Class: Pheme::TopicPublisher

Inherits:
Object
  • Object
show all
Includes:
Compression
Defined in:
lib/pheme/topic_publisher.rb

Constant Summary collapse

SNS_SIZE_LIMIT =

Constant with message size limit. The message size also includes some metadata: ‘name’ and ‘type’. We give ourselves a buffer for this metadata.

Source: docs.aws.amazon.com/sns/latest/dg/SNSMessageAttributes.html#SNSMessageAttributesNTV

256.kilobytes
EXPECTED_METADATA_SIZE = 
1.kilobyte
MESSAGE_SIZE_LIMIT = 
SNS_SIZE_LIMIT - EXPECTED_METADATA_SIZE

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Compression

#compress, #decompress

Constructor Details

#initialize(topic_arn: self.class._topic_arn) ⇒ TopicPublisher

Returns a new instance of TopicPublisher.

Raises:

  • (ArgumentError) 


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# File 'lib/pheme/topic_publisher.rb', line 26

def initialize(topic_arn: self.class._topic_arn)
  raise ArgumentError, "must specify non-nil topic_arn" if topic_arn.blank?

  @topic_arn = topic_arn
end

Class Attribute Details

._topic_arn ⇒ Object (readonly)

Returns the value of attribute _topic_arn.



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# File 'lib/pheme/topic_publisher.rb', line 19

def _topic_arn
  @_topic_arn
end

Instance Attribute Details

#topic_arn ⇒ Object

Returns the value of attribute topic_arn.



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# File 'lib/pheme/topic_publisher.rb', line 31

def topic_arn
  @topic_arn
end

Class Method Details

.topic_arn(topic_arn) ⇒ Object 



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# File 'lib/pheme/topic_publisher.rb', line 21

def topic_arn(topic_arn)
  @_topic_arn = topic_arn
end

Instance Method Details

#publish(message, sns_client: Pheme.configuration.sns_client, message_attributes: nil) ⇒ Object 



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# File 'lib/pheme/topic_publisher.rb', line 37

def publish(message, sns_client: Pheme.configuration.sns_client, message_attributes: nil)
  payload = {
    message: "#{self.class} publishing message to #{topic_arn}",
    body: message,
    publisher: self.class.to_s,
    topic_arn: topic_arn,
  }
  Pheme.logger.info(payload.to_json)

  sns_client.publish(topic_arn: topic_arn, message: serialize(message), message_attributes: message_attributes)
end

#publish_events ⇒ Object

Raises:

  • (NotImplementedError) 


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# File 'lib/pheme/topic_publisher.rb', line 33

def publish_events
  raise NotImplementedError
end

#serialize(message) ⇒ Object 



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# File 'lib/pheme/topic_publisher.rb', line 49

def serialize(message)
  message = message.to_json unless message.is_a? String

  return compress(message) if message.bytesize > MESSAGE_SIZE_LIMIT

  message
end