debian-mirror-gitlab/debian/gems-compat/opentracing-0.4.3/lib/opentracing/tracer.rb
2019-03-14 13:13:30 +05:30

117 lines
5 KiB
Ruby

module OpenTracing
# Tracer is the entry point API between instrumentation code and the tracing
# implementation.
#
# This implementation both defines the public Tracer API, and provides a
# default no-op behavior.
#
class Tracer
# @return [ScopeManager] the current ScopeManager, which may be a no-op but
# may not be nil.
def scope_manager
ScopeManager::NOOP_INSTANCE
end
# @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.
def active_span
scope = scope_manager.active
scope.span if scope
end
# Returns 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 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] The newly-started and activated Scope
def start_active_span(operation_name,
child_of: nil,
references: nil,
start_time: Time.now,
tags: nil,
ignore_active_scope: false,
finish_on_close: true)
Scope::NOOP_INSTANCE.tap do |scope|
yield scope if block_given?
end
end
# Like #start_active_span, but the returned Span has not been 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.
# @return [Span] the newly-started Span instance, which has not been
# automatically registered via the ScopeManager
def start_span(operation_name,
child_of: nil,
references: nil,
start_time: Time.now,
tags: nil,
ignore_active_scope: false)
Span::NOOP_INSTANCE
end
# 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`
def inject(span_context, format, carrier)
case format
when OpenTracing::FORMAT_TEXT_MAP, OpenTracing::FORMAT_BINARY, OpenTracing::FORMAT_RACK
return nil
else
warn 'Unknown inject format'
end
end
# 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, nil] the extracted SpanContext or nil if none could be found
def extract(format, carrier)
case format
when OpenTracing::FORMAT_TEXT_MAP, OpenTracing::FORMAT_BINARY, OpenTracing::FORMAT_RACK
return SpanContext::NOOP_INSTANCE
else
warn 'Unknown extract format'
nil
end
end
end
end