/usr/lib/python3/dist-packages/plainbox/impl/session/jobs.py is in python3-plainbox 0.5.3-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 | # This file is part of Checkbox.
#
# Copyright 2012, 2013 Canonical Ltd.
# Written by:
# Zygmunt Krynicki <zygmunt.krynicki@canonical.com>
#
# Checkbox is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 3,
# as published by the Free Software Foundation.
#
# Checkbox is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Checkbox. If not, see <http://www.gnu.org/licenses/>.
"""
:mod:`plainbox.impl.session.jobs` -- jobs state handling
========================================================
This module contains a helper class for associating job state within a
particular session. The :class:`JobState` class holds references to a
:class:`JobDefinition` and :class:`JobResult` as well as a list of inhibitors
that prevent the job from being runnable in a particular session.
"""
import logging
from plainbox.abc import IJobResult
from plainbox.i18n import gettext as _
from plainbox.impl.result import MemoryJobResult
from plainbox.impl.signal import Signal
logger = logging.getLogger("plainbox.session.jobs")
class JobReadinessInhibitor:
"""
Class representing the cause of a job not being ready to execute.
It is intended to be consumed by UI layers and to provide them with enough
information to render informative error messages or other visual feedback
that will aid the user in understanding why a job cannot be started.
There are four possible not ready causes:
UNDESIRED:
This job was not selected to run in this session
PENDING_DEP:
This job depends on another job which was not started yet
FAILED_DEP:
This job depends on another job which was started and failed
PENDING_RESOURCE:
This job has a resource requirement expression that uses a resource
produced by another job which was not started yet
FAILED_RESOURCE:
This job has a resource requirement that evaluated to a false value
All causes apart from UNDESIRED use the related_job property to encode a
job that is related to the problem. The PENDING_RESOURCE and
FAILED_RESOURCE causes also store related_expression that describes the
relevant requirement expression.
There are three attributes that can be accessed:
cause:
Encodes the reason why a job is not ready, see above.
related_job:
Provides additional context for the problem. This is not the job
that is affected, rather, the job that is causing the problem.
related_expression:
Provides additional context for the problem caused by a failing
resource expression.
"""
# XXX: PENDING_RESOURCE is not strict, there are multiple states that are
# clumped here which is something I don't like. A resource may be still
# "pending" as in PENDING_DEP (it has not ran yet) or it could have ran but
# failed to produce any data, it could also be prevented from running
# because it has unmet dependencies. In essence it tells us nothing about
# if related_job.can_start() is true or not.
#
# XXX: FAILED_RESOURCE is "correct" but somehow misleading, FAILED_RESOURCE
# is used to represent a resource expression that evaluated to a non-True
# value
UNDESIRED, PENDING_DEP, FAILED_DEP, PENDING_RESOURCE, FAILED_RESOURCE \
= range(5)
_cause_display = {
UNDESIRED: "UNDESIRED",
PENDING_DEP: "PENDING_DEP",
FAILED_DEP: "FAILED_DEP",
PENDING_RESOURCE: "PENDING_RESOURCE",
FAILED_RESOURCE: "FAILED_RESOURCE"
}
def __init__(self, cause, related_job=None, related_expression=None):
"""
Initialize a new inhibitor with the specified cause.
If cause is other than UNDESIRED a related_job is necessary. If cause
is either PENDING_RESOURCE or FAILED_RESOURCE related_expression is
necessary as well. A ValueError is raised when this is violated.
"""
if cause not in self._cause_display:
raise ValueError(_("unsupported value for cause"))
if cause != self.UNDESIRED and related_job is None:
raise ValueError(
# TRANSLATORS: please don't translate related_job, None and
# cause
_("related_job must not be None when cause is {}").format(
self._cause_display[cause]))
if cause in (self.PENDING_RESOURCE, self.FAILED_RESOURCE) \
and related_expression is None:
