Merge branch '18051-webdav-cache'

[arvados.git] / sdk / python / arvados / keep.py

diff --git a/sdk/python/arvados/keep.py b/sdk/python/arvados/keep.py
index e6e93f080659abf9a51cec9d4425cafe8bdc976b..bc07851835e2471ee9f1055b689fe6a789ea4d62 100644 (file)
--- a/sdk/python/arvados/keep.py
+++ b/sdk/python/arvados/keep.py
@@ -4,6 +4,7 @@
 
 from __future__ import absolute_import
 from __future__ import division
 
 from __future__ import absolute_import
 from __future__ import division

+import copy

 from future import standard_library
 from future.utils import native_str
 standard_library.install_aliases()
 from future import standard_library
 from future.utils import native_str
 standard_library.install_aliases()


@@ -291,7 +292,9 @@ class KeepClient(object):
 
         def __init__(self, root, user_agent_pool=queue.LifoQueue(),
                      upload_counter=None,
 
         def __init__(self, root, user_agent_pool=queue.LifoQueue(),
                      upload_counter=None,

-                     download_counter=None, **headers):
+                     download_counter=None,
+                     headers={},
+                     insecure=False):

             self.root = root
             self._user_agent_pool = user_agent_pool
             self._result = {'error': None}
             self.root = root
             self._user_agent_pool = user_agent_pool
             self._result = {'error': None}


@@ -303,6 +306,7 @@ class KeepClient(object):
             self.put_headers = headers
             self.upload_counter = upload_counter
             self.download_counter = download_counter
             self.put_headers = headers
             self.upload_counter = upload_counter
             self.download_counter = download_counter

+            self.insecure = insecure

 
         def usable(self):
             """Is it worth attempting a request?"""
 
         def usable(self):
             """Is it worth attempting a request?"""


@@ -370,9 +374,13 @@ class KeepClient(object):
                         '{}: {}'.format(k,v) for k,v in self.get_headers.items()])
                     curl.setopt(pycurl.WRITEFUNCTION, response_body.write)
                     curl.setopt(pycurl.HEADERFUNCTION, self._headerfunction)
                         '{}: {}'.format(k,v) for k,v in self.get_headers.items()])
                     curl.setopt(pycurl.WRITEFUNCTION, response_body.write)
                     curl.setopt(pycurl.HEADERFUNCTION, self._headerfunction)

+                    if self.insecure:
+                        curl.setopt(pycurl.SSL_VERIFYPEER, 0)
+                    else:
+                        curl.setopt(pycurl.CAINFO, arvados.util.ca_certs_path())

                     if method == "HEAD":
                         curl.setopt(pycurl.NOBODY, True)
                     if method == "HEAD":
                         curl.setopt(pycurl.NOBODY, True)

-                    self._setcurltimeouts(curl, timeout)
+                    self._setcurltimeouts(curl, timeout, method=="HEAD")

 
                     try:
                         curl.perform()
 
                     try:
                         curl.perform()


@@ -416,6 +424,10 @@ class KeepClient(object):
                 _logger.info("HEAD %s: %s bytes",
                          self._result['status_code'],
                          self._result.get('content-length'))
                 _logger.info("HEAD %s: %s bytes",
                          self._result['status_code'],
                          self._result.get('content-length'))

+                if self._result['headers'].get('x-keep-locator'):
+                    # This is a response to a remote block copy request, return
+                    # the local copy block locator.
+                    return self._result['headers'].get('x-keep-locator')

                 return True
 
             _logger.info("GET %s: %s bytes in %s msec (%.3f MiB/sec)",
                 return True
 
             _logger.info("GET %s: %s bytes in %s msec (%.3f MiB/sec)",


@@ -435,7 +447,9 @@ class KeepClient(object):
                 return None
             return self._result['body']
 
                 return None
             return self._result['body']
 

