
134
135
137 """
138 Indicates whether a command is available on $PATH somewhere.
139 This should work on both Windows and UNIX platforms.
140 @param command: Commang to search for
141 @return: Boolean true/false depending on whether command is available.
142 """
143 if os.environ.has_key("PATH"):
144 for path in os.environ["PATH"].split(os.sep):
145 if os.path.exists(os.path.join(path, command)):
146 return True
147 return False
148
149
150
151
152
153
155 """
156 Builds a complete path from a list of components.
157 For instance, constructs C{"/a/b/c"} from C{["/a", "b", "c",]}.
158 @param components: List of components.
159 @returns: String path constructed from components.
160 @raise ValueError: If a path cannot be encoded properly.
161 """
162 path = components[0]
163 for component in components[1:]:
164 path = os.path.join(path, component)
165 return encodePath(path)
166
167
168
169
170
171
173 """
174 Recursively removes an entire directory.
175 This is basically taken from an example on python.com.
176 @param tree: Directory tree to remove.
177 @raise ValueError: If a path cannot be encoded properly.
178 """
179 tree = encodePath(tree)
180 for root, dirs, files in os.walk(tree, topdown=False):
181 for name in files:
182 path = os.path.join(root, name)
183 if os.path.islink(path):
184 os.remove(path)
185 elif os.path.isfile(path):
186 os.remove(path)
187 for name in dirs:
188 path = os.path.join(root, name)
189 if os.path.islink(path):
190 os.remove(path)
191 elif os.path.isdir(path):
192 os.rmdir(path)
193 os.rmdir(tree)
194
195
196
197
198
199
201 """
202 Extracts the indicated tar file to the indicated tmpdir.
203 @param tmpdir: Temp directory to extract to.
204 @param filepath: Path to tarfile to extract.
205 @raise ValueError: If a path cannot be encoded properly.
206 """
207 tmpdir = encodePath(tmpdir)
208 filepath = encodePath(filepath)
209 tar = tarfile.open(filepath)
210 tar.posix = False
211 for tarinfo in tar:
212 tar.extract(tarinfo, tmpdir)
213
214
215
216
217
218
220 """
221 Changes a file age using the C{os.utime} function.
222 @param filename: File to operate on.
223 @param subtract: Number of seconds to subtract from the current time.
224 @raise ValueError: If a path cannot be encoded properly.
225 """
226 filename = encodePath(filename)
227 if subtract is None:
228 os.utime(filename, None)
229 else:
230 newTime = time.time() - subtract
231 os.utime(filename, (newTime, newTime))
232
233
234
235
236
237
239 """
240 Returns the user's current umask inverted to a mode.
241 A mode is mostly a bitwise inversion of a mask, i.e. mask 002 is mode 775.
242 @return: Umask converted to a mode, as an integer.
243 """
244 umask = os.umask(0777)
245 os.umask(umask)
246 return int(~umask & 0777)
247
248
249
250
251
252
254 """
255 Returns the name of the currently-logged in user. This might fail under
256 some circumstances - but if it does, our tests would fail anyway.
257 """
258 return getpass.getuser()
259
260
261
262
263
264
266 """
267 Generates a random filename with the given length.
268 @param length: Length of filename.
269 @return Random filename.
270 """
271 characters = [None] * length
272 for i in xrange(length):
273 characters[i] = random.choice(string.uppercase)
274 if prefix is None:
275 prefix = ""
276 if suffix is None:
277 suffix = ""
278 return "%s%s%s" % (prefix, "".join(characters), suffix)
279
280
281
282
283
284
286 """
287 Equivalent of C{failUnlessRaises}, but used for property assignments instead.
288
289 It's nice to be able to use C{failUnlessRaises} to check that a method call
290 raises the exception that you expect. Unfortunately, this method can't be
291 used to check Python propery assignments, even though these property
292 assignments are actually implemented underneath as methods.
293
294 This function (which can be easily called by unit test classes) provides an
295 easy way to wrap the assignment checks. It's not pretty, or as intuitive as
296 the original check it's modeled on, but it does work.
297
298 Let's assume you make this method call::
299
300 testCase.failUnlessAssignRaises(ValueError, collectDir, "absolutePath", absolutePath)
301
302 If you do this, a test case failure will be raised unless the assignment::
303
304 collectDir.absolutePath = absolutePath
305
306 fails with a C{ValueError} exception. The failure message differentiates
307 between the case where no exception was raised and the case where the wrong
308 exception was raised.
309
310 @note: Internally, the C{missed} and C{instead} variables are used rather
311 than directly calling C{testCase.fail} upon noticing a problem because the
312 act of "failure" itself generates an exception that would be caught by the
313 general C{except} clause.
314
315 @param testCase: PyUnit test case object (i.e. self).
316 @param exception: Exception that is expected to be raised.
317 @param object: Object whose property is to be assigned to.
318 @param property: Name of the property, as a string.
319 @param value: Value that is to be assigned to the property.
320
321 @see: C{unittest.TestCase.failUnlessRaises}
322 """
323 missed = False
324 instead = None
325 try:
326 exec "object.%s = value" % property
327 missed = True
328 except exception: pass
329 except Exception, e: instead = e
330 if missed:
331 testCase.fail("Expected assignment to raise %s, but got no exception." % (exception.__name__))
332 if instead is not None:
333 testCase.fail("Expected assignment to raise %s, but got %s instead." % (ValueError, instead.__class__.__name__))
334
335
336
337
338
339
341 """
342 Captures the output (stdout, stderr) of a function or a method.
343
344 Some of our functions don't do anything other than just print output. We
345 need a way to test these functions (at least nominally) but we don't want
346 any of the output spoiling the test suite output.
347
348 This function just creates a dummy file descriptor that can be used as a
349 target by the callable function, rather than C{stdout} or C{stderr}.
350
351 @note: This method assumes that C{callable} doesn't take any arguments
352 besides keyword argument C{fd} to specify the file descriptor.
353
354 @param callable: Callable function or method.
355
356 @return: Output of function, as one big string.
357 """
358 fd = StringIO()
359 callable(fd=fd)
360 result = fd.getvalue()
361 fd.close()
362 return result
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460 """
461 Returns boolean indicating whether the effective user id is root.
462 This is always true on platforms that have no concept of root, like Windows.
463 """
464 if platformWindows():
465 return True
466 else:
467 return os.geteuid() == 0
468
469
470
471
472
473
475 """
476 Returns a list of available locales on the system
477 @return: List of string locale names
478 """
479 locales = []
480 output = executeCommand(["locale"], [ "-a", ], returnOutput=True, ignoreStderr=True)[1]
481 for line in output:
482 locales.append(line.rstrip())
483 return locales
484