X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/3dfc071494cbb0386ecd7269c72a435fc7f9cc24..63b03a39adfd78961c5bbb6a3a2d02ccd8c92e4d:/sdk/python/arvados/keep.py diff --git a/sdk/python/arvados/keep.py b/sdk/python/arvados/keep.py index 37b1c17902..8d0a89d777 100644 --- a/sdk/python/arvados/keep.py +++ b/sdk/python/arvados/keep.py @@ -1,6 +1,4 @@ import gflags -import httplib -import httplib2 import logging import os import pprint @@ -21,9 +19,7 @@ import timer import datetime import ssl import socket - -_logger = logging.getLogger('arvados.keep') -global_client_object = None +import requests import arvados import arvados.config as config @@ -31,6 +27,9 @@ import arvados.errors import arvados.retry as retry import arvados.util +_logger = logging.getLogger('arvados.keep') +global_client_object = None + class KeepLocator(object): EPOCH_DATETIME = datetime.datetime.utcfromtimestamp(0) HINT_RE = re.compile(r'^[A-Z][A-Za-z0-9@_-]+$') @@ -59,6 +58,9 @@ class KeepLocator(object): self.permission_hint()] + self.hints if s is not None) + def stripped(self): + return "%s+%i" % (self.md5sum, self.size) + 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. @@ -165,15 +167,14 @@ class KeepBlockCache(object): self.ready.set() def size(self): - if self.content == None: + if self.content is 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: + with self._cache_lock: # Select all slots except those where ready.is_set() and content is # None (that means there was an error reading the block). self._cache = [c for c in self._cache if not (c.ready.is_set() and c.content is None)] @@ -184,32 +185,45 @@ class KeepBlockCache(object): del self._cache[i] break sm = sum([slot.size() for slot in self._cache]) - finally: - self._cache_lock.release() + + def _get(self, locator): + # 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 + return None + + def get(self, locator): + with self._cache_lock: + return self._get(locator) 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 = KeepBlockCache.CacheSlot(locator) - self._cache.insert(0, n) - return n, True - finally: - self._cache_lock.release() + with self._cache_lock: + n = self._get(locator) + if n: + return n, False + else: + # Add a new cache slot for the locator + n = KeepBlockCache.CacheSlot(locator) + self._cache.insert(0, n) + return n, True class KeepClient(object): + + # Default Keep server connection timeout: 2 seconds + # Default Keep server read timeout: 300 seconds + # Default Keep proxy connection timeout: 20 seconds + # Default Keep proxy read timeout: 300 seconds + DEFAULT_TIMEOUT = (2, 300) + DEFAULT_PROXY_TIMEOUT = (20, 300) + class ThreadLimiter(object): """ Limit the number of threads running at a given time to @@ -269,13 +283,14 @@ class KeepClient(object): class KeepService(object): # Make requests to a single Keep service, and track results. - HTTP_ERRORS = (httplib2.HttpLib2Error, httplib.HTTPException, + HTTP_ERRORS = (requests.exceptions.RequestException, socket.error, ssl.SSLError) - def __init__(self, root, **headers): + def __init__(self, root, session, **headers): self.root = root self.last_result = None self.success_flag = None + self.session = session self.get_headers = {'Accept': 'application/octet-stream'} self.get_headers.update(headers) self.put_headers = headers @@ -288,19 +303,19 @@ class KeepClient(object): def last_status(self): try: - return int(self.last_result[0].status) - except (AttributeError, IndexError, ValueError): + return self.last_result.status_code + except AttributeError: return None - def get(self, http, locator): - # http is an httplib2.Http object. + def get(self, locator, timeout=None): # 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) + result = self.session.get(url.encode('utf-8'), + headers=self.get_headers, + timeout=timeout) except self.HTTP_ERRORS as e: _logger.debug("Request fail: GET %s => %s: %s", url, type(e), str(e)) @@ -308,10 +323,10 @@ class KeepClient(object): else: self.last_result = result self.success_flag = retry.check_http_response_success(result) - content = result[1] + content = result.content _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) + (len(content)/(1024.0*1024))/t.secs if t.secs > 0 else 0) if self.success_flag: resp_md5 = hashlib.md5(content).hexdigest() if resp_md5 == locator.md5sum: @@ -320,12 +335,14 @@ class KeepClient(object): url, resp_md5) return None - def put(self, http, hash_s, body): + def put(self, hash_s, body, timeout=None): 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) + result = self.session.put(url.encode('utf-8'), + data=body, + headers=self.put_headers, + timeout=timeout) except self.HTTP_ERRORS as e: _logger.debug("Request fail: PUT %s => %s: %s", url, type(e), str(e)) @@ -362,70 +379,100 @@ class KeepClient(object): def run_with_limiter(self, limiter): if self.service.finished(): return - _logger.debug("KeepWriterThread %s proceeding %s %s", + _logger.debug("KeepWriterThread %s proceeding %s+%i %s", str(threading.current_thread()), self.args['data_hash'], + len(self.args['data']), 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'])) + self.args['data_hash'], + self.args['data'], + timeout=self.args.get('timeout', None))) status = self.service.last_status() if self._success: - resp, body = self.service.last_result - _logger.debug("KeepWriterThread %s succeeded %s %s", + result = self.service.last_result + _logger.debug("KeepWriterThread %s succeeded %s+%i %s", str(threading.current_thread()), self.args['data_hash'], + len(self.args['data']), 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']) + replicas_stored = int(result.headers['x-keep-replicas-stored']) except (KeyError, ValueError): replicas_stored = 1 - limiter.save_response(body.strip(), replicas_stored) + limiter.save_response(result.content.