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SNS Event Configurations

The SNS event will automatically handle many common things done when eventing off an SNS stream. Developers then have the ability to further extend that functionality with custom middleware. Below is a full list of all the configurations available and examples of their use.

Examples

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Lambda Configuration

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functions:
    sns-handler:
        handler: service/handlers/sns.handle
        memorySize: 512
        timeout: 900
        events:
            - sns:
                arn:
                    Fn::GetAtt: [ SomeTopic, 'Arn' ]

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from acai_aws.sns.requirements import requirements
from acai_aws.common import logger

@requirements(
    before=log_something,
    data_class=SomeClass,
    raise_body_error=True,
    schema='service/openapi.yml',
    required_body='v1-sns-body', # or jsonschema dict
    after=alert_something,
)
def handle(event):
    for record in event.records:
        logger.log(log=record)

# example data class
class SomeClass:
    def __init__(self, record):
        for k, v in record.body.items():
            setattr(self, k, v)

# example before function
def log_something(records, requirements):
    if 'something' in requirements:
        logger.log(log=records) 

# example after function
def alert_something(records, result, requirements):
    if 'something' in result and 'alert' in requirements:
        logger.log(log=records)

Requirements Configuration Options

option type required default description
before func no None a custom function to be ran before your records are pulled
after func no None a custom function to be ran after your records are pulled
data_class class no None a custom class that will be passed instead of the records object
raise_body_error bool no False will raise exception if body of record does not match schema provided
required_body str or dict no None will validate body of record against this schema
schema str no None file path pointing to the location of the openapi.yml file

SNS Record Properties

property type description
source str the source of the event
source_arn str the source arn of the event
region str the region of the event
body dict,str the body of the sns message
attributes dict the attributes dict of the message attributes; easier than use message attributes
message_attributes dict the message attributes of the message
version str the version sns event
subscription_arn str the subscription arn of the sns event
signature_version str the signature version of the sns event
timestamp str the timestamp of the sns event
signature str the signature of the sns event
signing_cert_url str the signing cert url of the sns event
message_id str the message id of the sns event
message str the message of the sns event
sns_type str the type of the sns event
unsubscribe_url str the unsubscribe_url of the sns event
topic_arn str the topic arn of the sns event
subject str the subject of the sns event

record.source

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print(record.source)

# output
'aws:sns'

record.source_arn

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print(record.source_arn)

# output
'arn:aws:sns:us-east-2:123456789012:my-queue'

record.region

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print(record.region)

# output
'us-east-1'

record.body

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print(record.body)

# output
{
    'key': 'value'
}

record.attributes

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print(record.attributes)

# output
{
    'SomeString': 'Some String',
    'SomeBinary': 'Some Binary',
}

record.message_attributes

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print(record.message_attributes)

# output
{
    'SomeString': {
        'DataType': 'string',
        'StringValue': 'Some String'
    },
    'SomeBinary': {
        'DataType': 'binary',
        'BinaryValue': 'Some Binary'
    }
}

record.version

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print(record.version)

# output
'1.0'

record.subscription_arn

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print(record.subscription_arn)

# output
'arn:aws:sns:us-east-1:123456789012:sns-lambda:21be56ed-a058-49f5-8c98-aedd2564c486'

record.signature_version

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print(record.signature_version)

# output
'1'

record.timestamp

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print(record.timestamp)

# output
'2019-01-02T12:45:07.000Z'

record.signature

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print(record.signature)

# output
'tcc6faL2yUC6dgZdmrwh1Y4cGa/ebXEkAi6RibDsvpi+tE/1+82j...65r=='

record.signing_cert_url

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print(record.signing_cert_url)

# output
'https://sns.us-east-1.amazonaws.com/SimpleNotificationService-ac565b8b1a6c5d002d285f9598aa1d9b.pem'

record.signing_cert_url

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print(record.signing_cert_url)

# output
'https://sns.us-east-1.amazonaws.com/SimpleNotificationService-ac565b8b1a6c5d002d285f9598aa1d9b.pem'

record.message_id

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print(record.message_id)

# output
'95df01b4-ee98-5cb9-9903-4c221d41eb5e'

record.message

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print(record.message)

# output
{
    'key': 'value'
}

record.sns_type

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print(record.sns_type)

# output
'Notification'

record.unsubscribe_url

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print(record.unsubscribe_url)

# output
'https://sns.us-east-1.amazonaws.com/?Action=Unsubscribe&SubscriptionArn=arn:aws:sns:us-east-1:123456789012:test-lambda:21be56ed-a058-49f5-8c98-aedd2564c486'

record.topic_arn

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print(record.topic_arn)

# output
'arn:aws:sns:us-east-1:123456789012:sns-lambda'

record.subject

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print(record.subject)

# output
'TestInvoke'