Class: Middleware::RequestTracker

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

Constant Summary collapse

STATIC_IP_SKIPPER =

You can add exceptions to our app rate limiter in the app.yml ENV section. example:

env:

DISCOURSE_MAX_REQS_PER_IP_EXCEPTIONS: >-
  14.15.16.32/27
  216.148.1.2

ENV["DISCOURSE_MAX_REQS_PER_IP_EXCEPTIONS"]&.split&.map { |ip| IPAddr.new(ip) }
@@detailed_request_loggers = 
nil
@@ip_skipper = 
nil

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(app, settings = {}) ⇒ RequestTracker

Returns a new instance of RequestTracker.



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# File 'lib/middleware/request_tracker.rb', line 61

def initialize(app, settings = {})
  @app = app
end

Class Method Details

.get_data(env, result, timing, request = nil) ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 99

def self.get_data(env, result, timing, request = nil)
  status, headers = result
  status = status.to_i

  request ||= Rack::Request.new(env)
  helper = Middleware::AnonymousCache::Helper.new(env, request)

  env_track_view = env["HTTP_DISCOURSE_TRACK_VIEW"]
  track_view = status == 200
  track_view &&= env_track_view != "0" && env_track_view != "false"
  track_view &&=
    env_track_view || (request.get? && !request.xhr? && headers["Content-Type"] =~ %r{text/html})
  track_view = !!track_view
  has_auth_cookie = Auth::DefaultCurrentUserProvider.find_v0_auth_cookie(request).present?
  has_auth_cookie ||= Auth::DefaultCurrentUserProvider.find_v1_auth_cookie(env).present?

  is_api ||= !!env[Auth::DefaultCurrentUserProvider::API_KEY_ENV]
  is_user_api ||= !!env[Auth::DefaultCurrentUserProvider::USER_API_KEY_ENV]

  is_message_bus = request.path.start_with?("#{Discourse.base_path}/message-bus/")
  is_topic_timings = request.path.start_with?("#{Discourse.base_path}/topics/timings")

  h = {
    status: status,
    is_crawler: helper.is_crawler?,
    has_auth_cookie: has_auth_cookie,
    is_api: is_api,
    is_user_api: is_user_api,
    is_background: is_message_bus || is_topic_timings,
    is_mobile: helper.is_mobile?,
    track_view: track_view,
    timing: timing,
    queue_seconds: env["REQUEST_QUEUE_SECONDS"],
  }

  if h[:is_background]
    h[:background_type] = if is_message_bus
      if request.query_string.include?("dlp=t")
        "message-bus-dlp"
      elsif env["HTTP_DONT_CHUNK"]
        "message-bus-dontchunk"
      else
        "message-bus"
      end
    else
      "topic-timings"
    end
  end

  if h[:is_crawler]
    user_agent = env["HTTP_USER_AGENT"]
    if user_agent && (user_agent.encoding != Encoding::UTF_8)
      user_agent = user_agent.encode("utf-8")
      user_agent.scrub!
    end
    h[:user_agent] = user_agent
  end

  if cache = headers["X-Discourse-Cached"]
    h[:cache] = cache
  end

  h
end

.ip_skipper ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 57

def self.ip_skipper
  @@ip_skipper
end

.log_request(data) ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 65

def self.log_request(data)
  if data[:is_api]
    ApplicationRequest.increment!(:api)
  elsif data[:is_user_api]
    ApplicationRequest.increment!(:user_api)
  elsif data[:track_view]
    if data[:is_crawler]
      ApplicationRequest.increment!(:page_view_crawler)
      WebCrawlerRequest.increment!(data[:user_agent])
    elsif data[:has_auth_cookie]
      ApplicationRequest.increment!(:page_view_logged_in)
      ApplicationRequest.increment!(:page_view_logged_in_mobile) if data[:is_mobile]
    elsif !SiteSetting.
      ApplicationRequest.increment!(:page_view_anon)
      ApplicationRequest.increment!(:page_view_anon_mobile) if data[:is_mobile]
    end
  end

  ApplicationRequest.increment!(:http_total)

  status = data[:status]
  if status >= 500
    ApplicationRequest.increment!(:http_5xx)
  elsif data[:is_background]
    ApplicationRequest.increment!(:http_background)
  elsif status >= 400
    ApplicationRequest.increment!(:http_4xx)
  elsif status >= 300
    ApplicationRequest.increment!(:http_3xx)
  elsif status >= 200
    ApplicationRequest.increment!(:http_2xx)
  end
end

