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-.. dynamodb_tut:
-
-============================================
-An Introduction to boto's DynamoDB interface
-============================================
-
-This tutorial focuses on the boto interface to AWS' DynamoDB_. This tutorial
-assumes that you have boto already downloaded and installed.
-
-.. _DynamoDB: http://aws.amazon.com/dynamodb/
-
-
-Creating a Connection
----------------------
-
-The first step in accessing DynamoDB is to create a connection to the service.
-To do so, the most straight forward way is the following::
-
- >>> import boto
- >>> conn = boto.connect_dynamodb(
- aws_access_key_id='<YOUR_AWS_KEY_ID>',
- aws_secret_access_key='<YOUR_AWS_SECRET_KEY>')
- >>> conn
- <boto.dynamodb.layer2.Layer2 object at 0x3fb3090>
-
-Bear in mind that if you have your credentials in boto config in your home
-directory, the two keyword arguments in the call above are not needed. More
-details on configuration can be found in :doc:`boto_config_tut`.
-
-The :py:func:`boto.connect_dynamodb` functions returns a
-:py:class:`boto.dynamodb.layer2.Layer2` instance, which is a high-level API
-for working with DynamoDB. Layer2 is a set of abstractions that sit atop
-the lower level :py:class:`boto.dynamodb.layer1.Layer1` API, which closely
-mirrors the Amazon DynamoDB API. For the purpose of this tutorial, we'll
-just be covering Layer2.
-
-
-Listing Tables
---------------
-
-Now that we have a DynamoDB connection object, we can then query for a list of
-existing tables in that region::
-
- >>> conn.list_tables()
- ['test-table', 'another-table']
-
-
-Creating Tables
----------------
-
-DynamoDB tables are created with the
-:py:meth:`Layer2.create_table <boto.dynamodb.layer2.Layer2.create_table>`
-method. While DynamoDB's items (a rough equivalent to a relational DB's row)
-don't have a fixed schema, you do need to create a schema for the table's
-hash key element, and the optional range key element. This is explained in
-greater detail in DynamoDB's `Data Model`_ documentation.
-
-We'll start by defining a schema that has a hash key and a range key that
-are both keys::
-
- >>> message_table_schema = conn.create_schema(
- hash_key_name='forum_name',
- hash_key_proto_value=str,
- range_key_name='subject',
- range_key_proto_value=str
- )
-
-The next few things to determine are table name and read/write throughput. We'll
-defer explaining throughput to the DynamoDB's `Provisioned Throughput`_ docs.
-
-We're now ready to create the table::
-
- >>> table = conn.create_table(
- name='messages',
- schema=message_table_schema,
- read_units=10,
- write_units=10
- )
- >>> table
- Table(messages)
-
-This returns a :py:class:`boto.dynamodb.table.Table` instance, which provides
-simple ways to create (put), update, and delete items.
-
-
-Getting a Table
----------------
-
-To retrieve an existing table, use
-:py:meth:`Layer2.get_table <boto.dynamodb.layer2.Layer2.get_table>`::
-
- >>> conn.list_tables()
- ['test-table', 'another-table', 'messages']
- >>> table = conn.get_table('messages')
- >>> table
- Table(messages)
-
-:py:meth:`Layer2.get_table <boto.dynamodb.layer2.Layer2.get_table>`, like
-:py:meth:`Layer2.create_table <boto.dynamodb.layer2.Layer2.create_table>`,
-returns a :py:class:`boto.dynamodb.table.Table` instance.
-
-Keep in mind that :py:meth:`Layer2.get_table <boto.dynamodb.layer2.Layer2.get_table>`
-will make an API call to retrieve various attributes of the table including the
-creation time, the read and write capacity, and the table schema. If you
-already know the schema, you can save an API call and create a
-:py:class:`boto.dynamodb.table.Table` object without making any calls to
-Amazon DynamoDB::
-
- >>> table = conn.table_from_schema(
- name='messages',
- schema=message_table_schema)
-
-If you do this, the following fields will have ``None`` values:
-
- * create_time
- * status
- * read_units
- * write_units
-
-In addition, the ``item_count`` and ``size_bytes`` will be 0.
