Class: Datadog::Tracing::Contrib::Rails::ExceptionMiddleware

Inherits:
Object
  • Object
show all
Defined in:
lib/datadog/tracing/contrib/rails/middlewares.rb

Overview

This is only here to catch errors, the Rack module does something very similar, however, since it’s not in the same place in the stack, when the Rack middleware is called, error is already swallowed and handled by Rails so we miss the call stack, for instance.

Instance Method Summary collapse

Constructor Details

#initialize(app) ⇒ ExceptionMiddleware

Returns a new instance of ExceptionMiddleware.



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# File 'lib/datadog/tracing/contrib/rails/middlewares.rb', line 14

def initialize(app)
  @app = app
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/datadog/tracing/contrib/rails/middlewares.rb', line 18

def call(env)
  @app.call(env)
# rubocop:disable Lint/RescueException
# Here we really want to catch *any* exception, not only StandardError,
# as we really have no clue of what is in the block,
# and it is user code which should be executed no matter what.
# It's not a problem since we re-raise it afterwards so for example a
# SignalException::Interrupt would still bubble up.
rescue Exception => e
  span = Tracing.active_span
  if !span.nil? && ActionPack::Utils.exception_is_error?(e)
    # Only set error if it's supposed to be flagged as such
    # e.g. we don't want to flag 404s.
    # You can add custom errors via `config.action_dispatch.rescue_responses`
    span.set_error(e)

    # Some exception gets handled by Rails middleware before it can be set on Rack middleware
    # The rack span is the root span of the request and should make sure it has the full exception
    # set on it.
    env[Contrib::Rack::Ext::RACK_ENV_REQUEST_SPAN].set_error(e) if env[Contrib::Rack::Ext::RACK_ENV_REQUEST_SPAN]
  end
  raise e
end