-        def put(self, hash_s, body, timeout=None):
+        def put(self, hash_s, body, timeout=None, headers={}):
+            put_headers = copy.copy(self.put_headers)
+            put_headers.update(headers)

             url = self.root + hash_s
             _logger.debug("Request: PUT %s", url)
             curl = self._get_user_agent()
             url = self.root + hash_s
             _logger.debug("Request: PUT %s", url)
             curl = self._get_user_agent()


@@ -459,9 +473,13 @@ class KeepClient(object):
                     curl.setopt(pycurl.INFILESIZE, len(body))
                     curl.setopt(pycurl.READFUNCTION, body_reader.read)
                     curl.setopt(pycurl.HTTPHEADER, [
                     curl.setopt(pycurl.INFILESIZE, len(body))
                     curl.setopt(pycurl.READFUNCTION, body_reader.read)
                     curl.setopt(pycurl.HTTPHEADER, [

-                        '{}: {}'.format(k,v) for k,v in self.put_headers.items()])
+                        '{}: {}'.format(k,v) for k,v in put_headers.items()])

                     curl.setopt(pycurl.WRITEFUNCTION, response_body.write)
                     curl.setopt(pycurl.HEADERFUNCTION, self._headerfunction)
                     curl.setopt(pycurl.WRITEFUNCTION, response_body.write)
                     curl.setopt(pycurl.HEADERFUNCTION, self._headerfunction)

+                    if self.insecure:
+                        curl.setopt(pycurl.SSL_VERIFYPEER, 0)
+                    else:
+                        curl.setopt(pycurl.CAINFO, arvados.util.ca_certs_path())

                     self._setcurltimeouts(curl, timeout)
                     try:
                         curl.perform()
                     self._setcurltimeouts(curl, timeout)
                     try:
                         curl.perform()


@@ -505,7 +523,7 @@ class KeepClient(object):
                 self.upload_counter.add(len(body))
             return True
 
                 self.upload_counter.add(len(body))
             return True
 

-        def _setcurltimeouts(self, curl, timeouts):
+        def _setcurltimeouts(self, curl, timeouts, ignore_bandwidth=False):

             if not timeouts:
                 return
             elif isinstance(timeouts, tuple):
             if not timeouts:
                 return
             elif isinstance(timeouts, tuple):


@@ -518,8 +536,9 @@ class KeepClient(object):
                 conn_t, xfer_t = (timeouts, timeouts)
                 bandwidth_bps = KeepClient.DEFAULT_TIMEOUT[2]
             curl.setopt(pycurl.CONNECTTIMEOUT_MS, int(conn_t*1000))
                 conn_t, xfer_t = (timeouts, timeouts)
                 bandwidth_bps = KeepClient.DEFAULT_TIMEOUT[2]
             curl.setopt(pycurl.CONNECTTIMEOUT_MS, int(conn_t*1000))

-            curl.setopt(pycurl.LOW_SPEED_TIME, int(math.ceil(xfer_t)))
-            curl.setopt(pycurl.LOW_SPEED_LIMIT, int(math.ceil(bandwidth_bps)))
+            if not ignore_bandwidth:
+                curl.setopt(pycurl.LOW_SPEED_TIME, int(math.ceil(xfer_t)))
+                curl.setopt(pycurl.LOW_SPEED_LIMIT, int(math.ceil(bandwidth_bps)))

 
         def _headerfunction(self, header_line):
             if isinstance(header_line, bytes):
 
         def _headerfunction(self, header_line):
             if isinstance(header_line, bytes):


@@ -540,38 +559,68 @@ class KeepClient(object):
             self._lastheadername = name
             self._headers[name] = value
             # Returning None implies all bytes were written
             self._lastheadername = name
             self._headers[name] = value
             # Returning None implies all bytes were written

-    
+

 
     class KeepWriterQueue(queue.Queue):
 
     class KeepWriterQueue(queue.Queue):

-        def __init__(self, copies):
+        def __init__(self, copies, classes=[]):

             queue.Queue.__init__(self) # Old-style superclass
             self.wanted_copies = copies
             queue.Queue.__init__(self) # Old-style superclass
             self.wanted_copies = copies