raise ValueError(_(
# TRANSLATORS: please don't translate related_expression, None
# and cause.
"related_expression must not be None when cause is {}"
).format(self._cause_display[cause]))
self.cause = cause
self.related_job = related_job
self.related_expression = related_expression
def __eq__(self, other):
if isinstance(other, JobReadinessInhibitor):
return ((self.cause, self.related_job, self.related_expression)
== (self.cause, self.related_job, self.related_expression))
return NotImplemented
def __ne__(self, other):
if isinstance(other, JobReadinessInhibitor):
return ((self.cause, self.related_job, self.related_expression)
!= (self.cause, self.related_job, self.related_expression))
return NotImplemented
@property
def cause_name(self):
return self._cause_display[self.cause]
def __repr__(self):
return "<{} cause:{} related_job:{!r} related_expression:{!r}>".format(
self.__class__.__name__, self._cause_display[self.cause],
self.related_job, self.related_expression)
def __str__(self):
if self.cause == self.UNDESIRED:
# TRANSLATORS: as in undesired job
return _("undesired")
elif self.cause == self.PENDING_DEP:
return _("required dependency {!r} did not run yet").format(
self.related_job.id)
elif self.cause == self.FAILED_DEP:
return _("required dependency {!r} has failed").format(
self.related_job.id)
elif self.cause == self.PENDING_RESOURCE:
return _(
"resource expression {!r} could not be evaluated because"
" the resource it depends on did not run yet"
).format(self.related_expression.text)
else:
assert self.cause == self.FAILED_RESOURCE
return _("resource expression {!r} evaluates to false").format(
self.related_expression.text)
# A global instance of :class:`JobReadinessInhibitor` with the UNDESIRED cause.
# This is used a lot and it makes no sense to instantiate all the time.
UndesiredJobReadinessInhibitor = JobReadinessInhibitor(
JobReadinessInhibitor.UNDESIRED)
class JobState:
"""
Class representing the state of a job in a session.
Contains two basic properties of each job:
* the readiness_inhibitor_list that prevent the job form starting
* the result (outcome) of the run (IJobResult)
For convenience (to SessionState implementation) it also has a reference to
the job itself. This class is a pure state holder an will typically
collaborate with the SessionState class and the UI layer.
"""
def __init__(self, job):
"""
Initialize a new job state object.
The job will be inhibited by a single UNDESIRED inhibitor and will have
a result with OUTCOME_NONE that basically says it did not run yet.
"""
self._job = job
self._readiness_inhibitor_list = [UndesiredJobReadinessInhibitor]
self._result = MemoryJobResult({
'outcome': IJobResult.OUTCOME_NONE
})
def __repr__(self):
fmt = ("<{} job:{!r} readiness_inhibitor_list:{!r} result:{!r}>")
return fmt.format(self.__class__.__name__, self._job,
self._readiness_inhibitor_list, self._result)
@property
def job(self):
"""
the job associated with this state
"""
return self._job
@job.setter
def job(self, job):
"""
Changes the job associated with this state
"""
#FIXME: This setter should not exist. job attribute should be
#read-only. This is a temporary kludge to get session restoring
#over DBus working. Once a solution that doesn't involve setting
#a JobState's job attribute is implemented, please remove this
#awful method.
self._job = job
def _readiness_inhibitor_list():
doc = "the list of readiness inhibitors of the associated job"
def fget(self):
return self._readiness_inhibitor_list
def fset(self, value):
self._readiness_inhibitor_list = value
return (fget, fset, None, doc)
readiness_inhibitor_list = property(*_readiness_inhibitor_list())
def _result():
doc = "the result of running the associated job"
def fget(self):
return self._result
def fset(self, new):
old = self._result
if old != new:
self._result = new
self.on_result_changed(old, new)
return (fget, fset, None, doc)
result = property(*_result())
@Signal.define
def on_result_changed(self, old, new):
"""
Event fired when the result associated with this job state changes
"""
logger.info(
"<%s %s>.on_result_changed(%r, %r)",
self.__class__.__name__, id(self), old, new)
def can_start(self):
"""
Quickly check if the associated job can run right now.
"""
return len(self._readiness_inhibitor_list) == 0
def get_readiness_description(self):
"""
Get a human readable description of the current readiness state
"""
if self._readiness_inhibitor_list:
return _("job cannot be started: {}").format(
", ".join((str(inhibitor)
for inhibitor in self._readiness_inhibitor_list)))
else:
return "job can be started"
def _get_persistance_subset(self):
# Don't save resource job results, fresh data are required
# so we can't reuse the old ones
# The inhibitor list needs to be recomputed as well, don't save it.
state = {}
state['_job'] = self._job
if self._job.plugin == 'resource':
state['_result'] = MemoryJobResult({
'outcome': IJobResult.OUTCOME_NONE
})
else:
state['_result'] = self._result
return state
@classmethod
def from_json_record(cls, record):
"""
Create a JobState instance from JSON record
"""
obj = cls(record['_job'])
obj._readiness_inhibitor_list = [UndesiredJobReadinessInhibitor]
obj._result = record['_result']
return obj
|