X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/f6b88a9e7e9727f0397f1febbad8c08f6a20463d..d2f68bd1e108c3f2dda2322c427050d019b17e04:/sdk/python/arvados/keep.py?ds=inline diff --git a/sdk/python/arvados/keep.py b/sdk/python/arvados/keep.py index cc7dbd4161..cca9345bc5 100644 --- a/sdk/python/arvados/keep.py +++ b/sdk/python/arvados/keep.py @@ -27,6 +27,22 @@ import arvados.errors import arvados.retry as retry import arvados.util +try: + # Workaround for urllib3 bug. + # The 'requests' library enables urllib3's SNI support by default, which uses pyopenssl. + # However, urllib3 prior to version 1.10 has a major bug in this feature + # (OpenSSL WantWriteError, https://github.com/shazow/urllib3/issues/412) + # Unfortunately Debian 8 is stabilizing on urllib3 1.9.1 which means the + # following workaround is necessary to be able to use + # the arvados python sdk with the distribution-provided packages. + import urllib3 + from pkg_resources import parse_version + if parse_version(urllib3.__version__) < parse_version('1.10'): + from urllib3.contrib import pyopenssl + pyopenssl.extract_from_urllib3() +except ImportError: + pass + _logger = logging.getLogger('arvados.keep') global_client_object = None @@ -46,7 +62,7 @@ class KeepLocator(object): self.size = None for hint in pieces: if self.HINT_RE.match(hint) is None: - raise ValueError("unrecognized hint data {}".format(hint)) + raise ValueError("invalid hint format: {}".format(hint)) elif hint.startswith('A'): self.parse_permission_hint(hint) else: @@ -59,7 +75,10 @@ class KeepLocator(object): if s is not None) def stripped(self): - return "%s+%i" % (self.md5sum, self.size) + if self.size is not None: + return "%s+%i" % (self.md5sum, self.size) + else: + return self.md5sum def _make_hex_prop(name, length): # Build and return a new property with the given name that @@ -404,11 +423,11 @@ class KeepClient(object): replicas_stored = int(result.headers['x-keep-replicas-stored']) except (KeyError, ValueError): replicas_stored = 1 - limiter.save_response(result.text.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.text) + self.service.last_result.content) def __init__(self, api_client=None, proxy=None, @@ -418,35 +437,57 @@ class KeepClient(object): """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 (in seconds) for HTTP requests to Keep + + :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 initial 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. + Because timeouts are often a result of transient server load, the + actual connection timeout will be increased by a factor of two on + each retry. Default: (2, 300). - * proxy_timeout: The timeout (in seconds) for HTTP requests to + + :proxy_timeout: + The initial 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 + (connection_timeout, read_timeout). The behavior described + above for adjusting connection timeouts on retry also applies. + 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: @@ -477,6 +518,7 @@ class KeepClient(object): if not proxy.endswith('/'): proxy += '/' self.api_token = api_token + self._gateway_services = {} self._keep_services = [{ 'uuid': 'proxy', '_service_root': proxy, @@ -490,18 +532,25 @@ class KeepClient(object): api_client = arvados.api('v1') self.api_client = api_client self.api_token = api_client.api_token + self._gateway_services = {} self._keep_services = None self.using_proxy = None self._static_services_list = False - 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. + def current_timeout(self, attempt_number): + """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. The `attempt_number` indicates + how many times the operation has been tried already (starting from 0 + for the first try), and scales the connection timeout portion of the + return value accordingly. + """ # 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 + t = self.proxy_timeout if self.using_proxy else self.timeout + return (t[0] * (1 << attempt_number), t[1]) def build_services_list(self, force_rebuild=False): if (self._static_services_list or @@ -513,21 +562,31 @@ class KeepClient(object): except Exception: # API server predates Keep services. keep_services = self.api_client.keep_disks().list() - self._keep_services = keep_services.execute().get('items') - if not self._keep_services: + accessible = keep_services.execute().get('items') + if not accessible: raise arvados.errors.NoKeepServersError() - self.using_proxy = any(ks.get('service_type') == 'proxy' - for ks in self._keep_services) - # Precompute the base URI for each service. - for r in self._keep_services: + for r in accessible: r['_service_root'] = "{}://[{}]:{:d}/".format( 'https' if r['service_ssl_flag'] else 'http', r['service_host'], r['service_port']) + + # Gateway services are only used when specified by UUID, + # so there's nothing to gain by filtering them by + # service_type. + self._gateway_services = {ks.get('uuid'): ks for ks in accessible} + _logger.debug(str(self._gateway_services)) + + self._keep_services = [ + ks for ks in accessible + if ks.get('service_type') in ['disk', 'proxy']] _logger.debug(str(self._keep_services)) + self.using_proxy = any(ks.get('service_type') == 'proxy' + for ks in 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. @@ -537,31 +596,46 @@ class KeepClient(object): """ return hashlib.md5(data_hash + service_uuid[-15:]).hexdigest() - def weighted_service_roots(self, data_hash, force_rebuild=False): + def weighted_service_roots(self, locator, 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. + the given hash+hints. """ 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) + sorted_roots = [] + + # Use the services indicated by the given +K@... remote + # service hints, if any are present and can be resolved to a + # URI. + for hint in locator.hints: + if hint.startswith('K@'): + if len(hint) == 7: + sorted_roots.append( + "https://keep.