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SpanManager

Current span management for OpenTracing in Ruby.

Installation

Add this line to your application's Gemfile:

gem 'spanmanager'

And then execute:

$ bundle

Or install it yourself as:

$ gem install spanmanager

ManagedSpanSource

ManagedSpanSource is a pluggable class that keeps track of the current active span. It relieves application developers from passing the current span around through their code. Application developers won't need to interact with a ManagedSpanSource reference directly, only implicitly through SpanManager::Tracer.

ManagedSpanSource provides the following methods:

  1. make_active(span) wraps and makes the given span active.
  2. active_span returns the current active span.
  3. clear unconditionally cleans up all manages spans.

ThreadLocalManagedSpanSource

ThreadLocalManagedSpanSource is an actual implementation of ManagedSpanSource. Allows an application access and manipulation of the current span state on per thread basis. Maintains a stack-like thread-local storage of managed spans.

ManagedSpan

ManagedSpan is a wrapper that forwards all calls to another OpenTracing::Span and layers on an in-process propagation capabilities. The behaviour of finish method is changed. In addition to calling finish on wrapped span, if not yet deactivated, marks the end of active period for the span.

Provides the following additional methods:

  1. deactivate marks the end of active period for the current span.
  2. active? returns whether the span is active or not.
  3. wrapped returns the wrapped span.

SpanManager::Tracer

The library exposes a convenience OpenTracing::Tracer that automates managing current span.

It's a wrapper that forwards all calls to another OpenTracing::Tracer implementation e.g. Lightstep, Jaeger etc. Spans which you will create through this tracer will be automatically activated when started, and deactivated when they finish.

Provides the following additional methods:

  1. wrapped returns the wrapped tracer.

Usage

require 'spanmanager'

OpenTracing.global_tracer = SpanManager::Tracer.new(Jaeger::Client.build, SpanManager::ThreadLocalManagedSpanSource.new)

To start a new active span, use the regular and known start_span method. If you use the default argument for child_of argument then the currently active span becomes an implicit parent of a newly-started span. It means that you no longer have to pass the current span through the code.

When you finish the span, and if not yet deactivated, marks the end of the active period for the span. For ThreadLocalManagedSpanSource it means it's removed from the top of the stack on a per-thread basis.

rack_span = tracer.start_span("/GET users")
db_span = tracer.start_span("GetUsers") # rack_span became an implicit parent of db_span
db_span.finish
rack_span.finish

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/iaintshine/ruby-spanmanager. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

Thanks

The development of the gem was heavily inspired by Span manager implementation for Java.

Thank You for inspiration!