CodernityDB python 3

libs/CodernityDB3/sharded_hash.py

@@ -0,0 +1,146 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Copyright 2011-2013 Codernity (http://codernity.com)
+#
+# 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 CodernityDB3.hash_index import UniqueHashIndex, HashIndex
+from CodernityDB3.sharded_index import ShardedIndex
+from CodernityDB3.index import IndexPreconditionsException
+
+from random import getrandbits
+import uuid
+
+
+class IU_ShardedUniqueHashIndex(ShardedIndex):
+
+    custom_header = """import uuid
+from random import getrandbits
+from CodernityDB3.sharded_index import ShardedIndex
+"""
+
+    def __init__(self, db_path, name, *args, **kwargs):
+        if kwargs.get('sh_nums', 0) > 255:
+            raise IndexPreconditionsException("Too many shards")
+        kwargs['ind_class'] = UniqueHashIndex
+        super(IU_ShardedUniqueHashIndex, self).__init__(db_path,
+                                                        name, *args, **kwargs)
+        self.patchers.append(self.wrap_insert_id_index)
+
+    @staticmethod
+    def wrap_insert_id_index(db_obj, clean=False):
+        def _insert_id_index(_rev, data):
+            """
+            Performs insert on **id** index.
+            """
+            _id, value = db_obj.id_ind.make_key_value(data)  # may be improved
+            trg_shard = _id[:2]
+            storage = db_obj.id_ind.shards_r[trg_shard].storage
+            start, size = storage.insert(value)
+            db_obj.id_ind.insert(_id, _rev, start, size)
+            return _id
+        if not clean:
+            if hasattr(db_obj, '_insert_id_index_orig'):
+                raise IndexPreconditionsException(
+                    "Already patched, something went wrong")
+            setattr(db_obj, "_insert_id_index_orig", db_obj._insert_id_index)
+            setattr(db_obj, "_insert_id_index", _insert_id_index)
+        else:
+            setattr(db_obj, "_insert_id_index", db_obj._insert_id_index_orig)
+            delattr(db_obj, "_insert_id_index_orig")
+
+    def create_key(self):
+        h = uuid.UUID(int=getrandbits(128), version=4).hex
+        trg = self.last_used + 1
+        if trg >= self.sh_nums:
+            trg = 0
+        self.last_used = trg
+        h = '%02x%30s' % (trg, h[2:])
+        return h
+
+    def delete(self, key, *args, **kwargs):
+        trg_shard = key[:2]
+        op = self.shards_r[trg_shard]
+        return op.delete(key, *args, **kwargs)
+
+    def update(self, key, *args, **kwargs):
+        trg_shard = key[:2]
+        self.last_used = int(trg_shard, 16)
+        op = self.shards_r[trg_shard]
+        return op.update(key, *args, **kwargs)
+
+    def insert(self, key, *args, **kwargs):
+        trg_shard = key[:2]  # in most cases it's in create_key BUT not always
+        self.last_used = int(key[:2], 16)
+        op = self.shards_r[trg_shard]
+        return op.insert(key, *args, **kwargs)
+
+    def get(self, key, *args, **kwargs):
+        trg_shard = key[:2]
+        self.last_used = int(trg_shard, 16)
+        op = self.shards_r[trg_shard]
+        return op.get(key, *args, **kwargs)
+
+
+class ShardedUniqueHashIndex(IU_ShardedUniqueHashIndex):
+
+    # allow unique hash to be used directly
+    custom_header = 'from CodernityDB3.sharded_hash import IU_ShardedUniqueHashIndex'
+
+    pass
+
+
+class IU_ShardedHashIndex(ShardedIndex):
+
+    custom_header = """from CodernityDB3.sharded_index import ShardedIndex"""
+
+    def __init__(self, db_path, name, *args, **kwargs):
+        kwargs['ind_class'] = HashIndex
+        super(IU_ShardedHashIndex, self).__init__(db_path, name, *
+                                                  args, **kwargs)
+
+    def calculate_shard(self, key):
+        """
+        Must be implemented. It has to return shard to be used by key
+
+        :param key: key
+        :returns: target shard
+        :rtype: int
+        """
+        raise NotImplementedError()
+
+    def delete(self, doc_id, key, *args, **kwargs):
+        trg_shard = self.calculate_shard(key)
+        op = self.shards_r[trg_shard]
+        return op.delete(doc_id, key, *args, **kwargs)
+
+    def insert(self, doc_id, key, *args, **kwargs):
+        trg_shard = self.calculate_shard(key)
+        op = self.shards_r[trg_shard]
+        return op.insert(doc_id, key, *args, **kwargs)
+
+    def update(self, doc_id, key, *args, **kwargs):
+        trg_shard = self.calculate_shard(key)
+        op = self.shards_r[trg_shard]
+        return op.insert(doc_id, key, *args, **kwargs)
+
+    def get(self, key, *args, **kwargs):
+        trg_shard = self.calculate_shard(key)
+        op = self.shards_r[trg_shard]
+        return op.get(key, *args, **kwargs)
+
+
+class ShardedHashIndex(IU_ShardedHashIndex):
+    pass