feat(data-classes): add AttributeValueType to DynamoDBStreamEvent

[michaelbrewer]

Issue #, if available:

#461

Description of changes:

Changes:

• Add new enum AttributeValueType for the type of AttributeValue
• Add new property get_type to return said enum
• Add new property get_value which returns converted value
• Update docs with any revisited changes in the type conversion process

Example usage:

from aws_lambda_powertools.utilities.data_classes import event_source, DynamoDBStreamEvent
from aws_lambda_powertools.utilities.data_classes.dynamo_db_stream_event import AttributeValueType, AttributeValue
from aws_lambda_powertools.utilities.typing import LambdaContext


@event_source(data_class=DynamoDBStreamEvent)
def lambda_handler(event: DynamoDBStreamEvent, context: LambdaContext):
    for record in event.records:
        key: AttributeValue = record.dynamodb.keys["id"]
        if key == AttributeValueType.Number:
            assert key.get_value == key.n_value
            print(key.get_value)
        elif key == AttributeValueType.Map:
            assert key.get_value == key.map_value
            print(key.get_value)

Where AttributeValueType is:

class AttributeValueType(Enum):
    Binary = "B"
    BinarySet = "BS"
    Boolean = "BOOL"
    List = "L"
    Map = "M"
    Number = "N"
    NumberSet = "NS"
    Null = "NULL"
    String = "S"
    StringSet = "SS"

How AttributeValue does the raw values

Example Values:

• b_value:
  {"B": "dGhpcyB0ZXh0IGlzIGJhc2U2NC1lbmNvZGVk"}
• bs_value
  {"BS": ["U3Vubnk=", "UmFpbnk=", "U25vd3k="]}
• bool_value
  {"BOOL": True}
• list_value/l_value
  {"L": [ {"S": "Cookies"} , {"S": "Coffee"}, {"N": "3.14159"}]}
• map_value/m_value
  {"M": {"Name": {"S": "Joe"}, "Age": {"N": "35"}}}
• n_value
  {"N": "123.45"}
• ns_value
  {"NS": ["42.2", "-19", "7.5", "3.14"]}
• null_value
  {"NULL": True}
• s_value
  {"S": "Hello"}
• ss_value
  {"SS": ["Giraffe", "Hippo" ,"Zebra"]}

NOTE: All return types are Optional

Return types

Property	Description	Raw Return Type
b_value	An attribute of type Base64-encoded binary data object	str
bs_value	An attribute of type Array of Base64-encoded binary data objects	List[str]
bool_value	An attribute of type Boolean	bool
list_value l_value	An attribute of type Array of AttributeValue objects	List["AttributeValue"]
map_value m_value	An attribute of type String to AttributeValue object map	Dict[str, "AttributeValue"]
n_value	An attribute of type Number	str
ns_value	An attribute of type Number Set	List[str]
null_value	An attribute of type Null	bool
s_value	An attribute of type String	str
ss_value	An attribute of type Array of strings	List[str]

How Dynamodb Type does deserialization

DynamoDB	Python
{'NULL': True}	None
{'BOOL': True/False}	True/False
{'N': str(value)}	Decimal(str(value))
{'S': string}	string
{'B': bytes}	Binary(bytes)
{'NS': [str(value)]}	set([Decimal(str(value))])
{'SS': [string]}	set([string])
{'BS': [bytes]}	set([bytes])
{'L': list}	list
{'M': dict}	dict

Checklist

• Meet tenets criteria
• Update tests
• Update docs
• PR title follows conventional commit semantics

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[codecov-commenter]

Codecov Report

Merging #462 (ca79f4a) into develop (675cc24) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #462   +/-   ##
========================================
  Coverage    99.90%   99.90%           
========================================
  Files          105      105           
  Lines         4202     4231   +29     
  Branches       205      205           
========================================
+ Hits          4198     4227   +29     
  Misses           1        1           
  Partials         3        3           

Impacted Files	Coverage Δ
...s/utilities/data_classes/dynamo_db_stream_event.py	100.00% <100.00%> (ø)

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[michaelbrewer]

@gwlester what do you think?

[gwlester]

Looks great!

Thanks for the fast work!

[heitorlessa]

I'll release 1.17.0 tomorrow and I could get this included too, if we could have an example usage in the docs. Thanks a lot!

[gwlester]

Will this be in the next Release?

[heitorlessa]

Thanks @michaelbrewer for the changes!

I'm gonna look into the CI failures

[michaelbrewer]

Thanks @michaelbrewer for the changes!

I'm gonna look into the CI failures

Failures seem to be intermittent getting the codecov token

[heitorlessa]

Yeah I raised a ticket back then and seemed resolved for a while. I also noticed concurrent doc builds fail due to git divergence when using Mike

…

On Tue, 8 Jun 2021 at 06:17, Michael Brewer ***@***.***> wrote: Thanks @michaelbrewer <https://github.com/michaelbrewer> for the changes! I'm gonna look into the CI failures Failures seem to be intermittent getting the codecov token — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#462 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAZPQBEONM7D62KQZVLNPETTRWKWHANCNFSM46FQ3JSQ> .

[gwlester]

FYI, added it into the code (Dynamo Stream -> Lambda -> TimeStream -- for audit trail) and it works great!!!

Thanks again!

[heitorlessa]

Fantastic to hear!

…

On Wed, 9 Jun 2021 at 22:29, Gerald Leter ***@***.***> wrote: FYI, added it into the code (Dynamo Stream -> Lambda -> TimeStream -- for audit trail) and it works great!!! Thanks again! — You are receiving this because you modified the open/close state. Reply to this email directly, view it on GitHub <#462 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAZPQBESHOLPZGB4VE3GMRDTR7FL3ANCNFSM46FQ3JSQ> .