Richard Jankowski | 8af3c0e | 2018-08-14 16:07:18 -0400 | [diff] [blame] | 1 | # Copyright 2017-present Open Networking Foundation |
| 2 | # |
| 3 | # Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | # you may not use this file except in compliance with the License. |
| 5 | # You may obtain a copy of the License at |
| 6 | # |
| 7 | # http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | # |
| 9 | # Unless required by applicable law or agreed to in writing, software |
| 10 | # distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | # See the License for the specific language governing permissions and |
| 13 | # limitations under the License. |
| 14 | |
| 15 | from common.kvstore.kv_client import DEFAULT_TIMEOUT, Event, KVClient, KVPair, RETRY_BACKOFF |
| 16 | from common.utils.asleep import asleep |
| 17 | from common.utils.deferred_utils import DeferredWithTimeout, TimeOutError |
| 18 | from consul import ConsulException |
| 19 | from consul.twisted import Consul |
| 20 | from structlog import get_logger |
| 21 | from twisted.internet.defer import inlineCallbacks, returnValue, Deferred |
| 22 | |
| 23 | log = get_logger() |
| 24 | |
| 25 | class ConsulClient(KVClient): |
| 26 | |
| 27 | def __init__(self, kv_host, kv_port): |
| 28 | KVClient.__init__(self, kv_host, kv_port) |
| 29 | self.session_id = None |
| 30 | self.client = Consul(kv_host, kv_port) |
| 31 | self.watcher = None |
| 32 | |
| 33 | @inlineCallbacks |
| 34 | def get(self, key, timeout=DEFAULT_TIMEOUT): |
| 35 | result = yield self._op_with_retry('GET', key, None, timeout) |
| 36 | returnValue(result) |
| 37 | |
| 38 | @inlineCallbacks |
| 39 | def list(self, key, timeout=DEFAULT_TIMEOUT): |
| 40 | result = yield self._op_with_retry('LIST', key, None, timeout) |
| 41 | returnValue(result) |
| 42 | |
| 43 | @inlineCallbacks |
| 44 | def put(self, key, value, timeout=DEFAULT_TIMEOUT): |
| 45 | _, err = yield self._op_with_retry('PUT', key, value, timeout) |
| 46 | returnValue(err) |
| 47 | |
| 48 | @inlineCallbacks |
| 49 | def delete(self, key, timeout=DEFAULT_TIMEOUT): |
| 50 | _, err = yield self._op_with_retry('DELETE', key, None, timeout) |
| 51 | returnValue(err) |
| 52 | |
| 53 | @inlineCallbacks |
| 54 | def reserve(self, key, value, ttl, timeout=DEFAULT_TIMEOUT): |
| 55 | result = yield self._op_with_retry('RESERVE', key, value, timeout, ttl=ttl) |
| 56 | returnValue(result) |
| 57 | |
| 58 | @inlineCallbacks |
| 59 | def renew_reservation(self, key, timeout=DEFAULT_TIMEOUT): |
| 60 | result, err = yield self._op_with_retry('RENEW', key, None, timeout) |
| 61 | returnValue(err) |
| 62 | |
| 63 | @inlineCallbacks |
| 64 | def release_reservation(self, key, timeout=DEFAULT_TIMEOUT): |
| 65 | result, err = yield self._op_with_retry('RELEASE', key, None, timeout) |
| 66 | returnValue(err) |
| 67 | |
| 68 | @inlineCallbacks |
| 69 | def release_all_reservations(self, timeout=DEFAULT_TIMEOUT): |
| 70 | result, err = yield self._op_with_retry('RELEASE-ALL', None, None, timeout) |
| 71 | returnValue(err) |
| 72 | |
| 73 | def watch(self, key, key_change_callback, timeout=DEFAULT_TIMEOUT): |
| 74 | self._retriggering_watch(key, key_change_callback, timeout) |
| 75 | |
| 76 | @inlineCallbacks |
| 77 | def _retriggering_watch(self, key, key_change_callback, timeout): |
