X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/c1e7255a85dfc2807ba78e1cf9d109d896c80b42..ebb2559b3a09636ff687316bbe512e0e8a86b168:/sdk/python/tests/test_keep_client.py

diff --git a/sdk/python/tests/test_keep_client.py b/sdk/python/tests/test_keep_client.py
index f5ab6148d0..85b5bc81f0 100644
--- a/sdk/python/tests/test_keep_client.py
+++ b/sdk/python/tests/test_keep_client.py
@@ -1,56 +1,58 @@
-# usage example:
-#
-# ARVADOS_API_TOKEN=abc ARVADOS_API_HOST=arvados.local python -m unittest discover
-
+import hashlib
+import mock
 import os
+import pycurl
+import random
+import re
+import socket
+import threading
+import time
 import unittest
+import urlparse
 
 import arvados
+import arvados.retry
+import arvados_testutil as tutil
+import keepstub
 import run_test_server
 
-class KeepTestCase(unittest.TestCase):
+class KeepTestCase(run_test_server.TestCaseWithServers):
+    MAIN_SERVER = {}
+    KEEP_SERVER = {}
+
     @classmethod
     def setUpClass(cls):
         super(KeepTestCase, cls).setUpClass()
-        try:
-            del os.environ['KEEP_LOCAL_STORE']
-        except KeyError:
-            pass
-
-        # Make sure these are clear, we want to talk to the Keep servers
-        # directly.
-        os.environ["ARVADOS_KEEP_PROXY"] = ""
-        os.environ["ARVADOS_EXTERNAL_CLIENT"] = ""
-
-        run_test_server.run()
-        run_test_server.run_keep()
-        arvados.keep.global_client_object = None
-        arvados.config._settings = None
         run_test_server.authorize_with("admin")
-
-    @classmethod
-    def tearDownClass(cls):
-        super(KeepTestCase, cls).tearDownClass()
-        run_test_server.stop()
-        run_test_server.stop_keep()
+        cls.api_client = arvados.api('v1')
+        cls.keep_client = arvados.KeepClient(api_client=cls.api_client,
+                                             proxy='', local_store='')
 
     def test_KeepBasicRWTest(self):
-        foo_locator = arvados.Keep.put('foo')
-        self.assertEqual(foo_locator,
-                         'acbd18db4cc2f85cedef654fccc4a4d8+3',
-                         'wrong md5 hash from Keep.put("foo"): ' + foo_locator)
-        self.assertEqual(arvados.Keep.get(foo_locator),
+        self.assertEqual(0, self.keep_client.upload_counter.get())
+        foo_locator = self.keep_client.put('foo')
+        self.assertRegexpMatches(
+            foo_locator,
+            '^acbd18db4cc2f85cedef654fccc4a4d8\+3',
+            'wrong md5 hash from Keep.put("foo"): ' + foo_locator)
+
+        # 6 bytes because uploaded 2 copies
+        self.assertEqual(6, self.keep_client.upload_counter.get())
+
+        self.assertEqual(0, self.keep_client.download_counter.get())
+        self.assertEqual(self.keep_client.get(foo_locator),
                          'foo',
                          'wrong content from Keep.get(md5("foo"))')
+        self.assertEqual(3, self.keep_client.download_counter.get())
 
     def test_KeepBinaryRWTest(self):
         blob_str = '\xff\xfe\xf7\x00\x01\x02'
-        blob_locator = arvados.Keep.put(blob_str)
-        self.assertEqual(blob_locator,
-                         '7fc7c53b45e53926ba52821140fef396+6',
-                         ('wrong locator from Keep.put(<binarydata>):' +
-                          blob_locator))
-        self.assertEqual(arvados.Keep.get(blob_locator),
+        blob_locator = self.keep_client.put(blob_str)
+        self.assertRegexpMatches(
+            blob_locator,
+            '^7fc7c53b45e53926ba52821140fef396\+6',
+            ('wrong locator from Keep.put(<binarydata>):' + blob_locator))
+        self.assertEqual(self.keep_client.get(blob_locator),
                          blob_str,
                          'wrong content from Keep.get(md5(<binarydata>))')
 
@@ -58,63 +60,87 @@ class KeepTestCase(unittest.TestCase):
         blob_str = '\xff\xfe\xfd\xfc\x00\x01\x02\x03'
         for i in range(0,23):
             blob_str = blob_str + blob_str
-        blob_locator = arvados.Keep.put(blob_str)
-        self.assertEqual(blob_locator,
-                         '84d90fc0d8175dd5dcfab04b999bc956+67108864',
-                         ('wrong locator from Keep.put(<binarydata>): ' +
-                          blob_locator))
-        self.assertEqual(arvados.Keep.get(blob_locator),
+        blob_locator = self.keep_client.put(blob_str)
+        self.assertRegexpMatches(
+            blob_locator,
+            '^84d90fc0d8175dd5dcfab04b999bc956\+67108864',
+            ('wrong locator from Keep.put(<binarydata>): ' + blob_locator))
+        self.assertEqual(self.keep_client.get(blob_locator),
                          blob_str,
                          'wrong content from Keep.get(md5(<binarydata>))')
 
+    @unittest.skip("unreliable test - please fix and close #8752")
     def test_KeepSingleCopyRWTest(self):
         blob_str = '\xff\xfe\xfd\xfc\x00\x01\x02\x03'
-        blob_locator = arvados.Keep.put(blob_str, copies=1)
-        self.assertEqual(blob_locator,
-                         'c902006bc98a3eb4a3663b65ab4a6fab+8',
-                         ('wrong locator from Keep.put(<binarydata>): ' +
-                          blob_locator))
-        self.assertEqual(arvados.Keep.get(blob_locator),
+        blob_locator = self.keep_client.put(blob_str, copies=1)
+        self.assertRegexpMatches(
+            blob_locator,
+            '^c902006bc98a3eb4a3663b65ab4a6fab\+8',
+            ('wrong locator from Keep.put(<binarydata>): ' + blob_locator))
+        self.assertEqual(self.keep_client.get(blob_locator),
                          blob_str,
                          'wrong content from Keep.get(md5(<binarydata>))')
 
-class KeepPermissionTestCase(unittest.TestCase):
-    @classmethod
-    def setUpClass(cls):
-        try:
-            del os.environ['KEEP_LOCAL_STORE']
-        except KeyError:
-            pass
+    def test_KeepEmptyCollectionTest(self):
+        blob_locator = self.keep_client.put('', copies=1)
+        self.assertRegexpMatches(
+            blob_locator,
+            '^d41d8cd98f00b204e9800998ecf8427e\+0',
+            ('wrong locator from Keep.put(""): ' + blob_locator))
 
-        run_test_server.run()
-        run_test_server.run_keep(blob_signing_key='abcdefghijk0123456789',
-                                 enforce_permissions=True)
+    def test_unicode_must_be_ascii(self):
+        # If unicode type, must only consist of valid ASCII
+        foo_locator = self.keep_client.put(u'foo')
+        self.assertRegexpMatches(
+            foo_locator,
+            '^acbd18db4cc2f85cedef654fccc4a4d8\+3',
+            'wrong md5 hash from Keep.put("foo"): ' + foo_locator)
 
