1 # Copyright 2016 The Chromium OS Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 import abc 6 import copy 7 import logging 8 9 import common 10 from autotest_lib.server.cros import provision 11 12 13 class HostInfo(object): 14 """Holds label/attribute information about a host as understood by infra. 15 16 This class is the source of truth of label / attribute information about a 17 host for the test runner (autoserv) and the tests, *from the point of view 18 of the infrastructure*. 19 20 Typical usage: 21 store = AfeHostInfoStore(...) 22 host_info = store.get() 23 update_somehow(host_info) 24 store.commit(host_info) 25 26 Besides the @property listed below, the following rw variables are part of 27 the public API: 28 labels: The list of labels for this host. 29 attributes: The list of attributes for this host. 30 """ 31 32 __slots__ = ['labels', 'attributes'] 33 34 # Constants related to exposing labels as more semantic properties. 35 _BOARD_PREFIX = 'board' 36 _OS_PREFIX = 'os' 37 _POOL_PREFIX = 'pool' 38 39 def __init__(self, labels=None, attributes=None): 40 """ 41 @param labels: (optional list) labels to set on the HostInfo. 42 @param attributes: (optional dict) attributes to set on the HostInfo. 43 """ 44 self.labels = labels if labels is not None else [] 45 self.attributes = attributes if attributes is not None else {} 46 47 48 @property 49 def build(self): 50 """Retrieve the current build for the host. 51 52 TODO(pprabhu) Make provision.py depend on this instead of the other way 53 around. 54 55 @returns The first build label for this host (if there are multiple). 56 None if no build label is found. 57 """ 58 for label_prefix in [provision.CROS_VERSION_PREFIX, 59 provision.ANDROID_BUILD_VERSION_PREFIX, 60 provision.TESTBED_BUILD_VERSION_PREFIX]: 61 build_labels = self._get_stripped_labels_with_prefix(label_prefix) 62 if build_labels: 63 return build_labels[0] 64 return None 65 66 67 @property 68 def board(self): 69 """Retrieve the board label value for the host. 70 71 @returns: The (stripped) board label, or None if no label is found. 72 """ 73 return self.get_label_value(self._BOARD_PREFIX) 74 75 76 @property 77 def os(self): 78 """Retrieve the os for the host. 79 80 @returns The os (str) or None if no os label exists. Returns the first 81 matching os if mutiple labels are found. 82 """ 83 return self.get_label_value(self._OS_PREFIX) 84 85 86 @property 87 def pools(self): 88 """Retrieve the set of pools for the host. 89 90 @returns: set(str) of pool values. 91 """ 92 return set(self._get_stripped_labels_with_prefix(self._POOL_PREFIX)) 93 94 95 def get_label_value(self, prefix): 96 """Retrieve the value stored as a label with a well known prefix. 97 98 @param prefix: The prefix of the desired label. 99 @return: For the first label matching 'prefix:value', returns value. 100 Returns '' if no label matches the given prefix. 101 """ 102 values = self._get_stripped_labels_with_prefix(prefix) 103 return values[0] if values else '' 104 105 106 def _get_stripped_labels_with_prefix(self, prefix): 107 """Search for labels with the prefix and remove the prefix. 108 109 e.g. 110 prefix = blah 111 labels = ['blah:a', 'blahb', 'blah:c', 'doo'] 112 returns: ['a', 'c'] 113 114 @returns: A list of stripped labels. [] in case of no match. 115 """ 116 full_prefix = prefix + ':' 117 prefix_len = len(full_prefix) 118 return [label[prefix_len:] for label in self.labels 119 if label.startswith(full_prefix)] 120 121 122 def __str__(self): 123 return ('HostInfo [Labels: %s, Attributes: %s' 124 % (self.labels, self.attributes)) 125 126 127 class StoreError(Exception): 128 """Raised when a CachingHostInfoStore operation fails.""" 129 130 131 class CachingHostInfoStore(object): 132 """Abstract class to obtain and update host information from the infra. 133 134 This class describes the API used to retrieve host information from the 135 infrastructure. The actual, uncached implementation to obtain / update host 136 information is delegated to the concrete store classes. 