| 78 | self.key_watches[key] = ConsulWatch(self.client, key, key_change_callback, timeout) |
| 79 | yield self.key_watches[key].start() |
| 80 | |
| 81 | def close_watch(self, key, timeout=DEFAULT_TIMEOUT): |
| 82 | if key in self.key_watches: |
| 83 | self.key_watches[key].stop() |
| 84 | |
| 85 | @inlineCallbacks |
| 86 | def _op_with_retry(self, operation, key, value, timeout, *args, **kw): |
| 87 | log.debug('kv-op', operation=operation, key=key, timeout=timeout, args=args, kw=kw) |
| 88 | err = None |
| 89 | result = None |
| 90 | while True: |
| 91 | try: |
| 92 | if operation == 'GET': |
| 93 | result = yield self._get(key, **kw) |
| 94 | elif operation == 'LIST': |
| 95 | result, err = yield self._list(key) |
| 96 | elif operation == 'PUT': |
| 97 | # Put returns a boolean response |
| 98 | result = yield self.client.kv.put(key, value) |
| 99 | if not result: |
| 100 | err = 'put-failed' |
| 101 | elif operation == 'DELETE': |
| 102 | # Delete returns a boolean response |
| 103 | result = yield self.client.kv.delete(key) |
| 104 | if not result: |
| 105 | err = 'delete-failed' |
| 106 | elif operation == 'RESERVE': |
| 107 | result, err = yield self._reserve(key, value, **kw) |
| 108 | elif operation == 'RENEW': |
| 109 | result, err = yield self._renew_reservation(key) |
| 110 | elif operation == 'RELEASE': |
| 111 | result, err = yield self._release_reservation(key) |
| 112 | elif operation == 'RELEASE-ALL': |
| 113 | err = yield self._release_all_reservations() |
| 114 | self._clear_backoff() |
| 115 | break |
| 116 | except ConsulException as ex: |
| 117 | if 'ConnectionRefusedError' in ex.message: |
| 118 | log.exception('comms-exception', ex=ex) |
| 119 | yield self._backoff('consul-not-up') |
| 120 | else: |
| 121 | log.error('consul-specific-exception', ex=ex) |
| 122 | err = ex |
| 123 | except Exception as ex: |
| 124 | log.error('consul-exception', ex=ex) |
| 125 | err = ex |
| 126 | |
| 127 | if timeout > 0 and self.retry_time > timeout: |
| 128 | err = 'operation-timed-out' |
| 129 | if err is not None: |
| 130 | self._clear_backoff() |
| 131 | break |
| 132 | |
| 133 | returnValue((result,err)) |
| 134 | |
| 135 | @inlineCallbacks |
| 136 | def _get(self, key, **kw): |
| 137 | kvp = None |
| 138 | index, rec = yield self.client.kv.get(key, **kw) |
| 139 | if rec is not None: |
| 140 | kvp = KVPair(rec['Key'], rec['Value'], index) |
| 141 | returnValue(kvp) |
| 142 | |
| 143 | @inlineCallbacks |
| 144 | def _list(self, key): |
| 145 | err = None |
| 146 | list = [] |
| 147 | index, recs = yield self.client.kv.get(key, recurse=True) |
| 148 | for rec in recs: |
| 149 | list.append(KVPair(rec['Key'], rec['Value'], rec['ModifyIndex'])) |
| 150 | returnValue((list, err)) |
| 151 | |
| 152 | @inlineCallbacks |
| 153 | def _reserve(self, key, value, **kw): |
| 154 | for name, val in kw.items(): |
| 155 | if name == 'ttl': |
| 156 | ttl = val |
| 157 | break |
| 158 | reserved = False |
| 159 | err = 'reservation-failed' |
| 160 | owner = None |
| 161 | |
| 162 | # Create a session |
| 163 | self.session_id = yield self.client.session.create(behavior='delete', |
| 164 | ttl=ttl) # lock_delay=1) |
| 165 | log.debug('create-session', id=self.session_id) |
| 166 | # Try to acquire the key |
