Class: OpenTelemetry::Baggage::Propagation::TextMapExtractor

Inherits:
Object
  • Object
show all
Defined in:
lib/opentelemetry/baggage/propagation/text_map_extractor.rb

Overview

Extracts baggage from carriers in the W3C Baggage format

Instance Method Summary collapse

Constructor Details

#initialize(default_getter = Context::Propagation.text_map_getter) ⇒ TextMapExtractor

Returns a new TextMapExtractor that extracts context using the specified getter

Parameters:

  • default_getter (optional Getter) (defaults to: Context::Propagation.text_map_getter) —

    The default getter used to read headers from a carrier during extract. Defaults to a Context::Propagation::TextMapGetter instance.



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# File 'lib/opentelemetry/baggage/propagation/text_map_extractor.rb', line 21

def initialize(default_getter = Context::Propagation.text_map_getter)
  @default_getter = default_getter
end

Instance Method Details

#extract(carrier, context, getter = nil) ⇒ Context

Extract remote baggage from the supplied carrier. If extraction fails, the original context will be returned

Parameters:

  • carrier (Carrier) —

    The carrier to get the header from

  • context (Context) —

    The context to be updated with extracted baggage

  • getter (optional Getter) (defaults to: nil) —

    If the optional getter is provided, it will be used to read the header from the carrier, otherwise the default getter will be used.

Returns:

  • (Context) —

    context updated with extracted baggage, or the original context if extraction fails



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# File 'lib/opentelemetry/baggage/propagation/text_map_extractor.rb', line 35

def extract(carrier, context, getter = nil)
  getter ||= @default_getter
  header = getter.get(carrier, BAGGAGE_KEY)

  entries = header.gsub(/\s/, '').split(',')

  baggage = entries.each_with_object({}) do |entry, memo|
    # The ignored variable below holds properties as per the W3C spec.
    # OTel is not using them currently, but they might be used for
    # metadata in the future
    kv, = entry.split(';', 2)
    k, v = kv.split('=').map!(&CGI.method(:unescape))
    memo[k] = v
  end

  context.set_value(ContextKeys.baggage_key, baggage)
rescue StandardError
  context
end