Change http proxy span pattern

[TonyCTHsu]

2.0 Upgrade Guide notes

🚨 Breaking changes:

The request_queuing option on rack/rails must be boolean. Change your configuration from

Datadog.configure do |c|
  c.tracing.instrument :rack, request_queuing: :include_request
  # or 
  c.tracing.instrument :rack, request_queuing: :exclude_request
end

To

Datadog.configure do |c|
  c.tracing.instrument :rack, request_queuing: true
end

With request_queuing enabled, the behaviour changes from 1 span to 2 spans. The original http_server.queue span rename to http.proxy.request, with an additional measured span http.proxy.queue span representing the time spent in a load balancer queue before reaching application. For example:

From

To

🚨 Migration help

Changing the name of the top-level span (http_server.queue -> http.proxy.request) would break a lot of stuff (monitors, dashboards, notebooks). The following snippet rename the top-level span back to help migration.

Datadog::Tracing.before_flush(
  Datadog::Tracing::Pipeline::SpanProcessor.new do |span|
    if span.name == 'http.proxy.request'
      span.name = 'http_server.queue'
    end
  end
)

[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (dd655fb) 98.08% compared to head (fedaf89) 98.08%.
Report is 14 commits behind head on 2.0.

Files	Patch %	Lines
lib/datadog/tracing/contrib/rack/middlewares.rb	94.11%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##              2.0    #3369      +/-   ##
==========================================
- Coverage   98.08%   98.08%   -0.01%     
==========================================
  Files        1250     1252       +2     
  Lines       72360    72301      -59     
  Branches     3394     3390       -4     
==========================================
- Hits        70975    70916      -59     
  Misses       1385     1385              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.