+            self.wanted_storage_classes = classes

             self.successful_copies = 0
             self.successful_copies = 0

+            self.confirmed_storage_classes = {}

             self.response = None
             self.response = None

-            self.successful_copies_lock = threading.Lock()
-            self.pending_tries = copies
+            self.storage_classes_tracking = True
+            self.queue_data_lock = threading.RLock()
+            self.pending_tries = max(copies, len(classes))

             self.pending_tries_notification = threading.Condition()
             self.pending_tries_notification = threading.Condition()

-        
-        def write_success(self, response, replicas_nr):
-            with self.successful_copies_lock:
+
+        def write_success(self, response, replicas_nr, classes_confirmed):
+            with self.queue_data_lock:

                 self.successful_copies += replicas_nr
                 self.successful_copies += replicas_nr

+                if classes_confirmed is None:
+                    self.storage_classes_tracking = False
+                elif self.storage_classes_tracking:
+                    for st_class, st_copies in classes_confirmed.items():
+                        try:
+                            self.confirmed_storage_classes[st_class] += st_copies
+                        except KeyError:
+                            self.confirmed_storage_classes[st_class] = st_copies
+                    self.pending_tries = max(self.wanted_copies - self.successful_copies, len(self.pending_classes()))

                 self.response = response
             with self.pending_tries_notification:
                 self.pending_tries_notification.notify_all()
                 self.response = response
             with self.pending_tries_notification:
                 self.pending_tries_notification.notify_all()

-        
+

         def write_fail(self, ks):
             with self.pending_tries_notification:
                 self.pending_tries += 1
                 self.pending_tries_notification.notify()
         def write_fail(self, ks):
             with self.pending_tries_notification:
                 self.pending_tries += 1
                 self.pending_tries_notification.notify()

-        
+

         def pending_copies(self):
         def pending_copies(self):

-            with self.successful_copies_lock:
+            with self.queue_data_lock:

                 return self.wanted_copies - self.successful_copies
 
                 return self.wanted_copies - self.successful_copies
 

+        def satisfied_classes(self):
+            with self.queue_data_lock:
+                if not self.storage_classes_tracking:
+                    # Notifies disabled storage classes expectation to
+                    # the outer loop.
+                    return None
+            return list(set(self.wanted_storage_classes) - set(self.pending_classes()))
+
+        def pending_classes(self):
+            with self.queue_data_lock:
+                if (not self.storage_classes_tracking) or (self.wanted_storage_classes is None):
+                    return []
+                unsatisfied_classes = copy.copy(self.wanted_storage_classes)
+                for st_class, st_copies in self.confirmed_storage_classes.items():
+                    if st_class in unsatisfied_classes and st_copies >= self.wanted_copies:
+                        unsatisfied_classes.remove(st_class)
+                return unsatisfied_classes
+

         def get_next_task(self):
             with self.pending_tries_notification:
                 while True:
         def get_next_task(self):
             with self.pending_tries_notification:
                 while True:

-                    if self.pending_copies() < 1:
+                    if self.pending_copies() < 1 and len(self.pending_classes()) == 0:

                         # This notify_all() is unnecessary --
                         # write_success() already called notify_all()
                         # when pending<1 became true, so it's not
                         # This notify_all() is unnecessary --
                         # write_success() already called notify_all()
                         # when pending<1 became true, so it's not


@@ -598,41 +647,40 @@ class KeepClient(object):
 
 
     class KeepWriterThreadPool(object):
 
 
     class KeepWriterThreadPool(object):

-        def __init__(self, data, data_hash, copies, max_service_replicas, timeout=None):
+        def __init__(self, data, data_hash, copies, max_service_replicas, timeout=None, classes=[]):

             self.total_task_nr = 0
             self.total_task_nr = 0

-            self.wanted_copies = copies

             if (not max_service_replicas) or (max_service_replicas >= copies):
                 num_threads = 1
             else:
                 num_threads = int(math.ceil(1.0*copies/max_service_replicas))
             _logger.debug("Pool max threads is %d", num_threads)
             self.workers = []
             if (not max_service_replicas) or (max_service_replicas >= copies):
                 num_threads = 1
             else:
                 num_threads = int(math.ceil(1.0*copies/max_service_replicas))
             _logger.debug("Pool max threads is %d", num_threads)
             self.workers = []