-If you create a table object directly from a schema object and
-decide later that you need to retrieve any of these additional
-attributes, you can use the
-:py:meth:`Table.refresh <boto.dynamodb.table.Table.refresh>` method::
-
- >>> from boto.dynamodb.schema import Schema
- >>> table = conn.table_from_schema(
- name='messages',
- schema=Schema.create(hash_key=('forum_name', 'S'),
- range_key=('subject', 'S')))
- >>> print table.write_units
- None
- >>> # Now we decide we need to know the write_units:
- >>> table.refresh()
- >>> print table.write_units
- 10
-
-
-The recommended best practice is to retrieve a table object once and
-use that object for the duration of your application. So, for example,
-instead of this::
-
- class Application(object):
- def __init__(self, layer2):
- self._layer2 = layer2
-
- def retrieve_item(self, table_name, key):
- return self._layer2.get_table(table_name).get_item(key)
-
-You can do something like this instead::
-
- class Application(object):
- def __init__(self, layer2):
- self._layer2 = layer2
- self._tables_by_name = {}
-
- def retrieve_item(self, table_name, key):
- table = self._tables_by_name.get(table_name)
- if table is None:
- table = self._layer2.get_table(table_name)
- self._tables_by_name[table_name] = table
- return table.get_item(key)
-
-
-Describing Tables
------------------
-
-To get a complete description of a table, use
-:py:meth:`Layer2.describe_table <boto.dynamodb.layer2.Layer2.describe_table>`::
-
- >>> conn.list_tables()
- ['test-table', 'another-table', 'messages']
- >>> conn.describe_table('messages')
- {
- 'Table': {
- 'CreationDateTime': 1327117581.624,
- 'ItemCount': 0,
- 'KeySchema': {
- 'HashKeyElement': {
- 'AttributeName': 'forum_name',
- 'AttributeType': 'S'
- },
- 'RangeKeyElement': {
- 'AttributeName': 'subject',
- 'AttributeType': 'S'
- }
- },
- 'ProvisionedThroughput': {
- 'ReadCapacityUnits': 10,
- 'WriteCapacityUnits': 10
- },
- 'TableName': 'messages',
- 'TableSizeBytes': 0,
- 'TableStatus': 'ACTIVE'
- }
- }
-
-
-Adding Items
-------------
-
-Continuing on with our previously created ``messages`` table, adding an::
-
- >>> table = conn.get_table('messages')
- >>> item_data = {
- 'Body': 'http://url_to_lolcat.gif',
- 'SentBy': 'User A',
- 'ReceivedTime': '12/9/2011 11:36:03 PM',
- }
- >>> item = table.new_item(
- # Our hash key is 'forum'
- hash_key='LOLCat Forum',
- # Our range key is 'subject'
- range_key='Check this out!',
- # This has the
- attrs=item_data
- )
-
-The
-:py:meth:`Table.new_item <boto.dynamodb.table.Table.new_item>` method creates
-a new :py:class:`boto.dynamodb.item.Item` instance with your specified
-hash key, range key, and attributes already set.
-:py:class:`Item <boto.dynamodb.item.Item>` is a :py:class:`dict` sub-class,
-meaning you can edit your data as such::
-
- item['a_new_key'] = 'testing'
- del item['a_new_key']
-
-After you are happy with the contents of the item, use
-:py:meth:`Item.put <boto.dynamodb.item.Item.put>` to commit it to DynamoDB::
-
- >>> item.put()
-
-
-Retrieving Items
-----------------
-
-Now, let's check if it got added correctly. Since DynamoDB works under an
-'eventual consistency' mode, we need to specify that we wish a consistent read,
-as follows::
-
- >>> table = conn.get_table('messages')
- >>> item = table.get_item(
- # Your hash key was 'forum_name'
- hash_key='LOLCat Forum',
- # Your range key was 'subject'
- range_key='Check this out!'
- )
- >>> item
- {
- # Note that this was your hash key attribute (forum_name)
- 'forum_name': 'LOLCat Forum',
- # This is your range key attribute (subject)
- 'subject': 'Check this out!'
- 'Body': 'http://url_to_lolcat.gif',
- 'ReceivedTime': '12/9/2011 11:36:03 PM',
- 'SentBy': 'User A',
- }
-
-
-Updating Items
---------------
-
-To update an item's attributes, simply retrieve it, modify the value, then
-:py:meth:`Item.put <boto.dynamodb.item.Item.put>` it again::
-
- >>> table = conn.get_table('messages')
- >>> item = table.get_item(
- hash_key='LOLCat Forum',
- range_key='Check this out!'
- )
- >>> item['SentBy'] = 'User B'
- >>> item.put()
-
-Working with Decimals
----------------------
-
-To avoid the loss of precision, you can stipulate that the
-``decimal.Decimal`` type be used for numeric values::
-
- >>> import decimal
- >>> conn.use_decimals()
- >>> table = conn.get_table('messages')
- >>> item = table.new_item(
- hash_key='LOLCat Forum',
- range_key='Check this out!'