| 167 | result = yield self.client.kv.put(key, value, acquire=self.session_id) |
| 168 | log.debug('key-acquire', key=key, value=value, sess=self.session_id, result=result) |
| 169 | |
| 170 | # Check if reservation succeeded |
| 171 | index, record = yield self.client.kv.get(key) |
| 172 | if record is not None and 'Value' in record: |
| 173 | owner = record['Value'] |
| 174 | log.debug('get-key', session=record['Session'], owner=owner) |
| 175 | if record['Session'] == self.session_id and owner == value: |
| 176 | reserved = True |
| 177 | log.debug('key-reserved', key=key, value=value, ttl=ttl) |
| 178 | # Add key to reservation list |
| 179 | self.key_reservations[key] = self.session_id |
| 180 | else: |
| 181 | log.debug('reservation-held-by-another', owner=owner) |
| 182 | |
| 183 | if reserved: |
| 184 | err = None |
| 185 | returnValue((owner, err)) |
| 186 | |
| 187 | @inlineCallbacks |
| 188 | def _renew_reservation(self, key): |
| 189 | result = None |
| 190 | err = None |
| 191 | if key not in self.key_reservations: |
| 192 | err = 'key-not-reserved' |
| 193 | else: |
| 194 | session_id = self.key_reservations[key] |
| 195 | # A successfully renewed session returns an object with fields: |
| 196 | # Node, CreateIndex, Name, ModifyIndex, ID, Behavior, TTL, |
| 197 | # LockDelay, and Checks |
| 198 | result = yield self.client.session.renew(session_id=session_id) |
| 199 | log.debug('session-renew', result=result) |
| 200 | if result is None: |
| 201 | err = 'session-renewal-failed' |
| 202 | returnValue((result, err)) |
| 203 | |
| 204 | @inlineCallbacks |
| 205 | def _release_reservation(self, key): |
| 206 | err = None |
| 207 | if key not in self.key_reservations: |
| 208 | err = 'key-not-reserved' |
| 209 | else: |
| 210 | session_id = self.key_reservations[key] |
| 211 | # A successfully destroyed session returns a boolean result |
| 212 | success = yield self.client.session.destroy(session_id) |
| 213 | log.debug('session-destroy', result=success) |
| 214 | if not success: |
| 215 | err = 'session-destroy-failed' |
| 216 | self.session_id = None |
| 217 | self.key_reservations.pop(key) |
| 218 | returnValue((success, err)) |
| 219 | |
| 220 | @inlineCallbacks |
| 221 | def _release_all_reservations(self): |
| 222 | err = None |
| 223 | keys_to_delete = [] |
| 224 | for key in self.key_reservations: |
| 225 | session_id = self.key_reservations[key] |
| 226 | # A successfully destroyed session returns a boolean result |
| 227 | success = yield self.client.session.destroy(session_id) |
| 228 | if not success: |
| 229 | err = 'session-destroy-failed' |
| 230 | log.debug('session-destroy', id=session_id, result=success) |
| 231 | self.session_id = None |
| 232 | keys_to_delete.append(key) |
| 233 | for key in keys_to_delete: |
| 234 | self.key_reservations.pop(key) |
| 235 | returnValue(err) |
| 236 | |
| 237 | |
| 238 | class ConsulWatch(): |
| 239 | |
| 240 | def __init__(self, consul, key, callback, timeout): |
| 241 | self.client = consul |
| 242 | self.key = key |
| 243 | self.index = None |
| 244 | self.callback = callback |
| 245 | self.timeout = timeout |
| 246 | self.period = 60 |
| 247 | self.running = True |
| 248 | self.retries = 0 |
| 249 | self.retry_time = 0 |
| 250 | |
| 251 | @inlineCallbacks |
| 252 | def start(self): |
| 253 | self.running = True |