-    @classmethod
-    def tearDownClass(cls):
-        run_test_server.stop()
-        run_test_server.stop_keep()
+        with self.assertRaises(UnicodeEncodeError):
+            # Error if it is not ASCII
+            self.keep_client.put(u'\xe2')
+
+        with self.assertRaises(arvados.errors.ArgumentError):
+            # Must be a string type
+            self.keep_client.put({})
+
+    def test_KeepHeadTest(self):
+        locator = self.keep_client.put('test_head')
+        self.assertRegexpMatches(
+            locator,
+            '^b9a772c7049325feb7130fff1f8333e9\+9',
+            'wrong md5 hash from Keep.put for "test_head": ' + locator)
+        self.assertEqual(True, self.keep_client.head(locator))
+        self.assertEqual(self.keep_client.get(locator),
+                         'test_head',
+                         'wrong content from Keep.get for "test_head"')
+
+class KeepPermissionTestCase(run_test_server.TestCaseWithServers):
+    MAIN_SERVER = {}
+    KEEP_SERVER = {'blob_signing_key': 'abcdefghijk0123456789',
+                   'enforce_permissions': True}
 
     def test_KeepBasicRWTest(self):
         run_test_server.authorize_with('active')
-        foo_locator = arvados.Keep.put('foo')
+        keep_client = arvados.KeepClient()
+        foo_locator = keep_client.put('foo')
         self.assertRegexpMatches(
             foo_locator,
             r'^acbd18db4cc2f85cedef654fccc4a4d8\+3\+A[a-f0-9]+@[a-f0-9]+$',
             'invalid locator from Keep.put("foo"): ' + foo_locator)
-        self.assertEqual(arvados.Keep.get(foo_locator),
+        self.assertEqual(keep_client.get(foo_locator),
                          'foo',
                          'wrong content from Keep.get(md5("foo"))')
 
         # GET with an unsigned locator => NotFound
-        bar_locator = arvados.Keep.put('bar')
+        bar_locator = keep_client.put('bar')
         unsigned_bar_locator = "37b51d194a7513e45b56f6524f2d51f2+3"
         self.assertRegexpMatches(
             bar_locator,
             r'^37b51d194a7513e45b56f6524f2d51f2\+3\+A[a-f0-9]+@[a-f0-9]+$',
             'invalid locator from Keep.put("bar"): ' + bar_locator)
         self.assertRaises(arvados.errors.NotFoundError,
-                          arvados.Keep.get,
+                          keep_client.get,
                           unsigned_bar_locator)
 
         # GET from a different user => NotFound
@@ -125,14 +151,15 @@ class KeepPermissionTestCase(unittest.TestCase):
 
         # Unauthenticated GET for a signed locator => NotFound
         # Unauthenticated GET for an unsigned locator => NotFound
-        del arvados.config.settings()["ARVADOS_API_TOKEN"]
+        keep_client.api_token = ''
         self.assertRaises(arvados.errors.NotFoundError,
-                          arvados.Keep.get,
+                          keep_client.get,
                           bar_locator)
         self.assertRaises(arvados.errors.NotFoundError,
-                          arvados.Keep.get,
+                          keep_client.get,
                           unsigned_bar_locator)
 
+
 # KeepOptionalPermission: starts Keep with --permission-key-file
 # but not --enforce-permissions (i.e. generate signatures on PUT
 # requests, but do not require them for GET requests)
@@ -142,140 +169,1018 @@ class KeepPermissionTestCase(unittest.TestCase):
 # * authenticated request, unsigned locator
 # * unauthenticated request, signed locator
 # * unauthenticated request, unsigned locator
+class KeepOptionalPermission(run_test_server.TestCaseWithServers):
+    MAIN_SERVER = {}
+    KEEP_SERVER = {'blob_signing_key': 'abcdefghijk0123456789',
+                   'enforce_permissions': False}
 
-class KeepOptionalPermission(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
-        try:
-            del os.environ['KEEP_LOCAL_STORE']
-        except KeyError:
-            pass
-        run_test_server.run()
-        run_test_server.run_keep(blob_signing_key='abcdefghijk0123456789',
-                                 enforce_permissions=False)
+        super(KeepOptionalPermission, cls).setUpClass()
+        run_test_server.authorize_with("admin")
+        cls.api_client = arvados.api('v1')
 
-    @classmethod
-    def tearDownClass(cls):
-        run_test_server.stop()
-        run_test_server.stop_keep()
+    def setUp(self):
+        super(KeepOptionalPermission, self).setUp()
+        self.keep_client = arvados.KeepClient(api_client=self.api_client,
+                                              proxy='', local_store='')
 
-    def test_KeepAuthenticatedSignedTest(self):
-        run_test_server.authorize_with('active')
-        signed_locator = arvados.Keep.put('foo')
+    def _put_foo_and_check(self):
+        signed_locator = self.keep_client.put('foo')
         self.assertRegexpMatches(
             signed_locator,
             r'^acbd18db4cc2f85cedef654fccc4a4d8\+3\+A[a-f0-9]+@[a-f0-9]+$',
             'invalid locator from Keep.put("foo"): ' + signed_locator)
-        self.assertEqual(arvados.Keep.get(signed_locator),
+        return signed_locator
+
+    def test_KeepAuthenticatedSignedTest(self):
+        signed_locator = self._put_foo_and_check()
+        self.assertEqual(self.keep_client.get(signed_locator),
                          'foo',
                          'wrong content from Keep.get(md5("foo"))')
 
     def test_KeepAuthenticatedUnsignedTest(self):
-        run_test_server.authorize_with('active')
-        signed_locator = arvados.Keep.put('foo')
-        self.assertRegexpMatches(
-            signed_locator,
-            r'^acbd18db4cc2f85cedef654fccc4a4d8\+3\+A[a-f0-9]+@[a-f0-9]+$',
-            'invalid locator from Keep.put("foo"): ' + signed_locator)
-        self.assertEqual(arvados.Keep.get("acbd18db4cc2f85cedef654fccc4a4d8"),
+        signed_locator = self._put_foo_and_check()
+        self.assertEqual(self.keep_client.get("acbd18db4cc2f85cedef654fccc4a4d8"),
                          'foo',
                          'wrong content from Keep.get(md5("foo"))')
 
     def test_KeepUnauthenticatedSignedTest(self):
-        # Since --enforce-permissions is not in effect, GET requests
-        # need not be authenticated.
-        run_test_server.authorize_with('active')
-        signed_locator = arvados.Keep.put('foo')
-        self.assertRegexpMatches(
-            signed_locator,
-            r'^acbd18db4cc2f85cedef654fccc4a4d8\+3\+A[a-f0-9]+@[a-f0-9]+$',
-            'invalid locator from Keep.put("foo"): ' + signed_locator)
-
-        del arvados.config.settings()["ARVADOS_API_TOKEN"]
-        self.assertEqual(arvados.Keep.get(signed_locator),
+        # Check that signed GET requests work even when permissions
+        # enforcement is off.
+        signed_locator = self._put_foo_and_check()
+        self.keep_client.api_token = ''
+        self.assertEqual(self.keep_client.get(signed_locator),
                          'foo',
                          'wrong content from Keep.get(md5("foo"))')
 
     def test_KeepUnauthenticatedUnsignedTest(self):
         # Since --enforce-permissions is not in effect, GET requests
         # need not be authenticated.
-        run_test_server.authorize_with('active')
-        signed_locator = arvados.Keep.put('foo')
-        self.assertRegexpMatches(
-            signed_locator,
-            r'^acbd18db4cc2f85cedef654fccc4a4d8\+3\+A[a-f0-9]+@[a-f0-9]+$',
-            'invalid locator from Keep.put("foo"): ' + signed_locator)
-
-        del arvados.config.settings()["ARVADOS_API_TOKEN"]
-        self.assertEqual(arvados.Keep.get("acbd18db4cc2f85cedef654fccc4a4d8"),
+        signed_locator = self._put_foo_and_check()
+        self.keep_client.api_token = ''
+        self.assertEqual(self.keep_client.get("acbd18db4cc2f85cedef654fccc4a4d8"),
                          'foo',
                          'wrong content from Keep.get(md5("foo"))')
 
 
-class KeepProxyTestCase(unittest.TestCase):
+class KeepProxyTestCase(run_test_server.TestCaseWithServers):
+    MAIN_SERVER = {}
+    KEEP_SERVER = {}
+    KEEP_PROXY_SERVER = {}
+
     @classmethod
     def setUpClass(cls):
         super(KeepProxyTestCase, cls).setUpClass()
+        run_test_server.authorize_with('active')
+        cls.api_client = arvados.api('v1')
 
