Class: ActionDispatch::DebugLocks

Inherits:
Object
  • Object
show all
Defined in:
lib/action_dispatch/middleware/debug_locks.rb

Overview

# Action Dispatch DebugLocks

This middleware can be used to diagnose deadlocks in the autoload interlock.

To use it, insert it near the top of the middleware stack, using ‘config/application.rb`:

config.middleware.insert_before Rack::Sendfile, ActionDispatch::DebugLocks

After restarting the application and re-triggering the deadlock condition, the route ‘/rails/locks` will show a summary of all threads currently known to the interlock, which lock level they are holding or awaiting, and their current backtrace.

Generally a deadlock will be caused by the interlock conflicting with some other external lock or blocking I/O call. These cannot be automatically identified, but should be visible in the displayed backtraces.

NOTE: The formatting and content of this middleware’s output is intended for human consumption, and should be expected to change between releases.

This middleware exposes operational details of the server, with no access control. It should only be enabled when in use, and removed thereafter.

Instance Method Summary collapse

Constructor Details

#initialize(app, path = "/rails/locks") ⇒ DebugLocks

Returns a new instance of DebugLocks.



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# File 'lib/action_dispatch/middleware/debug_locks.rb', line 30

def initialize(app, path = "/rails/locks")
  @app = app
  @path = path
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/action_dispatch/middleware/debug_locks.rb', line 35

def call(env)
  req = ActionDispatch::Request.new env

  if req.get?
    path = req.path_info.chomp("/")
    if path == @path
      return render_details(req)
    end
  end

  @app.call(env)
end