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]) + self.service.last_result.content) - def __init__(self, api_client=None, proxy=None, timeout=300, + def __init__(self, api_client=None, proxy=None, + timeout=DEFAULT_TIMEOUT, proxy_timeout=DEFAULT_PROXY_TIMEOUT, api_token=None, local_store=None, block_cache=None, - num_retries=0): + num_retries=0, session=None): """Initialize a new KeepClient. Arguments: - * api_client: The API client to use to find Keep services. If not + :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 + + :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 (in seconds) for HTTP requests to Keep + non-proxy servers. A tuple of two floats is interpreted as + (connection_timeout, read_timeout): see + http://docs.python-requests.org/en/latest/user/advanced/#timeouts. + Default: (2, 300). + + :proxy_timeout: + The timeout (in seconds) for HTTP requests to + Keep proxies. A tuple of two floats is interpreted as + (connection_timeout, read_timeout). Default: (20, 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 + + :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. - * num_retries: The default number of times to retry failed requests. + + :num_retries: + The default number of times to retry failed requests. This will be used as the default num_retries value when get() and put() are called. Default 0. + + :session: + The requests.Session object to use for get() and put() requests. + Will create one if not specified. """ 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') + if api_client is None: + api_token = config.get('ARVADOS_API_TOKEN') + else: + api_token = api_client.api_token elif api_client is not None: raise ValueError( "can't build KeepClient with both API client and token") @@ -433,21 +480,26 @@ class KeepClient(object): local_store = os.environ.get('KEEP_LOCAL_STORE') self.block_cache = block_cache if block_cache else KeepBlockCache() + self.timeout = timeout + self.proxy_timeout = proxy_timeout 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.num_retries = num_retries + self.session = session if session is not None else requests.Session() if proxy: if not proxy.endswith('/'): proxy += '/' self.api_token = api_token - self.service_roots = [proxy] + self._keep_services = [{ + 'uuid': 'proxy', + '_service_root': proxy, + }] self.using_proxy = True - self.static_service_roots = True + self._static_services_list = True else: # It's important to avoid instantiating an API client # unless we actually need one, for testing's sake. @@ -455,13 +507,22 @@ class KeepClient(object): api_client = arvados.api('v1') self.api_client = api_client self.api_token = api_client.api_token - self.service_roots = None + self._keep_services = None self.using_proxy = None - self.static_service_roots = False + self._static_services_list = False - def build_service_roots(self, force_rebuild=False): - if (self.static_service_roots or - (self.service_roots and not force_rebuild)): + def current_timeout(self): + """Return the appropriate timeout to use for this client: the proxy + timeout setting if the backend service is currently a proxy, + the regular timeout setting otherwise. + """ + # TODO(twp): the timeout should be a property of a + # KeepService, not a KeepClient. See #4488. + return self.proxy_timeout if self.using_proxy else self.timeout + + def build_services_list(self, force_rebuild=False): + if (self._static_services_list or + (self._keep_services and not force_rebuild)): return with self.lock: try: @@ -469,68 +530,47 @@ class KeepClient(object): 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: + self._keep_services = keep_services.execute().get('items') + if not self._keep_services: raise arvados.errors.NoKeepServersError() self.using_proxy = any(ks.get('service_type') == 'proxy' - for ks in keep_services) - - roots = ("{}://[{}]:{:d}/".format( - 'https' if ks['service_ssl_flag'] else 'http', - ks['service_host'], - ks['service_port']) - for ks 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 + for ks in self._keep_services) + + # Precompute the base URI for each service. + for r in self._keep_services: + r['_service_root'] = "{}://[{}]:{:d}/".format( + 'https' if r['service_ssl_flag'] else 'http', + r['service_host'], + r['service_port']) + _logger.debug(str(self._keep_services)) + + def _service_weight(self, data_hash, service_uuid): + """Compute the weight of a Keep service endpoint for a data + block with a known hash. + + The weight is md5(h + u) where u is the last 15 characters of + the service endpoint's UUID. + """ + return hashlib.md5(data_hash + service_uuid[-15:]).hexdigest() + def weighted_service_roots(self, data_hash, force_rebuild=False): + """Return an array of Keep service endpoints, in the order in + which they should be probed when reading or writing data with + the given hash. + """ + self.build_services_list(force_rebuild) + + # Sort the available services by weight (heaviest first) for + # this data_hash, and return