import gflags
-import httplib
-import httplib2
import logging
import os
import pprint
import datetime
import ssl
import socket
-
-_logger = logging.getLogger('arvados.keep')
-global_client_object = None
+import requests
import arvados
import arvados.config as config
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@_-]+$')
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.
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)]
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
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
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))
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:
return content
- _logger.warning("Checksum fail: md5(%s) = %s", url, md5)
+ _logger.warning("Checksum fail: md5(%s) = %s",
+ 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))
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.text.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.text)
- def __init__(self, api_client=None, proxy=None, timeout=300,
- api_token=None, local_store=None, block_cache=None):
+ 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, session=None):
"""Initialize a new KeepClient.
Arguments:
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.
+ * 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
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.
+ This will be used as the default num_retries value when get() and
+ put() are called. Default 0.
"""
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")
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.
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:
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 = (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
+ 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:
+ 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
# 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
else:
return None
- def get(self, loc_s, num_retries=0):
+ @retry.retry_method
+ def get(self, loc_s, num_retries=None, cache_only=False):
"""Get data from Keep.
This method fetches one or more blocks of data from Keep. It
*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.
+ 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)
if not first:
v = slot.get()
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)
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)))
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)
- def put(self, data, copies=2, num_retries=0):
+ @retry.retry_method
+ def put(self, data, copies=2, num_retries=None):
"""Save data in Keep.
This method will get a list of Keep services from the API server, and
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.
+ exponential backoff. The default value is set when the
+ KeepClient is initialized.
"""
data_hash = hashlib.md5(data).hexdigest()
if copies < 1:
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:
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()))
+ 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)
+
+ def local_store_put(self, data, copies=1, num_retries=None):
+ """A stub for put().
- def local_store_put(self, data):
+ 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:
os.path.join(self.local_store, md5))
return locator
- def local_store_get(self, loc_s):
+ def local_store_get(self, loc_s, num_retries=None):
+ """Companion to local_store_put()."""
try:
locator = KeepLocator(loc_s)
except ValueError:
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)
projects / arvados.git / blobdiff