-        try:
-            del os.environ['KEEP_LOCAL_STORE']
-        except KeyError:
-            pass
-
-        os.environ["ARVADOS_KEEP_PROXY"] = ""
-        os.environ["ARVADOS_EXTERNAL_CLIENT"] = ""
-
-        run_test_server.run()
-        run_test_server.run_keep()
-        arvados.keep.global_client_object = None
-        arvados.config._settings = None
-        run_test_server.run_keep_proxy("admin")
-        KeepProxyTestCase.arvados_keep_proxy = arvados.config.get("ARVADOS_KEEP_PROXY")
-
-    @classmethod
-    def tearDownClass(cls):
-        super(KeepProxyTestCase, cls).tearDownClass()
-        run_test_server.stop()
-        run_test_server.stop_keep()
-        run_test_server.stop_keep_proxy()
+    def tearDown(self):
+        arvados.config.settings().pop('ARVADOS_EXTERNAL_CLIENT', None)
+        super(KeepProxyTestCase, self).tearDown()
 
     def test_KeepProxyTest1(self):
-        # Will use ARVADOS_KEEP_PROXY environment variable that is set by
-        # run_keep_proxy() in setUpClass()
-
-        os.environ["ARVADOS_KEEP_PROXY"] = KeepProxyTestCase.arvados_keep_proxy
-        os.environ["ARVADOS_EXTERNAL_CLIENT"] = ""
-        arvados.keep.global_client_object = None
-        arvados.config._settings = None
-
-        baz_locator = arvados.Keep.put('baz')
-        self.assertEqual(baz_locator,
-                         '73feffa4b7f6bb68e44cf984c85f6e88+3',
-                         'wrong md5 hash from Keep.put("baz"): ' + baz_locator)
-        self.assertEqual(arvados.Keep.get(baz_locator),
+        # Will use ARVADOS_KEEP_SERVICES environment variable that
+        # is set by setUpClass().
+        keep_client = arvados.KeepClient(api_client=self.api_client,
+                                         local_store='')
+        baz_locator = keep_client.put('baz')
+        self.assertRegexpMatches(
+            baz_locator,
+            '^73feffa4b7f6bb68e44cf984c85f6e88\+3',
+            'wrong md5 hash from Keep.put("baz"): ' + baz_locator)
+        self.assertEqual(keep_client.get(baz_locator),
                          'baz',
                          'wrong content from Keep.get(md5("baz"))')
-
-        self.assertEqual(True, arvados.Keep.global_client_object().using_proxy)
+        self.assertTrue(keep_client.using_proxy)
 
