import gflags import httplib import httplib2 import logging import os import pprint import sys import types import subprocess import json import UserDict import re import hashlib import string import bz2 import zlib import fcntl import time import threading import timer import datetime import ssl import socket _logger = logging.getLogger('arvados.keep') global_client_object = None import arvados import arvados.config as config import arvados.errors import arvados.retry as retry import arvados.util class KeepLocator(object): EPOCH_DATETIME = datetime.datetime.utcfromtimestamp(0) HINT_RE = re.compile(r'^[A-Z][A-Za-z0-9@_-]+$') def __init__(self, locator_str): self.hints = [] self._perm_sig = None self._perm_expiry = None pieces = iter(locator_str.split('+')) self.md5sum = next(pieces) try: self.size = int(next(pieces)) except StopIteration: self.size = None for hint in pieces: if self.HINT_RE.match(hint) is None: raise ValueError("unrecognized hint data {}".format(hint)) elif hint.startswith('A'): self.parse_permission_hint(hint) else: self.hints.append(hint) def __str__(self): return '+'.join( str(s) for s in [self.md5sum, self.size, self.permission_hint()] + self.hints if s is not None) def _make_hex_prop(name, length): # Build and return a new property with the given name that # must be a hex string of the given length. data_name = '_{}'.format(name) def getter(self): return getattr(self, data_name) def setter(self, hex_str): if not arvados.util.is_hex(hex_str, length): raise ValueError("{} must be a {}-digit hex string: {}". format(name, length, hex_str)) setattr(self, data_name, hex_str) return property(getter, setter) md5sum = _make_hex_prop('md5sum', 32) perm_sig = _make_hex_prop('perm_sig', 40) @property def perm_expiry(self): return self._perm_expiry @perm_expiry.setter def perm_expiry(self, value): if not arvados.util.is_hex(value, 1, 8): raise ValueError( "permission timestamp must be a hex Unix timestamp: {}". format(value)) self._perm_expiry = datetime.datetime.utcfromtimestamp(int(value, 16)) def permission_hint(self): data = [self.perm_sig, self.perm_expiry] if None in data: return None data[1] = int((data[1] - self.EPOCH_DATETIME).total_seconds()) return "A{}@{:08x}".format(*data) def parse_permission_hint(self, s): try: self.perm_sig, self.perm_expiry = s[1:].split('@', 1) except IndexError: raise ValueError("bad permission hint {}".format(s)) def permission_expired(self, as_of_dt=None): if self.perm_expiry is None: return False elif as_of_dt is None: as_of_dt = datetime.datetime.now() return self.perm_expiry <= as_of_dt class Keep(object): """Simple interface to a global KeepClient object. THIS CLASS IS DEPRECATED. Please instantiate your own KeepClient with your own API client. The global KeepClient will build an API client from the current Arvados configuration, which may not match the one you built. """ _last_key = None @classmethod def global_client_object(cls): global global_client_object # Previously, KeepClient would change its behavior at runtime based # on these configuration settings. We simulate that behavior here # by checking the values and returning a new KeepClient if any of # them have changed. key = (config.get('ARVADOS_API_HOST'), config.get('ARVADOS_API_TOKEN'), config.flag_is_true('ARVADOS_API_HOST_INSECURE'), config.get('ARVADOS_KEEP_PROXY'), config.get('ARVADOS_EXTERNAL_CLIENT') == 'true', os.environ.get('KEEP_LOCAL_STORE')) if (global_client_object is None) or (cls._last_key != key): global_client_object = KeepClient() cls._last_key = key return global_client_object @staticmethod def get(locator, **kwargs): return Keep.global_client_object().get(locator, **kwargs) @staticmethod def put(data, **kwargs): return Keep.global_client_object().put(data, **kwargs) class KeepClient(object): class ThreadLimiter(object): """ Limit the number of threads running at a given time to {desired successes} minus {successes reported}. When successes reported == desired, wake up the remaining threads and tell them to quit. Should be used in a "with" block. """ def __init__(self, todo): self._todo = todo self._done = 0 self._response = None self._todo_lock = threading.Semaphore(todo) self._done_lock = threading.Lock() def __enter__(self): self._todo_lock.acquire() return self def __exit__(self, type, value, traceback): self._todo_lock.release() def shall_i_proceed(self): """ Return true if the current thread should do stuff. Return false if the current thread should just stop. """ with self._done_lock: return (self._done < self._todo) def save_response(self, response_body, replicas_stored): """ Records a response body (a locator, possibly signed) returned by the Keep server. It is not necessary to save more than one response, since we presume that any locator returned in response to a successful request is valid. """ with self._done_lock: self._done += replicas_stored self._response = response_body def response(self): """ Returns the body from the response to a PUT request. """ with self._done_lock: return self._response def done(self): """ Return how many successes were reported. """ with self._done_lock: return self._done class KeepService(object): # Make requests to a single Keep service, and track results. HTTP_ERRORS = (httplib2.HttpLib2Error, httplib.HTTPException, socket.error, ssl.SSLError) def __init__(self, root, **headers): self.root = root self.last_result = None self.success_flag = None self.get_headers = {'Accept': 'application/octet-stream'} self.get_headers.update(headers) self.put_headers = headers def usable(self): return self.success_flag is not False def finished(self): return self.success_flag is not None def last_status(self): try: return int(self.last_result[0].status) except (AttributeError, IndexError, ValueError): return None def get(self, http, locator): # http is an httplib2.Http object. # locator is a KeepLocator object. url = self.root + str(locator) _logger.debug("Request: GET %s", url) try: with timer.Timer() as t: result = http.request(url.encode('utf-8'), 'GET', headers=self.get_headers) except self.HTTP_ERRORS as e: _logger.debug("Request fail: GET %s => %s: %s", url, type(e), str(e)) self.last_result = e else: self.last_result = result self.success_flag = retry.check_http_response_success(result) content = result[1] _logger.info("%s response: %s bytes in %s msec (%.3f MiB/sec)", self.last_status(), len(content), t.msecs, (len(content)/(1024.0*1024))/t.secs) if self.success_flag: resp_md5 = hashlib.md5(content).hexdigest() if resp_md5 == locator.md5sum: return content _logger.warning("Checksum fail: md5(%s) = %s", url, md5) return None def put(self, http, hash_s, body): url = self.root + hash_s _logger.debug("Request: PUT %s", url) try: result = http.request(url.encode('utf-8'), 'PUT', headers=self.put_headers, body=body) except self.HTTP_ERRORS as e: _logger.debug("Request fail: PUT %s => %s: %s", url, type(e), str(e)) self.last_result = e else: self.last_result = result self.success_flag = retry.check_http_response_success(result) return self.success_flag class KeepWriterThread(threading.Thread): """ Write a blob of data to the given Keep server. On success, call save_response() of the given ThreadLimiter to save the returned locator. """ def __init__(self, keep_service, **kwargs): super(KeepClient.KeepWriterThread, self).__init__() self.service = keep_service self.args = kwargs self._success = False def success(self): return self._success def run(self): with self.args['thread_limiter'] as limiter: if not limiter.shall_i_proceed(): # My turn arrived, but the job has been done without # me. return self.run_with_limiter(limiter) def run_with_limiter(self, limiter): if self.service.finished(): return _logger.debug("KeepWriterThread %s proceeding %s %s", str(threading.current_thread()), self.args['data_hash'], self.args['service_root']) h = httplib2.Http(timeout=self.args.get('timeout', None)) self._success = bool(self.service.put( h, self.args['data_hash'], self.args['data'])) status = self.service.last_status() if self._success: resp, body = self.service.last_result _logger.debug("KeepWriterThread %s succeeded %s %s", str(threading.current_thread()), self.args['data_hash'], self.args['service_root']) # Tick the 'done' counter for the number of replica # reported stored by the server, for the case that # we're talking to a proxy or other backend that # stores to multiple copies for us. try: replicas_stored = int(resp['x-keep-replicas-stored']) except (KeyError, ValueError): replicas_stored = 1 limiter.save_response(body.strip(), replicas_stored) elif status is not None: _logger.debug("Request fail: PUT %s => %s %s", self.args['data_hash'], status, self.service.last_result[1]) def __init__(self, api_client=None, proxy=None, timeout=300, api_token=None, local_store=None): """Initialize a new KeepClient. Arguments: * api_client: The API client to use to find Keep services. If not provided, KeepClient will build one from available Arvados configuration. * proxy: If specified, this KeepClient will send requests to this Keep proxy. Otherwise, KeepClient will fall back to the setting of the ARVADOS_KEEP_PROXY configuration setting. If you want to ensure KeepClient does not use a proxy, pass in an empty string. * timeout: The timeout for all HTTP requests, in seconds. Default 300. * api_token: If you're not using an API client, but only talking directly to a Keep proxy, this parameter specifies an API token to authenticate Keep requests. It is an error to specify both api_client and api_token. If you specify neither, KeepClient will use one available from the Arvados configuration. * local_store: If specified, this KeepClient will bypass Keep services, and save data to the named directory. If unspecified, KeepClient will fall back to the setting of the $KEEP_LOCAL_STORE environment variable. If you want to ensure KeepClient does not use local storage, pass in an empty string. This is primarily intended to mock a server for testing. """ self.lock = threading.Lock() if proxy is None: proxy = config.get('ARVADOS_KEEP_PROXY') if api_token is None: api_token = config.get('ARVADOS_API_TOKEN') elif api_client is not None: raise ValueError( "can't build KeepClient with both API client and token") if local_store is None: local_store = os.environ.get('KEEP_LOCAL_STORE') if local_store: self.local_store = local_store self.get = self.local_store_get self.put = self.local_store_put else: self.timeout = timeout self.cache_max = 256 * 1024 * 1024 # Cache is 256MiB self._cache = [] self._cache_lock = threading.Lock() if proxy: if not proxy.endswith('/'): proxy += '/' self.api_token = api_token self.service_roots = [proxy] self.using_proxy = True self.static_service_roots = True else: # It's important to avoid instantiating an API client # unless we actually need one, for testing's sake. if api_client is None: api_client = arvados.api('v1') self.api_client = api_client self.api_token = api_client.api_token self.service_roots = None self.using_proxy = None self.static_service_roots = False def build_service_roots(self, force_rebuild=False): if (self.static_service_roots or (self.service_roots and not force_rebuild)): return with self.lock: try: keep_services = self.api_client.keep_services().accessible() except Exception: # API server predates Keep services. keep_services = self.api_client.keep_disks().list() keep_services = keep_services.execute().get('items') if not keep_services: raise arvados.errors.NoKeepServersError() self.using_proxy = (keep_services[0].get('service_type') == 'proxy') roots = (("http%s://%s:%d/" % ('s' if f['service_ssl_flag'] else '', f['service_host'], f['service_port'])) for f in keep_services) self.service_roots = sorted(set(roots)) _logger.debug(str(self.service_roots)) def shuffled_service_roots(self, hash, force_rebuild=False): self.build_service_roots(force_rebuild) # Build an ordering with which to query the Keep servers based on the # contents of the hash. # "hash" is a hex-encoded number at least 8 digits # (32 bits) long # seed used to calculate the next keep server from 'pool' # to be added to 'pseq' seed = hash # Keep servers still to be added to the ordering pool = self.service_roots[:] # output probe sequence pseq = [] # iterate while there are servers left to be assigned while len(pool) > 0: if len(seed) < 8: # ran out of digits in the seed if len(pseq) < len(hash) / 4: # the number