| 254 | index, rec = yield self._get_with_retry(self.key, None, |
| 255 | timeout=self.timeout) |
| 256 | self.index = str(index) |
| 257 | |
| 258 | @inlineCallbacks |
| 259 | def _get(key, deferred): |
| 260 | try: |
| 261 | index, rec = yield self._get_with_retry(key, None, |
| 262 | timeout=self.timeout, |
| 263 | index=self.index) |
| 264 | self.index = str(index) |
| 265 | if not deferred.called: |
| 266 | log.debug('got-result-cancelling-deferred') |
| 267 | deferred.callback((self.index, rec)) |
| 268 | except Exception as e: |
| 269 | log.exception('got-exception', e=e) |
| 270 | |
| 271 | while self.running: |
| 272 | try: |
| 273 | rcvd = DeferredWithTimeout(timeout=self.period) |
| 274 | _get(self.key, rcvd) |
| 275 | try: |
| 276 | # Update index for next watch iteration |
| 277 | index, rec = yield rcvd |
| 278 | log.debug('event-received', index=index, rec=rec) |
| 279 | # Notify client of key change event |
| 280 | if rec is None: |
| 281 | # Key has been deleted |
| 282 | self._send_event(Event(Event.DELETE, self.key, None)) |
| 283 | else: |
| 284 | self._send_event(Event(Event.PUT, rec['Key'], rec['Value'])) |
| 285 | except TimeOutError as e: |
| 286 | log.debug('no-events-over-watch-period', key=self.key) |
| 287 | except Exception as e: |
| 288 | log.exception('exception', e=e) |
| 289 | except Exception as e: |
| 290 | log.exception('exception', e=e) |
| 291 | |
| 292 | log.debug('close-watch', key=self.key) |
| 293 | |
| 294 | def stop(self): |
| 295 | self.running = False |
| 296 | self.callback = None |
| 297 | |
| 298 | @inlineCallbacks |
| 299 | def _get_with_retry(self, key, value, timeout, *args, **kw): |
| 300 | log.debug('watch-period', key=key, period=self.period, timeout=timeout, args=args, kw=kw) |
| 301 | err = None |
| 302 | result = None |
| 303 | while True: |
| 304 | try: |
| 305 | result = yield self.client.kv.get(key, **kw) |
| 306 | self._clear_backoff() |
| 307 | break |
| 308 | except ConsulException as ex: |
| 309 | err = ex |
| 310 | if 'ConnectionRefusedError' in ex.message: |
| 311 | self._send_event(Event(Event.CONNECTION_DOWN, self.key, None)) |
| 312 | log.exception('comms-exception', ex=ex) |
| 313 | yield self._backoff('consul-not-up') |
| 314 | else: |
| 315 | log.error('consul-specific-exception', ex=ex) |
| 316 | except Exception as ex: |
| 317 | err = ex |
| 318 | log.error('consul-exception', ex=ex) |
| 319 | |
| 320 | if timeout > 0 and self.retry_time > timeout: |
| 321 | err = 'operation-timed-out' |
| 322 | if err is not None: |
| 323 | self._clear_backoff() |
| 324 | break |
| 325 | |
| 326 | returnValue(result) |
| 327 | |
| 328 | def _send_event(self, event): |
| 329 | if self.callback is not None: |
| 330 | self.callback(event) |
| 331 | |
| 332 | def _backoff(self, msg): |
| 333 | wait_time = RETRY_BACKOFF[min(self.retries, len(RETRY_BACKOFF) - 1)] |
| 334 | self.retry_time += wait_time |
| 335 | self.retries += 1 |
| 336 | log.error(msg, next_retry_in_secs=wait_time, |
| 337 | total_delay_in_secs = self.retry_time, |
| 338 | retries=self.retries) |
| 339 | return asleep(wait_time) |
| 340 | |
| 341 | def _clear_backoff(self): |
| 342 | if self.retries: |
| 343 | log.debug('reconnected-to-kv', after_retries=self.retries) |
| 344 | self.retries = 0 |
| 345 | self.retry_time = 0 |