     def test_KeepProxyTest2(self):
-        # We don't want to use ARVADOS_KEEP_PROXY from run_keep_proxy() in
-        # setUpClass(), so clear it and set ARVADOS_EXTERNAL_CLIENT which will
-        # contact the API server.
-        os.environ["ARVADOS_KEEP_PROXY"] = ""
-        os.environ["ARVADOS_EXTERNAL_CLIENT"] = "true"
-        arvados.keep.global_client_object = None
-        arvados.config._settings = None
-
-        # Will send X-External-Client to server and get back the proxy from
-        # keep_services/accessible
-
-        baz_locator = arvados.Keep.put('baz2')
-        self.assertEqual(baz_locator,
-                         '91f372a266fe2bf2823cb8ec7fda31ce+4',
-                         'wrong md5 hash from Keep.put("baz2"): ' + baz_locator)
-        self.assertEqual(arvados.Keep.get(baz_locator),
+        # Don't instantiate the proxy directly, but set the X-External-Client
+        # header.  The API server should direct us to the proxy.
+        arvados.config.settings()['ARVADOS_EXTERNAL_CLIENT'] = 'true'
+        keep_client = arvados.KeepClient(api_client=self.api_client,
+                                         proxy='', local_store='')
+        baz_locator = keep_client.put('baz2')
+        self.assertRegexpMatches(
+            baz_locator,
+            '^91f372a266fe2bf2823cb8ec7fda31ce\+4',
+            'wrong md5 hash from Keep.put("baz2"): ' + baz_locator)
+        self.assertEqual(keep_client.get(baz_locator),
                          'baz2',
                          'wrong content from Keep.get(md5("baz2"))')
+        self.assertTrue(keep_client.using_proxy)
+
+    def test_KeepProxyTestMultipleURIs(self):
+        # Test using ARVADOS_KEEP_SERVICES env var overriding any
+        # existing proxy setting and setting multiple proxies
+        arvados.config.settings()['ARVADOS_KEEP_SERVICES'] = 'http://10.0.0.1 https://foo.example.org:1234/'
+        keep_client = arvados.KeepClient(api_client=self.api_client,
+                                         local_store='')
+        uris = [x['_service_root'] for x in keep_client._keep_services]
+        self.assertEqual(uris, ['http://10.0.0.1/',
+                                'https://foo.example.org:1234/'])
+
+    def test_KeepProxyTestInvalidURI(self):
+        arvados.config.settings()['ARVADOS_KEEP_SERVICES'] = 'bad.uri.org'
+        with self.assertRaises(arvados.errors.ArgumentError):
+            keep_client = arvados.KeepClient(api_client=self.api_client,
+                                             local_store='')
+
+
+class KeepClientServiceTestCase(unittest.TestCase, tutil.ApiClientMock):
+    def get_service_roots(self, api_client):
+        keep_client = arvados.KeepClient(api_client=api_client)
+        services = keep_client.weighted_service_roots(arvados.KeepLocator('0'*32))
+        return [urlparse.urlparse(url) for url in sorted(services)]
+
+    def test_ssl_flag_respected_in_roots(self):
+        for ssl_flag in [False, True]:
+            services = self.get_service_roots(self.mock_keep_services(
+                service_ssl_flag=ssl_flag))
+            self.assertEqual(
+                ('https' if ssl_flag else 'http'), services[0].scheme)
+
+    def test_correct_ports_with_ipv6_addresses(self):
+        service = self.get_service_roots(self.mock_keep_services(
+            service_type='proxy', service_host='100::1', service_port=10, count=1))[0]
+        self.assertEqual('100::1', service.hostname)
+        self.assertEqual(10, service.port)
+
+    # test_*_timeout verify that KeepClient instructs pycurl to use
+    # the appropriate connection and read timeouts. They don't care
+    # whether pycurl actually exhibits the expected timeout behavior
+    # -- those tests are in the KeepClientTimeout test class.
+
+    def test_get_timeout(self):
+        api_client = self.mock_keep_services(count=1)
+        force_timeout = socket.timeout("timed out")
+        with tutil.mock_keep_responses(force_timeout, 0) as mock:
+            keep_client = arvados.KeepClient(api_client=api_client)
+            with self.assertRaises(arvados.errors.KeepReadError):
+                keep_client.get('ffffffffffffffffffffffffffffffff')
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.CONNECTTIMEOUT_MS),
+                int(arvados.KeepClient.DEFAULT_TIMEOUT[0]*1000))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_TIME),
+                int(arvados.KeepClient.DEFAULT_TIMEOUT[1]))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_LIMIT),
+                int(arvados.KeepClient.DEFAULT_TIMEOUT[2]))
+
+    def test_put_timeout(self):
+        api_client = self.mock_keep_services(count=1)
+        force_timeout = socket.timeout("timed out")
+        with tutil.mock_keep_responses(force_timeout, 0) as mock:
+            keep_client = arvados.KeepClient(api_client=api_client)
+            with self.assertRaises(arvados.errors.KeepWriteError):
+                keep_client.put('foo')
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.CONNECTTIMEOUT_MS),
+                int(arvados.KeepClient.DEFAULT_TIMEOUT[0]*1000))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_TIME),
+                int(arvados.KeepClient.DEFAULT_TIMEOUT[1]))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_LIMIT),
+                int(arvados.KeepClient.DEFAULT_TIMEOUT[2]))
+
+    def test_head_timeout(self):
+        api_client = self.mock_keep_services(count=1)
+        force_timeout = socket.timeout("timed out")
+        with tutil.mock_keep_responses(force_timeout, 0) as mock:
+            keep_client = arvados.KeepClient(api_client=api_client)
+            with self.assertRaises(arvados.errors.KeepReadError):
+                keep_client.head('ffffffffffffffffffffffffffffffff')
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.CONNECTTIMEOUT_MS),
+                int(arvados.KeepClient.DEFAULT_TIMEOUT[0]*1000))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_TIME),
+                int(arvados.KeepClient.DEFAULT_TIMEOUT[1]))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_LIMIT),
+                int(arvados.KeepClient.DEFAULT_TIMEOUT[2]))
+
+    def test_proxy_get_timeout(self):
+        api_client = self.mock_keep_services(service_type='proxy', count=1)
+        force_timeout = socket.timeout("timed out")
+        with tutil.mock_keep_responses(force_timeout, 0) as mock:
+            keep_client = arvados.KeepClient(api_client=api_client)
+            with self.assertRaises(arvados.errors.KeepReadError):
+                keep_client.get('ffffffffffffffffffffffffffffffff')
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.CONNECTTIMEOUT_MS),
+                int(arvados.KeepClient.DEFAULT_PROXY_TIMEOUT[0]*1000))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_TIME),
+                int(arvados.KeepClient.DEFAULT_PROXY_TIMEOUT[1]))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_LIMIT),
+                int(arvados.KeepClient.DEFAULT_PROXY_TIMEOUT[2]))
+
+    def test_proxy_head_timeout(self):
+        api_client = self.mock_keep_services(service_type='proxy', count=1)
+        force_timeout = socket.timeout("timed out")
+        with tutil.mock_keep_responses(force_timeout, 0) as mock:
+            keep_client = arvados.KeepClient(api_client=api_client)
+            with self.assertRaises(arvados.errors.KeepReadError):
+                keep_client.head('ffffffffffffffffffffffffffffffff')
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.CONNECTTIMEOUT_MS),
+                int(arvados.KeepClient.DEFAULT_PROXY_TIMEOUT[0]*1000))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_TIME),
+                int(arvados.KeepClient.DEFAULT_PROXY_TIMEOUT[1]))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_LIMIT),
+                int(arvados.KeepClient.DEFAULT_PROXY_TIMEOUT[2]))
+
+    def test_proxy_put_timeout(self):
+        api_client = self.mock_keep_services(service_type='proxy', count=1)
+        force_timeout = socket.timeout("timed out")
+        with tutil.mock_keep_responses(force_timeout, 0) as mock:
+            keep_client = arvados.KeepClient(api_client=api_client)
+            with self.assertRaises(arvados.errors.KeepWriteError):
+                keep_client.put('foo')
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.CONNECTTIMEOUT_MS),
+                int(arvados.KeepClient.DEFAULT_PROXY_TIMEOUT[0]*1000))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_TIME),
+                int(arvados.KeepClient.DEFAULT_PROXY_TIMEOUT[1]))
+            self.assertEqual(
+                mock.responses[0].getopt(pycurl.LOW_SPEED_LIMIT),
+                int(arvados.KeepClient.DEFAULT_PROXY_TIMEOUT[2]))
+
+    def check_no_services_error(self, verb, exc_class):
+        api_client = mock.MagicMock(name='api_client')
+        api_client.keep_services().accessible().execute.side_effect = (
+            arvados.errors.ApiError)
