Closes #7235. Instead of setting KeepService's pycurl.TIMEOUT_MS, set pycurl.LOW_SPEE...
[arvados.git] / sdk / python / arvados / keep.py
index 48d115c7a43bb050b81860a51dfa8ed672d24407..e01fec412bc4e9cb83d47930b850b1a101e68438 100644 (file)
@@ -1,28 +1,16 @@
-import bz2
+import cStringIO
 import datetime
-import fcntl
-import functools
-import gflags
 import hashlib
-import json
 import logging
+import math
 import os
-import pprint
 import pycurl
 import Queue
 import re
 import socket
 import ssl
-import string
-import cStringIO
-import subprocess
-import sys
 import threading
-import time
 import timer
-import types
-import UserDict
-import zlib
 
 import arvados
 import arvados.config as config
@@ -76,7 +64,7 @@ class KeepLocator(object):
             return getattr(self, data_name)
         def setter(self, hex_str):
             if not arvados.util.is_hex(hex_str, length):
-                raise ValueError("{} must be a {}-digit hex string: {}".
+                raise ValueError("{} is not a {}-digit hex string: {}".
                                  format(name, length, hex_str))
             setattr(self, data_name, hex_str)
         return property(getter, setter)
@@ -225,65 +213,82 @@ class KeepBlockCache(object):
 class KeepClient(object):
 
     # Default Keep server connection timeout:  2 seconds
-    # Default Keep server read timeout:      300 seconds
+    # Default Keep server read timeout:       64 seconds
+    # Default Keep server bandwidth minimum:  32768 bytes per second
     # Default Keep proxy connection timeout:  20 seconds
-    # Default Keep proxy read timeout:       300 seconds
-    DEFAULT_TIMEOUT = (2, 300)
-    DEFAULT_PROXY_TIMEOUT = (20, 300)
+    # Default Keep proxy read timeout:        64 seconds
+    # Default Keep proxy bandwidth minimum:   32768 bytes per second
+    DEFAULT_TIMEOUT = (2, 64, 32768)
+    DEFAULT_PROXY_TIMEOUT = (20, 64, 32768)
 
     class ThreadLimiter(object):
-        """
-        Limit the number of threads running at a given time to
-        {desired successes} minus {successes reported}. When successes
-        reported == desired, wake up the remaining threads and tell
-        them to quit.
+        """Limit the number of threads writing to Keep at once.
+
+        This ensures that only a number of writer threads that could
+        potentially achieve the desired replication level run at once.
+        Once the desired replication level is achieved, queued threads
+        are instructed not to run.
 
         Should be used in a "with" block.
         """
-        def __init__(self, todo):
-            self._todo = todo
+        def __init__(self, want_copies, max_service_replicas):
+            self._started = 0
+            self._want_copies = want_copies
             self._done = 0
             self._response = None
-            self._todo_lock = threading.Semaphore(todo)
+            self._start_lock = threading.Condition()
+            if (not max_service_replicas) or (max_service_replicas >= want_copies):
+                max_threads = 1
+            else:
+                max_threads = math.ceil(float(want_copies) / max_service_replicas)
+            _logger.debug("Limiter max threads is %d", max_threads)
+            self._todo_lock = threading.Semaphore(max_threads)
             self._done_lock = threading.Lock()
+            self._local = threading.local()
 
         def __enter__(self):
+            self._start_lock.acquire()
+            if getattr(self._local, 'sequence', None) is not None:
+                # If the calling thread has used set_sequence(N), then
+                # we wait here until N other threads have started.
+                while self._started < self._local.sequence:
+                    self._start_lock.wait()
             self._todo_lock.acquire()
+            self._started += 1
+            self._start_lock.notifyAll()
+            self._start_lock.release()
             return self
 
         def __exit__(self, type, value, traceback):
             self._todo_lock.release()
 
+        def set_sequence(self, sequence):
+            self._local.sequence = sequence
+
         def shall_i_proceed(self):
             """
-            Return true if the current thread should do stuff. Return
-            false if the current thread should just stop.
+            Return true if the current thread should write to Keep.
+            Return false otherwise.
             """
             with self._done_lock:
-                return (self._done < self._todo)
+                return (self._done < self._want_copies)
 
         def save_response(self, response_body, replicas_stored):
             """
             Records a response body (a locator, possibly signed) returned by
-            the Keep server.  It is not necessary to save more than
-            one response, since we presume that any locator returned
-            in response to a successful request is valid.
+            the Keep server, and the number of replicas it stored.
             """
             with self._done_lock:
                 self._done += replicas_stored
                 self._response = response_body
 
         def response(self):
-            """
-            Returns the body from the response to a PUT request.
-            """
+            """Return the body from the response to a PUT request."""
             with self._done_lock:
                 return self._response
 
         def done(self):
-            """
-            Return how many successes were reported.
-            """
+            """Return the total number of replicas successfully stored."""
             with self._done_lock:
                 return self._done
 