-            self.queue = KeepClient.KeepWriterQueue(copies)
+            self.queue = KeepClient.KeepWriterQueue(copies, classes)

             # Create workers
             for _ in range(num_threads):
                 w = KeepClient.KeepWriterThread(self.queue, data, data_hash, timeout)
                 self.workers.append(w)
             # Create workers
             for _ in range(num_threads):
                 w = KeepClient.KeepWriterThread(self.queue, data, data_hash, timeout)
                 self.workers.append(w)

-        
+

         def add_task(self, ks, service_root):
             self.queue.put((ks, service_root))
             self.total_task_nr += 1
         def add_task(self, ks, service_root):
             self.queue.put((ks, service_root))
             self.total_task_nr += 1

-        
+

         def done(self):
         def done(self):

-            return self.queue.successful_copies
-        
+            return self.queue.successful_copies, self.queue.satisfied_classes()
+

         def join(self):
             # Start workers
             for worker in self.workers:
                 worker.start()
             # Wait for finished work
             self.queue.join()
         def join(self):
             # Start workers
             for worker in self.workers:
                 worker.start()
             # Wait for finished work
             self.queue.join()

-        
+

         def response(self):
             return self.queue.response
         def response(self):
             return self.queue.response

-    
-    
+
+

     class KeepWriterThread(threading.Thread):
     class KeepWriterThread(threading.Thread):

-        TaskFailed = RuntimeError()
+        class TaskFailed(RuntimeError): pass

 
         def __init__(self, queue, data, data_hash, timeout=None):
             super(KeepClient.KeepWriterThread, self).__init__()
 
         def __init__(self, queue, data, data_hash, timeout=None):
             super(KeepClient.KeepWriterThread, self).__init__()


@@ -649,29 +697,35 @@ class KeepClient(object):
                 except queue.Empty:
                     return
                 try:
                 except queue.Empty:
                     return
                 try:

-                    locator, copies = self.do_task(service, service_root)
+                    locator, copies, classes = self.do_task(service, service_root)

                 except Exception as e:
                 except Exception as e:

-                    if e is not self.TaskFailed:
+                    if not isinstance(e, self.TaskFailed):

                         _logger.exception("Exception in KeepWriterThread")
                     self.queue.write_fail(service)
                 else:
                         _logger.exception("Exception in KeepWriterThread")
                     self.queue.write_fail(service)
                 else:

-                    self.queue.write_success(locator, copies)
+                    self.queue.write_success(locator, copies, classes)

                 finally:
                     self.queue.task_done()
 
         def do_task(self, service, service_root):
                 finally:
                     self.queue.task_done()
 
         def do_task(self, service, service_root):

+            classes = self.queue.pending_classes()
+            headers = {}
+            if len(classes) > 0:
+                classes.sort()
+                headers['X-Keep-Storage-Classes'] = ', '.join(classes)

             success = bool(service.put(self.data_hash,
                                         self.data,
             success = bool(service.put(self.data_hash,
                                         self.data,

-                                        timeout=self.timeout))
+                                        timeout=self.timeout,
+                                        headers=headers))

             result = service.last_result()
 
             if not success:
             result = service.last_result()
 
             if not success:

-                if result.get('status_code', None):
+                if result.get('status_code'):

                     _logger.debug("Request fail: PUT %s => %s %s",
                                   self.data_hash,
                     _logger.debug("Request fail: PUT %s => %s %s",
                                   self.data_hash,

-                                  result['status_code'],
-                                  result['body'])
-                raise self.TaskFailed
+                                  result.get('status_code'),
+                                  result.get('body'))
+                raise self.TaskFailed()