- )
- >>> item['decimal_type'] = decimal.Decimal('1.12345678912345')
- >>> item.put()
- >>> print table.get_item('LOLCat Forum', 'Check this out!')
- {u'forum_name': 'LOLCat Forum', u'decimal_type': Decimal('1.12345678912345'),
- u'subject': 'Check this out!'}
-
-You can enable the usage of ``decimal.Decimal`` by using either the ``use_decimals``
-method, or by passing in the
-:py:class:`Dynamizer <boto.dynamodb.types.Dynamizer>` class for
-the ``dynamizer`` param::
-
- >>> from boto.dynamodb.types import Dynamizer
- >>> conn = boto.connect_dynamodb(dynamizer=Dynamizer)
-
-This mechanism can also be used if you want to customize the encoding/decoding
-process of DynamoDB types.
-
-
-Deleting Items
---------------
-
-To delete items, use the
-:py:meth:`Item.delete <boto.dynamodb.item.Item.delete>` method::
-
- >>> table = conn.get_table('messages')
- >>> item = table.get_item(
- hash_key='LOLCat Forum',
- range_key='Check this out!'
- )
- >>> item.delete()
-
-
-Deleting Tables
----------------
-
-.. WARNING::
- Deleting a table will also **permanently** delete all of its contents without prompt. Use carefully.
-
-There are two easy ways to delete a table. Through your top-level
-:py:class:`Layer2 <boto.dynamodb.layer2.Layer2>` object::
-
- >>> conn.delete_table(table)
-
-Or by getting the table, then using
-:py:meth:`Table.delete <boto.dynamodb.table.Table.delete>`::
-
- >>> table = conn.get_table('messages')
- >>> table.delete()
-
-
-.. _Data Model: http://docs.amazonwebservices.com/amazondynamodb/latest/developerguide/DataModel.html
-.. _Provisioned Throughput: http://docs.amazonwebservices.com/amazondynamodb/latest/developerguide/ProvisionedThroughputIntro.html
+.. dynamodb_tut:
+
+============================================
+An Introduction to boto's DynamoDB interface
+============================================
+
+This tutorial focuses on the boto interface to AWS' DynamoDB_. This tutorial
+assumes that you have boto already downloaded and installed.
+
+.. _DynamoDB: http://aws.amazon.com/dynamodb/
+
+
+Creating a Connection
+---------------------
+
+The first step in accessing DynamoDB is to create a connection to the service.
+To do so, the most straight forward way is the following::
+
+ >>> import boto.dynamodb
+ >>> conn = boto.dynamodb.connect_to_region(
+ 'us-west-2',
+ aws_access_key_id='<YOUR_AWS_KEY_ID>',
+ aws_secret_access_key='<YOUR_AWS_SECRET_KEY>')
+ >>> conn
+ <boto.dynamodb.layer2.Layer2 object at 0x3fb3090>
+
+Bear in mind that if you have your credentials in boto config in your home
+directory, the two keyword arguments in the call above are not needed. More
+details on configuration can be found in :doc:`boto_config_tut`.
+
+The :py:func:`boto.dynamodb.connect_to_region` function returns a
+:py:class:`boto.dynamodb.layer2.Layer2` instance, which is a high-level API
+for working with DynamoDB. Layer2 is a set of abstractions that sit atop
+the lower level :py:class:`boto.dynamodb.layer1.Layer1` API, which closely
+mirrors the Amazon DynamoDB API. For the purpose of this tutorial, we'll
+just be covering Layer2.
+
+
+Listing Tables
+--------------
+
+Now that we have a DynamoDB connection object, we can then query for a list of
+existing tables in that region::
+
+ >>> conn.list_tables()
+ ['test-table', 'another-table']
+
+
+Creating Tables
+---------------
+
+DynamoDB tables are created with the
+:py:meth:`Layer2.create_table <boto.dynamodb.layer2.Layer2.create_table>`
+method. While DynamoDB's items (a rough equivalent to a relational DB's row)
+don't have a fixed schema, you do need to create a schema for the table's
+hash key element, and the optional range key element. This is explained in
+greater detail in DynamoDB's `Data Model`_ documentation.
+
+We'll start by defining a schema that has a hash key and a range key that
+are both strings::
+
+ >>> message_table_schema = conn.create_schema(
+ hash_key_name='forum_name',
+ hash_key_proto_value=str,
+ range_key_name='subject',
+ range_key_proto_value=str
+ )
+
+The next few things to determine are table name and read/write throughput. We'll
+defer explaining throughput to the DynamoDB's `Provisioned Throughput`_ docs.