of servers added to the probe sequence is less # than the number of 4-digit slices in 'hash' so refill the # seed with the last 4 digits and then append the contents # of 'hash'. seed = hash[-4:] + hash else: # refill the seed with the contents of 'hash' seed += hash # Take the next 8 digits (32 bytes) and interpret as an integer, # then modulus with the size of the remaining pool to get the next # selected server. probe = int(seed[0:8], 16) % len(pool) # Append the selected server to the probe sequence and remove it # from the pool. pseq += [pool[probe]] pool = pool[:probe] + pool[probe+1:] # Remove the digits just used from the seed seed = seed[8:] _logger.debug(str(pseq)) return pseq class CacheSlot(object): def __init__(self, locator): self.locator = locator self.ready = threading.Event() self.content = None def get(self): self.ready.wait() return self.content def set(self, value): self.content = value self.ready.set() def size(self): if self.content == None: return 0 else: return len(self.content) def cap_cache(self): '''Cap the cache size to self.cache_max''' self._cache_lock.acquire() try: self._cache = filter(lambda c: not (c.ready.is_set() and c.content == None), self._cache) sm = sum([slot.size() for slot in self._cache]) while sm > self.cache_max: del self._cache[-1] sm = sum([slot.size() for a in self._cache]) finally: self._cache_lock.release() def reserve_cache(self, locator): '''Reserve a cache slot for the specified locator, or return the existing slot.''' self._cache_lock.acquire() try: # Test if the locator is already in the cache for i in xrange(0, len(self._cache)): if self._cache[i].locator == locator: n = self._cache[i] if i != 0: # move it to the front del self._cache[i] self._cache.insert(0, n) return n, False # Add a new cache slot for the locator n = KeepClient.CacheSlot(locator) self._cache.insert(0, n) return n, True finally: self._cache_lock.release() def map_new_services(self, roots_map, md5_s, force_rebuild, **headers): # roots_map is a dictionary, mapping Keep service root strings # to KeepService objects. Poll for Keep services, and add any # new ones to roots_map. Return the current list of local # root strings. headers.setdefault('Authorization', "OAuth2 %s" % (self.api_token,)) local_roots = self.shuffled_service_roots(md5_s, force_rebuild) for root in local_roots: if root not in roots_map: roots_map[root] = self.KeepService(root, **headers) return local_roots @staticmethod def _check_loop_result(result): # KeepClient RetryLoops should save results as a 2-tuple: the # actual result of the request, and the number of servers available # to receive the request this round. # This method returns True if there's a real result, False if # there are no more servers available, otherwise None. if isinstance(result, Exception): return None result, tried_server_count = result if (result is not None) and (result is not False): return True elif tried_server_count < 1: _logger.info("No more Keep services to try; giving up") return False else: return None def get(self, loc_s, num_retries=0): """Get data from Keep. This method fetches one or more blocks of data from Keep. It sends a request each Keep service registered with the API server (or the proxy provided when this client was instantiated), then each service named in location hints, in sequence. As soon as one service provides the data, it's returned. Arguments: * loc_s: A string of one or more comma-separated locators to fetch. This method returns the concatenation of these blocks. * num_retries: The number of times to retry GET requests to *each* Keep server if it returns temporary failures, with exponential backoff. Note that, in each loop, the method may try to fetch data from every available Keep service, along with any that are named in location hints in the locator. Default 0. """ if ',' in loc_s: return ''.join(self.get(x) for x in loc_s.split(',')) locator = KeepLocator(loc_s) expect_hash = locator.md5sum slot, first = self.reserve_cache(expect_hash) if not first: v = slot.get() return v # See #3147 for a discussion of the loop implementation. Highlights: # * Refresh the list of Keep services after each failure, in case # it's being updated. # * Retry until we succeed, we're out of retries, or every available # service has returned permanent failure. hint_roots = ['http://keep.