 
             _logger.debug("KeepWriterThread %s succeeded %s+%i %s",
                           str(threading.current_thread()),
 
             _logger.debug("KeepWriterThread %s succeeded %s+%i %s",
                           str(threading.current_thread()),


@@ -683,7 +737,18 @@ class KeepClient(object):
             except (KeyError, ValueError):
                 replicas_stored = 1
 
             except (KeyError, ValueError):
                 replicas_stored = 1
 

-            return result['body'].strip(), replicas_stored
+            classes_confirmed = {}
+            try:
+                scch = result['headers']['x-keep-storage-classes-confirmed']
+                for confirmation in scch.replace(' ', '').split(','):
+                    if '=' in confirmation:
+                        stored_class, stored_copies = confirmation.split('=')[:2]
+                        classes_confirmed[stored_class] = int(stored_copies)
+            except (KeyError, ValueError):
+                # Storage classes confirmed header missing or corrupt
+                classes_confirmed = None
+
+            return result['body'].strip(), replicas_stored, classes_confirmed

 
 
     def __init__(self, api_client=None, proxy=None,
 
 
     def __init__(self, api_client=None, proxy=None,


@@ -761,6 +826,11 @@ class KeepClient(object):
         if local_store is None:
             local_store = os.environ.get('KEEP_LOCAL_STORE')
 
         if local_store is None:
             local_store = os.environ.get('KEEP_LOCAL_STORE')
 

+        if api_client is None:
+            self.insecure = config.flag_is_true('ARVADOS_API_HOST_INSECURE')
+        else:
+            self.insecure = api_client.insecure
+

         self.block_cache = block_cache if block_cache else KeepBlockCache()
         self.timeout = timeout
         self.proxy_timeout = proxy_timeout
         self.block_cache = block_cache if block_cache else KeepBlockCache()
         self.timeout = timeout
         self.proxy_timeout = proxy_timeout


@@ -771,9 +841,12 @@ class KeepClient(object):
         self.get_counter = Counter()
         self.hits_counter = Counter()
         self.misses_counter = Counter()
         self.get_counter = Counter()
         self.hits_counter = Counter()
         self.misses_counter = Counter()

+        self._storage_classes_unsupported_warning = False
+        self._default_classes = []

 
         if local_store:
             self.local_store = local_store
 
         if local_store:
             self.local_store = local_store

+            self.head = self.local_store_head

             self.get = self.local_store_get
             self.put = self.local_store_put
         else:
             self.get = self.local_store_get
             self.put = self.local_store_put
         else:


@@ -810,6 +883,12 @@ class KeepClient(object):
                 self._writable_services = None
                 self.using_proxy = None
                 self._static_services_list = False
                 self._writable_services = None
                 self.using_proxy = None
                 self._static_services_list = False

+                try:
+                    self._default_classes = [
+                        k for k, v in self.api_client.config()['StorageClasses'].items() if v['Default']]
+                except KeyError:
+                    # We're talking to an old cluster
+                    pass

 
     def current_timeout(self, attempt_number):
         """Return the appropriate timeout to use for this client.
 
     def current_timeout(self, attempt_number):
         """Return the appropriate timeout to use for this client.


@@ -920,7 +999,7 @@ class KeepClient(object):
         _logger.debug("{}: {}".format(locator, sorted_roots))
         return sorted_roots
 
         _logger.debug("{}: {}".format(locator, sorted_roots))
         return sorted_roots
 

-    def map_new_services(self, roots_map, locator, force_rebuild, need_writable, **headers):
+    def map_new_services(self, roots_map, locator, force_rebuild, need_writable, 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
         # 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


@@ -933,7 +1012,8 @@ class KeepClient(object):
                     root, self._user_agent_pool,
                     upload_counter=self.upload_counter,
                     download_counter=self.download_counter,
                     root, self._user_agent_pool,
                     upload_counter=self.upload_counter,
                     download_counter=self.download_counter,