+
+We're now ready to create the table::
+
+ >>> table = conn.create_table(
+ name='messages',
+ schema=message_table_schema,
+ read_units=10,
+ write_units=10
+ )
+ >>> table
+ Table(messages)
+
+This returns a :py:class:`boto.dynamodb.table.Table` instance, which provides
+simple ways to create (put), update, and delete items.
+
+
+Getting a Table
+---------------
+
+To retrieve an existing table, use
+:py:meth:`Layer2.get_table <boto.dynamodb.layer2.Layer2.get_table>`::
+
+ >>> conn.list_tables()
+ ['test-table', 'another-table', 'messages']
+ >>> table = conn.get_table('messages')
+ >>> table
+ Table(messages)
+
+:py:meth:`Layer2.get_table <boto.dynamodb.layer2.Layer2.get_table>`, like
+:py:meth:`Layer2.create_table <boto.dynamodb.layer2.Layer2.create_table>`,
+returns a :py:class:`boto.dynamodb.table.Table` instance.
+
+Keep in mind that :py:meth:`Layer2.get_table <boto.dynamodb.layer2.Layer2.get_table>`
+will make an API call to retrieve various attributes of the table including the
+creation time, the read and write capacity, and the table schema. If you
+already know the schema, you can save an API call and create a
+:py:class:`boto.dynamodb.table.Table` object without making any calls to
+Amazon DynamoDB::
+
+ >>> table = conn.table_from_schema(
+ name='messages',
+ schema=message_table_schema)
+
+If you do this, the following fields will have ``None`` values:
+
+ * create_time
+ * status
+ * read_units
+ * write_units
+
+In addition, the ``item_count`` and ``size_bytes`` will be 0.
+If you create a table object directly from a schema object and
+decide later that you need to retrieve any of these additional
+attributes, you can use the
+:py:meth:`Table.refresh <boto.dynamodb.table.Table.refresh>` method::
+
+ >>> from boto.dynamodb.schema import Schema
+ >>> table = conn.table_from_schema(
+ name='messages',
+ schema=Schema.create(hash_key=('forum_name', 'S'),
+ range_key=('subject', 'S')))
+ >>> print table.write_units
+ None
+ >>> # Now we decide we need to know the write_units:
+ >>> table.refresh()
+ >>> print table.write_units
+ 10
+
+
+The recommended best practice is to retrieve a table object once and
+use that object for the duration of your application. So, for example,
+instead of this::
+
+ class Application(object):
+ def __init__(self, layer2):
+ self._layer2 = layer2
+
+ def retrieve_item(self, table_name, key):
+ return self._layer2.get_table(table_name).get_item(key)
+
+You can do something like this instead::
+
+ class Application(object):
+ def __init__(self, layer2):
+ self._layer2 = layer2
+ self._tables_by_name = {}
+
+ def retrieve_item(self, table_name, key):
+ table = self._tables_by_name.get(table_name)
+ if table is None:
+ table = self._layer2.get_table(table_name)
+ self._tables_by_name[table_name] = table
+ return table.get_item(key)
+
+
+Describing Tables
+-----------------
+
+To get a complete description of a table, use
+:py:meth:`Layer2.describe_table <boto.dynamodb.layer2.Layer2.describe_table>`::
+
+ >>> conn.list_tables()
+ ['test-table', 'another-table', 'messages']
+ >>> conn.describe_table('messages')
+ {
+ 'Table': {
+ 'CreationDateTime': 1327117581.624,
+ 'ItemCount': 0,
+ 'KeySchema': {
+ 'HashKeyElement': {
+ 'AttributeName': 'forum_name',
+ 'AttributeType': 'S'
+ },
+ 'RangeKeyElement': {
+ 'AttributeName': 'subject',
+ 'AttributeType': 'S'
+ }
+ },
+ 'ProvisionedThroughput': {
+ 'ReadCapacityUnits': 10,
+ 'WriteCapacityUnits': 10
+ },
+ 'TableName': 'messages',
+ 'TableSizeBytes': 0,
+ 'TableStatus': 'ACTIVE'
+ }
+ }
+
+
+Adding Items
+------------
+
+Continuing on with our previously created ``messages`` table, adding an::
+
+ >>> table = conn.get_table('messages')
+ >>> item_data = {
+ 'Body': 'http://url_to_lolcat.gif',
+ 'SentBy': 'User A',
+ 'ReceivedTime': '12/9/2011 11:36:03 PM',
+ }
+ >>> item = table.new_item(
+ # Our hash key is 'forum'
+ hash_key='LOLCat Forum',
+ # Our range key is 'subject'
+ range_key='Check this out!',
+ # This has the
+ attrs=item_data
+ )
+
+The
+:py:meth:`Table.new_item <boto.dynamodb.table.Table.new_item>` method creates
+a new :py:class:`boto.dynamodb.item.Item` instance with your specified
+hash key, range key, and attributes already set.