.populate_request_queue_seconds!(env) ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 186

def self.populate_request_queue_seconds!(env)
  if !env["REQUEST_QUEUE_SECONDS"]
    if queue_start = env["HTTP_X_REQUEST_START"]
      queue_start =
        if queue_start.start_with?("t=")
          queue_start.split("t=")[1].to_f
        else
          queue_start.to_f / 1000.0
        end
      queue_time = (Time.now.to_f - queue_start)
      env["REQUEST_QUEUE_SECONDS"] = queue_time
    end
  end
end

.register_detailed_request_logger(callback) ⇒ Object

register callbacks for detailed request loggers called on every request example:

Middleware::RequestTracker.detailed_request_logger(->|env, data| do

# do stuff with env and data

end



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# File 'lib/middleware/request_tracker.rb', line 27

def self.register_detailed_request_logger(callback)
  MethodProfiler.ensure_discourse_instrumentation!
  (@@detailed_request_loggers ||= []) << callback
end

.register_ip_skipper(&blk) ⇒ Object

Register a custom ‘ip_skipper`, a function that will skip rate limiting for any IP that returns true.

For example, if you never wanted to rate limit 1.2.3.4

“‘ Middleware::RequestTracker.register_ip_skipper do |ip|

ip == "1.2.3.4"

end “‘



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# File 'lib/middleware/request_tracker.rb', line 52

def self.register_ip_skipper(&blk)
  raise "IP skipper is already registered!" if @@ip_skipper
  @@ip_skipper = blk
end

.unregister_detailed_request_logger(callback) ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 32

def self.unregister_detailed_request_logger(callback)
  @@detailed_request_loggers.delete(callback)
  @detailed_request_loggers = nil if @@detailed_request_loggers.length == 0
end

.unregister_ip_skipper ⇒ Object

used for testing



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# File 'lib/middleware/request_tracker.rb', line 38

def self.unregister_ip_skipper
  @@ip_skipper = nil
end

Instance Method Details

#call(env) ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 201

def call(env)
  result = nil
  info = nil
  gc_stat_timing = nil

  # doing this as early as possible so we have an
  # accurate counter
  ::Middleware::RequestTracker.populate_request_queue_seconds!(env)

  request = Rack::Request.new(env)

  cookie = find_auth_cookie(env)
  if error_details = rate_limit(request, cookie)
    available_in, error_code = error_details
    message = <<~TEXT
      Slow down, too many requests from this IP address.
      Please retry again in #{available_in} seconds.
      Error code: #{error_code}.
    TEXT
    headers = {
      "Retry-After" => available_in.to_s,
      "Discourse-Rate-Limit-Error-Code" => error_code,
    }
    return 429, headers, [message]
  end
  env["discourse.request_tracker"] = self

  MethodProfiler.start

  if SiteSetting.instrument_gc_stat_per_request
    gc_stat_timing = GCStatInstrumenter.instrument { result = @app.call(env) }
  else
    result = @app.call(env)
  end

  info = MethodProfiler.stop

  # possibly transferred?
  if info && (headers = result[1])
    headers["X-Runtime"] = "%0.6f" % info[:total_duration]

    if GlobalSetting.enable_performance_http_headers
      if redis = info[:redis]
        headers["X-Redis-Calls"] = redis[:calls].to_s
        headers["X-Redis-Time"] = "%0.6f" % redis[:duration]
      end
      if sql = info[:sql]
        headers["X-Sql-Calls"] = sql[:calls].to_s
        headers["X-Sql-Time"] = "%0.6f" % sql[:duration]
      end
      if queue = env["REQUEST_QUEUE_SECONDS"]
        headers["X-Queue-Time"] = "%0.6f" % queue
      end
    end
  end

  if env[Auth::DefaultCurrentUserProvider::BAD_TOKEN] && (headers = result[1])
    headers["Discourse-Logged-Out"] = "1"
  end

  result
ensure
  if (limiters = env["DISCOURSE_RATE_LIMITERS"]) && env["DISCOURSE_IS_ASSET_PATH"]
    limiters.each(&:rollback!)
    env["DISCOURSE_ASSET_RATE_LIMITERS"].each do |limiter|
      begin
        limiter.performed!
      rescue RateLimiter::LimitExceeded
        # skip
      end
    end
  end

  if !env["discourse.request_tracker.skip"]
    info.merge!(gc_stat_timing) if gc_stat_timing
    log_request_info(env, result, info, request)
  end
end