-                    **headers)
+                    headers=headers,
+                    insecure=self.insecure)

         return local_roots
 
     @staticmethod
         return local_roots
 
     @staticmethod


@@ -962,15 +1042,20 @@ class KeepClient(object):
         else:
             return None
 
         else:
             return None
 

+    def refresh_signature(self, loc):
+        """Ask Keep to get the remote block and return its local signature"""
+        now = datetime.datetime.utcnow().isoformat("T") + 'Z'
+        return self.head(loc, headers={'X-Keep-Signature': 'local, {}'.format(now)})
+

     @retry.retry_method
     @retry.retry_method

-    def head(self, loc_s, num_retries=None):
-        return self._get_or_head(loc_s, method="HEAD", num_retries=num_retries)
+    def head(self, loc_s, **kwargs):
+        return self._get_or_head(loc_s, method="HEAD", **kwargs)

 
     @retry.retry_method
 
     @retry.retry_method

-    def get(self, loc_s, num_retries=None):
-        return self._get_or_head(loc_s, method="GET", num_retries=num_retries)
+    def get(self, loc_s, **kwargs):
+        return self._get_or_head(loc_s, method="GET", **kwargs)

 
 

-    def _get_or_head(self, loc_s, method="GET", num_retries=None):
+    def _get_or_head(self, loc_s, method="GET", num_retries=None, request_id=None, headers=None):

         """Get data from Keep.
 
         This method fetches one or more blocks of data from Keep.  It
         """Get data from Keep.
 
         This method fetches one or more blocks of data from Keep.  It


@@ -995,76 +1080,88 @@ class KeepClient(object):
 
         self.get_counter.add(1)
 
 
         self.get_counter.add(1)
 

-        locator = KeepLocator(loc_s)
-        if method == "GET":
-            slot, first = self.block_cache.reserve_cache(locator.md5sum)
-            if not first:
-                self.hits_counter.add(1)
-                v = slot.get()
-                return v
-
-        self.misses_counter.add(1)
-
-        # 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._user_agent_pool,
-                                   upload_counter=self.upload_counter,
-                                   download_counter=self.download_counter)
-            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.
-        sorted_roots = []
-        roots_map = {}
+        slot = None

         blob = None
         blob = None

-        loop = retry.RetryLoop(num_retries, self._check_loop_result,
-                               backoff_start=2)
-        for tries_left in loop:
-            try:
-                sorted_roots = self.map_new_services(
-                    roots_map, locator,
-                    force_rebuild=(tries_left < num_retries),
-                    need_writable=False)
-            except Exception as error:
-                loop.save_result(error)
-                continue
+        try:
+            locator = KeepLocator(loc_s)
+            if method == "GET":
+                slot, first = self.block_cache.reserve_cache(locator.md5sum)
+                if not first:
+                    self.hits_counter.add(1)
+                    blob = slot.get()
+                    if blob is None:
+                        raise arvados.errors.KeepReadError(
+                            "failed to read {}".format(loc_s))
+                    return blob
+
+            self.misses_counter.add(1)
+
+            if headers is None:
+                headers = {}
+            headers['X-Request-Id'] = (request_id or
+                                        (hasattr(self, 'api_client') and self.api_client.request_id) or
+                                        arvados.util.new_request_id())
+
+            # 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._user_agent_pool,
+                                       upload_counter=self.upload_counter,
+                                       download_counter=self.download_counter,
+                                       headers=headers,
+                                       insecure=self.insecure)
+                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.
+            sorted_roots = []
+            roots_map = {}
+            loop = retry.RetryLoop(num_retries, self._check_loop_result,
+                                   backoff_start=2)
+            for tries_left in loop:
+                try:
+                    sorted_roots = self.map_new_services(
+                        roots_map, locator,
+                        force_rebuild=(tries_left < num_retries),
+                        need_writable=False,
+                        headers=headers)
+                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 sorted_roots
-                               if roots_map[root].usable()]
-            for keep_service in services_to_try:
-                blob = keep_service.get(locator, method=method, timeout=self.current_timeout(num_retries-tries_left))
-                if blob is not None:
-                    break
-            loop.save_result((blob, len(services_to_try)))
-
-        # Always cache the result, then return it if we succeeded.
-        if method == "GET":
-            slot.set(blob)
-            self.block_cache.cap_cache()
-        if loop.success():
-            if method == "HEAD":
-                return True
-            else:
+                # Query KeepService objects that haven't returned
+                # permanent failure, in our specified shuffle order.
+                services_to_try = [roots_map[root]
+                                   for root in sorted_roots
+                                   if roots_map[root].usable()]
+                for keep_service in services_to_try:
+                    blob = keep_service.get(locator, method=method, timeout=self.current_timeout(num_retries-tries_left))
+                    if blob is not None:
+                        break
+                loop.save_result((blob, len(services_to_try)))
+
+            # Always cache the result, then return it if we succeeded.
+            if loop.success():