+:py:class:`Item <boto.dynamodb.item.Item>` is a :py:class:`dict` sub-class,
+meaning you can edit your data as such::
+
+ item['a_new_key'] = 'testing'
+ del item['a_new_key']
+
+After you are happy with the contents of the item, use
+:py:meth:`Item.put <boto.dynamodb.item.Item.put>` to commit it to DynamoDB::
+
+ >>> item.put()
+
+
+Retrieving Items
+----------------
+
+Now, let's check if it got added correctly. Since DynamoDB works under an
+'eventual consistency' mode, we need to specify that we wish a consistent read,
+as follows::
+
+ >>> table = conn.get_table('messages')
+ >>> item = table.get_item(
+ # Your hash key was 'forum_name'
+ hash_key='LOLCat Forum',
+ # Your range key was 'subject'
+ range_key='Check this out!'
+ )
+ >>> item
+ {
+ # Note that this was your hash key attribute (forum_name)
+ 'forum_name': 'LOLCat Forum',
+ # This is your range key attribute (subject)
+ 'subject': 'Check this out!'
+ 'Body': 'http://url_to_lolcat.gif',
+ 'ReceivedTime': '12/9/2011 11:36:03 PM',
+ 'SentBy': 'User A',
+ }
+
+
+Updating Items
+--------------
+
+To update an item's attributes, simply retrieve it, modify the value, then
+:py:meth:`Item.put <boto.dynamodb.item.Item.put>` it again::
+
+ >>> table = conn.get_table('messages')
+ >>> item = table.get_item(
+ hash_key='LOLCat Forum',
+ range_key='Check this out!'
+ )
+ >>> item['SentBy'] = 'User B'
+ >>> item.put()
+
+Working with Decimals
+---------------------
+
+To avoid the loss of precision, you can stipulate that the
+``decimal.Decimal`` type be used for numeric values::
+
+ >>> import decimal
+ >>> conn.use_decimals()
+ >>> table = conn.get_table('messages')
+ >>> item = table.new_item(
+ hash_key='LOLCat Forum',
+ range_key='Check this out!'
+ )
+ >>> item['decimal_type'] = decimal.Decimal('1.12345678912345')
+ >>> item.put()
+ >>> print table.get_item('LOLCat Forum', 'Check this out!')
+ {u'forum_name': 'LOLCat Forum', u'decimal_type': Decimal('1.12345678912345'),
+ u'subject': 'Check this out!'}
+
+You can enable the usage of ``decimal.Decimal`` by using either the ``use_decimals``
+method, or by passing in the
+:py:class:`Dynamizer <boto.dynamodb.types.Dynamizer>` class for
+the ``dynamizer`` param::
+
+ >>> from boto.dynamodb.types import Dynamizer
+ >>> conn = boto.dynamodb.connect_to_region(dynamizer=Dynamizer)
+
+This mechanism can also be used if you want to customize the encoding/decoding
+process of DynamoDB types.
+
+
+Deleting Items
+--------------
+
+To delete items, use the
+:py:meth:`Item.delete <boto.dynamodb.item.Item.delete>` method::
+
+ >>> table = conn.get_table('messages')
+ >>> item = table.get_item(
+ hash_key='LOLCat Forum',
+ range_key='Check this out!'
+ )
+ >>> item.delete()
+
+
+Deleting Tables
+---------------
+
+.. WARNING::
+ Deleting a table will also **permanently** delete all of its contents without prompt. Use carefully.
+
+There are two easy ways to delete a table. Through your top-level
+:py:class:`Layer2 <boto.dynamodb.layer2.Layer2>` object::
+
+ >>> conn.delete_table(table)
+
+Or by getting the table, then using
+:py:meth:`Table.delete <boto.dynamodb.table.Table.delete>`::
+
+ >>> table = conn.get_table('messages')
+ >>> table.delete()
+
+
+.. _Data Model: http://docs.amazonwebservices.com/amazondynamodb/latest/developerguide/DataModel.html
+.. _Provisioned Throughput: http://docs.amazonwebservices.com/amazondynamodb/latest/developerguide/ProvisionedThroughputIntro.html