Class: Logasm::Tracer

Inherits:
Object
  • Object
show all
Defined in:
lib/logasm/tracer.rb,
lib/logasm/tracer/span.rb,
lib/logasm/tracer/version.rb,
lib/logasm/tracer/trace_id.rb,
lib/logasm/tracer/span_context.rb

Overview

Implements OpenTracing API

See github.com/opentracing/opentracing-ruby/blob/master/lib/opentracing.rb and github.com/opentracing/opentracing-ruby/blob/master/lib/opentracing/tracer.rb

Defined Under Namespace

Modules: TraceId Classes: Span, SpanContext

Constant Summary collapse

FORMAT_TEXT_MAP = 
1
FORMAT_BINARY = 
2
FORMAT_RACK = 
3
VERSION = 
"0.2.1"

Instance Method Summary collapse

Constructor Details

#initialize(logger) ⇒ Tracer

Returns a new instance of Tracer.



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# File 'lib/logasm/tracer.rb', line 16

def initialize(logger)
  @logger = logger
end

Instance Method Details

#extract(format, carrier) ⇒ SpanContext

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

Parameters:

  • format (OpenTracing::FORMAT_TEXT_MAP, OpenTracing::FORMAT_BINARY, OpenTracing::FORMAT_RACK)
  • carrier (Carrier) —

    A carrier object of the type dictated by the specified ‘format`

Returns:

  • (SpanContext) —

    the extracted SpanContext or nil if none could be found



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# File 'lib/logasm/tracer.rb', line 67

def extract(format, carrier)
  case format
  when FORMAT_TEXT_MAP
    trace_id = carrier['trace-id']
    parent_id = carrier['parent-id']
    span_id = carrier['span-id']

    if trace_id && span_id
      SpanContext.new(trace_id: trace_id, parent_id: parent_id, span_id: span_id)
    else
      nil
    end
  when FORMAT_RACK
    trace_id = carrier['X-Trace-Id']
    parent_id = carrier['X-Trace-Parent-Id']
    span_id = carrier['X-Trace-Span-Id']

    if trace_id && span_id
      SpanContext.new(trace_id: trace_id, parent_id: parent_id, span_id: span_id)
    else
      nil
    end
  else
    @logger.error "Logasm::Tracer with format #{format} is not supported yet"
    nil
  end
end

#inject(span_context, format, carrier) ⇒ Object

Inject a SpanContext into the given carrier

Parameters:

  • span_context (SpanContext)
  • format (OpenTracing::FORMAT_TEXT_MAP, OpenTracing::FORMAT_BINARY, OpenTracing::FORMAT_RACK)
  • carrier (Carrier) —

    A carrier object of the type dictated by the specified ‘format`



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# File 'lib/logasm/tracer.rb', line 47

def inject(span_context, format, carrier)
  case format
  when FORMAT_TEXT_MAP
    carrier['trace-id'] = span_context.trace_id
    carrier['parent-id'] = span_context.parent_id
    carrier['span-id'] = span_context.span_id
  when FORMAT_RACK
    carrier['X-Trace-Id'] = span_context.trace_id
    carrier['X-Trace-Parent-Id'] = span_context.parent_id
    carrier['X-Trace-Span-Id'] = span_context.span_id
  else
    @logger.error "Logasm::Tracer with format #{format} is not supported yet"
  end
end

#start_span(operation_name, child_of: nil, start_time: Time.now, tags: {}) ⇒ Span

Starts a new span.

Parameters:

  • operation_name (String) —

    The operation name for the Span

  • child_of (SpanContext, Span) (defaults to: nil) —

    SpanContext that acts as a parent to the newly-started Span. If a Span instance is provided, its context is automatically substituted.

  • start_time (Time) (defaults to: Time.now) —

    When the Span started, if not now

  • tags (Hash) (defaults to: {}) —

    Tags to assign to the Span at start time

Returns:

  • (Span) —

    The newly-started Span



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# File 'lib/logasm/tracer.rb', line 30

def start_span(operation_name, child_of: nil, start_time: Time.now, tags: {}, **)
  context =
    if child_of
      parent_context = child_of.respond_to?(:context) ? child_of.context : child_of
      SpanContext.create_from_parent_context(parent_context)
    else
      SpanContext.create_parent_context
    end

  Span.new(context, operation_name, @logger, start_time: start_time, tags: tags)
end