Class: OpenTelemetry::CorrelationContext::Propagation::TextExtractor

Inherits:
Object
  • Object
show all
Includes:
OpenTelemetry::Context::Propagation::DefaultGetter
Defined in:
lib/opentelemetry/correlation_context/propagation/text_extractor.rb

Overview

Extracts correlations from carriers in the W3C Correlation Context format

Instance Method Summary collapse

Methods included from OpenTelemetry::Context::Propagation::DefaultGetter

#default_getter

Constructor Details

#initialize(correlation_context_key: 'Correlation-Context') ⇒ TextExtractor

Returns a new TextExtractor that extracts context using the specified header key

Parameters:

  • correlation_context_key (String) (defaults to: 'Correlation-Context') —

    The correlation context header key used in the carrier



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# File 'lib/opentelemetry/correlation_context/propagation/text_extractor.rb', line 22

def initialize(correlation_context_key: 'Correlation-Context')
  @correlation_context_key = correlation_context_key
end

Instance Method Details

#extract(carrier, context, &getter) {|Carrier, String| ... } ⇒ Context

Extract remote correlations 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 correlations

  • getter (optional Callable) —

    An optional callable that takes a carrier and a key and returns the value associated with the key. If omitted the default getter will be used which expects the carrier to respond to [] and []=.

Yields:

  • (Carrier, String) —

    if an optional getter is provided, extract will yield the carrier and the header key to the getter.

Returns:

  • (Context) —

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



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# File 'lib/opentelemetry/correlation_context/propagation/text_extractor.rb', line 38

def extract(carrier, context, &getter)
  getter ||= default_getter
  header = getter.call(carrier, @correlation_context_key)

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

  correlations = 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.correlation_context_key, correlations)
rescue StandardError
  context
end