@@ -475,11 +480,17 @@ class KeepClient(object):
             if not timeouts:
                 return
             elif isinstance(timeouts, tuple):
-                conn_t, xfer_t = timeouts
+                if len(timeouts) == 2:
+                    conn_t, xfer_t = timeouts
+                    bandwidth_bps = KeepClient.DEFAULT_TIMEOUT[2]
+                else:
+                    conn_t, xfer_t, bandwidth_bps = timeouts
             else:
                 conn_t, xfer_t = (timeouts, timeouts)
+                bandwidth_bps = KeepClient.DEFAULT_TIMEOUT[2]
             curl.setopt(pycurl.CONNECTTIMEOUT_MS, int(conn_t*1000))
-            curl.setopt(pycurl.TIMEOUT_MS, int(xfer_t*1000))
+            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):
             header_line = header_line.decode('iso-8859-1')
@@ -517,7 +528,11 @@ class KeepClient(object):
             return self._success
 
         def run(self):
-            with self.args['thread_limiter'] as limiter:
+            limiter = self.args['thread_limiter']
+            sequence = self.args['thread_sequence']
+            if sequence is not None:
+                limiter.set_sequence(sequence)
+            with limiter:
                 if not limiter.shall_i_proceed():
                     # My turn arrived, but the job has been done without
                     # me.
@@ -579,20 +594,22 @@ class KeepClient(object):
 
         :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).
+          non-proxy servers.  A tuple of three floats is interpreted as
+          (connection_timeout, read_timeout, minimum_bandwidth). A connection
+          will be aborted if the average traffic rate falls below
+          minimum_bandwidth bytes per second over an interval of read_timeout
+          seconds. 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, 64, 32768).
 
         :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). The behavior described
-          above for adjusting connection timeouts on retry also applies.
-          Default: (20, 300).
+          Keep proxies. A tuple of three floats is interpreted as
+          (connection_timeout, read_timeout, minimum_bandwidth). The behavior
+          described above for adjusting connection timeouts on retry also
+          applies.
+          Default: (20, 64, 32768).
 
         :api_token:
           If you're not using an API client, but only talking
@@ -639,6 +656,7 @@ class KeepClient(object):
             self.put = self.local_store_put
         else:
             self.num_retries = num_retries
+            self.max_replicas_per_service = None
             if proxy:
                 if not proxy.endswith('/'):
                     proxy += '/'
@@ -646,8 +664,10 @@ class KeepClient(object):
                 self._gateway_services = {}
                 self._keep_services = [{
                     'uuid': 'proxy',
+                    'service_type': 'proxy',
                     '_service_root': proxy,
                     }]
+                self._writable_services = self._keep_services
                 self.using_proxy = True
                 self._static_services_list = True
             else:
@@ -659,6 +679,7 @@ class KeepClient(object):
                 self.api_token = api_client.api_token
                 self._gateway_services = {}
                 self._keep_services = None
+                self._writable_services = None
                 self.using_proxy = None
                 self._static_services_list = False
 
@@ -675,7 +696,13 @@ class KeepClient(object):
         # TODO(twp): the timeout should be a property of a
         # KeepService, not a KeepClient. See #4488.
         t = self.proxy_timeout if self.using_proxy else self.timeout
-        return (t[0] * (1 << attempt_number), t[1])
+        if len(t) == 2:
+            return (t[0] * (1 << attempt_number), t[1])
+        else:
+            return (t[0] * (1 << attempt_number), t[1], t[2])
+    def _any_nondisk_services(self, service_list):
+        return any(ks.get('service_type', 'disk') != 'disk'
+                   for ks in service_list)
 
     def build_services_list(self, force_rebuild=False):
         if (self._static_services_list or
@@ -687,12 +714,16 @@ class KeepClient(object):
             except Exception:  # API server predates Keep services.
                 keep_services = self.api_client.keep_disks().list()
 
-            accessible = keep_services.execute().get('items')
-            if not accessible:
+            # 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['uuid']: ks for ks in
+                                      keep_services.execute()['items']}
+            if not self._gateway_services:
                 raise arvados.errors.NoKeepServersError()
 
