mirror of
https://github.com/discourse/discourse.git
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8d249457e8
--------- Co-authored-by: Jarek Radosz <jradosz@gmail.com>
172 lines
5.7 KiB
Ruby
172 lines
5.7 KiB
Ruby
# frozen_string_literal: true
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require "method_profiler"
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# This module allows us to hijack a request and send it to the client in the deferred job queue
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# For cases where we are making remote calls like onebox or proxying files and so on this helps
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# free up a unicorn worker while the remote IO is happening
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module Hijack
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def hijack(info: nil, &blk)
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controller_class = self.class
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if hijack = request.env["rack.hijack"]
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request.env["discourse.request_tracker.skip"] = true
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request_tracker = request.env["discourse.request_tracker"]
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# in the past unicorn would recycle env, this is not longer the case
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env = request.env
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# rack may clean up tempfiles unless we trick it and take control
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tempfiles = env[Rack::RACK_TEMPFILES]
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env[Rack::RACK_TEMPFILES] = nil
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request_copy = ActionDispatch::Request.new(env)
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transfer_timings = MethodProfiler.transfer
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scheduled = Concurrent::Promises.resolvable_event
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begin
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Scheduler::Defer.later(
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"hijack #{params["controller"]} #{params["action"]} #{info}",
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force: false,
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current_user: current_user&.id,
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&scheduled.method(:resolve)
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)
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rescue WorkQueue::WorkQueueFull
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return render plain: "", status: 503
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end
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# duplicate headers so other middleware does not mess with it
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# on the way down the stack
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original_headers = response.headers.dup
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io = hijack.call
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scheduled.on_resolution! do
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MethodProfiler.start(transfer_timings)
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begin
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Thread.current[Logster::Logger::LOGSTER_ENV] = env
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# do this first to confirm we have a working connection
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# before doing any work
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io.write "HTTP/1.1 "
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# this trick avoids double render, also avoids any litter that the controller hooks
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# place on the response
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instance = controller_class.new
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response = ActionDispatch::Response.new.tap { _1.request = request_copy }
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instance.set_response!(response)
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instance.set_request!(request_copy)
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original_headers&.each { |k, v| instance.response.headers[k] = v }
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view_start = Process.clock_gettime(Process::CLOCK_MONOTONIC)
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begin
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instance.instance_eval(&blk)
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rescue => e
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# TODO we need to reuse our exception handling in ApplicationController
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Discourse.warn_exception(
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e,
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message: "Failed to process hijacked response correctly",
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env: env,
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)
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end
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view_runtime = Process.clock_gettime(Process::CLOCK_MONOTONIC) - view_start
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instance.status = 500 unless instance.response_body || response.committed?
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response.commit!
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body = response.body
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headers = response.headers
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# add cors if needed
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if cors_origins = env[Discourse::Cors::ORIGINS_ENV]
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Discourse::Cors.apply_headers(cors_origins, env, headers)
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end
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headers["Content-Type"] ||= response.content_type || "text/plain"
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headers["Content-Length"] = body.bytesize
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headers["Connection"] = "close"
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headers["Discourse-Logged-Out"] = "1" if env[Auth::DefaultCurrentUserProvider::BAD_TOKEN]
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status_string = Rack::Utils::HTTP_STATUS_CODES[response.status.to_i] || "Unknown"
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io.write "#{response.status} #{status_string}\r\n"
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timings = MethodProfiler.stop
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if timings && duration = timings[:total_duration]
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headers["X-Runtime"] = "#{"%0.6f" % duration}"
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end
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headers.each { |name, val| io.write "#{name}: #{val}\r\n" }
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io.write "\r\n"
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io.write body
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rescue Errno::EPIPE, IOError
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# happens if client terminated before we responded, ignore
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io = nil
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ensure
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if Rails.configuration.try(:lograge).try(:enabled)
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if timings
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db_runtime = 0
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db_runtime = timings[:sql][:duration] if timings[:sql]
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subscriber = Lograge::LogSubscribers::ActionController.new
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payload =
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ActiveSupport::HashWithIndifferentAccess.new(
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controller: self.class.name,
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action: action_name,
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params: request.filtered_parameters,
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headers: request.headers,
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format: request.format.ref,
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method: request.request_method,
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path: request.fullpath,
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view_runtime: view_runtime * 1000.0,
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db_runtime: db_runtime * 1000.0,
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timings: timings,
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status: response.status,
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)
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event =
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ActiveSupport::Notifications::Event.new(
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"hijack",
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Time.now,
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Time.now + timings[:total_duration],
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"",
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payload,
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)
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subscriber.process_action(event)
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end
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end
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MethodProfiler.clear
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Thread.current[Logster::Logger::LOGSTER_ENV] = nil
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begin
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io.close if io
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rescue StandardError
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nil
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end
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if request_tracker
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status =
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begin
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response.status
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rescue StandardError
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500
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end
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request_tracker.log_request_info(env, [status, headers || {}, []], timings)
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end
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tempfiles&.each(&:close!)
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end
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end
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# not leaked out, we use 418 ... I am a teapot to denote that we are hijacked
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render plain: "", status: 418
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else
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blk.call
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end
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end
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end
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