137 138 We use two concrete stores: 139 AfeHostInfoStore: Directly obtains/updates the host information from 140 the AFE. 141 LocalHostInfoStore: Obtains/updates the host information from a local 142 file. 143 An extra store is provided for unittests: 144 InMemoryHostInfoStore: Just store labels / attributes in-memory. 145 """ 146 147 __metaclass__ = abc.ABCMeta 148 149 def __init__(self): 150 self._private_cached_info = None 151 152 153 def get(self, force_refresh=False): 154 """Obtain (possibly cached) host information. 155 156 @param force_refresh: If True, forces the cached HostInfo to be 157 refreshed from the store. 158 @returns: A HostInfo object. 159 """ 160 if force_refresh: 161 return self._get_uncached() 162 163 # |_cached_info| access is costly, so do it only once. 164 info = self._cached_info 165 if info is None: 166 return self._get_uncached() 167 return info 168 169 170 def commit(self, info): 171 """Update host information in the infrastructure. 172 173 @param info: A HostInfo object with the new information to set. You 174 should obtain a HostInfo object using the |get| or 175 |get_uncached| methods, update it as needed and then commit. 176 """ 177 logging.debug('Committing HostInfo to store %s', self) 178 try: 179 self._commit_impl(info) 180 self._cached_info = info 181 logging.debug('HostInfo updated to: %s', info) 182 except Exception: 183 self._cached_info = None 184 raise 185 186 187 @abc.abstractmethod 188 def _refresh_impl(self): 189 """Actual implementation to refresh host_info from the store. 190 191 Concrete stores must implement this function. 192 @returns: A HostInfo object. 193 """ 194 raise NotImplementedError 195 196 197 @abc.abstractmethod 198 def _commit_impl(self, host_info): 199 """Actual implementation to commit host_info to the store. 200 201 Concrete stores must implement this function. 202 @param host_info: A HostInfo object. 203 """ 204 raise NotImplementedError 205 206 207 def _get_uncached(self): 208 """Obtain freshly synced host information. 209 210 @returns: A HostInfo object. 211 """ 212 logging.debug('Refreshing HostInfo using store %s', self) 213 logging.debug('Old host_info: %s', self._cached_info) 214 try: 215 info = self._refresh_impl() 216 self._cached_info = info 217 except Exception: 218 self._cached_info = None 219 raise 220 221 logging.debug('New host_info: %s', info) 222 return info 223 224 225 @property 226 def _cached_info(self): 227 """Access the cached info, enforcing a deepcopy.""" 228 return copy.deepcopy(self._private_cached_info) 229 230 231 @_cached_info.setter 232 def _cached_info(self, info): 233 """Update the cached info, enforcing a deepcopy. 234 235 @param info: The new info to update from. 236 """ 237 self._private_cached_info = copy.deepcopy(info) 238 239 240 class InMemoryHostInfoStore(CachingHostInfoStore): 241 """A simple store that gives unittests direct access to backing data. 242 243 Unittests can access the |info| attribute to obtain the backing HostInfo. 244 """ 245 246 def __init__(self, info=None): 247 """Seed object with initial data. 248 249 @param info: Initial backing HostInfo object. 250 """ 251 super(InMemoryHostInfoStore, self).__init__() 252 self.info = info if info is not None else HostInfo() 253 254 255 def _refresh_impl(self): 256 """Return a copy of the private HostInfo.""" 257 return copy.deepcopy(self.info) 258 259 260 def _commit_impl(self, info): 261 """Copy HostInfo data to in-memory store. 262 263 @param info: The HostInfo object to commit. 264 """ 265 self.info = copy.deepcopy(info) 266 267 268 def get_store_from_machine(machine): 269 """Obtain the host_info_store object stuffed in the machine dict. 270 271 The machine argument to jobs can be a string (a hostname) or a dict because 272 of legacy reasons. If we can't get a real store, return a dummy. 273 """ 274 if isinstance(machine, dict): 275 return machine['host_info_store'] 276 else: 277 return InMemoryHostInfoStore() 278