their service_roots (base URIs) + # in that order. + sorted_roots = [ + svc['_service_root'] for svc in sorted( + self._keep_services, + reverse=True, + key=lambda svc: self._service_weight(data_hash, svc['uuid']))] + _logger.debug(data_hash + ': ' + str(sorted_roots)) + return sorted_roots def map_new_services(self, roots_map, md5_s, force_rebuild, **headers): # roots_map is a dictionary, mapping Keep service root strings @@ -538,10 +578,10 @@ class KeepClient(object): # 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) + local_roots = self.weighted_service_roots(md5_s, force_rebuild) for root in local_roots: if root not in roots_map: - roots_map[root] = self.KeepService(root, **headers) + roots_map[root] = self.KeepService(root, self.session, **headers) return local_roots @staticmethod @@ -562,6 +602,14 @@ class KeepClient(object): else: return None + def get_from_cache(self, loc): + """Fetch a block only if is in the cache, otherwise return None.""" + slot = self.block_cache.get(loc) + if slot.ready.is_set(): + return slot.get() + else: + return None + @retry.retry_method def get(self, loc_s, num_retries=None): """Get data from Keep. @@ -587,7 +635,6 @@ class KeepClient(object): return ''.join(self.get(x) for x in loc_s.split(',')) locator = KeepLocator(loc_s) expect_hash = locator.md5sum - slot, first = self.block_cache.reserve_cache(expect_hash) if not first: v = slot.get() @@ -601,7 +648,7 @@ class KeepClient(object): 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} + roots_map = {root: self.KeepService(root, self.session) for root in hint_roots} blob = None loop = retry.RetryLoop(num_retries, self._check_loop_result, backoff_start=2) @@ -619,9 +666,8 @@ class KeepClient(object): 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) + blob = keep_service.get(locator, timeout=self.current_timeout()) if blob is not None: break loop.save_result((blob, len(services_to_try))) @@ -632,17 +678,27 @@ class KeepClient(object): 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. + try: + all_roots = local_roots + hint_roots + except NameError: + # We never successfully fetched local_roots. + all_roots = hint_roots # 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) + not_founds = sum(1 for key in all_roots + if roots_map[key].last_status() in {403, 404, 410}) + service_errors = ((key, roots_map[key].last_result) + for key in all_roots) + if not roots_map: + raise arvados.errors.KeepReadError( + "failed to read {}: no Keep services available ({})".format( + loc_s, loop.last_result())) + elif not_founds == len(all_roots): + raise arvados.errors.NotFoundError( + "{} not found".format(loc_s), service_errors) else: - raise arvados.errors.KeepReadError(loc_s) + raise arvados.errors.KeepReadError( + "failed to read {}".format(loc_s), service_errors, label="service") @retry.retry_method def put(self, data, copies=2, num_retries=None): @@ -663,6 +719,12 @@ class KeepClient(object): exponential backoff. The default value is set when the KeepClient is initialized. """ + + if isinstance(data, unicode): + data = data.encode("ascii") + elif not isinstance(data, str): + raise arvados.errors.ArgumentError("Argument 'data' to KeepClient.put must be type 'str'") + data_hash = hashlib.md5(data).hexdigest() if copies < 1: return data_hash @@ -694,7 +756,7 @@ class KeepClient(object): data_hash=data_hash, service_root=service_root, thread_limiter=thread_limiter, - timeout=self.timeout) + timeout=self.current_timeout()) t.start() threads.append(t) for t in threads: @@ -703,14 +765,30 @@ class KeepClient(object): 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())) - - # Local storage methods need no-op num_retries arguments to keep - # integration tests happy. With better isolation they could - # probably be removed again. - def local_store_put(self, data, num_retries=0): + if not roots_map: + raise arvados.errors.KeepWriteError( + "failed to write {}: no Keep services available ({})".format( + data_hash, loop.last_result())) + else: + service_errors = ((key, roots_map[key].last_result) + for key in local_roots + if not roots_map[key].success_flag) + raise arvados.errors.KeepWriteError( + "failed to write {} (wanted {} copies but wrote {})".format( + data_hash, copies, thread_limiter.done()), service_errors, label="service") + + def local_store_put(self, data, copies=1, num_retries=None): + """A stub for put(). + + This method is used in place of the real put() method when + using local storage (see constructor's local_store argument). + + copies and num_retries arguments are ignored: they are here + only for the sake of offering the same call signature as + put(). + + Data stored this way can be retrieved via local_store_get(). + """ md5 = hashlib.md5(data).hexdigest() locator = '%s+%d' % (md5, len(data)) with open(os.path.join(self.local_store, md5 + '.tmp'), 'w') as f: @@ -719,7 +797,8 @@ class KeepClient(object): os.path.join(self.local_store, md5)) return locator - def local_store_get(self, loc_s, num_retries=0): + def local_store_get(self, loc_s, num_retries=None): + """Companion to local_store_put().""" try: locator = KeepLocator(loc_s) except ValueError: @@ -729,3 +808,6 @@ class KeepClient(object): return '' with open(os.path.join(self.local_store, locator.md5sum), 'r') as f: return f.read() + + def is_cached(self, locator): + return self.block_cache.reserve_cache(expect_hash)