1 # Copyright (c) 2012 Mitch Garnaat http://garnaat.org/ 2 # Copyright (c) 2012 Amazon.com, Inc. or its affiliates. All Rights Reserved 3 # 4 # Permission is hereby granted, free of charge, to any person obtaining a 5 # copy of this software and associated documentation files (the 6 # "Software"), to deal in the Software without restriction, including 7 # without limitation the rights to use, copy, modify, merge, publish, dis- 8 # tribute, sublicense, and/or sell copies of the Software, and to permit 9 # persons to whom the Software is furnished to do so, subject to the fol- 10 # lowing conditions: 11 # 12 # The above copyright notice and this permission notice shall be included 13 # in all copies or substantial portions of the Software. 14 # 15 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 16 # OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABIL- 17 # ITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT 18 # SHALL THE AUTHOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 19 # WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 20 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS 21 # IN THE SOFTWARE. 22 # 23 from boto.compat import six 24 25 26 class Batch(object): 27 """ 28 Used to construct a BatchGet request. 29 30 :ivar table: The Table object from which the item is retrieved. 31 32 :ivar keys: A list of scalar or tuple values. Each element in the 33 list represents one Item to retrieve. If the schema for the 34 table has both a HashKey and a RangeKey, each element in the 35 list should be a tuple consisting of (hash_key, range_key). If 36 the schema for the table contains only a HashKey, each element 37 in the list should be a scalar value of the appropriate type 38 for the table schema. NOTE: The maximum number of items that 39 can be retrieved for a single operation is 100. Also, the 40 number of items retrieved is constrained by a 1 MB size limit. 41 42 :ivar attributes_to_get: A list of attribute names. 43 If supplied, only the specified attribute names will 44 be returned. Otherwise, all attributes will be returned. 45 46 :ivar consistent_read: Specify whether or not to use a 47 consistent read. Defaults to False. 48 49 """ 50 51 def __init__(self, table, keys, attributes_to_get=None, 52 consistent_read=False): 53 self.table = table 54 self.keys = keys 55 self.attributes_to_get = attributes_to_get 56 self.consistent_read = consistent_read 57 58 def to_dict(self): 59 """ 60 Convert the Batch object into the format required for Layer1. 61 """ 62 batch_dict = {} 63 key_list = [] 64 for key in self.keys: 65 if isinstance(key, tuple): 66 hash_key, range_key = key 67 else: 68 hash_key = key 69 range_key = None 70 k = self.table.layer2.build_key_from_values(self.table.schema, 71 hash_key, range_key) 72 key_list.append(k) 73 batch_dict['Keys'] = key_list 74 if self.attributes_to_get: 75 batch_dict['AttributesToGet'] = self.attributes_to_get 76 if self.consistent_read: 77 batch_dict['ConsistentRead'] = True 78 else: 79 batch_dict['ConsistentRead'] = False 80 return batch_dict 81 82 83 class BatchWrite(object): 84 """ 85 Used to construct a BatchWrite request. Each BatchWrite object 86 represents a collection of PutItem and DeleteItem requests for 87 a single Table. 88 89 :ivar table: The Table object from which the item is retrieved. 90 91 :ivar puts: A list of :class:`boto.dynamodb.item.Item` objects 92 that you want to write to DynamoDB. 93 94 :ivar deletes: A list of scalar or tuple values. Each element in the 95 list represents one Item to delete. If the schema for the 96 table has both a HashKey and a RangeKey, each element in the 97 list should be a tuple consisting of (hash_key, range_key). If 98 the schema for the table contains only a HashKey, each element 99 in the list should be a scalar value of the appropriate type 100 for the table schema. 101 """ 102 103 def __init__(self, table, puts=None, deletes=None): 104 self.table = table 105 self.puts = puts or [] 106 self.deletes = deletes or [] 107 108 def to_dict(self): 109 """ 110 Convert the Batch object into the format required for Layer1. 