+        keep_client = arvados.KeepClient(api_client=api_client)
+        with self.assertRaises(exc_class) as err_check:
+            getattr(keep_client, verb)('d41d8cd98f00b204e9800998ecf8427e+0')
+        self.assertEqual(0, len(err_check.exception.request_errors()))
+
+    def test_get_error_with_no_services(self):
+        self.check_no_services_error('get', arvados.errors.KeepReadError)
+
+    def test_head_error_with_no_services(self):
+        self.check_no_services_error('head', arvados.errors.KeepReadError)
+
+    def test_put_error_with_no_services(self):
+        self.check_no_services_error('put', arvados.errors.KeepWriteError)
+
+    def check_errors_from_last_retry(self, verb, exc_class):
+        api_client = self.mock_keep_services(count=2)
+        req_mock = tutil.mock_keep_responses(
+            "retry error reporting test", 500, 500, 403, 403)
+        with req_mock, tutil.skip_sleep, \
+                self.assertRaises(exc_class) as err_check:
+            keep_client = arvados.KeepClient(api_client=api_client)
+            getattr(keep_client, verb)('d41d8cd98f00b204e9800998ecf8427e+0',
+                                       num_retries=3)
+        self.assertEqual([403, 403], [
+                getattr(error, 'status_code', None)
+                for error in err_check.exception.request_errors().itervalues()])
+
+    def test_get_error_reflects_last_retry(self):
+        self.check_errors_from_last_retry('get', arvados.errors.KeepReadError)
+
+    def test_head_error_reflects_last_retry(self):
+        self.check_errors_from_last_retry('head', arvados.errors.KeepReadError)
+
+    def test_put_error_reflects_last_retry(self):
+        self.check_errors_from_last_retry('put', arvados.errors.KeepWriteError)
+
+    def test_put_error_does_not_include_successful_puts(self):
+        data = 'partial failure test'
+        data_loc = tutil.str_keep_locator(data)
+        api_client = self.mock_keep_services(count=3)
+        with tutil.mock_keep_responses(data_loc, 200, 500, 500) as req_mock, \
+                self.assertRaises(arvados.errors.KeepWriteError) as exc_check:
+            keep_client = arvados.KeepClient(api_client=api_client)
+            keep_client.put(data)
+        self.assertEqual(2, len(exc_check.exception.request_errors()))
+
+    def test_proxy_put_with_no_writable_services(self):
+        data = 'test with no writable services'
+        data_loc = tutil.str_keep_locator(data)
+        api_client = self.mock_keep_services(service_type='proxy', read_only=True, count=1)
+        with tutil.mock_keep_responses(data_loc, 200, 500, 500) as req_mock, \
+                self.assertRaises(arvados.errors.KeepWriteError) as exc_check:
+          keep_client = arvados.KeepClient(api_client=api_client)
+          keep_client.put(data)
+        self.assertEqual(True, ("no Keep services available" in str(exc_check.exception)))
+        self.assertEqual(0, len(exc_check.exception.request_errors()))
+
+    def test_oddball_service_get(self):
+        body = 'oddball service get'
+        api_client = self.mock_keep_services(service_type='fancynewblobstore')
+        with tutil.mock_keep_responses(body, 200):
+            keep_client = arvados.KeepClient(api_client=api_client)
+            actual = keep_client.get(tutil.str_keep_locator(body))
+        self.assertEqual(body, actual)
+
+    def test_oddball_service_put(self):
+        body = 'oddball service put'
+        pdh = tutil.str_keep_locator(body)
+        api_client = self.mock_keep_services(service_type='fancynewblobstore')
+        with tutil.mock_keep_responses(pdh, 200):
+            keep_client = arvados.KeepClient(api_client=api_client)
+            actual = keep_client.put(body, copies=1)
+        self.assertEqual(pdh, actual)
+
+    def test_oddball_service_writer_count(self):
+        body = 'oddball service writer count'
+        pdh = tutil.str_keep_locator(body)
+        api_client = self.mock_keep_services(service_type='fancynewblobstore',
+                                             count=4)
+        headers = {'x-keep-replicas-stored': 3}
+        with tutil.mock_keep_responses(pdh, 200, 418, 418, 418,
+                                       **headers) as req_mock:
+            keep_client = arvados.KeepClient(api_client=api_client)
+            actual = keep_client.put(body, copies=2)
+        self.assertEqual(pdh, actual)
+        self.assertEqual(1, req_mock.call_count)
+
+
+@tutil.skip_sleep
+class KeepClientRendezvousTestCase(unittest.TestCase, tutil.ApiClientMock):
+
+    def setUp(self):
+        # expected_order[i] is the probe order for
+        # hash=md5(sprintf("%064x",i)) where there are 16 services
+        # with uuid sprintf("anything-%015x",j) with j in 0..15. E.g.,
+        # the first probe for the block consisting of 64 "0"
+        # characters is the service whose uuid is
+        # "zzzzz-bi6l4-000000000000003", so expected_order[0][0]=='3'.
+        self.services = 16
+        self.expected_order = [
+            list('3eab2d5fc9681074'),
+            list('097dba52e648f1c3'),
+            list('c5b4e023f8a7d691'),
+            list('9d81c02e76a3bf54'),
+            ]
+        self.blocks = [
+            "{:064x}".format(x)
+            for x in range(len(self.expected_order))]
+        self.hashes = [
+            hashlib.md5(self.blocks[x]).hexdigest()
+            for x in range(len(self.expected_order))]
+        self.api_client = self.mock_keep_services(count=self.services)
+        self.keep_client = arvados.KeepClient(api_client=self.api_client)
+
+    def test_weighted_service_roots_against_reference_set(self):
+        # Confirm weighted_service_roots() returns the correct order
+        for i, hash in enumerate(self.hashes):
+            roots = self.keep_client.weighted_service_roots(arvados.KeepLocator(hash))
+            got_order = [
+                re.search(r'//\[?keep0x([0-9a-f]+)', root).group(1)
+                for root in roots]
+            self.assertEqual(self.expected_order[i], got_order)
+
+    def test_get_probe_order_against_reference_set(self):
+        self._test_probe_order_against_reference_set(
+            lambda i: self.keep_client.get(self.hashes[i], num_retries=1))
+
+    def test_head_probe_order_against_reference_set(self):
+        self._test_probe_order_against_reference_set(
+            lambda i: self.keep_client.head(self.hashes[i], num_retries=1))
+
+    def test_put_probe_order_against_reference_set(self):
+        # copies=1 prevents the test from being sensitive to races
+        # between writer threads.
+        self._test_probe_order_against_reference_set(
+            lambda i: self.keep_client.put(self.blocks[i], num_retries=1, copies=1))
+
+    def _test_probe_order_against_reference_set(self, op):
+        for i in range(len(self.blocks)):
+            with tutil.mock_keep_responses('', *[500 for _ in range(self.services*2)]) as mock, \
+                 self.assertRaises(arvados.errors.KeepRequestError):
+                op(i)
+            got_order = [
+                re.search(r'//\[?keep0x([0-9a-f]+)', resp.getopt(pycurl.URL)).group(1)
+                for resp in mock.responses]
+            self.assertEqual(self.expected_order[i]*2, got_order)
+
+    def test_put_probe_order_multiple_copies(self):
+        for copies in range(2, 4):
+            for i in range(len(self.blocks)):
+                with tutil.mock_keep_responses('', *[500 for _ in range(self.services*3)]) as mock, \
+                     self.assertRaises(arvados.errors.KeepWriteError):
+                    self.keep_client.put(self.blocks[i], num_retries=2, copies=copies)
+                got_order = [
+                    re.search(r'//\[?keep0x([0-9a-f]+)', resp.getopt(pycurl.URL)).group(1)
+                    for resp in mock.responses]
+                # With T threads racing to make requests, the position
+                # of a given server in the sequence of HTTP requests
+                # (got_order) cannot be more than T-1 positions
+                # earlier than that server's position in the reference
+                # probe sequence (expected_order).
+                #
+                # Loop invariant: we have accounted for +pos+ expected
+                # probes, either by seeing them in +got_order+ or by
+                # putting them in +pending+ in the hope of seeing them
+                # later. As long as +len(pending)<T+, we haven't
+                # started a request too early.
+                pending = []
+                for pos, expected in enumerate(self.expected_order[i]*3):
+                    got = got_order[pos-len(pending)]
+                    while got in pending:
+                        del pending[pending.index(got)]
+                        got = got_order[pos-len(pending)]
+                    if got != expected:
+                        pending.append(expected)
+                        self.assertLess(
