Module: Datadog::Utils

Defined in:
lib/datadog/lambda/utils/logger.rb,
lib/datadog/lambda/utils/extension.rb

Overview

Utils contains utility functions shared between modules

Constant Summary collapse

EXTENSION_PATH = 
'/opt/extensions/datadog-agent'
EXTENSION_BASE_URL = 
'http://127.0.0.1:8124'
START_INVOCATION_PATH = 
'/lambda/start-invocation'
END_INVOCATION_PATH = 
'/lambda/end-invocation'
DD_SPAN_ID_HEADER = 
'x-datadog-span-id'
DD_PARENT_ID_HEADER = 
Datadog::Tracing::Distributed::Datadog::PARENT_ID_KEY
LAMBDA_RUNTIME_AWS_REQUEST_HEADER_ID = 
'lambda-runtime-aws-request-id'
START_INVOCATION_URI = 
URI(EXTENSION_BASE_URL + START_INVOCATION_PATH).freeze
END_INVOCATION_URI = 
URI(EXTENSION_BASE_URL + END_INVOCATION_PATH).freeze
PROPAGATOR =

Internal communications use Datadog tracing headers

Tracing::Distributed::Datadog.new(
  fetcher: Tracing::Contrib::HTTP::Distributed::Fetcher
)

Class Method Summary collapse

Class Method Details

.check_extension_running ⇒ Object 



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# File 'lib/datadog/lambda/utils/extension.rb', line 41

def self.check_extension_running
  File.exist?(EXTENSION_PATH)
end

.extension_running? ⇒ Boolean 



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# File 'lib/datadog/lambda/utils/extension.rb', line 35

def self.extension_running?
  return @is_extension_running unless @is_extension_running.nil?

  @is_extension_running = check_extension_running
end

.logger ⇒ Object 



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# File 'lib/datadog/lambda/utils/logger.rb', line 16

def self.logger
  @logger ||= Logger.new($stderr).tap do |logger|
    log_level = (ENV['DD_LOG_LEVEL'] || 'error').downcase
    logger.level = case log_level
                   when 'debug'
                     Logger::DEBUG
                   when 'info'
                     Logger::INFO
                   when 'warn'
                     Logger::WARN
                   else
                     Logger::ERROR
                   end
  end
end

.request_headers ⇒ Object

rubocop:enable Metrics/AbcSize



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# File 'lib/datadog/lambda/utils/extension.rb', line 89

def self.request_headers
  {
    # Header used to avoid tracing requests that are internal to
    # Datadog products.
    Datadog::Core::Transport::Ext::HTTP::HEADER_DD_INTERNAL_UNTRACED_REQUEST.to_sym => 'true'
  }
end

.send_end_invocation_request(response:, span_id:, request_context:) ⇒ Object

rubocop:disable Metrics/AbcSize



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# File 'lib/datadog/lambda/utils/extension.rb', line 61

def self.send_end_invocation_request(response:, span_id:, request_context:)
  return unless extension_running?

  request = Net::HTTP::Post.new(END_INVOCATION_URI)
  request.body = response.to_json
  request[Datadog::Core::Transport::Ext::HTTP::HEADER_DD_INTERNAL_UNTRACED_REQUEST] = 1

  trace_digest = Datadog::Tracing.active_trace&.to_digest

  PROPAGATOR.inject!(trace_digest, request)
  # Propagator doesn't inject span_id, so we do it manually
  # It is needed for the extension to take this span id
  request[DD_SPAN_ID_HEADER] = span_id.to_s

  request[LAMBDA_RUNTIME_AWS_REQUEST_HEADER_ID] = request_context.aws_request_id

  # Remove Parent ID if it is the same as the Span ID
  request.delete(DD_PARENT_ID_HEADER) if request[DD_PARENT_ID_HEADER] == span_id.to_s
  Datadog::Utils.logger.debug "End invocation request headers: #{request.to_hash}"

  Net::HTTP.start(END_INVOCATION_URI.host, END_INVOCATION_URI.port) do |http|
    http.request(request)
  end
rescue StandardError => e
  Datadog::Utils.logger.debug "failed on end invocation request to extension: #{e}"
end

.send_start_invocation_request(event:, request_context:) ⇒ Object 



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# File 'lib/datadog/lambda/utils/extension.rb', line 45

def self.send_start_invocation_request(event:, request_context:)
  return unless extension_running?

  headers = request_headers
  headers[LAMBDA_RUNTIME_AWS_REQUEST_HEADER_ID] = request_context.aws_request_id
  response = Net::HTTP.post(START_INVOCATION_URI, event.to_json, headers)

  # Add origin, since tracer expects it for extraction
  response[Datadog::Trace::DD_ORIGIN] = 'lambda'

  PROPAGATOR.extract(response)
rescue StandardError => e
  Datadog::Utils.logger.debug "failed on start invocation request to extension: #{e}"
end