111 """ 112 op_list = [] 113 for item in self.puts: 114 d = {'Item': self.table.layer2.dynamize_item(item)} 115 d = {'PutRequest': d} 116 op_list.append(d) 117 for key in self.deletes: 118 if isinstance(key, tuple): 119 hash_key, range_key = key 120 else: 121 hash_key = key 122 range_key = None 123 k = self.table.layer2.build_key_from_values(self.table.schema, 124 hash_key, range_key) 125 d = {'Key': k} 126 op_list.append({'DeleteRequest': d}) 127 return (self.table.name, op_list) 128 129 130 class BatchList(list): 131 """ 132 A subclass of a list object that contains a collection of 133 :class:`boto.dynamodb.batch.Batch` objects. 134 """ 135 136 def __init__(self, layer2): 137 list.__init__(self) 138 self.unprocessed = None 139 self.layer2 = layer2 140 141 def add_batch(self, table, keys, attributes_to_get=None, 142 consistent_read=False): 143 """ 144 Add a Batch to this BatchList. 145 146 :type table: :class:`boto.dynamodb.table.Table` 147 :param table: The Table object in which the items are contained. 148 149 :type keys: list 150 :param keys: A list of scalar or tuple values. Each element in the 151 list represents one Item to retrieve. If the schema for the 152 table has both a HashKey and a RangeKey, each element in the 153 list should be a tuple consisting of (hash_key, range_key). If 154 the schema for the table contains only a HashKey, each element 155 in the list should be a scalar value of the appropriate type 156 for the table schema. NOTE: The maximum number of items that 157 can be retrieved for a single operation is 100. Also, the 158 number of items retrieved is constrained by a 1 MB size limit. 159 160 :type attributes_to_get: list 161 :param attributes_to_get: A list of attribute names. 162 If supplied, only the specified attribute names will 163 be returned. Otherwise, all attributes will be returned. 164 """ 165 self.append(Batch(table, keys, attributes_to_get, consistent_read)) 166 167 def resubmit(self): 168 """ 169 Resubmit the batch to get the next result set. The request object is 170 rebuild from scratch meaning that all batch added between ``submit`` 171 and ``resubmit`` will be lost. 172 173 Note: This method is experimental and subject to changes in future releases 174 """ 175 del self[:] 176 177 if not self.unprocessed: 178 return None 179 180 for table_name, table_req in six.iteritems(self.unprocessed): 181 table_keys = table_req['Keys'] 182 table = self.layer2.get_table(table_name) 183 184 keys = [] 185 for key in table_keys: 186 h = key['HashKeyElement'] 187 r = None 188 if 'RangeKeyElement' in key: 189 r = key['RangeKeyElement'] 190 keys.append((h, r)) 191 192 attributes_to_get = None 193 if 'AttributesToGet' in table_req: 194 attributes_to_get = table_req['AttributesToGet'] 195 196 self.add_batch(table, keys, attributes_to_get=attributes_to_get) 197 198 return self.submit() 199 200 def submit(self): 201 res = self.layer2.batch_get_item(self) 202 if 'UnprocessedKeys' in res: 203 self.unprocessed = res['UnprocessedKeys'] 204 return res 205 206 def to_dict(self): 207 """ 208 Convert a BatchList object into format required for Layer1. 209 """ 210 d = {} 211 for batch in self: 212 b = batch.to_dict() 213 if b['Keys']: 214 d[batch.table.name] = b 215 return d 216 217 218 class BatchWriteList(list): 219 """ 220 A subclass of a list object that contains a collection of 221 :class:`boto.dynamodb.batch.BatchWrite` objects. 222 """ 223 224 def __init__(self, layer2): 225 list.__init__(self) 226 self.layer2 = layer2 227 228 def add_batch(self, table, puts=None, deletes=None): 229 """ 230 Add a BatchWrite to this BatchWriteList. 231 232 :type table: :class:`boto.dynamodb.table.Table` 233 :param table: The Table object in which the items are contained. 234 235 :type puts: list of :class:`boto.dynamodb.item.Item` objects 236 :param puts: A list of items that you want to write to DynamoDB. 237 238 :type deletes: A list 239 :param deletes: A list of scalar or tuple values. Each element 240 in the list represents one Item to delete. If the schema 241 for the table has both a HashKey and a RangeKey, each 242 element in the list should be a tuple consisting of 243 (hash_key, range_key). If the schema for the table 244 contains only a HashKey, each element in the list should 245 be a scalar value of the appropriate type for the table 246 schema. 247 """ 248 self.append(BatchWrite(table, puts, deletes)) 249 250 def submit(self): 251 return self.layer2.batch_write_item(self) 252 253 def to_dict(self): 254 """ 255 Convert a BatchWriteList object into format required for Layer1. 256 """ 257 d = {} 258 for batch in self: 259 table_name, batch_dict = batch.to_dict() 260 d[table_name] = batch_dict 261 return d 262
