Module: RailsTwirp::ExceptionHandling

Extended by:
ActiveSupport::Concern
Includes:
AbstractController::Logger
Included in:
Base
Defined in:
lib/rails_twirp/exception_handling.rb

Instance Method Summary collapse

Instance Method Details

#process_action ⇒ Object 



11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
 
# File 'lib/rails_twirp/exception_handling.rb', line 11

def process_action(*)
  super
rescue => e
  # Only the exceptions which are not captured by ActionController-like "rescue_from" end up here.
  # The idea is that any exception which is rescued by the controller is treated as part of the business
  # logic, and thus taking action on it is the responsibility of the controller which uses "rescue_from".
  # If an exception ends up here it means it wasn't captured by the handlers defined in the controller.

  # We adopt the same error handling logic as Rails' standard middlewares:
  # 1. When we 'show exceptions' we make the exception bubble up—this is useful for testing
  #    If the exception gets raised here, error reporting will happen in the middleware of the APM package
  #    higher in the call stack.
  #

  # A backtrace cleaner acts like a filter that only shows us the backtrace
  # with a selection of useful lines compared to all lines the code goes through.
  backtrace_cleaner = http_request.get_header("action_dispatch.backtrace_cleaner")

  # Contains various exception related methods we can use and takes the backtrace_cleaner into consideration.
  exception_wrapper = ActionDispatch::ExceptionWrapper.new(backtrace_cleaner, e)
  # ExceptionWrapper.show? contains the logic that chooses to pass exceptions through or not based on the
  # `Rails.application.config.action_dispatch.show_exceptions` setting of :none, :rescuable and :all
  raise e unless exception_wrapper.show?(http_request)

  # 2. We report the error to the error tracking service, this needs to be configured.
  RailsTwirp.unhandled_exception_handler&.call(e)

  # 3. When we want to show detailed exceptions we include the exception message in the error
  if http_request.get_header("action_dispatch.show_detailed_exceptions")
    self.response_body = Twirp::Error.internal_with(e)
    return
  end

  # 4. Otherwise we just return a vague internal error message
  self.response_body = Twirp::Error.internal("Internal error")
end