/
request_id.rb
42 lines (37 loc) · 1.49 KB
/
request_id.rb
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# frozen_string_literal: true
require "securerandom"
require "active_support/core_ext/string/access"
module ActionDispatch
# Makes a unique request id available to the +action_dispatch.request_id+ env variable (which is then accessible
# through <tt>ActionDispatch::Request#request_id</tt> or the alias <tt>ActionDispatch::Request#uuid</tt>) and sends
# the same id to the client via the X-Request-Id header.
#
# The unique request id is either based on the X-Request-Id header in the request, which would typically be generated
# by a firewall, load balancer, or the web server, or, if this header is not available, a random uuid. If the
# header is accepted from the outside world, we sanitize it to a max of 255 chars and alphanumeric and dashes only.
#
# The unique request id can be used to trace a request end-to-end and would typically end up being part of log files
# from multiple pieces of the stack.
class RequestId
def initialize(app, header:)
@app = app
@header = header
end
def call(env)
req = ActionDispatch::Request.new env
req.request_id = make_request_id(req.headers[@header])
@app.call(env).tap { |_status, headers, _body| headers[@header] = req.request_id }
end
private
def make_request_id(request_id)
if request_id.presence
request_id.gsub(/[^\w\-@]/, "").first(255)
else
internal_request_id
end
end
def internal_request_id
SecureRandom.uuid
end
end
end