+                            len(pending), copies,
+                            "pending={}, with copies={}, got {}, expected {}".format(
+                                pending, copies, repr(got_order), repr(self.expected_order[i]*3)))
+
+    def test_probe_waste_adding_one_server(self):
+        hashes = [
+            hashlib.md5("{:064x}".format(x)).hexdigest() for x in range(100)]
+        initial_services = 12
+        self.api_client = self.mock_keep_services(count=initial_services)
+        self.keep_client = arvados.KeepClient(api_client=self.api_client)
+        probes_before = [
+            self.keep_client.weighted_service_roots(arvados.KeepLocator(hash)) for hash in hashes]
+        for added_services in range(1, 12):
+            api_client = self.mock_keep_services(count=initial_services+added_services)
+            keep_client = arvados.KeepClient(api_client=api_client)
+            total_penalty = 0
+            for hash_index in range(len(hashes)):
+                probe_after = keep_client.weighted_service_roots(
+                    arvados.KeepLocator(hashes[hash_index]))
+                penalty = probe_after.index(probes_before[hash_index][0])
+                self.assertLessEqual(penalty, added_services)
+                total_penalty += penalty
+            # Average penalty per block should not exceed
+            # N(added)/N(orig) by more than 20%, and should get closer
+            # to the ideal as we add data points.
+            expect_penalty = (
+                added_services *
+                len(hashes) / initial_services)
+            max_penalty = (
+                expect_penalty *
+                (120 - added_services)/100)
+            min_penalty = (
+                expect_penalty * 8/10)
+            self.assertTrue(
+                min_penalty <= total_penalty <= max_penalty,
+                "With {}+{} services, {} blocks, penalty {} but expected {}..{}".format(
+                    initial_services,
+                    added_services,
+                    len(hashes),
+                    total_penalty,
+                    min_penalty,
+                    max_penalty))
+
+    def check_64_zeros_error_order(self, verb, exc_class):
+        data = '0' * 64
+        if verb == 'get':
+            data = tutil.str_keep_locator(data)
+        # Arbitrary port number:
+        aport = random.randint(1024,65535)
+        api_client = self.mock_keep_services(service_port=aport, count=self.services)
+        keep_client = arvados.KeepClient(api_client=api_client)
+        with mock.patch('pycurl.Curl') as curl_mock, \
+             self.assertRaises(exc_class) as err_check:
+            curl_mock.return_value.side_effect = socket.timeout
+            getattr(keep_client, verb)(data)
+        urls = [urlparse.urlparse(url)
+                for url in err_check.exception.request_errors()]
+        self.assertEqual([('keep0x' + c, aport) for c in '3eab2d5fc9681074'],
+                         [(url.hostname, url.port) for url in urls])
+
+    def test_get_error_shows_probe_order(self):
+        self.check_64_zeros_error_order('get', arvados.errors.KeepReadError)
+
+    def test_put_error_shows_probe_order(self):
+        self.check_64_zeros_error_order('put', arvados.errors.KeepWriteError)
+
+
+class KeepClientTimeout(unittest.TestCase, tutil.ApiClientMock):
+    # BANDWIDTH_LOW_LIM must be less than len(DATA) so we can transfer
+    # 1s worth of data and then trigger bandwidth errors before running
+    # out of data.
+    DATA = 'x'*2**11
+    BANDWIDTH_LOW_LIM = 1024
+    TIMEOUT_TIME = 1.0
+
+    class assertTakesBetween(unittest.TestCase):
+        def __init__(self, tmin, tmax):
+            self.tmin = tmin
+            self.tmax = tmax
+
+        def __enter__(self):
+            self.t0 = time.time()
+
+        def __exit__(self, *args, **kwargs):
+            # Round times to milliseconds, like CURL. Otherwise, we
+            # fail when CURL reaches a 1s timeout at 0.9998s.
+            delta = round(time.time() - self.t0, 3)
+            self.assertGreaterEqual(delta, self.tmin)
+            self.assertLessEqual(delta, self.tmax)
+
+    class assertTakesGreater(unittest.TestCase):
+        def __init__(self, tmin):
+            self.tmin = tmin
+
+        def __enter__(self):
+            self.t0 = time.time()
+
+        def __exit__(self, *args, **kwargs):
+            delta = round(time.time() - self.t0, 3)
+            self.assertGreaterEqual(delta, self.tmin)
+
+    def setUp(self):
+        sock = socket.socket()
+        sock.bind(('0.0.0.0', 0))
+        self.port = sock.getsockname()[1]
+        sock.close()
+        self.server = keepstub.Server(('0.0.0.0', self.port), keepstub.Handler)
+        self.thread = threading.Thread(target=self.server.serve_forever)
+        self.thread.daemon = True # Exit thread if main proc exits
+        self.thread.start()
+        self.api_client = self.mock_keep_services(
+            count=1,
+            service_host='localhost',
+            service_port=self.port,
+        )
+
+    def tearDown(self):
+        self.server.shutdown()
+
+    def keepClient(self, timeouts=(0.1, TIMEOUT_TIME, BANDWIDTH_LOW_LIM)):
+        return arvados.KeepClient(
+            api_client=self.api_client,
+            timeout=timeouts)
+
+    def test_timeout_slow_connect(self):
+        # Can't simulate TCP delays with our own socket. Leave our
+        # stub server running uselessly, and try to connect to an
+        # unroutable IP address instead.
+        self.api_client = self.mock_keep_services(
+            count=1,
+            service_host='240.0.0.0',
+        )
+        with self.assertTakesBetween(0.1, 0.5):
+            with self.assertRaises(arvados.errors.KeepWriteError):
+                self.keepClient().put(self.DATA, copies=1, num_retries=0)
+
+    def test_low_bandwidth_no_delays_success(self):
+        self.server.setbandwidth(2*self.BANDWIDTH_LOW_LIM)
+        kc = self.keepClient()
+        loc = kc.put(self.DATA, copies=1, num_retries=0)
+        self.assertEqual(self.DATA, kc.get(loc, num_retries=0))
+
+    def test_too_low_bandwidth_no_delays_failure(self):
+        # Check that lessening bandwidth corresponds to failing
+        kc = self.keepClient()
+        loc = kc.put(self.DATA, copies=1, num_retries=0)
+        self.server.setbandwidth(0.5*self.BANDWIDTH_LOW_LIM)
+        with self.assertTakesGreater(self.TIMEOUT_TIME):
+            with self.assertRaises(arvados.errors.KeepReadError) as e:
+                kc.get(loc, num_retries=0)
+        with self.assertTakesGreater(self.TIMEOUT_TIME):
+            with self.assertRaises(arvados.errors.KeepWriteError):
+                kc.put(self.DATA, copies=1, num_retries=0)
+
+    def test_low_bandwidth_with_server_response_delay_failure(self):
+        kc = self.keepClient()
+        loc = kc.put(self.DATA, copies=1, num_retries=0)
+        self.server.setbandwidth(self.BANDWIDTH_LOW_LIM)
+        self.server.setdelays(response=self.TIMEOUT_TIME)
+        with self.assertTakesGreater(self.TIMEOUT_TIME):
+            with self.assertRaises(arvados.errors.KeepReadError) as e:
+                kc.get(loc, num_retries=0)
+        with self.assertTakesGreater(self.TIMEOUT_TIME):
+            with self.assertRaises(arvados.errors.KeepWriteError):
+                kc.put(self.DATA, copies=1, num_retries=0)
+        with self.assertTakesGreater(self.TIMEOUT_TIME):
+            with self.assertRaises(arvados.errors.KeepReadError) as e:
+                kc.head(loc, num_retries=0)
+
+    def test_low_bandwidth_with_server_mid_delay_failure(self):
+        kc = self.keepClient()
+        loc = kc.put(self.DATA, copies=1, num_retries=0)
+        self.server.setbandwidth(self.BANDWIDTH_LOW_LIM)
+        self.server.setdelays(mid_write=self.TIMEOUT_TIME, mid_read=self.TIMEOUT_TIME)
+        with self.assertTakesGreater(self.TIMEOUT_TIME):
+            with self.assertRaises(arvados.errors.KeepReadError) as e:
+                kc.get(loc, num_retries=0)
+        with self.assertTakesGreater(self.TIMEOUT_TIME):
+            with self.assertRaises(arvados.errors.KeepWriteError):
+                kc.put(self.DATA, copies=1, num_retries=0)
+
+    def test_timeout_slow_request(self):
+        loc = self.keepClient().put(self.DATA, copies=1, num_retries=0)
+        self.server.setdelays(request=.2)
+        self._test_connect_timeout_under_200ms(loc)
+        self.server.setdelays(request=2)
+        self._test_response_timeout_under_2s(loc)
+
+    def test_timeout_slow_response(self):
+        loc = self.keepClient().put(self.DATA, copies=1, num_retries=0)
+        self.server.setdelays(response=.2)
+        self._test_connect_timeout_under_200ms(loc)
+        self.server.setdelays(response=2)
+        self._test_response_timeout_under_2s(loc)
+
+    def test_timeout_slow_response_body(self):
