X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/00af5ad16232b856ef1f3620a4f62f0946c681a7..33d63c6d42e824744305df3e720f8e9cbcc87d78:/sdk/python/arvados/keep.py diff --git a/sdk/python/arvados/keep.py b/sdk/python/arvados/keep.py index e8be158c4f..e414d267a1 100644 --- a/sdk/python/arvados/keep.py +++ b/sdk/python/arvados/keep.py @@ -17,6 +17,7 @@ import zlib import fcntl import time import threading +import timer global_client_object = None @@ -138,62 +139,181 @@ class KeepClient(object): def __init__(self): self.lock = threading.Lock() self.service_roots = None + self._cache_lock = threading.Lock() + self._cache = [] + # default 256 megabyte cache + self.cache_max = 256 * 1024 * 1024 def shuffled_service_roots(self, hash): if self.service_roots == None: self.lock.acquire() - keep_disks = arvados.api().keep_disks().list().execute()['items'] - roots = (("http%s://%s:%d/" % - ('s' if f['service_ssl_flag'] else '', - f['service_host'], - f['service_port'])) - for f in keep_disks) - self.service_roots = sorted(set(roots)) - logging.debug(str(self.service_roots)) - self.lock.release() + try: + keep_disks = arvados.api().keep_disks().list().execute()['items'] + roots = (("http%s://%s:%d/" % + ('s' if f['service_ssl_flag'] else '', + f['service_host'], + f['service_port'])) + for f in keep_disks) + self.service_roots = sorted(set(roots)) + logging.debug(str(self.service_roots)) + finally: + self.lock.release() + + # 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: - if len(pseq) < len(hash) / 4: # first time around + # 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) + + print seed[0:8], int(seed[0:8], 16), len(pool), probe + + # 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:] logging.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 get(self, locator): + #logging.debug("Keep.get %s" % (locator)) + if re.search(r',', locator): return ''.join(self.get(x) for x in locator.split(',')) if 'KEEP_LOCAL_STORE' in os.environ: return KeepClient.local_store_get(locator) expect_hash = re.sub(r'\+.*', '', locator) - for service_root in self.shuffled_service_roots(expect_hash): - url = service_root + expect_hash - api_token = config.get('ARVADOS_API_TOKEN') - headers = {'Authorization': "OAuth2 %s" % api_token, - 'Accept': 'application/octet-stream'} - blob = self.get_url(url, headers, expect_hash) - if blob: - return blob - for location_hint in re.finditer(r'\+K@([a-z0-9]+)', locator): - instance = location_hint.group(1) - url = 'http://keep.' + instance + '.arvadosapi.com/' + expect_hash - blob = self.get_url(url, {}, expect_hash) - if blob: - return blob + + slot, first = self.reserve_cache(expect_hash) + #logging.debug("%s %s %s" % (slot, first, expect_hash)) + + if not first: + v = slot.get() + return v + + try: + for service_root in self.shuffled_service_roots(expect_hash): + url = service_root + expect_hash + api_token = config.get('ARVADOS_API_TOKEN') + headers = {'Authorization': "OAuth2 %s" % api_token, + 'Accept': 'application/octet-stream'} + blob = self.get_url(url, headers, expect_hash) + if blob: + slot.set(blob) + self.cap_cache() + return blob + + for location_hint in re.finditer(r'\+K@([a-z0-9]+)', locator): + instance = location_hint.group(1) + url = 'http://keep.' + instance + '.arvadosapi.com/' + expect_hash + blob = self.get_url(url, {}, expect_hash) + if blob: + slot.set(blob) + self.cap_cache() + return blob + except: + slot.set(None) + self.cap_cache() + raise + + slot.set(None) + self.cap_cache() raise arvados.errors.NotFoundError("Block not found: %s" % expect_hash) def get_url(self, url, headers, expect_hash): h = httplib2.Http() try: - resp, content = h.request(url.encode('utf-8'), 'GET', - headers=headers) + logging.info("Request: GET %s" % (url)) + with timer.Timer() as t: + resp, content = h.request(url.encode('utf-8'), 'GET', + headers=headers) + logging.info("Received %s bytes in %s msec (%s MiB/sec)" % (len(content), + t.msecs, + (len(content)/(1024*1024))/t.secs)) if re.match(r'^2\d\d$', resp['status']): m = hashlib.new('md5') m.update(content)