class Jaeger::Tracer

Attributes

scope_manager[R]

@return [ScopeManager] the current ScopeManager, which may be a no-op

but may not be nil.

Public Class Methods

new(reporter:, sampler:, injectors:, extractors:) click to toggle source
# File lib/jaeger/tracer.rb, line 5
def initialize(reporter:, sampler:, injectors:, extractors:)
  @reporter = reporter
  @sampler = sampler
  @injectors = injectors
  @extractors = extractors
  @scope_manager = ScopeManager.new
end

Public Instance Methods

active_span() click to toggle source

@return [Span, nil] the active span. This is a shorthand for

`scope_manager.active.span`, and nil will be returned if
Scope#active is nil.
# File lib/jaeger/tracer.rb, line 20
def active_span
  scope = scope_manager.active
  scope.span if scope
end
extract(format, carrier) click to toggle source

Extract a SpanContext in the given format from the given carrier.

@param format [OpenTracing::FORMAT_TEXT_MAP, OpenTracing::FORMAT_BINARY, OpenTracing::FORMAT_RACK] @param carrier [Carrier] A carrier object of the type dictated by the specified `format` @return [SpanContext] the extracted SpanContext or nil if none could be found

# File lib/jaeger/tracer.rb, line 157
def extract(format, carrier)
  @extractors
    .fetch(format)
    .lazy
    .map { |extractor| extractor.extract(carrier) }
    .reject(&:nil?)
    .first
end
inject(span_context, format, carrier) click to toggle source

Inject a SpanContext into the given carrier

@param span_context [SpanContext] @param format [OpenTracing::FORMAT_TEXT_MAP, OpenTracing::FORMAT_BINARY, OpenTracing::FORMAT_RACK] @param carrier [Carrier] A carrier object of the type dictated by the specified `format`

# File lib/jaeger/tracer.rb, line 146
def inject(span_context, format, carrier)
  @injectors.fetch(format).each do |injector|
    injector.inject(span_context, carrier)
  end
end
start_active_span(operation_name, child_of: nil, references: nil, start_time: Time.now, tags: {}, ignore_active_scope: false, finish_on_close: true, **) { |scope| ... } click to toggle source

Creates a newly started and activated Scope

If the Tracer's ScopeManager#active is not nil, no explicit references are provided, and `ignore_active_scope` is false, then an inferred References#CHILD_OF reference is created to the ScopeManager#active's SpanContext when start_active is invoked.

@param operation_name [String] The operation name for the Span @param child_of [SpanContext, Span] SpanContext that acts as a parent to

the newly-started Span. If a Span instance is provided, its
context is automatically substituted. See [Reference] for more
information.

If specified, the `references` parameter must be omitted.

@param references [Array<Reference>] An array of reference

objects that identify one or more parent SpanContexts.

@param start_time [Time] When the Span started, if not now @param tags [Hash] Tags to assign to the Span at start time @param ignore_active_scope [Boolean] whether to create an implicit

References#CHILD_OF reference to the ScopeManager#active.

@param finish_on_close [Boolean] whether span should automatically be

finished when Scope#close is called

@yield [Scope] If an optional block is passed to start_active_span it

will yield the newly-started Scope. If `finish_on_close` is true then the
Span will be finished automatically after the block is executed.

@return [Scope, Object] If passed an optional block, start_active_span

returns the block's return value, otherwise it returns the newly-started
and activated Scope
# File lib/jaeger/tracer.rb, line 112
def start_active_span(operation_name,
                      child_of: nil,
                      references: nil,
                      start_time: Time.now,
                      tags: {},
                      ignore_active_scope: false,
                      finish_on_close: true,
                      **)
  span = start_span(
    operation_name,
    child_of: child_of,
    references: references,
    start_time: start_time,
    tags: tags,
    ignore_active_scope: ignore_active_scope
  )
  scope = @scope_manager.activate(span, finish_on_close: finish_on_close)

  if block_given?
    begin
      yield scope
    ensure
      scope.close
    end
  else
    scope
  end
end
start_span(operation_name, child_of: nil, references: nil, start_time: Time.now, tags: {}, ignore_active_scope: false, **) { |span| ... } click to toggle source

Starts a new span.

This is similar to start_active_span, but the returned Span will not be registered via the ScopeManager.

@param operation_name [String] The operation name for the Span @param child_of [SpanContext, Span] SpanContext that acts as a parent to

the newly-started Span. If a Span instance is provided, its
context is automatically substituted. See [Reference] for more
information.

If specified, the `references` parameter must be omitted.

@param references [Array<Reference>] An array of reference

objects that identify one or more parent SpanContexts.

@param start_time [Time] When the Span started, if not now @param tags [Hash] Tags to assign to the Span at start time @param ignore_active_scope [Boolean] whether to create an implicit

References#CHILD_OF reference to the ScopeManager#active.

@yield [Span] If passed an optional block, start_span will yield the

newly-created span to the block. The span will be finished automatically
after the block is executed.

@return [Span, Object] If passed an optional block, start_span will return

the block's return value, otherwise it returns the newly-started Span
instance, which has not been automatically registered via the
ScopeManager
# File lib/jaeger/tracer.rb, line 51
def start_span(operation_name,
               child_of: nil,
               references: nil,
               start_time: Time.now,
               tags: {},
               ignore_active_scope: false,
               **)
  context, sampler_tags = prepare_span_context(
    operation_name: operation_name,
    child_of: child_of,
    references: references,
    ignore_active_scope: ignore_active_scope
  )
  span = Span.new(
    context,
    operation_name,
    @reporter,
    start_time: start_time,
    references: references,
    tags: tags.merge(sampler_tags)
  )

  if block_given?
    begin
      yield(span)
    ensure
      span.finish
    end
  else
    span
  end
end

Private Instance Methods

context_from_active_scope(ignore_active_scope) click to toggle source
# File lib/jaeger/tracer.rb, line 206
def context_from_active_scope(ignore_active_scope)
  return if ignore_active_scope

  active_scope = @scope_manager.active
  active_scope.span.context if active_scope
end
context_from_child_of(child_of) click to toggle source
# File lib/jaeger/tracer.rb, line 191
def context_from_child_of(child_of)
  return nil unless child_of
  child_of.respond_to?(:context) ? child_of.context : child_of
end
context_from_references(references) click to toggle source
# File lib/jaeger/tracer.rb, line 196
def context_from_references(references)
  return nil if !references || references.none?

  # Prefer CHILD_OF reference if present
  ref = references.detect do |reference|
    reference.type == OpenTracing::Reference::CHILD_OF
  end
  (ref || references[0]).context
end
prepare_span_context(operation_name:, child_of:, references:, ignore_active_scope:) click to toggle source
# File lib/jaeger/tracer.rb, line 168
def prepare_span_context(operation_name:, child_of:, references:, ignore_active_scope:)
  context =
    context_from_child_of(child_of) ||
    context_from_references(references) ||
    context_from_active_scope(ignore_active_scope)

  if context
    [SpanContext.create_from_parent_context(context), {}]
  else
    trace_id = TraceId.generate
    is_sampled, tags = @sampler.sample(
      trace_id: trace_id,
      operation_name: operation_name
    )
    span_context = SpanContext.new(
      trace_id: trace_id,
      span_id: trace_id,
      flags: is_sampled ? SpanContext::Flags::SAMPLED : SpanContext::Flags::NONE
    )
    [span_context, tags]
  end
end