+        loc = self.keepClient().put(self.DATA, copies=1, num_retries=0)
+        self.server.setdelays(response_body=.2)
+        self._test_connect_timeout_under_200ms(loc)
+        self.server.setdelays(response_body=2)
+        self._test_response_timeout_under_2s(loc)
+
+    def _test_connect_timeout_under_200ms(self, loc):
+        # Allow 100ms to connect, then 1s for response. Everything
+        # should work, and everything should take at least 200ms to
+        # return.
+        kc = self.keepClient(timeouts=(.1, 1))
+        with self.assertTakesBetween(.2, .3):
+            kc.put(self.DATA, copies=1, num_retries=0)
+        with self.assertTakesBetween(.2, .3):
+            self.assertEqual(self.DATA, kc.get(loc, num_retries=0))
+
+    def _test_response_timeout_under_2s(self, loc):
+        # Allow 10s to connect, then 1s for response. Nothing should
+        # work, and everything should take at least 1s to return.
+        kc = self.keepClient(timeouts=(10, 1))
+        with self.assertTakesBetween(1, 9):
+            with self.assertRaises(arvados.errors.KeepReadError):
+                kc.get(loc, num_retries=0)
+        with self.assertTakesBetween(1, 9):
+            with self.assertRaises(arvados.errors.KeepWriteError):
+                kc.put(self.DATA, copies=1, num_retries=0)
+
+
+class KeepClientGatewayTestCase(unittest.TestCase, tutil.ApiClientMock):
+    def mock_disks_and_gateways(self, disks=3, gateways=1):
+        self.gateways = [{
+                'uuid': 'zzzzz-bi6l4-gateway{:08d}'.format(i),
+                'owner_uuid': 'zzzzz-tpzed-000000000000000',
+                'service_host': 'gatewayhost{}'.format(i),
+                'service_port': 12345,
+                'service_ssl_flag': True,
+                'service_type': 'gateway:test',
+        } for i in range(gateways)]
+        self.gateway_roots = [
+            "https://{service_host}:{service_port}/".format(**gw)
+            for gw in self.gateways]
+        self.api_client = self.mock_keep_services(
+            count=disks, additional_services=self.gateways)
+        self.keepClient = arvados.KeepClient(api_client=self.api_client)
+
+    @mock.patch('pycurl.Curl')
+    def test_get_with_gateway_hint_first(self, MockCurl):
+        MockCurl.return_value = tutil.FakeCurl.make(
+            code=200, body='foo', headers={'Content-Length': 3})
+        self.mock_disks_and_gateways()
+        locator = 'acbd18db4cc2f85cedef654fccc4a4d8+3+K@' + self.gateways[0]['uuid']
+        self.assertEqual('foo', self.keepClient.get(locator))
+        self.assertEqual(self.gateway_roots[0]+locator,
+                         MockCurl.return_value.getopt(pycurl.URL))
+        self.assertEqual(True, self.keepClient.head(locator))
+
+    @mock.patch('pycurl.Curl')
+    def test_get_with_gateway_hints_in_order(self, MockCurl):
+        gateways = 4
+        disks = 3
+        mocks = [
+            tutil.FakeCurl.make(code=404, body='')
+            for _ in range(gateways+disks)
+        ]
+        MockCurl.side_effect = tutil.queue_with(mocks)
+        self.mock_disks_and_gateways(gateways=gateways, disks=disks)
+        locator = '+'.join(['acbd18db4cc2f85cedef654fccc4a4d8+3'] +
+                           ['K@'+gw['uuid'] for gw in self.gateways])
+        with self.assertRaises(arvados.errors.NotFoundError):
+            self.keepClient.get(locator)
+        # Gateways are tried first, in the order given.
+        for i, root in enumerate(self.gateway_roots):
+            self.assertEqual(root+locator,
+                             mocks[i].getopt(pycurl.URL))
+        # Disk services are tried next.
+        for i in range(gateways, gateways+disks):
+            self.assertRegexpMatches(
+                mocks[i].getopt(pycurl.URL),
+                r'keep0x')
+
+    @mock.patch('pycurl.Curl')
+    def test_head_with_gateway_hints_in_order(self, MockCurl):
+        gateways = 4
+        disks = 3
+        mocks = [
+            tutil.FakeCurl.make(code=404, body='')
+            for _ in range(gateways+disks)
+        ]
+        MockCurl.side_effect = tutil.queue_with(mocks)
+        self.mock_disks_and_gateways(gateways=gateways, disks=disks)
+        locator = '+'.join(['acbd18db4cc2f85cedef654fccc4a4d8+3'] +
+                           ['K@'+gw['uuid'] for gw in self.gateways])
+        with self.assertRaises(arvados.errors.NotFoundError):
+            self.keepClient.head(locator)
+        # Gateways are tried first, in the order given.
+        for i, root in enumerate(self.gateway_roots):
+            self.assertEqual(root+locator,
+                             mocks[i].getopt(pycurl.URL))
+        # Disk services are tried next.
+        for i in range(gateways, gateways+disks):
+            self.assertRegexpMatches(
+                mocks[i].getopt(pycurl.URL),
+                r'keep0x')
+
+    @mock.patch('pycurl.Curl')
+    def test_get_with_remote_proxy_hint(self, MockCurl):
+        MockCurl.return_value = tutil.FakeCurl.make(
+            code=200, body='foo', headers={'Content-Length': 3})
+        self.mock_disks_and_gateways()
+        locator = 'acbd18db4cc2f85cedef654fccc4a4d8+3+K@xyzzy'
+        self.assertEqual('foo', self.keepClient.get(locator))
+        self.assertEqual('https://keep.xyzzy.arvadosapi.com/'+locator,
+                         MockCurl.return_value.getopt(pycurl.URL))
+
+    @mock.patch('pycurl.Curl')
+    def test_head_with_remote_proxy_hint(self, MockCurl):
+        MockCurl.return_value = tutil.FakeCurl.make(
+            code=200, body='foo', headers={'Content-Length': 3})
+        self.mock_disks_and_gateways()
+        locator = 'acbd18db4cc2f85cedef654fccc4a4d8+3+K@xyzzy'
+        self.assertEqual(True, self.keepClient.head(locator))
+        self.assertEqual('https://keep.xyzzy.arvadosapi.com/'+locator,
+                         MockCurl.return_value.getopt(pycurl.URL))
+
+
+class KeepClientRetryTestMixin(object):
+    # Testing with a local Keep store won't exercise the retry behavior.
+    # Instead, our strategy is:
+    # * Create a client with one proxy specified (pointed at a black
+    #   hole), so there's no need to instantiate an API client, and
+    #   all HTTP requests come from one place.
+    # * Mock httplib's request method to provide simulated responses.
+    # This lets us test the retry logic extensively without relying on any
+    # supporting servers, and prevents side effects in case something hiccups.
+    # To use this mixin, define DEFAULT_EXPECT, DEFAULT_EXCEPTION, and
+    # run_method().
+    #
+    # Test classes must define TEST_PATCHER to a method that mocks
+    # out appropriate methods in the client.
+
+    PROXY_ADDR = 'http://[%s]:65535/' % (tutil.TEST_HOST,)
+    TEST_DATA = 'testdata'
+    TEST_LOCATOR = 'ef654c40ab4f1747fc699915d4f70902+8'
+
+    def setUp(self):
+        self.client_kwargs = {'proxy': self.PROXY_ADDR, 'local_store': ''}
+
+    def new_client(self, **caller_kwargs):
+        kwargs = self.client_kwargs.copy()
+        kwargs.update(caller_kwargs)
+        return arvados.KeepClient(**kwargs)
+
+    def run_method(self, *args, **kwargs):
+        raise NotImplementedError("test subclasses must define run_method")
+
+    def check_success(self, expected=None, *args, **kwargs):
+        if expected is None:
+            expected = self.DEFAULT_EXPECT
+        self.assertEqual(expected, self.run_method(*args, **kwargs))
+
+    def check_exception(self, error_class=None, *args, **kwargs):
+        if error_class is None:
+            error_class = self.DEFAULT_EXCEPTION
+        self.assertRaises(error_class, self.run_method, *args, **kwargs)
+
+    def test_immediate_success(self):
+        with self.TEST_PATCHER(self.DEFAULT_EXPECT, 200):
+            self.check_success()
+
+    def test_retry_then_success(self):
+        with self.TEST_PATCHER(self.DEFAULT_EXPECT, 500, 200):
+            self.check_success(num_retries=3)
+
+    def test_exception_then_success(self):
+        with self.TEST_PATCHER(self.DEFAULT_EXPECT, Exception('mock err'), 200):
+            self.check_success(num_retries=3)
+
+    def test_no_default_retry(self):
+        with self.TEST_PATCHER(self.DEFAULT_EXPECT, 500, 200):
+            self.check_exception()
+
+    def test_no_retry_after_permanent_error(self):
+        with self.TEST_PATCHER(self.DEFAULT_EXPECT, 403, 200):
+            self.check_exception(num_retries=3)
+
+    def test_error_after_retries_exhausted(self):
+        with self.TEST_PATCHER(self.DEFAULT_EXPECT, 500, 500, 200):
+            self.check_exception(num_retries=1)
+
+    def test_num_retries_instance_fallback(self):
+        self.client_kwargs['num_retries'] = 3
+        with self.TEST_PATCHER(self.DEFAULT_EXPECT, 500, 200):
+            self.check_success()
+
+
+@tutil.skip_sleep
+class KeepClientRetryGetTestCase(KeepClientRetryTestMixin, unittest.TestCase):
+    DEFAULT_EXPECT = KeepClientRetryTestMixin.TEST_DATA