#find_auth_cookie(env) ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 286

def find_auth_cookie(env)
  min_allowed_timestamp = Time.now.to_i - (UserAuthToken::ROTATE_TIME_MINS + 1) * 60
  cookie = Auth::DefaultCurrentUserProvider.find_v1_auth_cookie(env)
  cookie if cookie && cookie[:issued_at] >= min_allowed_timestamp
end

#is_private_ip?(ip) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/middleware/request_tracker.rb', line 292

def is_private_ip?(ip)
  ip = IPAddr.new(ip)
  !!(ip && (ip.private? || ip.loopback?))
rescue IPAddr::AddressFamilyError, IPAddr::InvalidAddressError
  false
end

#log_later(data) ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 280

def log_later(data)
  Scheduler::Defer.later("Track view") do
    self.class.log_request(data) unless Discourse.pg_readonly_mode?
  end
end

#log_request_info(env, result, info, request = nil) ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 164

def log_request_info(env, result, info, request = nil)
  # we got to skip this on error ... its just logging
  data =
    begin
      self.class.get_data(env, result, info, request)
    rescue StandardError
      nil
    end

  if data
    if result && (headers = result[1])
      headers["X-Discourse-TrackView"] = "1" if data[:track_view]
    end

    if @@detailed_request_loggers
      @@detailed_request_loggers.each { |logger| logger.call(env, data) }
    end

    log_later(data)
  end
end

#rate_limit(request, cookie) ⇒ Object 



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# File 'lib/middleware/request_tracker.rb', line 299

def rate_limit(request, cookie)
  warn =
    GlobalSetting.max_reqs_per_ip_mode == "warn" ||
      GlobalSetting.max_reqs_per_ip_mode == "warn+block"
  block =
    GlobalSetting.max_reqs_per_ip_mode == "block" ||
      GlobalSetting.max_reqs_per_ip_mode == "warn+block"

  return if !block && !warn

  ip = request.ip

  if !GlobalSetting.max_reqs_rate_limit_on_private
    return if is_private_ip?(ip)
  end

  return if @@ip_skipper&.call(ip)
  return if STATIC_IP_SKIPPER&.any? { |entry| entry.include?(ip) }

  ip_or_id = ip
  limit_on_id = false
  if cookie && cookie[:user_id] && cookie[:trust_level] &&
       cookie[:trust_level] >= GlobalSetting.skip_per_ip_rate_limit_trust_level
    ip_or_id = cookie[:user_id]
    limit_on_id = true
  end

  limiter10 =
    RateLimiter.new(
      nil,
      "global_ip_limit_10_#{ip_or_id}",
      GlobalSetting.max_reqs_per_ip_per_10_seconds,
      10,
      global: !limit_on_id,
      aggressive: true,
      error_code: limit_on_id ? "id_10_secs_limit" : "ip_10_secs_limit",
    )

  limiter60 =
    RateLimiter.new(
      nil,
      "global_ip_limit_60_#{ip_or_id}",
      GlobalSetting.max_reqs_per_ip_per_minute,
      60,
      global: !limit_on_id,
      error_code: limit_on_id ? "id_60_secs_limit" : "ip_60_secs_limit",
      aggressive: true,
    )

  limiter_assets10 =
    RateLimiter.new(
      nil,
      "global_ip_limit_10_assets_#{ip_or_id}",
      GlobalSetting.max_asset_reqs_per_ip_per_10_seconds,
      10,
      error_code: limit_on_id ? "id_assets_10_secs_limit" : "ip_assets_10_secs_limit",
      global: !limit_on_id,
    )

  request.env["DISCOURSE_RATE_LIMITERS"] = [limiter10, limiter60]
  request.env["DISCOURSE_ASSET_RATE_LIMITERS"] = [limiter_assets10]

  if !limiter_assets10.can_perform?
    if warn
      Discourse.warn(
        "Global asset IP rate limit exceeded for #{ip}: 10 second rate limit",
        uri: request.env["REQUEST_URI"],
      )
    end

    return limiter_assets10.seconds_to_wait(Time.now.to_i), limiter_assets10.error_code if block
  end

  begin
    type = 10
    limiter10.performed!

    type = 60
    limiter60.performed!

    nil
  rescue RateLimiter::LimitExceeded => e
    if warn
      Discourse.warn(
        "Global IP rate limit exceeded for #{ip}: #{type} second rate limit",
        uri: request.env["REQUEST_URI"],
      )
    end
    if block
      [e.available_in, e.error_code]
    else
      nil
    end
  end
end