{}.arvadosapi.com/".format(hint[2:])) + elif len(hint) == 29: + svc = self._gateway_services.get(hint[2:]) + if svc: + sorted_roots.append(svc['_service_root']) + + # Sort the available local services by weight (heaviest first) + # for this locator, and return their service_roots (base URIs) # in that order. - sorted_roots = [ + sorted_roots.extend([ 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)) + key=lambda svc: self._service_weight(locator.md5sum, svc['uuid']))]) + _logger.debug("{}: {}".format(locator, sorted_roots)) return sorted_roots - def map_new_services(self, roots_map, md5_s, force_rebuild, **headers): + def map_new_services(self, roots_map, locator, 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.weighted_service_roots(md5_s, force_rebuild) + local_roots = self.weighted_service_roots(locator, force_rebuild) for root in local_roots: if root not in roots_map: roots_map[root] = self.KeepService(root, self.session, **headers) @@ -585,8 +659,16 @@ 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 and slot.ready.is_set(): + return slot.get() + else: + return None + @retry.retry_method - def get(self, loc_s, num_retries=None, cache_only=False): + def get(self, loc_s, num_retries=None): """Get data from Keep. This method fetches one or more blocks of data from Keep. It @@ -605,42 +687,44 @@ class KeepClient(object): to fetch data from every available Keep service, along with any that are named in location hints in the locator. The default value is set when the KeepClient is initialized. - * cache_only: If true, return the block data only if already present in - cache, otherwise return None. """ if ',' in loc_s: return ''.join(self.get(x) for x in loc_s.split(',')) locator = KeepLocator(loc_s) - expect_hash = locator.md5sum - - if cache_only: - slot = self.block_cache.get(expect_hash) - if slot.ready.is_set(): - return slot.get() - else: - return None - - slot, first = self.block_cache.reserve_cache(expect_hash) + slot, first = self.block_cache.reserve_cache(locator.md5sum) if not first: v = slot.get() return v + # If the locator has hints specifying a prefix (indicating a + # remote keepproxy) or the UUID of a local gateway service, + # read data from the indicated service(s) instead of the usual + # list of local disk services. + hint_roots = ['http://keep.{}.arvadosapi.com/'.format(hint[2:]) + for hint in locator.hints if hint.startswith('K@') and len(hint) == 7] + hint_roots.extend([self._gateway_services[hint[2:]]['_service_root'] + for hint in locator.hints if ( + hint.startswith('K@') and + len(hint) == 29 and + self._gateway_services.get(hint[2:]) + )]) + # Map root URLs to their KeepService objects. + roots_map = {root: self.KeepService(root, self.session) for root in hint_roots} + # 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, self.session) for root in hint_roots} + sorted_roots = [] + roots_map = {} 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, + sorted_roots = self.map_new_services( + roots_map, locator, force_rebuild=(tries_left < num_retries)) except Exception as error: loop.save_result(error) @@ -649,10 +733,10 @@ class KeepClient(object): # 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) + for root in sorted_roots if roots_map[root].usable()] for keep_service in services_to_try: - blob = keep_service.get(locator, timeout=self.current_timeout()) + blob = keep_service.get(locator, timeout=self.current_timeout(num_retries-tries_left)) if blob is not None: break loop.save_result((blob, len(services_to_try))) @@ -663,27 +747,22 @@ class KeepClient(object): if loop.success(): return blob - 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 key in all_roots + not_founds = sum(1 for key in sorted_roots if roots_map[key].last_status() in {403, 404, 410}) service_errors = ((key, roots_map[key].last_result) - for key in all_roots) + for key in sorted_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): + elif not_founds == len(sorted_roots): raise arvados.errors.NotFoundError( "{} not found".format(loc_s), service_errors) else: raise arvados.errors.KeepReadError( - "failed to read {}".format(loc_s), service_errors) + "failed to read {}".format(loc_s), service_errors, label="service") @retry.retry_method def put(self, data, copies=2, num_retries=None): @@ -704,9 +783,16 @@ 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 + locator = KeepLocator(data_hash + '+' + str(len(data))) headers = {} if self.using_proxy: @@ -719,7 +805,7 @@ class KeepClient(object): for tries_left in loop: try: local_roots = self.map_new_services( - roots_map, data_hash, + roots_map, locator, force_rebuild=(tries_left < num_retries), **headers) except Exception as error: loop.save_result(error) @@ -735,7 +821,7 @@ class KeepClient(object): data_hash=data_hash, service_root=service_root, thread_limiter=thread_limiter, - timeout=self.current_timeout()) + timeout=self.current_timeout(num_retries-tries_left)) t.start() threads.append(t) for t in threads: @@ -754,7 +840,7 @@ class KeepClient(object): 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) + 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().