canvas-lms/app/middleware/request_context_generator.rb

119 lines
4.2 KiB
Ruby

#
# Copyright (C) 2011 - present Instructure, Inc.
#
# This file is part of Canvas.
#
# Canvas is free software: you can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the Free
# Software Foundation, version 3 of the License.
#
# Canvas is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE. See the GNU Affero General Public License for more
# details.
#
# You should have received a copy of the GNU Affero General Public License along
# with this program. If not, see <http://www.gnu.org/licenses/>.
#
require 'securerandom'
class RequestContextGenerator
def initialize(app)
@app = app
end
def call(env)
request_id = generate_request_id(env)
# rack.session.options (where the session_id is saved by our session
# store) isn't availalbe at this point in the middleware stack. It is
# lazily loaded the first time the session is accessed, so we won't get
# session_ids in the log on the very first request (usually loading the
# login page). It is written out to a cookie so that we can pick it up for
# logs in subsequent requests. See RequestContextSession, we can't write it
# to a cookie in this middleware because the cookie header has already been
# written by the time this app.call returns.
session_id = ActionDispatch::Request.new(env).cookie_jar[:log_session_id]
meta_headers = ""
Thread.current[:context] = {
request_id: request_id,
session_id: session_id,
meta_headers: meta_headers,
}
# logged here to get as close to the beginning of the request being
# processed as possible
RequestContextGenerator.store_request_queue_time(env['HTTP_X_REQUEST_START'])
status, headers, body = @app.call(env)
# The session id may have been reset in the request, in which case
# we want to log the new one,
session_id = (env['rack.session.options'] || {})[:id]
headers['X-Session-Id'] = session_id if session_id
headers['X-Request-Context-Id'] = request_id
headers['X-Canvas-Meta'] = meta_headers if meta_headers.present?
[ status, headers, body ]
end
def self.request_id
Thread.current[:context].try(:[], :request_id)
end
def self.add_meta_header(name, value)
return if value.blank?
meta_headers = Thread.current[:context].try(:[], :meta_headers)
return if !meta_headers
meta_headers << "#{name}=#{value};"
end
def self.store_interaction_seconds_update(token, interaction_seconds)
data = PageView.decode_token(token)
if data
self.add_meta_header("r", "#{data[:request_id]}|#{data[:created_at]}|#{interaction_seconds}")
end
end
def self.store_request_queue_time(header_val)
if header_val
match = header_val.match(/t=(?<req_start>\d+)/)
return unless match
delta = (Time.now.utc.to_f * 1000000).to_i - match['req_start'].to_i
RequestContextGenerator.add_meta_header("q", delta)
end
end
def self.store_request_meta(request, context)
self.add_meta_header("o", request.path_parameters[:controller])
self.add_meta_header("n", request.path_parameters[:action])
if context
self.add_meta_header("t", context.class)
self.add_meta_header("i", context.id)
end
end
def self.store_page_view_meta(page_view)
self.add_meta_header("x", page_view.interaction_seconds)
self.add_meta_header("p", page_view.participated? ? "t" : "f")
self.add_meta_header("e", page_view.asset_user_access_id)
self.add_meta_header("f", page_view.created_at.try(:utc).try(:iso8601, 2))
end
private
def generate_request_id(env)
if env['HTTP_X_REQUEST_CONTEXT_ID'] && env['HTTP_X_REQUEST_CONTEXT_SIGNATURE']
request_context_id = Canvas::Security.base64_decode(env['HTTP_X_REQUEST_CONTEXT_ID'])
request_context_signature = Canvas::Security.base64_decode(env['HTTP_X_REQUEST_CONTEXT_SIGNATURE'])
if Canvas::Security.verify_hmac_sha512(request_context_id, request_context_signature)
return request_context_id
else
Rails.logger.info("ignoring X-Request-Context-Id header, signature could not be verified")
end
end
SecureRandom.uuid
end
end