                 return blob
                 return blob

+        finally:
+            if slot is not None:
+                slot.set(blob)
+                self.block_cache.cap_cache()

 
         # Q: Including 403 is necessary for the Keep tests to continue
         # passing, but maybe they should expect KeepReadError instead?
 
         # Q: Including 403 is necessary for the Keep tests to continue
         # passing, but maybe they should expect KeepReadError instead?


@@ -1081,10 +1178,10 @@ class KeepClient(object):
                 "{} not found".format(loc_s), service_errors)
         else:
             raise arvados.errors.KeepReadError(
                 "{} not found".format(loc_s), service_errors)
         else:
             raise arvados.errors.KeepReadError(

-                "failed to read {}".format(loc_s), service_errors, label="service")
+                "failed to read {} after {}".format(loc_s, loop.attempts_str()), service_errors, label="service")

 
     @retry.retry_method
 
     @retry.retry_method

-    def put(self, data, copies=2, num_retries=None):
+    def put(self, data, copies=2, num_retries=None, request_id=None, classes=None):

         """Save data in Keep.
 
         This method will get a list of Keep services from the API server, and
         """Save data in Keep.
 
         This method will get a list of Keep services from the API server, and


@@ -1101,8 +1198,12 @@ class KeepClient(object):
           *each* Keep server if it returns temporary failures, with
           exponential backoff.  The default value is set when the
           KeepClient is initialized.
           *each* Keep server if it returns temporary failures, with
           exponential backoff.  The default value is set when the
           KeepClient is initialized.

+        * classes: An optional list of storage class names where copies should
+          be written.

         """
 
         """
 

+        classes = classes or self._default_classes
+

         if not isinstance(data, bytes):
             data = data.encode()
 
         if not isinstance(data, bytes):
             data = data.encode()
 


@@ -1114,35 +1215,61 @@ class KeepClient(object):
             return loc_s
         locator = KeepLocator(loc_s)
 
             return loc_s
         locator = KeepLocator(loc_s)
 

-        headers = {}
-        # Tell the proxy how many copies we want it to store
-        headers['X-Keep-Desired-Replicas'] = str(copies)
+        headers = {
+            'X-Request-Id': (request_id or
+                             (hasattr(self, 'api_client') and self.api_client.request_id) or
+                             arvados.util.new_request_id()),
+            'X-Keep-Desired-Replicas': str(copies),
+        }

         roots_map = {}
         loop = retry.RetryLoop(num_retries, self._check_loop_result,
                                backoff_start=2)
         roots_map = {}
         loop = retry.RetryLoop(num_retries, self._check_loop_result,
                                backoff_start=2)

-        done = 0
+        done_copies = 0
+        done_classes = []

         for tries_left in loop:
             try:
                 sorted_roots = self.map_new_services(
                     roots_map, locator,
         for tries_left in loop:
             try:
                 sorted_roots = self.map_new_services(
                     roots_map, locator,

