Erasure Code Reconstructor

This patch adds the erasure code reconstructor. It follows the
design of the replicator but:
  - There is no notion of update() or update_deleted().
  - There is a single job processor
  - Jobs are processed partition by partition.
  - At the end of processing a rebalanced or handoff partition, the
    reconstructor will remove successfully reverted objects if any.

And various ssync changes such as the addition of reconstruct_fa()
function called from ssync_sender which performs the actual
reconstruction while sending the object to the receiver

Co-Authored-By: Alistair Coles <alistair.coles@hp.com>
Co-Authored-By: Thiago da Silva <thiago@redhat.com>
Co-Authored-By: John Dickinson <me@not.mn>
Co-Authored-By: Clay Gerrard <clay.gerrard@gmail.com>
Co-Authored-By: Tushar Gohad <tushar.gohad@intel.com>
Co-Authored-By: Samuel Merritt <sam@swiftstack.com>
Co-Authored-By: Christian Schwede <christian.schwede@enovance.com>
Co-Authored-By: Yuan Zhou <yuan.zhou@intel.com>
blueprint ec-reconstructor
Change-Id: I7d15620dc66ee646b223bb9fff700796cd6bef51

test/probe/test_reconstructor_rebuild.py

@@ -0,0 +1,170 @@
+#!/usr/bin/python -u
+# Copyright (c) 2010-2012 OpenStack Foundation
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+# implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from hashlib import md5
+import unittest
+import uuid
+import shutil
+import random
+
+from test.probe.common import ECProbeTest
+
+from swift.common import direct_client
+from swift.common.storage_policy import EC_POLICY
+from swift.common.manager import Manager
+
+from swiftclient import client
+
+
+class Body(object):
+
+    def __init__(self, total=3.5 * 2 ** 20):
+        self.total = total
+        self.hasher = md5()
+        self.size = 0
+        self.chunk = 'test' * 16 * 2 ** 10
+
+    @property
+    def etag(self):
+        return self.hasher.hexdigest()
+
+    def __iter__(self):
+        return self
+
+    def next(self):
+        if self.size > self.total:
+            raise StopIteration()
+        self.size += len(self.chunk)
+        self.hasher.update(self.chunk)
+        return self.chunk
+
+    def __next__(self):
+        return self.next()
+
+
+class TestReconstructorRebuild(ECProbeTest):
+
+    def setUp(self):
+        super(TestReconstructorRebuild, self).setUp()
+        self.container_name = 'container-%s' % uuid.uuid4()
+        self.object_name = 'object-%s' % uuid.uuid4()
+        # sanity
+        self.assertEqual(self.policy.policy_type, EC_POLICY)
+        self.reconstructor = Manager(["object-reconstructor"])
+
+    def proxy_get(self):
+        # GET object
+        headers, body = client.get_object(self.url, self.token,
+                                          self.container_name,
+                                          self.object_name,
+                                          resp_chunk_size=64 * 2 ** 10)
+        resp_checksum = md5()
+        for chunk in body:
+            resp_checksum.update(chunk)
+        return resp_checksum.hexdigest()
+
+    def direct_get(self, node, part):
+        req_headers = {'X-Backend-Storage-Policy-Index': int(self.policy)}
+        headers, data = direct_client.direct_get_object(
+            node, part, self.account, self.container_name,
+            self.object_name, headers=req_headers,
+            resp_chunk_size=64 * 2 ** 20)
+        hasher = md5()
+        for chunk in data:
+            hasher.update(chunk)
+        return hasher.hexdigest()
+
+    def _check_node(self, node, part, etag, headers_post):
+        # get fragment archive etag
+        fragment_archive_etag = self.direct_get(node, part)
+
+        # remove data from the selected node
+        part_dir = self.storage_dir('object', node, part=part)
+        shutil.rmtree(part_dir, True)
+
+        # this node can't servce the data any more
+        try:
+            self.direct_get(node, part)
+        except direct_client.DirectClientException as err:
+            self.assertEqual(err.http_status, 404)
+        else:
+            self.fail('Node data on %r was not fully destoryed!' %
+                      (node,))
+
+        # make sure we can still GET the object and its correct, the
+        # proxy is doing decode on remaining fragments to get the obj
+        self.assertEqual(etag, self.proxy_get())
+
+        # fire up reconstructor
+        self.reconstructor.once()
+
+        # fragment is rebuilt exactly as it was before!
+        self.assertEqual(fragment_archive_etag,
+                         self.direct_get(node, part))
+
+        # check meta
+        meta = client.head_object(self.url, self.token,
+                                  self.container_name,
+                                  self.object_name)
+        for key in headers_post:
+            self.assertTrue(key in meta)
+            self.assertEqual(meta[key], headers_post[key])
+
+    def _format_node(self, node):
+        return '%s#%s' % (node['device'], node['index'])
+
+    def test_main(self):
+        # create EC container
+        headers = {'X-Storage-Policy': self.policy.name}
+        client.put_container(self.url, self.token, self.container_name,
+                             headers=headers)
+
+        # PUT object
+        contents = Body()
+        headers = {'x-object-meta-foo': 'meta-foo'}
+        headers_post = {'x-object-meta-bar': 'meta-bar'}
+
+        etag = client.put_object(self.url, self.token,
+                                 self.container_name,
+                                 self.object_name,
+                                 contents=contents, headers=headers)
+        client.post_object(self.url, self.token, self.container_name,
+                           self.object_name, headers=headers_post)
+        del headers_post['X-Auth-Token']  # WTF, where did this come from?
+
+        # built up a list of node lists to kill data from,
+        # first try a single node
+        # then adjacent nodes and then nodes >1 node apart
+        opart, onodes = self.object_ring.get_nodes(
+            self.account, self.container_name, self.object_name)
+        single_node = [random.choice(onodes)]
+        adj_nodes = [onodes[0], onodes[-1]]
+        far_nodes = [onodes[0], onodes[-2]]
+        test_list = [single_node, adj_nodes, far_nodes]
+
+        for node_list in test_list:
+            for onode in node_list:
+                try:
+                    self._check_node(onode, opart, etag, headers_post)
+                except AssertionError as e:
+                    self.fail(
+                        str(e) + '\n... for node %r of scenario %r' % (
+                            self._format_node(onode),
+                            [self._format_node(n) for n in node_list]))
+
+
+if __name__ == "__main__":
+    unittest.main()