{}.arvadosapi.com/'.format(hint[2:]) for hint in locator.hints if hint.startswith('K@')] # Map root URLs their KeepService objects. roots_map = {root: self.KeepService(root) for root in hint_roots} blob = None loop = retry.RetryLoop(num_retries, self._check_loop_result, backoff_start=2) for tries_left in loop: try: local_roots = self.map_new_services( roots_map, expect_hash, force_rebuild=(tries_left < num_retries)) except Exception as error: loop.save_result(error) continue # Query KeepService objects that haven't returned # permanent failure, in our specified shuffle order. services_to_try = [roots_map[root] for root in (local_roots + hint_roots) if roots_map[root].usable()] http = httplib2.Http(timeout=self.timeout) for keep_service in services_to_try: blob = keep_service.get(http, locator) if blob is not None: break loop.save_result((blob, len(services_to_try))) # Always cache the result, then return it if we succeeded. slot.set(blob) self.cap_cache() if loop.success(): return blob # No servers fulfilled the request. Count how many responded # "not found;" if the ratio is high enough (currently 75%), report # Not Found; otherwise a generic error. # Q: Including 403 is necessary for the Keep tests to continue # passing, but maybe they should expect KeepReadError instead? not_founds = sum(1 for ks in roots_map.values() if ks.last_status() in set([403, 404, 410])) if roots_map and ((float(not_founds) / len(roots_map)) >= .75): raise arvados.errors.NotFoundError(loc_s) else: raise arvados.errors.KeepReadError(loc_s) def put(self, data, copies=2, num_retries=0): """Save data in Keep. This method will get a list of Keep services from the API server, and send the data to each one simultaneously in a new thread. Once the uploads are finished, if enough copies are saved, this method returns the most recent HTTP response body. If requests fail to upload enough copies, this method raises KeepWriteError. Arguments: * data: The string of data to upload. * copies: The number of copies that the user requires be saved. Default 2. * num_retries: The number of times to retry PUT requests to *each* Keep server if it returns temporary failures, with exponential backoff. Default 0. """ data_hash = hashlib.md5(data).hexdigest() if copies < 1: return data_hash headers = {} if self.using_proxy: # Tell the proxy how many copies we want it to store headers['X-Keep-Desired-Replication'] = str(copies) roots_map = {} thread_limiter = KeepClient.ThreadLimiter(copies) loop = retry.RetryLoop(num_retries, self._check_loop_result, backoff_start=2) for tries_left in loop: try: local_roots = self.map_new_services( roots_map, data_hash, force_rebuild=(tries_left < num_retries), **headers) except Exception as error: loop.save_result(error) continue threads = [] for service_root, ks in roots_map.iteritems(): if ks.finished(): continue t = KeepClient.KeepWriterThread( ks, data=data, data_hash=data_hash, service_root=service_root, thread_limiter=thread_limiter, timeout=self.timeout) t.start() threads.append(t) for t in threads: t.join() loop.save_result((thread_limiter.done() >= copies, len(threads))) if loop.success(): return thread_limiter.response() raise arvados.errors.KeepWriteError( "Write fail for %s: wanted %d but wrote %d" % (data_hash, copies, thread_limiter.done())) def local_store_put(self, data): md5 = hashlib.md5(data).hexdigest() locator = '%s+%d' % (md5, len(data)) with open(os.path.join(self.local_store, md5 + '.tmp'), 'w') as f: f.write(data) os.rename(os.path.join(self.local_store, md5 + '.tmp'), os.path.join(self.local_store, md5)) return locator def local_store_get(self, loc_s): try: locator = KeepLocator(loc_s) except ValueError: raise arvados.errors.NotFoundError( "Invalid data locator: '%s'" % loc_s) if locator.md5sum == config.EMPTY_BLOCK_LOCATOR.split('+')[0]: return '' with open(os.path.join(self.local_store, locator.md5sum), 'r') as f: return f.read()