-                    force_rebuild=(tries_left < num_retries), need_writable=True, **headers)
+                    force_rebuild=(tries_left < num_retries),
+                    need_writable=True,
+                    headers=headers)

             except Exception as error:
                 loop.save_result(error)
                 continue
 
             except Exception as error:
                 loop.save_result(error)
                 continue
 

-            writer_pool = KeepClient.KeepWriterThreadPool(data=data, 
+            pending_classes = []
+            if done_classes is not None:
+                pending_classes = list(set(classes) - set(done_classes))
+            writer_pool = KeepClient.KeepWriterThreadPool(data=data,

                                                         data_hash=data_hash,
                                                         data_hash=data_hash,

-                                                        copies=copies - done,
+                                                        copies=copies - done_copies,

                                                         max_service_replicas=self.max_replicas_per_service,
                                                         max_service_replicas=self.max_replicas_per_service,

-                                                        timeout=self.current_timeout(num_retries - tries_left))
+                                                        timeout=self.current_timeout(num_retries - tries_left),
+                                                        classes=pending_classes)

             for service_root, ks in [(root, roots_map[root])
                                      for root in sorted_roots]:
                 if ks.finished():
                     continue
                 writer_pool.add_task(ks, service_root)
             writer_pool.join()
             for service_root, ks in [(root, roots_map[root])
                                      for root in sorted_roots]:
                 if ks.finished():
                     continue
                 writer_pool.add_task(ks, service_root)
             writer_pool.join()

-            done += writer_pool.done()
-            loop.save_result((done >= copies, writer_pool.total_task_nr))
+            pool_copies, pool_classes = writer_pool.done()
+            done_copies += pool_copies
+            if (done_classes is not None) and (pool_classes is not None):
+                done_classes += pool_classes
+                loop.save_result(
+                    (done_copies >= copies and set(done_classes) == set(classes),
+                    writer_pool.total_task_nr))
+            else:
+                # Old keepstore contacted without storage classes support:
+                # success is determined only by successful copies.
+                #
+                # Disable storage classes tracking from this point forward.
+                if not self._storage_classes_unsupported_warning:
+                    self._storage_classes_unsupported_warning = True
+                    _logger.warning("X-Keep-Storage-Classes header not supported by the cluster")
+                done_classes = None
+                loop.save_result(
+                    (done_copies >= copies, writer_pool.total_task_nr))

 
         if loop.success():
             return writer_pool.response()
 
         if loop.success():
             return writer_pool.response()


@@ -1155,10 +1282,10 @@ class KeepClient(object):
                               for key in sorted_roots
                               if roots_map[key].last_result()['error'])
             raise arvados.errors.KeepWriteError(
                               for key in sorted_roots
                               if roots_map[key].last_result()['error'])
             raise arvados.errors.KeepWriteError(

-                "failed to write {} (wanted {} copies but wrote {})".format(
-                    data_hash, copies, writer_pool.done()), service_errors, label="service")
+                "failed to write {} after {} (wanted {} copies but wrote {})".format(
+                    data_hash, loop.attempts_str(), (copies, classes), writer_pool.done()), service_errors, label="service")

 
 

-    def local_store_put(self, data, copies=1, num_retries=None):
+    def local_store_put(self, data, copies=1, num_retries=None, classes=[]):

         """A stub for put().
 
         This method is used in place of the real put() method when
         """A stub for put().
 
         This method is used in place of the real put() method when


@@ -1190,5 +1317,17 @@ class KeepClient(object):
         with open(os.path.join(self.local_store, locator.md5sum), 'rb') as f:
             return f.read()
 
         with open(os.path.join(self.local_store, locator.md5sum), 'rb') as f:
             return f.read()
 

+    def local_store_head(self, loc_s, num_retries=None):
+        """Companion to local_store_put()."""
+        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 True
+        if os.path.exists(os.path.join(self.local_store, locator.md5sum)):
+            return True
+

     def is_cached(self, locator):
         return self.block_cache.reserve_cache(expect_hash)
     def is_cached(self, locator):
         return self.block_cache.reserve_cache(expect_hash)