Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/iaintshine/ruby-test-tracer

OpenTracing compatible Tracer implementation to be used in tests in Ruby
https://github.com/iaintshine/ruby-test-tracer

opentracing rspec ruby tests tracer

Last synced: 4 months ago
JSON representation

OpenTracing compatible Tracer implementation to be used in tests in Ruby

Awesome Lists containing this project

README 

        
[![Build Status](https://travis-ci.org/iaintshine/ruby-test-tracer.svg?branch=master)](https://travis-ci.org/iaintshine/ruby-test-tracer)

# Test::Tracer



Fully OpenTracing compatible in-memory Tracer implementation which records all the spans, and includes methods which you might find helpful during testing. The tracer is fully agnostic to any testing framework.



The framework came to alive, because I had a constant need of some kind of "recording" tracer that I could use during tests of new instrumentation libraries for OpenTracing like rails-tracer, tracing-logger etc.



## Installation



Add this line to your application's Gemfile:



```ruby

gem 'test-tracer'

```



And then execute:



    $ bundle



Or install it yourself as:



    $ gem install test-tracer



## Test::Tracer



In addition to OT compatible methods `Test::Tracer` provides the following methods:



1. `spans` returns all spans, including those in progress.

2. `finished_spans` returns only finished spans.



The tracer plays nicely with other wrapping tracers until your wrapped span, and span context implements `wrapped`

method. The method must return the wrapped item. You can customize the behaviour by implementing `Test::Wrapped::Extractor` and setting `wrapped_span_extractor` and/or `wrapped_span_context_extractor`.



### Usage



```ruby

require "test-tracer"



describe "Test::Tracer examples" do

  let(:tracer) { Test::Tracer.new }



  context "when we expect no traces" do

    it "does not have any traces started" do

      expect(tracer.spans).to be_empty

    end



    it "does not have any traces recorded" do

      expect(tracer.finished_spans).to be_empty

    end

  end



  context "when we expect traces to be present" do

    it "does have some traces started" do

      expect(tracer.spans).not_to be_empty

    end



    it "does have some traces recorded" do

      expect(tracer.finished_spans).not_to be_empty

    end

  end



  context "when we expect exactly N traces" do

    it "has N traces started" do

      expect(tracer.spans.size).to eq(N)

    end



    it "has N traces recorded" do

      expect(tracer.finished_spans.size).to eq(N)

    end

  end

end

```



## Test::Span



In addition to OT compatible methods `Test::Span` provides the following methods:



1. `tracer` returns the tracer the span was created by.

1. `in_progress?`, `started?`, `finished?` informs whether the span is in progress, or it's finished.

2. `start_time` returns when the span was started.

2. `end_time` returns when the span was finished, or nil if still in progress.

2. `tags` returns the span's tags.

2. `logs` returns the span's logs, an array of `Test::Span::LogEntry`s.



The modification operations e.g. `operation_name=`, `set_tag`, `set_baggage_item` on a span are not allowed after it's finished. It throws `Test::Span::SpanAlreadyFinished` exception. The same with `finish`. The span can be finished only once.



### Usage



```ruby

require "test-tracer"



describe "Test::Span examples" do

  let(:tracer) { Test::Tracer.new }



  context "when a new span was started" do

    let(:span) { tracer.start_span("operation name", tags: {'component' => 'ActiveRecord'}) }



    it "is in progress" do

      expect(span.in_progress?).to eq(true) 

    end



    it "does have the proper name" do

      expect(span.operation_name).to eq("operation name")

    end



    it "does include standard OT tags" do

      expect(span.tags).to include('component' => 'ActiveRecord')

    end



    it "does not have any log entries" do

      expect(span.logs).to be_empty

    end

  end



  context "when an event was logged" do

    let(:span) do 

      current_span = tracer.start_span("operation name")

      current_span.log(event: "exceptional message", severity: Logger::ERROR, pid: $1)

      current_span

    end



    it "does have some log entries recorded" do

      expect(span.logs).not_to be_empty

    end



    it "includes all the event attributes" do

      log = span.logs.first

      expect(log.event).to eq("exceptional message")

      expect(log.fields).to include(severity: Logger::ERROR)

    end

  end



  context "when a span was finished" do

    let(:span) { tracer.start_span("operation name").finish }



    it "is not in progress" do

      expect(span.in_progress?).to eq(false)

    end



    it "can't be finished twice" do

      expect { span.finish }.to raise_error(Test::Span::SpanAlreadyFinished)

    end

  end

end

```



## Test::SpanContext



Context propagation is fully implemented by the tracer, and is inspired by [Jaeger](http://jaeger.readthedocs.io/en/latest/) and [TraceContext](https://github.com/TraceContext/tracecontext-spec/pull/1/files). In addition to OT compatible methods `Test::SpanContext` provides the following methods:



1. `trace_id` returns the ID of the whole trace forest.

1. `span_id` returns the ID of the current span.

2. `parent_span_id` returns the ID of the parent span.



### Usage



```ruby

require "test-tracer"



describe "Test::SpanContext examples" do

  let(:tracer) { Test::Tracer.new }



  context "when a new span was started as child of root" do

    let(:root_context) { tracer.start_span("root span").context } 

    let(:child_context) { tracer.start_span("child span", child_of: root_context).context }



    it "all have the same trace_id" do

      expect(child_context.trace_id).to eq(root_context.trace_id)

    end



    it "propagates parent child relationship" do

      expect(child_context.parent_span_id).to eq(root_context.span_id)

    end

  end

end

```



## 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](https://rubygems.org).



## Contributing



Bug reports and pull requests are welcome on GitHub at https://github.com/iaintshine/ruby-test-tracer. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.