             # Precompute the base URI for each service.
-            for r in accessible:
+            for r in self._gateway_services.itervalues():
                 host = r['service_host']
                 if not host.startswith('[') and host.find(':') >= 0:
                     # IPv6 URIs must be formatted like http://[::1]:80/...
@@ -702,19 +733,19 @@ class KeepClient(object):
                     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)
+                ks for ks in self._gateway_services.itervalues()
+                if not ks.get('service_type', '').startswith('gateway:')]
+            self._writable_services = [ks for ks in self._keep_services
+                                       if not ks.get('read_only')]
+
+            # For disk type services, max_replicas_per_service is 1
+            # It is unknown (unlimited) for other service types.
+            if self._any_nondisk_services(self._writable_services):
+                self.max_replicas_per_service = None
+            else:
+                self.max_replicas_per_service = 1
 
     def _service_weight(self, data_hash, service_uuid):
         """Compute the weight of a Keep service endpoint for a data
@@ -725,7 +756,7 @@ class KeepClient(object):
         """
         return hashlib.md5(data_hash + service_uuid[-15:]).hexdigest()
 
-    def weighted_service_roots(self, locator, force_rebuild=False):
+    def weighted_service_roots(self, locator, force_rebuild=False, need_writable=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+hints.
@@ -733,7 +764,6 @@ class KeepClient(object):
         self.build_services_list(force_rebuild)
 
         sorted_roots = []
-
         # Use the services indicated by the given +K@... remote
         # service hints, if any are present and can be resolved to a
         # URI.
@@ -750,21 +780,25 @@ class KeepClient(object):
         # Sort the available local services by weight (heaviest first)
         # for this locator, and return their service_roots (base URIs)
         # in that order.
+        use_services = self._keep_services
+        if need_writable:
+            use_services = self._writable_services
+        self.using_proxy = self._any_nondisk_services(use_services)
         sorted_roots.extend([
             svc['_service_root'] for svc in sorted(
-                self._keep_services,
+                use_services,
                 reverse=True,
                 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, locator, force_rebuild, **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
         # root strings.
         headers.setdefault('Authorization', "OAuth2 %s" % (self.api_token,))
-        local_roots = self.weighted_service_roots(locator, force_rebuild)
+        local_roots = self.weighted_service_roots(locator, force_rebuild, need_writable)
         for root in local_roots:
             if root not in roots_map:
                 roots_map[root] = self.KeepService(
@@ -858,7 +892,8 @@ class KeepClient(object):
             try:
                 sorted_roots = self.map_new_services(
                     roots_map, locator,
-                    force_rebuild=(tries_left < num_retries))
+                    force_rebuild=(tries_left < num_retries),
+                    need_writable=False)
             except Exception as error:
                 loop.save_result(error)
                 continue
@@ -920,32 +955,34 @@ class KeepClient(object):
         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'")
+            raise arvados.errors.ArgumentError("Argument 'data' to KeepClient.put is not type 'str'")
 
         data_hash = hashlib.md5(data).hexdigest()
+        loc_s = data_hash + '+' + str(len(data))
         if copies < 1:
-            return data_hash
-        locator = KeepLocator(data_hash + '+' + str(len(data)))
+            return loc_s
+        locator = KeepLocator(loc_s)
 
         headers = {}
-        if self.using_proxy:
-            # Tell the proxy how many copies we want it to store
-            headers['X-Keep-Desired-Replication'] = str(copies)
+        # Tell the proxy how many copies we want it to store
+        headers['X-Keep-Desired-Replication'] = str(copies)
         roots_map = {}
-        thread_limiter = KeepClient.ThreadLimiter(copies)
         loop = retry.RetryLoop(num_retries, self._check_loop_result,
                                backoff_start=2)
         for tries_left in loop:
             try:
-                local_roots = self.map_new_services(
+                sorted_roots = self.map_new_services(
                     roots_map, locator,
-                    force_rebuild=(tries_left < num_retries), **headers)
+                    force_rebuild=(tries_left < num_retries), need_writable=True, **headers)
             except Exception as error:
                 loop.save_result(error)
                 continue
 
+            thread_limiter = KeepClient.ThreadLimiter(
+                copies, self.max_replicas_per_service)
             threads = []
-            for service_root, ks in roots_map.iteritems():
+            for service_root, ks in [(root, roots_map[root])
+                                     for root in sorted_roots]:
                 if ks.finished():
                     continue
                 t = KeepClient.KeepWriterThread(
@@ -954,7 +991,8 @@ class KeepClient(object):
                     data_hash=data_hash,
                     service_root=service_root,
                     thread_limiter=thread_limiter,
-                    timeout=self.current_timeout(num_retries-tries_left))
+                    timeout=self.current_timeout(num_retries-tries_left),
+                    thread_sequence=len(threads))
                 t.start()
                 threads.append(t)
             for t in threads:
@@ -969,7 +1007,7 @@ class KeepClient(object):
                     data_hash, loop.last_result()))
         else:
             service_errors = ((key, roots_map[key].last_result()['error'])
-                              for key in local_roots
+                              for key in sorted_roots
                               if roots_map[key].last_result()['error'])
             raise arvados.errors.KeepWriteError(
                 "failed to write {} (wanted {} copies but wrote {})".format(