Class: LambdaLoadout::Handler

Inherits:
Object
  • Object
show all
Defined in:
lib/lambda_loadout/middleware.rb

Overview

Decorator-style wrapper for Lambda handlers

Provides a simple DSL for wrapping Lambda handlers with observability.

Examples:

Basic usage

LambdaLoadout::Handler.configure do |config|
  config.service = "payment"
  config.namespace = "MyApp"
end

def lambda_handler(event:, context:)
  LambdaLoadout::Handler.call(event, context) do |logger, metrics|
    logger.info("Processing event")
    metrics.add_metric(name: "EventProcessed", unit: "Count", value: 1)

    { statusCode: 200 }
  end
end

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.capture_cold_start ⇒ Object

Returns the value of attribute capture_cold_start.



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# File 'lib/lambda_loadout/middleware.rb', line 86

def capture_cold_start
  @capture_cold_start
end

.log_level ⇒ Object

Returns the value of attribute log_level.



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# File 'lib/lambda_loadout/middleware.rb', line 86

def log_level
  @log_level
end

.namespace ⇒ Object

Returns the value of attribute namespace.



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# File 'lib/lambda_loadout/middleware.rb', line 86

def namespace
  @namespace
end

.service ⇒ Object

Returns the value of attribute service.



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# File 'lib/lambda_loadout/middleware.rb', line 86

def service
  @service
end

Class Method Details

.call(event, context, capture_cold_start: @capture_cold_start || true) {|logger, metrics| ... } ⇒ Object

Call handler with observability

Parameters:

  • event (Hash) —

    Lambda event

  • context (Object) —

    Lambda context

  • capture_cold_start (Boolean) (defaults to: @capture_cold_start || true) —

    Override cold start capture

Yields:

Returns:

  • (Object) —

    Result of block execution



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# File 'lib/lambda_loadout/middleware.rb', line 103

def call(event, context, capture_cold_start: @capture_cold_start || true, &block)
  logger = LambdaLoadout::Logger.new(
    service: @service,
    level: @log_level || :info
  )

  metrics = LambdaLoadout::Metrics.new(
    namespace: @namespace || 'LambdaLoadout',
    service: @service
  )

  logger.inject_lambda_context(context)
  logger.info('Lambda invocation started', event_keys: event.keys)

  begin
    result = block.call(logger, metrics)
    metrics.add_cold_start_metric(context) if capture_cold_start
    logger.info('Lambda invocation completed successfully')
    result
  rescue StandardError => e
    logger.exception(e, message: 'Lambda invocation failed')
    metrics.add_metric(name: 'LambdaError', unit: 'Count', value: 1)
    metrics.add_dimension(name: 'error_type', value: e.class.name)
    raise
  ensure
    begin
      metrics.flush
    rescue StandardError
      nil
    end
  end
end

.configure {|self| ... } ⇒ void

This method returns an undefined value.

Configure global handler defaults

Yields:

  • (self) —

    Configuration block



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# File 'lib/lambda_loadout/middleware.rb', line 92

def configure
  yield self
end