+    DEFAULT_EXCEPTION = arvados.errors.KeepReadError
+    HINTED_LOCATOR = KeepClientRetryTestMixin.TEST_LOCATOR + '+K@xyzzy'
+    TEST_PATCHER = staticmethod(tutil.mock_keep_responses)
+
+    def run_method(self, locator=KeepClientRetryTestMixin.TEST_LOCATOR,
+                   *args, **kwargs):
+        return self.new_client().get(locator, *args, **kwargs)
+
+    def test_specific_exception_when_not_found(self):
+        with tutil.mock_keep_responses(self.DEFAULT_EXPECT, 404, 200):
+            self.check_exception(arvados.errors.NotFoundError, num_retries=3)
+
+    def test_general_exception_with_mixed_errors(self):
+        # get should raise a NotFoundError if no server returns the block,
+        # and a high threshold of servers report that it's not found.
+        # This test rigs up 50/50 disagreement between two servers, and
+        # checks that it does not become a NotFoundError.
+        client = self.new_client()
+        with tutil.mock_keep_responses(self.DEFAULT_EXPECT, 404, 500):
+            with self.assertRaises(arvados.errors.KeepReadError) as exc_check:
+                client.get(self.HINTED_LOCATOR)
+            self.assertNotIsInstance(
+                exc_check.exception, arvados.errors.NotFoundError,
+                "mixed errors raised NotFoundError")
+
+    def test_hint_server_can_succeed_without_retries(self):
+        with tutil.mock_keep_responses(self.DEFAULT_EXPECT, 404, 200, 500):
+            self.check_success(locator=self.HINTED_LOCATOR)
+
+    def test_try_next_server_after_timeout(self):
+        with tutil.mock_keep_responses(
+                (socket.timeout("timed out"), 200),
+                (self.DEFAULT_EXPECT, 200)):
+            self.check_success(locator=self.HINTED_LOCATOR)
+
+    def test_retry_data_with_wrong_checksum(self):
+        with tutil.mock_keep_responses(
+                ('baddata', 200),
+                (self.DEFAULT_EXPECT, 200)):
+            self.check_success(locator=self.HINTED_LOCATOR)
+
+@tutil.skip_sleep
+class KeepClientRetryHeadTestCase(KeepClientRetryTestMixin, unittest.TestCase):
+    DEFAULT_EXPECT = True
+    DEFAULT_EXCEPTION = arvados.errors.KeepReadError
+    HINTED_LOCATOR = KeepClientRetryTestMixin.TEST_LOCATOR + '+K@xyzzy'
+    TEST_PATCHER = staticmethod(tutil.mock_keep_responses)
+
+    def run_method(self, locator=KeepClientRetryTestMixin.TEST_LOCATOR,
+                   *args, **kwargs):
+        return self.new_client().head(locator, *args, **kwargs)
+
+    def test_specific_exception_when_not_found(self):
+        with tutil.mock_keep_responses(self.DEFAULT_EXPECT, 404, 200):
+            self.check_exception(arvados.errors.NotFoundError, num_retries=3)
+
+    def test_general_exception_with_mixed_errors(self):
+        # head should raise a NotFoundError if no server returns the block,
+        # and a high threshold of servers report that it's not found.
+        # This test rigs up 50/50 disagreement between two servers, and
+        # checks that it does not become a NotFoundError.
+        client = self.new_client()
+        with tutil.mock_keep_responses(self.DEFAULT_EXPECT, 404, 500):
+            with self.assertRaises(arvados.errors.KeepReadError) as exc_check:
+                client.head(self.HINTED_LOCATOR)
+            self.assertNotIsInstance(
+                exc_check.exception, arvados.errors.NotFoundError,
+                "mixed errors raised NotFoundError")
+
+    def test_hint_server_can_succeed_without_retries(self):
+        with tutil.mock_keep_responses(self.DEFAULT_EXPECT, 404, 200, 500):
+            self.check_success(locator=self.HINTED_LOCATOR)
+
+    def test_try_next_server_after_timeout(self):
+        with tutil.mock_keep_responses(
+                (socket.timeout("timed out"), 200),
+                (self.DEFAULT_EXPECT, 200)):
+            self.check_success(locator=self.HINTED_LOCATOR)
+
+@tutil.skip_sleep
+class KeepClientRetryPutTestCase(KeepClientRetryTestMixin, unittest.TestCase):
+    DEFAULT_EXPECT = KeepClientRetryTestMixin.TEST_LOCATOR
+    DEFAULT_EXCEPTION = arvados.errors.KeepWriteError
+    TEST_PATCHER = staticmethod(tutil.mock_keep_responses)
+
+    def run_method(self, data=KeepClientRetryTestMixin.TEST_DATA,
+                   copies=1, *args, **kwargs):
+        return self.new_client().put(data, copies, *args, **kwargs)
+
+    def test_do_not_send_multiple_copies_to_same_server(self):
+        with tutil.mock_keep_responses(self.DEFAULT_EXPECT, 200):
+            self.check_exception(copies=2, num_retries=3)
+
+
+class AvoidOverreplication(unittest.TestCase, tutil.ApiClientMock):
+
+    class FakeKeepService(object):
+        def __init__(self, delay, will_succeed=False, will_raise=None, replicas=1):
+            self.delay = delay
+            self.will_succeed = will_succeed
+            self.will_raise = will_raise
+            self._result = {}
+            self._result['headers'] = {}
+            self._result['headers']['x-keep-replicas-stored'] = str(replicas)
+            self._result['body'] = 'foobar'
+
+        def put(self, data_hash, data, timeout):
+            time.sleep(self.delay)
+            if self.will_raise is not None:
+                raise self.will_raise
+            return self.will_succeed
+
+        def last_result(self):
+            if self.will_succeed:
+                return self._result
+
+        def finished(self):
+            return False
+    
+    def setUp(self):
+        self.copies = 3
+        self.pool = arvados.KeepClient.KeepWriterThreadPool(
+            data = 'foo',
+            data_hash = 'acbd18db4cc2f85cedef654fccc4a4d8+3',
+            max_service_replicas = self.copies,
+            copies = self.copies
+        )
+
+    def test_only_write_enough_on_success(self):
+        for i in range(10):
+            ks = self.FakeKeepService(delay=i/10.0, will_succeed=True)
+            self.pool.add_task(ks, None)
+        self.pool.join()
+        self.assertEqual(self.pool.done(), self.copies)
+
+    def test_only_write_enough_on_partial_success(self):
+        for i in range(5):
+            ks = self.FakeKeepService(delay=i/10.0, will_succeed=False)
+            self.pool.add_task(ks, None)
+            ks = self.FakeKeepService(delay=i/10.0, will_succeed=True)
+            self.pool.add_task(ks, None)
+        self.pool.join()
+        self.assertEqual(self.pool.done(), self.copies)
+
+    def test_only_write_enough_when_some_crash(self):
+        for i in range(5):
+            ks = self.FakeKeepService(delay=i/10.0, will_raise=Exception())
+            self.pool.add_task(ks, None)
+            ks = self.FakeKeepService(delay=i/10.0, will_succeed=True)
+            self.pool.add_task(ks, None)
+        self.pool.join()
+        self.assertEqual(self.pool.done(), self.copies)
+
+    def test_fail_when_too_many_crash(self):
+        for i in range(self.copies+1):
+            ks = self.FakeKeepService(delay=i/10.0, will_raise=Exception())
+            self.pool.add_task(ks, None)
+        for i in range(self.copies-1):
+            ks = self.FakeKeepService(delay=i/10.0, will_succeed=True)
+            self.pool.add_task(ks, None)
+        self.pool.join()
+        self.assertEqual(self.pool.done(), self.copies-1)
+    
+
+@tutil.skip_sleep
+class RetryNeedsMultipleServices(unittest.TestCase, tutil.ApiClientMock):
+    # Test put()s that need two distinct servers to succeed, possibly
+    # requiring multiple passes through the retry loop.
+
+    def setUp(self):
+        self.api_client = self.mock_keep_services(count=2)
+        self.keep_client = arvados.KeepClient(api_client=self.api_client)
+
+    def test_success_after_exception(self):
+        with tutil.mock_keep_responses(
+                'acbd18db4cc2f85cedef654fccc4a4d8+3',
+                Exception('mock err'), 200, 200) as req_mock:
+            self.keep_client.put('foo', num_retries=1, copies=2)
+        self.assertEqual(3, req_mock.call_count)
+
+    def test_success_after_retryable_error(self):
+        with tutil.mock_keep_responses(
+                'acbd18db4cc2f85cedef654fccc4a4d8+3',
+                500, 200, 200) as req_mock:
+            self.keep_client.put('foo', num_retries=1, copies=2)
+        self.assertEqual(3, req_mock.call_count)
 
-        self.assertEqual(True, arvados.Keep.global_client_object().using_proxy)
+    def test_fail_after_final_error(self):
+        # First retry loop gets a 200 (can't achieve replication by
+        # storing again on that server) and a 400 (can't retry that
+        # server at all), so we shouldn't try a third request.
+        with tutil.mock_keep_responses(
+                'acbd18db4cc2f85cedef654fccc4a4d8+3',
+                200, 400, 200) as req_mock:
+            with self.assertRaises(arvados.errors.KeepWriteError):
+                self.keep_client.put('foo', num_retries=1, copies=2)
+        self.assertEqual(2, req_mock.call_count)